Model Engine Maker

Engines => Your Own Design => Topic started by: Brian Rupnow on August 25, 2020, 01:37:35 PM

Title: Trevithick
Post by: Brian Rupnow on August 25, 2020, 01:37:35 PM
Does anyone have a 3d cad model of the Trevithick? It might be something I would consider building. I have done a fairly complete search of the internet, and found one set of plans in an Autocad format and one which is in a 3D format I can not open. My Solidworks Software is pretty versatile and can open most formats. a .step, a .X_t, or a .step would be nice.---Brian
(https://imagizer.imageshack.com/img924/8934/UntWw6.jpg)
Title: Re: Trevithick
Post by: techonehundred on August 25, 2020, 08:23:16 PM
I am sure you have already seen this link that has a downloadable STL file.

https://grabcad.com/library/trevithick-second-steam-locomotive-1 (https://grabcad.com/library/trevithick-second-steam-locomotive-1)

I also found this pdf, but on the drawing is an email address.  It looks like it was made on 3d cad.  Maybe the author could help.  It is from 2006, but worth a try.
https://pro-parovoz.ru/files/pdf/trevithick_second_steam_locomotive.pdf (https://pro-parovoz.ru/files/pdf/trevithick_second_steam_locomotive.pdf)
Title: Re: Trevithick
Post by: crueby on August 25, 2020, 08:36:42 PM
I have Autocad Fusion, can try opening/converting the file you were having trouble with. Can you send me a link?
Title: Re: Trevithick
Post by: techonehundred on August 25, 2020, 08:40:50 PM
Chris, Here is a link to the Autocad I found.  Not sure if it is the same one that Brian found. but worth a try.

https://grabcad.com/library/trevithick-steam-locomotive-2 (https://grabcad.com/library/trevithick-steam-locomotive-2)
Title: Re: Trevithick
Post by: crueby on August 25, 2020, 09:15:54 PM
Downloaded both from GrabCad - the locomotive-1 has a nice looking design in .stl format, Fusion had no trouble opening it, but the stl file version is a single body of the whole thing in mesh format, not individual bodies for the parts. Not sure if that will help you, Brian.

The locomotive-2 one is a .dwg file that Fusion can view, but it does not have 3D bodies that I can tell.

 
Title: Re: Trevithick
Post by: JULIUS on August 25, 2020, 09:48:48 PM
Brian

The picture shown is from someone who took my drawings/design and redrew it using GrabaCad
I made two sets of drawings one design is for 10.25 inch gauge and one for 5 inch gauge.
The 10.25 is more a display model than a working model a but the 5 inch is a working model.
All my work is done in SolidWorks.
If you wish I can send you the PDF files first so you can have a look whether or not you like it.
I also can send you the SolidWorks 3D models. The models aer drawn in SolidWorks 2018.
Can you forward your e-mail address to me so that I can send you all the required information.

Kind regards

Julius
Title: Re: Trevithick
Post by: Brian Rupnow on August 25, 2020, 09:57:08 PM
Julius--My Solidworks is 2015, so I can't open a newer version. However, if you could save the overall model as a .step or .x_t file I could open it. That would be very kind of you. I would probably take the 5" model and redo it to be driven by air, with a much simplified suspension, as I did the Stephenson's Rocket.---Brian  brupnow@rogers.com
Title: Re: Trevithick
Post by: Pete49 on August 26, 2020, 04:32:57 AM
Brian the .stl files are for 3D printers and is a set of gcode instructions to print it out.
You probably know this but just in case it helps.
Title: Re: Trevithick
Post by: Brian Rupnow on August 26, 2020, 05:24:09 PM
I don't have a 3D printer, and I don't have any CNC machines. I do have gear cutters and can cut my own 24DP gears in any size I choose. I have been doing a lot of searching for info about the Trevithick engine, and the only thing I'm not clear on is how the valve operated. The centrally located cylinder is double acting and has a pair of stabilizing guide rods fixed to the main structure on either side of the piston rod which act as a cross head guide . It also has a bow shaped piece across the front of the cylinder rod. A link from one end of that bow shaped piece goes back to a crank handle on the small gear, and a link from the other end of the bow runs back to the very large flywheel. So far, I'm not seeing anything that I recognize as a valve to reverse the pressurized steam into the other end of the cylinder.  Does anyone have more insight?
Title: Re: Trevithick
Post by: Brian Rupnow on August 26, 2020, 06:03:53 PM
I just found an excellent animation of the steam valve on the engine. I haven't seen this done before, and I have to decide whether it is something I can build. The steam valve is combined with and part of he cylinder, all in the same bore.
rul0iazn3d8
Title: Re: Trevithick
Post by: Brian Rupnow on August 27, 2020, 03:22:13 PM
As in all things, I have to determine what scale I want to build this engine at. That is going to be easy for me this time, because the largest gear I can cut on my milling machine is 108 teeth, which is 4.584" outer diameter. All other components will have to be scaled to accommodate this known part size.
(https://imagizer.imageshack.com/img923/462/ZZ9FTW.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on August 27, 2020, 04:29:39 PM
So, based on ratio and proportion, and the fact that my largest gear is going to have 108 teeth, this lets me establish that the smaller gears at the drive wheels are going to be 50 teeth and the small drive gear is going to be a 36 tooth. All three of these gears are tied to the large gear by a function of adding the pitch diameters together and dividing by 2. I arbitrarily select the horizontal distance between gears, and so now they are fixed in position and can not be moved. No thought has been given to the width of the Trevithick yet, because that will be dependent on the diameter of the boiler.
(https://imagizer.imageshack.com/img922/3412/3opnEp.jpg)
Title: Re: Trevithick
Post by: Jasonb on August 27, 2020, 05:01:10 PM
Why are you limited to 108 teeth? on something like this cranking the rotary table without index plates would be OK so something like 180 teeth (2 degree) increments would be easy enough.

If there is a real reason to be limited to 108T then change the DP so you can get a larger diameter

Other drawings for this engine use 115/33/50 gears so slightly different proportions to yours.
Title: Re: Trevithick
Post by: Brian Rupnow on August 27, 2020, 06:19:53 PM
The largest gear I've actually MADE is 108 tooth. So far we don't have much, but the basic proportions are blocked out. If I don't go and eat some lunch I'm going to fall of my chair!!
(https://imagizer.imageshack.com/img924/6273/AaHwBl.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on August 27, 2020, 06:58:38 PM
Hi Jason--I'm more or less just eyeballing pdf files for my dimensions and ratios. Do you have anything on this cylinder and valve assembly that you could share with me. I've watched the animation a dozen times, and it looks like something I could "imagineer" from scratch, but life would get a whole lot simpler if I had a set of details for reference.---Brian
Title: Re: Trevithick
Post by: Jasonb on August 27, 2020, 07:10:18 PM
take up one of the other offeres in this thread that's the drawings I'm looking at, also has the cylinder and valve construction.
Title: Re: Trevithick
Post by: Charles Lamont on August 27, 2020, 08:41:55 PM
Brian, as I made this steam distribution valve for the full size replica of Trevithick's Catch Me Who Can locomotive, I can explain it. First, to save me a bit of time, please check out this:
https://en.wikipedia.org/wiki/Four-way_valve
Also, please check your messages in this forum.
Charles
Title: Re: Trevithick
Post by: Brian Rupnow on August 27, 2020, 09:20:44 PM
Charles--i have checked my messages. There is nothing new there.---Brian
Title: Re: Trevithick
Post by: JULIUS on August 27, 2020, 10:23:54 PM
Brian

The 10.25" model drawings are attached.
Title: Re: Trevithick
Post by: JULIUS on August 27, 2020, 10:25:08 PM
second lot
Title: Re: Trevithick
Post by: Charles Lamont on August 27, 2020, 10:33:51 PM
Brian, sorry, I think it must have been an email.
Title: Re: Trevithick
Post by: JULIUS on August 27, 2020, 10:42:25 PM
Brian

Here are the drawings of the 5" loco

Julius
Title: Re: Trevithick
Post by: Brian Rupnow on August 27, 2020, 10:57:21 PM
Just as I was reaching a point where I didn't want to go any farther without more knowledge about the cylinder and valve, Julius from New Zealand has came thru with a bunch of drawings and saved me. Thank you Julius, from the far side of the world!!!
(https://imagizer.imageshack.com/img923/1226/ljqXlm.jpg)
(https://imagizer.imageshack.com/img922/6231/ywGxGF.jpg)
Title: Re: Trevithick
Post by: crueby on August 27, 2020, 11:03:52 PM
Looks to be a fun project, watching along with great interest.    :popcorn: :popcorn: :popcorn:

And thanks from me to Julius, I have picked up a lot from your past plan postings too!   :ThumbsUp:
Title: Re: Trevithick
Post by: Charles Lamont on August 27, 2020, 11:12:59 PM
The arrangement shown in Julius's drawings is ingenious, but totally unlike anything Trevithick actually used.

These videos may help with an understanding of how the valve is tripped by tappets at each end of the stroke:
kWHXX0L2ozc9CnzNGyJKzo1tZ22zOn3Oo
Title: Re: Trevithick
Post by: Brian Rupnow on August 28, 2020, 01:12:28 AM
Charles--Have a look at the video in post #9. The animation in that link is exactly the same as what Julius posted.---Wait a minute--The man who made that video and animation refers to the drawings created by Julius. I like Julius' version better, but I wonder if anyone has actually built it and had it in service?
Title: Re: Trevithick
Post by: Jasonb on August 28, 2020, 07:38:35 AM
Just as I was reaching a point where I didn't want to go any farther without more knowledge about the cylinder and valve, Julius from New Zealand has came thru with a bunch of drawings and saved me. Thank you Julius, from the far side of the world!!!


He offered them to you several days ago and that was the offer I said to take up. Not just the drawings but the CAD files as well

Do bear in mind that Julius generally has a "for personal use only" note with his drawings so a bit bad form to start charging for drawings that may not have been possible without his.
Title: Re: Trevithick
Post by: Charles Lamont on August 28, 2020, 08:36:28 AM
I have seen in the flesh finished examples of this model, which is based on the surviving original engine in The Science Museum (London).  The model has the correct type of rotary 4-way valve.

The video in post no 9 is particularly unfortunate, as it goes to great lengths to promulgate a completely false idea of how Trevithick's engines worked, based on Julius's invention of a shuttle valve.

http://www.brunell.com/product.asp?cookiecheck=yes&P_ID=135&numLanguageID=1
Title: Re: Trevithick
Post by: Mcgyver on August 28, 2020, 12:53:28 PM
People like Julius who freely contribute so many great drawings do a great service to the hobby - THANK YOU!

It risk of looking like the ungrateful lout inspecting the gift horse's teeth, I like to table a thought from the peanut gallery.

It would be really helpful these drawings included some comments on their origin or pedigree.  A small engine can be a makers interpretation, freelance or at the other end of the spectrum a rivet counted model of a prototype.  All are good, however including a bit of info around this would be so very helpful to those of looking at the drawings as potential builds.

This is particular frustrating with grabcad - so much content but you just have zero idea of where the author is coming from.   It could be anything from an artistic interpretation that would never work to an exact reproduction of from a 100 year ME issue or done from first hand measurements by the author, and so on.  Not knowing seriously degrades the usefulness of the drawings/models that a lot of time was put into;  what could be a 10/10 becomes a 2.

If people did this, the person on grabcad would have given credit to Julius and say whether he'd mod'd it or reproduced it exactly etc...it would create a chain would enhance things imo

Just a thought - and thanks again Julius for all you contribute

Mike
Title: Re: Trevithick
Post by: crueby on August 28, 2020, 01:44:13 PM
I have seen in the flesh finished examples of this model, which is based on the surviving original engine in The Science Museum (London).  The model has the correct type of rotary 4-way valve.

The video in post no 9 is particularly unfortunate, as it goes to great lengths to promulgate a completely false idea of how Trevithick's engines worked, based on Julius's invention of a shuttle valve.

http://www.brunell.com/product.asp?cookiecheck=yes&P_ID=135&numLanguageID=1 (http://www.brunell.com/product.asp?cookiecheck=yes&P_ID=135&numLanguageID=1)
Charles, do you have any information/links on how the piston valves worked on the Trevithick loco? The videos you posted dont show any detail, though you can hear the valve actuating in a way consistant with what Julius drew. You say his layout is not right, but what IS the right way?Thanks!
Title: Re: Trevithick
Post by: Brian Rupnow on August 28, 2020, 03:53:29 PM
More bits and pieces designed this morning. Time to stop for a coffee now.
(https://imagizer.imageshack.com/img924/5771/b2t2Ax.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on August 28, 2020, 04:39:24 PM
I'm getting closer and closer to decision time on the steam cylinder and valve. Charles Lamont raises a valid point---I haven't found any Trevithick engine running the type of valve that Julius has drawings for. After much googling, I have found out that the Trevithick engine used a bell-crank lever to open and close a rotary 4-way valve. This means that the cylinder is basically just a plain cylinder, and the actual valving all happens in a separate block. It undoubtedly works, because there are a few recreated Trevithick engines running round using the rotary 4 way valve operated thru a Bell crank, as well as one completed model from Germany. I like the design by Julius, because there are no Bell cranks nor pivot points involved. Of course, the immediate question is has anybody built an engine using Julius' version of the valve, and how well did it work. Since I am not a stickler for authenticity, it seems I have three choices. I can use the same valve that Trevithick used, except I would be working from "scratch" and would have to develop the design for something a lot smaller in scale---OR--I can use what appears to be a much simpler cylinder/valve designed by Julius, ---OR---I can use a cylinder and valve body almost identical to that used on the Stephenson's Rocket, although if I do it ends up being a complete departure from what Trevithick did, but I know that it works.
Title: Re: Trevithick
Post by: Charles Lamont on August 28, 2020, 06:11:07 PM
Charles, do you have any information/links on how the piston valves worked on the Trevithick loco? The videos you posted dont show any detail, though you can hear the valve actuating in a way consistant with what Julius drew. You say his layout is not right, but what IS the right way?Thanks!

I haven't seen a link. I will look out and reduce to uploadable size some photos that will do the trick. I may be some time.
Title: Re: Trevithick
Post by: Brian Rupnow on August 28, 2020, 06:32:27 PM
In this video you can see the actuator operating the bell crank that controls the steam valve. I did find one excellent animation of the Trevithick 4 way valve yesterday, but I've watched so many Trevithick videos on Youtube that I'm going cross-eyed and can't find it today.
K40XrR67fas
Title: Re: Trevithick
Post by: crueby on August 28, 2020, 08:12:41 PM
Just found this one

https://museum.wales/media/9970/steaming_day.mp4
https://museum.wales/articles/2008-12-15/Richard-Trevithicks-steam-locomotive/

Title: Re: Trevithick
Post by: Brian Rupnow on August 28, 2020, 08:26:03 PM
Quite possibly the worst singing I have ever heard in my life!! :Lol: :Lol:
Title: Re: Trevithick
Post by: crueby on August 28, 2020, 08:42:00 PM
Quite possibly the worst singing I have ever heard in my life!! :Lol: :Lol:
Yeah, leave the speakers off but good details in a few places.
Title: Re: Trevithick
Post by: JULIUS on August 28, 2020, 09:39:25 PM
Brian

After watching the videos I saw how the 4 way valve was operated (By the way the singing was lousy.)
I have made a design of Robert Trevithick London Steam Carriage and I designed a 4 way valve to make this machine work. it is very similar to the one which I saw in the video.
If you are interested I can place those drawings on this forum.
The valving is not complicated but tricky.

Julius
Title: Re: Trevithick
Post by: Charles Lamont on August 28, 2020, 10:29:20 PM
The first two photos show the surviving stationary engine in the Science Museum.

1) Left of the cylinder is the regulator lever sticking out horizontally. The quadrant has holes to peg the regulator in position. Imediately left of that is the valve actuating stick. The two main bars have the top and bottom tappets sandwiched between and at the bottom of the slot, sloping down towards us, is the valve lever. Beside that is the tappet guide, running in its own narrower slot.

2) The cylinder head can be see towards the right, middle. The 4-way valve stem is sticking out to the right. The exhaust flange is on the back of the head, with the pipe through the feedwater heater to the chimney. Above the valve you can see the passage to the top of the cylinder cast into the head. The regulator cock is not visible, immediately in front of the 4-way.

3) The same arrangement on our replica, except ours is the other side of the cylinder (for a reason). The valve actuating arm is pointing downwards at the top of the left hand slot. The guide at the centre of the view is temporary and has since been replaced with something less ugly. In the slot immediately above the arm you can see how the leather facing on the oak tappet has become polished.

4) Here we have our cylinder head with the lap I made for the tapered cock bores. The small bore at the back is the regulator, and the port in it is the steam inlet from the boiler.
The connecting port from the regulator to the 4-way is clearly visible, and you can just see a bit of the port that connects to the bottom of the cylinder. The big chamfer on the left contains the port to the top of the cylinder, and the exhaust port is opposite the regulator port.

5) In this one you can see the previous operation in which the valve chambers are being bored on the 4ft vertical borer. The patterns were borrowed from The Trevithick Society, and the same head is used on their Puffing Devil. Of interest, just above the top edge of the angle plate are the trapezoidal steam inlet port to the regulator on the right, and the connecting port for the bottom end of the cylinder on the left. The exhaust passage goes 90 degrees round the outside to the exhaust port at the back.

6) The top of the cylinder into which the liner has just been shrink fitted, hence the bloom of ice. The passage on the left runs right down the outside of the cylinder to connect at the bottom. Again, the funny shaped port lets steam up from the boiler.

7) Here the head is sitting in position on the cylinder. The exhaust flange can be seen on the right of the head casting.

8 ) Dave Reynolds, on the left, is to blame for the whole idea and most of the design. I'm in the middle, and Allan MacKenzie is on the right. Not seen, in addition to the overalls and panamas is another important accessory - the driver's starting umbrella. 
Title: Re: Trevithick
Post by: Brian Rupnow on August 28, 2020, 11:25:26 PM
Julius--Yes, if you have pictures of an alternate valve system, we would all appreciate seeing them. I couldn't get my cheap Huwlit-Packard printer to print your drawings, so I sent them out to a commercial printers this afternoon. I want to recreate the valve/cylinder you have designed in 3d Solidworks to get a better understanding of it, and to see if the scale can be reduced to work with my model of the Trevithick engine. Has anyone built a valve/cylinder to your drawings (as posted here) and had it run successfully? Thank you for your help and interest.---Brian
Title: Re: Trevithick
Post by: Charles Lamont on August 29, 2020, 12:01:29 AM
Julius, could you expand on your thinking behind your shuttle valve arrangement, please? BTW, I hope you don't think I have set out to denigrate your design, I have just wanted to make sure that it was understood that it was not authentic.
Title: Re: Trevithick
Post by: crueby on August 29, 2020, 12:42:39 AM
Hi Charles,


Were you guys able to open up the valve on the original engine, or at least see old drawings or photos? Great that the engine survived! Thanks for your information!
Title: Re: Trevithick
Post by: Brian Rupnow on August 29, 2020, 01:29:38 AM
HAH!!! Found it. The animation of Trevithick's valve/cylinder starts about 13 minutes in.
DXknPScdDJc
Title: Re: Trevithick
Post by: crueby on August 29, 2020, 02:20:46 AM
Brilliant description. Glad you found it!
Title: Re: Trevithick
Post by: Brian Rupnow on August 29, 2020, 08:20:35 PM
I have spent today making a 3D model of Julius' valve/cylinder combination. I haven't spent any time yet determining how it's going to work, but at least I have all of the components modeled and mated. As modeled, this cylinder is only 18mm bore (about 11/16") x about 3 3/8" stroke. The piston rod is 4 mm diameter, (about 0.157") diameter. There are a bunch of ports which have to be added yet to the cylinder and a number of pipes to transfer air.
(https://imagizer.imageshack.com/img923/7233/LMWXSJ.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on August 29, 2020, 08:35:06 PM
I have been asked how the Trevithick compares size-wise to the Stephensons Rocket. It's roughly in the same ballpark, but far from being identical.
(https://imagizer.imageshack.com/img923/197/Ax7O0J.jpg)
Title: Re: Trevithick
Post by: JULIUS on August 29, 2020, 09:50:55 PM
Brian

Attached are the drawings which I mentioned before.
This steam engine uses a 4 port valve
I have a video of how this valve works, but I have to send this to your e-mail address because it is too large to put it on this forum

Julius
Title: Re: Trevithick
Post by: Brian Rupnow on August 30, 2020, 12:00:32 AM
I have been moving the piston and steam valve around on my CAD system to see if everything makes sense. It seems to, with the exception of one cylinder port and I have asked Julius to check the position of the one hole in question. I have also asked again if anyone has actually built this configuration that he has drawn. Once I am completely happy with what Julius has sent me, I will start modifying it to give the bore and stroke that I need for my Trevithick model. Julius makes beautiful drawings. I have been badly spoiled by the practice in Canada of putting a detail of each part on it's own individual drawing. I've had to do some serious hunting on his drawings to find the parts I need to model.
Title: Re: Trevithick
Post by: Brian Rupnow on August 30, 2020, 12:09:33 AM
Julius sent me this today, an animation of how the four way rotary steam valve is operated on the original Trevithick engine.
BOpAPeblG8w
Title: Re: Trevithick
Post by: sbwhart on August 30, 2020, 12:39:20 PM
Is this what your building Brian

-y4Xzphnz6I
I've actually bin to a Travithick day and seen Puffing Billy come up the hill in Canborne and seen the steersman fighting to keep control of it:- Scarry  :ShakeHead:

Her's another one bit longer and with more detail

FEjGBgBxSNM
Stew
Title: Re: Trevithick
Post by: Brian Rupnow on August 30, 2020, 12:53:35 PM
I am building the Pennydaren which can be seen in this video.
rul0iazn3d8feature=emb_logo
Title: Re: Trevithick
Post by: fumopuc on August 30, 2020, 03:08:53 PM
Hi Brian,
may be this is of interest for you to watch.
A member of our German forum has build one some years ago.
https://youtu.be/5i3S_dqMMoM (https://youtu.be/5i3S_dqMMoM)
Here are two videos from this summer, he has installed his own tracks in his garden now.
https://youtu.be/IuQbT753kmo (https://youtu.be/IuQbT753kmo)
And a ride around one or more laps.
https://youtu.be/OaFAzVg9KXY (https://youtu.be/OaFAzVg9KXY)
And here the model of the steam wagon, also build by him.
https://youtu.be/FNfDD81BOnY (https://youtu.be/FNfDD81BOnY)
Title: Re: Trevithick
Post by: Brian Rupnow on August 30, 2020, 04:27:38 PM
Fumopuc--great videos. The engine seems to perform very well.---Brian  I am going a bit batty this morning, checking to see that the correct ports are covered and uncovered in the cylinder as the piston and valve move back and forth in the cylinder. This is the kind of thing that you really want to get right on paper (or computer) because the next phase, building it in metal gets costly and time consuming if the ports aren't where they should be.
Title: Re: Trevithick
Post by: Brian Rupnow on August 30, 2020, 11:50:07 PM
It's been a long and interesting day. I have taken the cylinder that Julius sent me, changed the diameter and the stroke length, eliminated some of the seals that crossed ports in the cylinder and changed the piston rod size. All I can do now is hope that I got it right and build it. I don't have a "safety net" of other designers and engineers to check some of this stuff for me. I won't build anything else on the project until this cylinder is finished, because this cylinder is the heart of the whole operation. There are no cams or eccentrics on this engine. The spool valve inside the end of the cylinder replaces all of that. There are seven ports on the sides of this cylinder. I am going to solder short lengths of small brass tubing to the outside of the cylinder at the ports and use flexible nylon tubing to connect them all. It will all be hidden inside the body of the Trevithick boiler.  I will keep you posted as this develops.
(https://imagizer.imageshack.com/img922/3249/FkpBP7.jpg)
Title: Re: Trevithick
Post by: Art K on August 31, 2020, 03:24:30 AM
I can totally understand fighting to steer that up the hill, it does look like steel shod wooden wheels & no suspension, and a tiller to boot. I wouldn't want to be in his shoes, he's a brave man!
Art
Title: Re: Trevithick
Post by: Brian Rupnow on August 31, 2020, 03:34:31 PM
This morning the new cylinder is completely designed. I have moved all of the ports around into the bottom 60 degrees of the cylinder so they can be connected with flexible tubing. I have also redesigned the cylinder and end caps so that there is no welding or silver soldering, because I am concerned about warping the long cylinder from heat related issues. The cylinder body is now made from much heavier wall material so that I can tap the ports for 1/4"-20 threads, which lets me screw in the hose barbs with a bit of loctite so no heat is involved. I got some rather disturbing news this morning from Julius. He doesn't know if anyone has ever actually built this cylinder or not. To my knowledge I have never seen one like this myself. I don't care to be a guini pig for untried designs that haven't been built successfully by somebody else.
(https://imagizer.imageshack.com/img923/8210/9HFK56.jpg)

Title: Re: Trevithick
Post by: michaelr on August 31, 2020, 04:03:42 PM
Hello Brian,

This site may be of interest to you, it's a build log for a model Trevithick Dredger Engine which has a similar cylinder/valve arrangement only it's a vertical cylinder.
https://johnsmachines.com/2019/02/16/a-tour-of-the-model-dredger-engine/ (https://johnsmachines.com/2019/02/16/a-tour-of-the-model-dredger-engine/)

Michael.
Title: Re: Trevithick
Post by: Brian Rupnow on August 31, 2020, 09:20:26 PM
Thank you Michaelr---I haven't had time for an in-depth look at what you posted, but I will certainly have a look at it later today. I have decided to go ahead and build the cylinder even though nobody knows if it has been built before to Julius' drawings. If it works, then Hooray, I'll be a hero. If it doesn't work, I will be able to salvage most of it to work with a more conventional valve system. I picked up the material for it today. The main cylinder body is going to be made from hot rolled steel. This is not something that I would normally use, but since the engine will be ran on compressed air it should be okay. I generally would use grey cast iron for a cylinder if it was for an i.c. engine or driven by steam.
(https://imagizer.imageshack.com/img924/6955/uGFtXQ.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on August 31, 2020, 11:48:47 PM
And the ugly 1 1/2" piece of hot rolled has yielded a nice cylinder. 1.375" o.d. x 0.75" i.d. x about 5 1/2" long.    O.D. machined with brazed carbide at 680 rpm, inside drilled and reamed to 0.75". Hot rolled steel is such a nice steel to machine. I can get a much nicer surface finish on hot rolled than I can on cold rolled. Tomorrow I have about a billion holes to drill and tap.
(https://imagizer.imageshack.com/img924/4303/JDKdRp.jpg)
Title: Re: Trevithick
Post by: crueby on August 31, 2020, 11:53:09 PM
Moving right along! Watching along here!   :popcorn: :popcorn:
Title: Re: Trevithick
Post by: Brian Rupnow on September 01, 2020, 06:13:24 PM
I spent some time designing this morning, and decided to make the piston rod 3/16" diameter with all the attendant changes to parts which mate with the piston rod. (It was 1/8" diameter before). I am happy with things as they are now, and the success of this design depends on the drawing of the cylinder I received from Julius. You have to admit---it looks pretty wild!!
 (https://imagizer.imageshack.com/img923/8088/IkDQDq.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on September 01, 2020, 09:00:12 PM
Yow!!!--That's a lot of holes. Hope they're all in the right place---
(https://imagizer.imageshack.com/img922/6412/4rQIKp.jpg)
Title: Re: Trevithick
Post by: Art K on September 02, 2020, 03:02:44 AM
Brian,
That's quite a project you've got going there. Sorta looks like a Christmas tree, mind with the branches lopped off on one side. I've watched some of the videos of how the valve mechanism works and I'm glad they came up with the sliding valve.
Art
Title: Re: Trevithick
Post by: crueby on September 02, 2020, 03:29:31 AM
Fascinating to see this come together, early steam technology while they were learning at light speed.
Title: Re: Trevithick
Post by: derekwarner on September 02, 2020, 04:11:52 AM
Brian.......

I cannot see any nomination for the material of the piston seal elements

With the piston seals being pressure energised, o-rings will tend to shear a slice as they become displaced into the sharpely cut port area when traversing the outer body

The Company Paul Wurth from Luxemburg designed specialist Blast Furnace rotating hydraulic cylinders [very similar internal construction to your  proposed build].......to overcome this sealing issue, cast iron piston ring sets are requuired and operating at 350 Bar - cross port leakage over the cast iron ring sets is amazingly low

http://www.paulwurth.com/The-Group/Company-Profile

Derek
Title: Re: Trevithick
Post by: crueby on September 02, 2020, 04:19:21 AM
I think the piston as drawn is set up so it never crosses a port, so it could use o rings. For the valve, which does cross ports, are rings really needed? I made the spool valves on several engines, including the Stanley, without rings on the spool valves, with no issues.
Title: Re: Trevithick
Post by: Jasonb on September 02, 2020, 07:10:17 AM
Does not look like the piston slides over any ports to me and if a single ring were in the middle of the piston it certrainly would not even partly overlap.so OK with an O ring. If it did over[lap a port then you would be in trouble as the valve would want to move in teh opposite direction and you would have a direct route from inlet to exhaust >:(

The divider between cylinder and valve chamber does not move so that can use o rings as a static seal.

Brian's shuttle is not shown with any o rings
Title: Re: Trevithick
Post by: Brian Rupnow on September 02, 2020, 01:13:39 PM
Yes gentlemen, that is the plan. No rings on the spool---a lapped fit. Two rings on the cylinder divider that is stationary, and one ring on the pistons which doesn't pass any ports. And--The hose barbs which screw into the sides of the cylinder will intentionally be made too long on the threaded ends, so they can be machined flush with the inside of the cylinder bore.
Title: Re: Trevithick
Post by: derekwarner on September 02, 2020, 02:23:35 PM
Apologies....being on the opposite upside down side of the World........must have misinterpreted the design images  :headscratch: ....... Derek
Title: Re: Trevithick
Post by: Brian Rupnow on September 03, 2020, 01:18:47 AM
I'm slowly going ahead with the valve as designed by Julius. We have visiting grandchildren this week, and next week after they all go back to school it will be too dangerous for good wife and I to see them until a Covid vaccine is found.  As for the valve which Julius designed, I can see the theory behind it, but I simply can't tell if it works until I have built one to see if it works or not. I think the cylinder is going to have a large "dead spot" at each end of the stroke, but with a large enough flywheel (which the Trevithick engine does) it may not matter. I have almost melted the internet searching for information about the original Trevithick 4-way valve, and the good news is that I think I have sussed it out. Now, whether the Julius design works or not, I simply have to build a rotary valve engine. If I do, I will publish the drawings on all my forums because this stuff is so neat that everyone should have free access to it.
(https://imagizer.imageshack.com/img923/6201/7DwSNQ.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on September 03, 2020, 11:47:34 PM
Today we have both cylinder end caps finished. That little bit of shaft you see sticking out the end isn't really the piston rod.---I'ts just a "fooler".  I still have to make the packing gland, and then I will start on the hose barbs that screw into the sides of the cylinder. I miscounted earlier when I said there were seven ports.---Actually there are eight.
(https://imagizer.imageshack.com/img924/3690/vzKJ6h.jpg)
Title: Re: Trevithick
Post by: crueby on September 04, 2020, 12:00:40 AM
Great progress, if the valving doesn't work out, should be a good flute.
Title: Re: Trevithick
Post by: Craig DeShong on September 04, 2020, 10:27:02 PM
Some very interesting projects you're working on Brian.  I'm loving following along.  You seem to be caught in an "early stem locomotive" paradigm.

I'm always looking for the interesting "next project"  maybe a "Tom Thumb" might be in order?

 
Title: Re: Trevithick
Post by: Brian Rupnow on September 05, 2020, 12:22:01 AM
Eight little hose barbs, all in a row. This cylinder is going to look like a porcupine. If I can just get a 1/4"-20 thread on the end of each one without destroying it, I'll be very happy!!!
(https://imagizer.imageshack.com/img923/7406/BFZ5N7.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on September 05, 2020, 01:29:46 AM
Craig--after building engines for 12 years (currently have about 35 of them), my biggest challenge is finding something new and different to build. I don't have a great enthusiasm for early railroad engines, but you have to admit, the sheer "mechinicalness" of the Trevithick and the Stephenson's Rocket are awesome.
Title: Re: Trevithick
Post by: Brian Rupnow on September 05, 2020, 03:14:57 PM
Holy Porcapine Roy!!!--That's a lot of hose barbs. I finished drilling and threading the hose barbs this morning and installed them all into tapped holes in the cylinder body with 638 Loctite. Next up will be the cylinder divider, piston, and spool.
(https://imagizer.imageshack.com/img922/1953/5FM0jm.jpg)
Title: Re: Trevithick
Post by: crueby on September 05, 2020, 07:19:01 PM
There's a company near me that repairs pipe organs, you may have a new career there...


 :popcorn: :popcorn: :popcorn:
Title: Re: Trevithick
Post by: Brian Rupnow on September 05, 2020, 10:45:28 PM
Today yielded a piston, a spool valve, and a cylinder partition plate. Those o-rings are Viton---Didn't need to be because there is no heat involved, but that's what I had. I still have to drill and tap 3 holes in the cylinder partition plate.
(https://imagizer.imageshack.com/img924/8302/KcyWwX.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on September 08, 2020, 01:20:29 AM
The self reversing cylinder as designed by Julius is almost ready for final assembly.  I have all the parts finished, but I have to buy a very small center drill tomorrow to use for starting a 1 mm diameter drilled hole thru a collar which sets out of site inside the spool. I honestly don't know what to expect here. If it works, I will be greatly impressed. If it doesn't, I will go ahead with a design using a rotary valve as used on the original Trevithick engine.
(https://imagizer.imageshack.com/img923/7779/g1SIRb.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on September 08, 2020, 04:17:09 PM
I had to do it. I've been thinking of a 4 way valve for the last week, so this morning I had to spend a bit of quiet time and model one. I'm not even sure of what I will do with it yet, but at least my head is clearer now that I have a model that I can understand.
(https://imagizer.imageshack.com/img922/70/IYIhsK.jpg)
Title: Re: Trevithick
Post by: crueby on September 08, 2020, 04:20:53 PM
Well, if the slide valve version you have been building works, you will just have to build one of Trevithicks other locos or wagons to use the 4-way valve in!
 :popcorn: :popcorn: :popcorn:
Title: Re: Trevithick
Post by: Brian Rupnow on September 08, 2020, 07:26:03 PM
Unfortunately, I couldn't get the cylinder with the spool valve to work. I have tried all of the tricks that I know, and it just isn't happening for me. There is a small diameter cross pin (1 mm) thru the center shaft and a collar that is pinned to the shaft, and they are both hidden inside the spool when assembled. When trying this out with 20 psi of air pressure, the 1 mm diameter pin immediately sheared off. The pin was made of 1 mm diameter unheat-treated drill rod, so it was certainly the strongest steel that I had. I am going to go ahead and re-use the piston, piston rod, and front and rear cylinder caps and guide bushing. I will make up a new cylinder  which is operated by a 4-way rotary valve, same as the original Trevithick engine.
Title: Re: Trevithick
Post by: Craig DeShong on September 08, 2020, 10:31:15 PM
Sometimes you have to take a step backward, before you can take two steps forward.  We’ve all been there.  It’s just part of ‘designing your own’. 

Great progress over all.  Learning something that doesn’t work is still learning. :old:
Title: Re: Trevithick
Post by: Brian Rupnow on September 10, 2020, 04:42:37 PM
So, after a rather questionable beginning, we start again. This time it will be with a 4 way valve which I design, and a rather plain Jane cylinder. I changed the shape of the boiler, because the convex end adds a level of complexity that I don't need to deal with. This entire project is going to depend on my ability to design and build a 4 way valve, so that is where I will begin.
(https://imagizer.imageshack.com/img922/4317/56F7Q0.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on September 10, 2020, 11:45:44 PM
Tomorrow I will start building a 4 way valve. The main body will be mild steel, while the green center spindle is machined from cast iron and will be lapped into the steel housing for a very close fit.  First, before I machine anything, I have to go across town to Hercules O-Ring and buy the o-rings I need to seal things up. (They are shown in red in the assembly model.) There is no heat involved here, so they will be Buna-N material. My design is very much dependent on the actual size and cross section of the o-rings. When the transparent red cap is attached to the green spindle with a #10 shcs., the rubber o-rings will be partially compressed.
(https://imagizer.imageshack.com/img923/6034/UI3ME3.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on September 11, 2020, 07:26:03 PM
Well, that was pretty painless. The only catch was that the o-rings are 9 cents each, but the minimum sale is $15.00---As a result of this I have enough of that size of o-ring to last for the rest of my natural life!!!
(https://imagizer.imageshack.com/img922/5632/dq7ofl.jpg)
Title: Re: Trevithick
Post by: Craig DeShong on September 12, 2020, 12:17:38 AM
Well, that was pretty painless. The only catch was that the o-rings are 9 cents each, but the minimum sale is $15.00---As a result of this I have enough of that size of o-ring to last for the rest of my natural life!!!

Well, plan on living quite a while longer then  :ThumbsUp:

Glad you're back on track... ever though this model doesn't have any (tracks :insane:)
Title: Re: Trevithick
Post by: Brian Rupnow on September 13, 2020, 01:30:10 AM
I think this is going to work. So far, I have only tested it with the "Blow your guts out" method, and when the spindle is turned so that the slots don't align with the port you are blowing in, you can't blow.--When they are aligned, you can. I know, that's a pretty cheesy way to test something, but it's cheap and quick. I still have to make the cap which attaches to the end of the spindle which doesn't have a flange, and compresses the o-rings.  I will make that last part tomorrow, and hopefully the valve will function the way I want it to. I am attaching a video link about Trevithick's engine, and about 13 minutes in you can see an animation of the same valve as built by Trevithick over 200 years ago.
(https://imagizer.imageshack.com/img922/268/wOBzVC.jpg)
DXknPScdDJc
Title: Re: Trevithick
Post by: Brian Rupnow on September 14, 2020, 01:28:27 AM
The 4 way valve is finished. Not the handsomest piece I've ever crafted, but only the round metal top part with the 3/32" rod will show above the boiler housing. As the piston travels in and out, a mechanism on the cross head will move that rod thru a 90 degree arc, thus reversing the flow of compressed air to the cylinder. It is assembled dry right now for trial "fit-up", but will be greased with white lithium based grease to make it easier to rotate the center spindle for operating.  I have to figure out some way of testing it tomorrow. Might have to "borrow" a cylinder off something else to test the valve and see if it does what I want.
(https://imagizer.imageshack.com/img924/1658/QHrF2V.jpg)
Title: Re: Trevithick
Post by: Art K on September 14, 2020, 02:28:58 AM
Brian,
I watched that video last night. He was quite creative to come up with ways to make this work. His whole flue setup being riveted and not leaking, yeah they made boats later that were riveted but when the modern way of welding it was a century away. I liked the pegs to keep from overstearing.
Art
Title: Re: Trevithick
Post by: crueby on September 14, 2020, 02:49:49 AM
Very interesting setup. It will be interesting to see how sensitive it is to timing the valve changes to the stroke.   :popcorn:
Title: Re: Trevithick
Post by: Charles Lamont on September 14, 2020, 09:43:29 AM
Art K, boilers were riveted right up to the end of steam, but Trevithick did not have the use of pneumatic hammers to do the caulking.

crueby, if the tappets are set to open the valve fully by turning it through exactly 90°, there is nothing you can do about timing. However, there is a way to
make the valve operation more or less 'snappy' at the design stage. If the operating radius of the radial actuating arm on the valve is large, then the actuation will be slow, the valve will start to move relatively early in the piston stroke, and there will be a lot of advance. If the lever operating radius is small, the arc length of the motion is smaller, so the motion of the valve actuating rod can be a smaller proportion of the piston stroke, with the actuation closer to the dead centres, resulting in the exhaust closing and steam admission occurring somewhat later in the stroke. Tom Brogden's full size replica of Trevithick's London Steam Carriage has a clever trip arrangement, the details of which I don't remember, which flips the valve over very smartly. This arrangement was deduced from Trevithick & Vivian's 1802 patent.
Title: Re: Trevithick
Post by: Charles Lamont on September 14, 2020, 12:19:21 PM
Hopefully, this illustrates the point about the rotary valve arm radius:
Title: Re: Trevithick
Post by: Brian Rupnow on September 16, 2020, 10:15:24 PM
Today was very successful. I recreated Trevithick's rotary valve, and mounted it on a cylinder which it operates quite nicely. I didn't want to go ahead with any of the other parts of the model until I knew that I could make this work. i'm very pleased with the way this worked out.
(https://imagizer.imageshack.com/img923/9472/mkcU3M.jpg)
s_vrDuJ8_FE
Title: Re: Trevithick
Post by: crueby on September 16, 2020, 10:35:49 PM
Excellent result!
Title: Re: Trevithick
Post by: Art K on September 17, 2020, 03:12:54 AM
Looks good Brian, works just as designed.  :whoohoo:
Art
Title: Re: Trevithick
Post by: Brian Rupnow on September 17, 2020, 09:35:42 PM
OH MY GOD---There are an incredible number of rods and rod supports to control the cylinder valve on this monster!!! Trevithick was able to get his 4 way valve much closer to the centerline of his cylinder than I have. This is kind of "first draft" to give me some idea of what I'm dealing with. I have shown the arm which actuates the valve in three positions. I show it in the "neutral" center position and in the two "maximum" positions it swings to.
(https://imagizer.imageshack.com/img924/3537/I14l7l.jpg)
Title: Re: Trevithick
Post by: Charles Lamont on September 17, 2020, 11:30:51 PM
Brian,

In your latest video, just in case you have not spotted it, the valve is working the wrong way. For self-acting, you will need either the air inlet on the other side, or the valve rotated 90° in the lever cap, so that at the end of the in-stroke, moving the valve to the left makes the piston stroke right.

HTH, Charles

 
Title: Re: Trevithick
Post by: Brian Rupnow on September 17, 2020, 11:53:58 PM
Charles--I have thought about that, and I'm still not sure if I'm wrong or right. The only good thing about it is that all of those fixtures I've modelled today will work on either side of the engine centerline. If I reverse the side which the valve actuator sticks out from, it will effectively reverse the valve.  EDIT--I just repositioned the valve lever 180 degrees to the opposite side, and I was right, it reverses the action of the cylinder. You have experience with the original engine, and I trust that what you say is correct.---I just have to wrap my head around the sequence of what happens.---Brian
Title: Re: Trevithick
Post by: Art K on September 18, 2020, 03:10:22 AM
Brian,
I have to admit that I'm glad that it is not I that am building this steam contraption. With that corn cob of pipes and tubes and valve, whew, just makes me tired thinking about it. Charles obviously knows his stuff relating to steam!
Art
Title: Re: Trevithick
Post by: Brian Rupnow on September 18, 2020, 03:49:12 PM
A couple of quick updates this morning. Originally, I had planned on welding a plate to close off the end of the boiler. Only problem with that is that there would be no possible way to get the cylinder with valve attached into place, as it has to go into the boiler endplate with the valve sticking up thru the top of the boiler all at once. So, a quick solution is to make the boiler endplate a separate piece which bolts into the end of the boiler. That way I can mount the cylinder in the endplate, then bolt the endplate into the boiler. Since I can now make the endplate from thicker material (7/16"), then I can mount the long yellow guide rod support to this plate, rather than the axle mount. This makes for a much smaller guide rod support.--In other news, I sent the large flywheel drawing (6 3/4" diameter) out to a waterjet cutter yesterday, and a quote come back for $80 to waterjet cut the flywheel. To me, this is ridiculous, so I sent it out again this morning to three other water-jet cutters for quotes.
(https://imagizer.imageshack.com/img924/4294/3BlBam.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on September 18, 2020, 06:19:49 PM
I now have three quotes to waterjet cut the flywheel. One for $80, one for $125, and one for $42---it certainly pays to go out for quotes.
Title: Re: Trevithick
Post by: Charles Lamont on September 18, 2020, 11:49:12 PM
Brian, just a couple of thoughts:

If you could make the valve and particularly its actuating buckle a bit more compact, it could sit on the part of the cylinder that is outside the boiler. That would get over your problem of having the valve poking out through the top of the boiler, and would be more like the prototype.

The arrangement you have drawn with the tappets striking the valve actuating peg is the way it was done on the preserved vertical cylindered engine. The horizontal ones seem to have been the other way round, with the rod driving the valve with (say) a scotch yoke arrangement and the tappets knocked by the arm on the crosshead. This you could dispense with most of the green guide bits in your arrangement. That might not be too clear, so I have sketched it out. 
Title: Re: Trevithick
Post by: Brian Rupnow on September 19, 2020, 01:07:37 AM
Charles--You are correct, but I'm not really able to miniaturize the valve to a point where it is small enough to do what you suggest.
Title: Re: Trevithick
Post by: Brian Rupnow on September 19, 2020, 05:09:12 PM
I had to step back and have another look at all the rods and supports which I had in place to operate the valve.--There were far too many. So--I spent a couple of hours this morning redoing them, and managed to eliminate quite a few. I have sent the flywheel drawing out to a waterjet cutter and he will call me when it is finished. I purchased a piece of welded steel tubing for the main boiler body. It is 4" outside diameter with a 3/16" wall thickness. Of course this was slightly different than my original model, but in this case it was cheaper/faster to change my model to accommodate the pipe size.
(https://imagizer.imageshack.com/img923/5516/pLC5AA.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on September 20, 2020, 08:47:34 PM
Yesterday I made a new rod end for the cylinder, and machined a new separate flange, which weirdly enough doesn't get bolted to anything on the cylinder. It does bolt to the outside of the boiler endplate and is there for show, but nothing functional. Today I cut the boiler tube to the correct length on my lathe. That steel tube had some kind of nasty varnish on the outside diameter, so I used my angle grinder and then my jitterbug sander to clean up the outside diameter while the tube was turning in the lathe. Tomorrow I will pick up some new material to make the boiler end-plates from, and Tuesday I pick up my water-jet cut flywheel. Most of this engine will get painted, so I'm not too concerned about using a combination of steel and aluminum parts.
(https://imagizer.imageshack.com/img922/5795/qHeKg4.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on September 22, 2020, 04:42:04 PM
Now that, boys and girls, is a beautiful thing!! Water jet cutting leaves great edges that need very little clean-up. If it wasn't so expensive, I would have more of it done. The flywheel is laying on top of a bunch of plates which will be finished before the end of the day using conventional machining techniques.
(https://imagizer.imageshack.com/img922/2430/rY03wR.jpg)
Title: Re: Trevithick
Post by: crueby on September 22, 2020, 05:19:19 PM
That wheel came out great. How parallel are the inner/outer edges to each other? Close enough not to need any more milling?
Title: Re: Trevithick
Post by: Brian Rupnow on September 22, 2020, 07:29:02 PM
As far as I can tell, it only needs a slight kiss on the o.d. and to have a hub bolted on.
Title: Re: Trevithick
Post by: propforward on September 22, 2020, 07:44:04 PM
Now that, boys and girls, is a beautiful thing!! Water jet cutting leaves great edges that need very little clean-up. If it wasn't so expensive, I would have more of it done. The flywheel is laying on top of a bunch of plates which will be finished before the end of the day using conventional machining techniques.


Very nice work.

It might be that the post processing of your CAD files is where some of the expense is.

If you're not already doing it, you might ask them what file type they are using to program their waterjet, and see if you can supply what they need. We use dxf files up to a very specific year version on ours - and convert to that from solidworks in the flat pattern.

Also, if your edges are coming out so niceley, maybe see about upping the cut speed, and living with a slightly rougher edge with some stock on it for clean up later on. Might save a bit of time, and therefore money. But - may increase their programming time. Might be a wash.

Don't know, just some thoughts for you to run by your waterjet people if you like.
Title: Re: Trevithick
Post by: Brian Rupnow on September 22, 2020, 11:27:16 PM
I supplied the water-jet cutter with the file he asked for. I have no control over what cut speed the guy uses. interesting thought though--I sent the drawing out to four places for quotes and received quotes of $125, $80, $50 and $47. It pays to shop around.
Title: Re: Trevithick
Post by: Art K on September 23, 2020, 03:40:27 AM
Brian,
That is a mighty fine looking flywheel. This project is coming along good.
Art
Title: Re: Trevithick
Post by: Brian Rupnow on September 23, 2020, 09:56:08 PM
I haven't ran off. There is a lot of time spent on fitting and creating new platework, and I didn't want to post every single part that I made. The cylinder is fitted into the boiler, with a little bit of design change to allow for clearances. The plate stands that support the boiler and provide bearing surfaces for the axles are almost finished, but as you can see, they haven't been drilled for axles yet. Tomorrow I will finish those plates and machine two more that run parallel to the boiler, and drill and tap the boiler shell for the bolts which holds the end stands in place. The wheels are going to be the last parts made for this engine. I can actually go ahead and make all the parts required to make the engine run without finishing the wheels and the gears.
(https://imagizer.imageshack.com/img923/1328/3IM3fL.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on September 24, 2020, 11:25:14 PM
Todays job was to finish all of the axle brackets and assemble them to the boiler shell. This gets a bit tricky, because with no real suspension, if things are a bit off you end up with one wheel out of the four "up in the air".--It won't matter so much on this model, because it's not going to be a high miler, but I do like to get it right.
(https://imagizer.imageshack.com/img924/5975/6d37hj.jpg)
Title: Re: Trevithick
Post by: Charles Lamont on September 25, 2020, 09:39:03 AM
Two rigid axles was not an option on the replica Catch Me Who Can.  With only one driving axle it is easier to arrange. The carrying axle has axleboxes sliding in horns in the usual way, and a transverse leaf spring hidden under the boiler. This should also make the footplate ride a bit less rough. ISTR one of the Coalbrookdale Engine replicas broke an axle quite early in its career. 
Title: Re: Trevithick
Post by: Brian Rupnow on September 25, 2020, 09:12:24 PM
And behold, the great horned beast!! Is it not a beautiful thing? I think it's a Rupnowsaurus!!!
(https://imagizer.imageshack.com/img923/9990/nJ5WnA.jpg)
Title: Re: Trevithick
Post by: crueby on September 25, 2020, 09:21:40 PM
Looks like a torture device for shop gnomes.
Title: Re: Trevithick
Post by: Brian Rupnow on September 25, 2020, 11:34:33 PM
You know that saying about "Old dogs can't learn new tricks".--Not really true---I'm an old dog and I'm still learning new tricks. The cross-head on this engine (purple colored) has a long protrusion welded on top of it that operates the rotary valve. The fact that it is quite long will make the cross-head want to bind as it moves under pressure from the cylinder. This is technically called an "overturning moment". The way to overcome that binding is to make the area on the cross-head which slides along the cross-head guides as long as possible. Since that is probably the next thing I'm going to build, an update to the 3D model was called for.
(https://imagizer.imageshack.com/img922/2729/iUirol.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on September 26, 2020, 07:15:32 PM
Today I finished the cross-head, and I'm quite pleased with the results.  In the 3D model I posted yesterday, I thought that the extended bearing surfaces added to the cross-head looked kind of "clunky", so I changed the design after I  had posted the model, and made the two extension pieces from round brass, which extend completely thru the rectangular body. They are loctited in place. The vertical part of the cross-head which operates the valve control rod is silver soldered to the cross-head main body.
(https://imagizer.imageshack.com/img924/4198/jn6Q3s.jpg)
Title: Re: Trevithick
Post by: crueby on September 26, 2020, 07:20:25 PM
Watching along here, great stuff.
Title: Re: Trevithick
Post by: Brian Rupnow on September 27, 2020, 12:57:35 AM
Today is a "banner day", as I have completed the cross-head and cross-head guides, and my air cylinder and rotary valve are moving the cross-head thru it's travel. Everything is a bit herky-jerky right now, because everything is new and stiff. Once it has been operated a number of times, any "tight spots" will be smoothed down and the travel will be much smoother.
(https://imagizer.imageshack.com/img923/3671/lmlJVz.jpg)
-8n-77EDhEE
Title: Re: Trevithick
Post by: crueby on September 27, 2020, 02:01:49 AM
Love it!   :ThumbsUp:
Title: Re: Trevithick
Post by: Brian Rupnow on September 27, 2020, 07:55:18 PM
Here is a fun little video of "running in' the cross-head and cross-head guides to make them operate smoothly without binding.
k98R9-F3M8I(https://imagizer.imageshack.com/img923/3449/gArtWm.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on September 27, 2020, 10:15:43 PM
I have now reached the point where I can't do much more until I mount the shaft which the flywheel mounts to.--And--the exact position of that shaft depends totally on the meshing of all the gears. I only have to actually cut 3 gears--the ones attached to the wheels will be made as one extra thick gear, then split with my parting tool to yield two identical gears. I have a tiny bit of cosmetic work to do on the "boiler", but that can wait, for now. I can make all of the smaller gears tomorrow if I have the material to make them.
Title: Re: Trevithick
Post by: Brian Rupnow on September 28, 2020, 04:01:47 PM
This morning I went searching about for material to make all of my gears. Okay--Good news is that I already have a 36 tooth gear left over from some project, that can be repurposed. It is the gear which sets up on the same shaft as the flywheel, and by all rights should be made of steel. Since this is only a demonstration engine that will see very few miles, I will use this gear anyways. I hunted up two bronze flywheels from the old Rupnow Hit and Miss engine, which has been scrapped and caniballized, but they aren't really of  size that I can use. I found a really big round piece of mild steel that was a cut-off from something else I built, which will do to get the 108 tooth gear from.--And---I have a big long piece of 2 1/2" diameter hot-rolled which will work fine for the 50 tooth gears that attach to the wheels.  In other news--Yesterday, on my "fat mans walk" I lost a pair of bifocal glasses. As soon as wife and I got home, I realized that I didn't have them, so we went back and walked the trail again looking for them, but no luck. I have put up a sign at each end of the trail explaining what I had lost and my phone number, in case someone else found them.--If not, I'm out $300. That would have bought me a lot of material for my hobby.
(https://imagizer.imageshack.com/img923/1219/qAHwsR.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on September 28, 2020, 06:24:01 PM
Okay---Here we go---hang on. The 2 1/2" round hotrolled has been cut off, to a sufficient length to give me two or three gears and a handle to hold in my rotary table chuck.  The large outer diameter has been turned to what the actual outside diameter of the gear will be. The smaller diameter is turned to a diameter that is smaller than the root diameter of the gear teeth to be cut, and long enough so that I don't run the gear cutter into the hardened chuck jaws. That will immediately ruin a cutter. Don't ask how I know this. The center has been drilled and reamed to 1/4", which is the diameter of the axles on my Trevithick.
(https://imagizer.imageshack.com/img924/5496/OUyn2z.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on September 28, 2020, 09:23:41 PM
I've just finished cutting the 50 tooth gears. A couple of things here worth mentioning. Any time I cut  gears, I try and make the gear blank a bit longer than necessary. That way I get the two gears I wanted, plus a "free-bee" that I can use on some future machine. I use the tailstock support, because the material is sticking out quite a long ways from the chuck. At the very front of the table, you will see two "table stops" that I set before I started cutting, so I can't run the cutter into the hardened chuck jaws nor into the tailstock support. Lastly, you can see that I used my cut-off tool in the lathe before I started cutting the gears. I cut just deep enough to be lower than the root diameter of the gear teeth. This avoids pulling burrs on all of the gear teeth, which happens if you wait until after the teeth are cut to part off the individual gears.
(https://imagizer.imageshack.com/img924/1276/epcp3E.jpg)
Title: Re: Trevithick
Post by: Craig DeShong on September 28, 2020, 09:42:49 PM
... so that I don't run the gear cutter into the hardened chuck jaws. That will immediately ruin a cutter. Don't ask how I know this.

I see that not only me, but Brian sometimes needs to learn the "hard way".  It's an expensive lesson to learn. :facepalm:

... Lastly, you can see that I used my cut-off tool in the lathe before I started cutting the gears. I cut just deep enough to be lower than the root diameter of the gear teeth. This avoids pulling burrs on all of the gear teeth, which happens if you wait until after the teeth are cut to part off the individual gears.

Ugh, why didn’t I think of that. :NotWorthy:  Thanks Brian.  Another great tip to “file away”.
Title: Re: Trevithick
Post by: Brian Rupnow on September 28, 2020, 09:58:13 PM
Thanks for saying "Hi" Craig---I'm following your very interesting project also. This is what I end up with. Two 50 tooth gears to go on the Trevithick, and one spare to be used on some future project. The centers will eventually be removed from these two gears and they will be attached to the wheels as shown on the 3D model, but for now they can stay mounted on the axles until I finish all the gears and see that they mesh properly.
(https://imagizer.imageshack.com/img923/4527/L3qVXx.jpg)
Title: Re: Trevithick
Post by: tghs on September 28, 2020, 11:15:46 PM
this popped up in my saved searches page  https://www.ebay.com/itm/Magic-Lantern-Slide-STEAM-ENGINES-NO6-THE-TREVITHICK-BOILER-C1920-PHOTO-INDUSTRY-/363122432870?&_trksid=p2056016.l4276
Title: Re: Trevithick
Post by: crueby on September 28, 2020, 11:39:06 PM
this popped up in my saved searches page  https://www.ebay.com/itm/Magic-Lantern-Slide-STEAM-ENGINES-NO6-THE-TREVITHICK-BOILER-C1920-PHOTO-INDUSTRY-/363122432870?&_trksid=p2056016.l4276 (https://www.ebay.com/itm/Magic-Lantern-Slide-STEAM-ENGINES-NO6-THE-TREVITHICK-BOILER-C1920-PHOTO-INDUSTRY-/363122432870?&_trksid=p2056016.l4276)
That is very interesting!  I wonder if it is a photo of a patent model, judging from the sign below it?
Title: Re: Trevithick
Post by: Brian Rupnow on September 29, 2020, 12:01:53 AM
It could be the Trevithick, but 1920 is over a hundred years after the Trevithick was built in 1805, so it could be anything.
Title: Re: Trevithick
Post by: crueby on September 29, 2020, 12:02:39 AM
It could be the Trevithick, but 1920 is over a hundred years after the Trevithick was built in 1805, so it could be anything.
Good point!!
Title: Re: Trevithick
Post by: ShopShoe on September 29, 2020, 02:03:10 PM
Too bad "The History Detectives" is off the air. (U.S. Public Broadcasting show that was on a few years ago where a team of researchers followed clues back to determine what an artifact actually was.)

In this case they could have obtained the lantern slide and followed back what is known about it to find where the boiler was displayed and how it might have been labeled.

My guess is that someone found this boiler (dug it up, from the condition) and matched it to what was known about the original Trevithick and put it on display. Hence the quotation marks.

Then one of the many firms that went around documenting things to sell image collections to users of magic lanterns photographed this display. There were a lot of firms doing this for magic lanterns and for stereoscopes. There may have been a catalog of the images originally that may still be archived somewhere or in a private collection.

(Editorial comment follows)

What is a shame is that a lot of artifacts, or primary-source documents related to those artifacts, are actually saved somewhere and not properly tracked so anyone can find them. I also feel sad that the rush to "digitize" everything sometimes results in someone making spur-of-the-moment decisions to destroy or discard parts of the record so what the future searchers for information can find are only a bunch of "pretty pictures" that no longer have the provenance or the context necessary to understand the past..........

ShopShoe
Title: Re: Trevithick
Post by: tghs on September 29, 2020, 02:39:02 PM
if look on the seller's other items he posting a good selection from what must have been a set on steam power,, "each slide has a set number" https://www.ebay.com/itm/Magic-Lantern-Slide-STEAM-ENGINES-NO32-RICHARD-TREVITHICK-PORTRAIT-C1920-PHOTO/363122432897?hash=item548bc89b81:g:bTMAAOSwEOhfYKVY
Title: Re: Trevithick
Post by: Charles Lamont on September 29, 2020, 02:57:02 PM
That is definitely an early Trevithick boiler, cylinder and crosshead. There were dozens of these stationary engines made in the early 1800's. 
Title: Re: Trevithick
Post by: Brian Rupnow on September 29, 2020, 07:35:51 PM
I've spent the morning preparing the 108 tooth gear blank. The gear as shown consists of outer rim, inner hub, and six spokes. If you can see it in the picture, the ends of the spokes are just below the root depth of the gear teeth. I'm going to use my new super duper TIG welder to weld the outer ends of the spokes to the outer rim, and fill the rest of the hole with filler rod up to the outer surface of the rim, which right now is 0.040" larger than the finished blank. Theory is that if the welding goes well, I will then machine off that extra 0.040" from the o.d. and machine the gear teeth. Then I will hold the gear by the i.d. of the rim, which is concentric with the outside of the outer rim, to finish drilling and reaming the center of the hub. In the background you can see that I have taken a piece of aluminum scrap and drilled it in three places for 1/4" diameter stub shafts to mount the finished 50 tooth and 36 tooth gears on to verify that they mesh correctly. (they do).
(https://imagizer.imageshack.com/img923/6280/tLfFcM.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on September 29, 2020, 11:59:47 PM
Everything went according to plan--Except, maybe the plan wasn't so good. The six 3/16" spokes have a lot of "give" to them. It becomes somewhat like trying to machine a sponge. Any pressure from the cutting tool and everything squirms all over the place. First I tried it without welding the spokes to the hub.--No good, in fact, terrible. Went back out to the main garage and welded the spokes to the hub on the side that doesn't show.--Marginally better, but kind of like trying to polish a turd. I will have a better idea tomorrow if I can save this or not, when I go to cut the gear teeth.
(https://imagizer.imageshack.com/img924/4323/pt2V72.jpg)
Title: Re: Trevithick
Post by: Craig DeShong on September 30, 2020, 12:57:04 AM
Well Foo Brian, I would have though you’d  be ok.  Maybe mount to a faceplate?
Title: Re: Trevithick
Post by: Brian Rupnow on September 30, 2020, 01:10:43 AM
After thinking about the time and work involved in cutting 108 gear teeth, I've decided not to run with this idea. The gear is stuck right out on the front of the engine, and I hate wobbling and orbiting gears and flywheels worse than snakes. Not certain right now what I will use as an alternate method to spokes, but  I will think on it and let you know.
Title: Re: Trevithick
Post by: Brian Rupnow on September 30, 2020, 02:36:58 PM
So, today we try for another kick at the can. My beautiful 108 tooth gear with spokes was not a good idea. Today we aim for something a little simpler, a gear machined from 1/4" mild steel plate with a bolt on hub and bronze bushing. At this point I have to say that I'm an incurable optimist.--I'm always sure that my parts are going to turn out beautiful, even when previous experience has shown me different. I have learned (over and over again) not to weld on things and expect them to stay true and square and symmetrical.
(https://imagizer.imageshack.com/img922/9117/IFrZDy.jpg)
Title: Re: Trevithick
Post by: sid pileski on September 30, 2020, 03:37:02 PM
Brian- isn't that gear another candidate for the water jet?
Make the file a little bigger than needed, machine true once you get it back, continue on with the gear cutting.

Seems pretty straight forward if your worried about milling out the spokes.

Sid
Title: Re: Trevithick
Post by: Brian Rupnow on September 30, 2020, 04:10:10 PM
Sid--You are absolutely right. I can't afford it. At least, I don't want to afford it. Dang, I wish I had a cnc machine and a water-jet cutter.
Title: Re: Trevithick
Post by: Brian Rupnow on September 30, 2020, 05:51:14 PM
Holey crow!!! Start over again with 1/4" hotrolled plate.
(https://imagizer.imageshack.com/img923/569/6IBvay.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on September 30, 2020, 06:26:02 PM
And more of the same, using the "EBVQ" method. (Eats blades very quickly).
(https://imagizer.imageshack.com/img922/4015/Ov5b4F.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on September 30, 2020, 09:24:12 PM
In this shot, the gear profile has been very roughly cut out on the bandsaw, and a hub is attached to it. This lets me grip the hub in my rotary table chuck, and machine the radiused area of the windows. The sides of the windows have not been machined yet, but that will be my next step.
(https://imagizer.imageshack.com/img923/9697/jaXsaA.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on September 30, 2020, 10:30:53 PM
Machining the sides of the windows was easier than I thought it would be. Once you move things around with the X and Y table controls and the rotary table until you have one of the window sides parallel, (I took 0.080" depth of cut until I was thru the 1/4" plate), then if you have 4 windows you can just advance the rotary table 90 degrees and you are ready for the next side.
(https://imagizer.imageshack.com/img922/475/rAIKYo.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on September 30, 2020, 11:13:50 PM
And finally, at the end of the day, the gear is ready to have it's teeth cut. This is about where I left off yesterday. It becomes pretty clear why people make large gears and flywheels with either solid webs or circular holes in the webs. It makes far greater economic sense to buy a flywheel casting or have a gear or flywheel water-jet cut. I still have "filing and fettling" to do on this gear but it is turning out like I had hoped.
(https://imagizer.imageshack.com/img924/3276/oEuq8k.jpg)
Title: Re: Trevithick
Post by: crueby on September 30, 2020, 11:19:30 PM
Great job on gear MkII - looks very good.
Title: Re: Trevithick
Post by: Art K on October 01, 2020, 03:29:57 AM
Brian,
It seems I got a few days behind and you've made a lot of progress in that time. I liked your term ebvq. I think most of us have done that. I had to machine a hole for a previous job. It was 12- 14 inches as I recall. The only tool they had to do this (don't remember what it was called) was a large bar that was held in the mill spindle with a single lathe style tool that could be adjusted to change the diameter. I had to cut it small and move it out to finished size. It was a time consuming nerve wracking PITA.
Art
Title: Re: Trevithick
Post by: Brian Rupnow on October 01, 2020, 04:04:13 PM
And that, my friends, is a beautiful thing. I have a new description of anxiety---It's that feeling you get when you've finished the 108th tooth and you move the rotary table one more step, and take a final pass to see if you are cutting metal or air. All went well.
(https://imagizer.imageshack.com/img923/8713/sH8tsS.jpg)
Title: Re: Trevithick
Post by: Twizseven on October 01, 2020, 05:09:38 PM
That looks very good Brian.  Lot of work to get to that point, but you got there in the end.  Have a  :DrinkPint:

Colin
Title: Re: Trevithick
Post by: Brian Rupnow on October 01, 2020, 08:39:53 PM
It's never quite as easy as I think it's going to be, but I like this. I tapped the side of the boiler and installed the big gear with a 3/8" shoulder bolt. Sid had commented that I should have used gears with a larger, coarser tooth, but I think this doesn't really seem that far out of proportion.
(https://imagizer.imageshack.com/img924/6845/j0O2BT.jpg)
Title: Re: Trevithick
Post by: crueby on October 01, 2020, 10:10:08 PM
Great result, watching along, this is a very different engine than I am used to seeing, which is great!
Title: Re: Trevithick
Post by: Brian Rupnow on October 01, 2020, 10:21:41 PM
Hi Chris--This is definitely a different kind of beast. Imagine--Trevithick came up with this machine 215 years ago. It wasn't a commercial success, but what a mind he must have had.
Title: Re: Trevithick
Post by: Brian Rupnow on October 02, 2020, 01:27:40 AM
Jason--I was just reading thru my build log, and I see that you questioned why I couldn't make gears with more than 108 teeth. That limitation was a result of headroom on my old smaller milling machine. Once the outer diameter of the gear got larger than 4.6" outside diameter I was getting interference between the gear blank and the underside of the "head" of the machine. With my new (kind of new) larger mill, I can cut a much larger gear if I wanted to. ---Brian
Title: Re: Trevithick
Post by: Brian Rupnow on October 03, 2020, 12:22:56 AM
I was hoping to post a short video of all the gears and flywheel turning, but I didn't quite make it. My butt is absolutely kicked for today. Tomorrow I'll put a set-screw in the flywheel hub and make a short video.  It has been a day long thrash here, but I'm happy with what I've accomplished.
(https://imagizer.imageshack.com/img922/9154/wd13tI.jpg)
Title: Re: Trevithick
Post by: Art K on October 03, 2020, 01:11:37 AM
Brian.
You've had a long hard day at the factory. Now you should sit back and relax with a pint!
Art
Title: Re: Trevithick
Post by: Brian Rupnow on October 03, 2020, 04:20:52 PM
And, as promised, here is a neat video of all the gear-train and flywheel in action.
yhfd7DwWXrQ
Title: Re: Trevithick
Post by: Brian Rupnow on October 03, 2020, 09:41:56 PM
After yesterdays hard slog, I wanted something a bit less critical to make today. A smoke-stack!!! Has to be visually appealing but no real finicky sizes and meshes involved. Good stuff!!! All I need on this end now is a faux burner door and a spigot to get my compressed air inside the machine.
(https://imagizer.imageshack.com/img924/896/IIv3sn.jpg)
Title: Re: Trevithick
Post by: Admiral_dk on October 04, 2020, 11:27:49 AM
It really starts to look like a Trevithick engine now Brian  :ThumbsUp:
Title: Re: Trevithick
Post by: Brian Rupnow on October 04, 2020, 01:27:55 PM
Thanks Admiral--it is beginning to come together.---Brian
Title: Re: Trevithick
Post by: Brian Rupnow on October 04, 2020, 07:59:09 PM
Today I had to make 4 temporary wheels for this thing. They are the same diameter and thickness as the finished wheels will be. I can keep track of where things should be and how to make dimensional allowances for it up to a certain point, and then I start to lose bits and pieces. This way keeps me on track, one less thing I have to be thinking of and remembering. These wheels were made from scrap pieces of 3/8" plate. Also, I machined an air inlet tube and screwed it into the back-plate just to the left of the smoke stack.  It is a cold, wet, and dismal day here and I'm about to head upstairs and lose myself in a good book.
(https://imagizer.imageshack.com/img924/9029/4XqdU6.jpg)
(https://imagizer.imageshack.com/img924/4986/gMAhzk.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on October 05, 2020, 03:08:15 PM
Before I can make any more progress, I have to back up a little and repair a problem. The elbows which feed air to my 4 way rotary valve are interfering with the inside of the "boiler" pipe. I have designed a new "close fit" elbow, and will be machining and installing a  couple of them today, so I can start working on the business end of my Trevithick.
(https://imagizer.imageshack.com/img923/5036/1N4aIM.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on October 05, 2020, 11:58:46 PM
This is the new "clearance style" 90 degree elbows finished. You will notice a small hole in the top of the right hand elbow. I didn't plan that. A dab of J.B. Weld will fix it. Tomorrow, assuming everything fits properly, it's almost time to turn my hand to the mechanism that operates the 4 way valve.
(https://imagizer.imageshack.com/img924/2291/NucMsg.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on October 06, 2020, 11:03:30 PM
Today was a day for fettling and fitting. The new elbows on the 4 way valve gave me the clearance I needed, so I was able to bolt the end with cylinder attached to the boiler.  I routed the air supply hose from the 4 way valve to the hose barb in the back plate, and routed the exhaust thru the backplate and into the smoke stack. The only new part  machined today is the arm attached to the bronze gear which sets on the flywheel shaft. I'm hoping that my local nut and bolt store has 3/16" shoulder bolts, which will attach the "connecting rods" to the new arm and to the flywheel. I'm thinking that the boiler would look a lot better with a flange at each end. I may buy some material to add a flange to each end of the the boiler.
(https://imagizer.imageshack.com/img924/7676/5R1NN3.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on October 07, 2020, 06:20:24 PM
Well Rats!!! Nobody in Barrie carries 3/16" shoulder bolts. I went a head and made my own, now I can connect my connecting rods to the flywheel and crank arm.
(https://imagizer.imageshack.com/img924/3483/whq1NE.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on October 07, 2020, 09:34:59 PM
If I had some 1/8" rod bent and threaded, I'd have connecting rods finished. The four brass ends are shown in place in this picture. I've got so much junk on top of my "assembly table" hat it's hard to see. Tomorrow I'll make and install connecting rods.
(https://imagizer.imageshack.com/img922/8925/IkUTIs.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on October 08, 2020, 05:38:09 PM
It's time for a change in my game plan. I had originally planned on using 1/8" diameter cold rolled steel round-bar with soldered brass ends for connecting rods. Tried that yesterday, but found that 1/8" is far too skinny and bendable. not going to work. Went out today and spent some of the Rupnow fortune on spherical rod ends. The con-rod diameter will now match the o.d. of the female rod ends.
(https://imagizer.imageshack.com/img924/9159/jZnZJK.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on October 08, 2020, 09:17:13 PM
Here we have the "heavy con-rod" on the non gear side, with a spherical rod end on each end. As things work out, the con rod on this side doesn't really need an offset, which is fine with me. Tomorrow I will work on the gear side con rod, which definitely will have an offset in it to clear the hub on the 108 tooth gear.
(https://imagizer.imageshack.com/img924/7971/MftsrC.jpg)
Title: Re: Trevithick
Post by: crueby on October 08, 2020, 10:40:25 PM
 :popcorn: :popcorn: :popcorn:
Title: Re: Trevithick
Post by: Brian Rupnow on October 09, 2020, 01:41:36 AM
Couple of things I should mention.-- That new con-rod is way too large in diameter, but it won't deflect under load, and once the engine is running it will be replaced with a smaller diameter piece.--And--I picked up a piece of material today large enough to create "flanges" for the ends of the boiler. I think that if these boiler "flanges" are added they will do much to make this model look more like the original Trevithick engine. It's a bit difficult to imagine with the 3D model being more colors than the rainbow, but I think it will look better.
(https://imagizer.imageshack.com/img922/8258/9keSFr.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on October 09, 2020, 09:56:31 PM
I couldn't stand how big and clunky a 1/2" diameter con rod looked. Today I made new con rods from  5/16" diameter cold rolled steel to replace the first one which was 1/2" diameter aluminum. Everything looks a lot more proportional now. Video to follow when my camera battery is charged.
(https://imagizer.imageshack.com/img922/7678/4bfq6u.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on October 10, 2020, 02:33:39 PM
This is a video of the Trevithick engine being put through all of it's mechanical paces. It is an extremely interesting engine to see working.---Brian
URKQz_K08UI
Title: Re: Trevithick
Post by: Art K on October 11, 2020, 03:58:59 AM
Brian,
Your Trevithick looks great a literal mechanical marvel. Unfortunate thing that the rails failed.
Art
Title: Re: Trevithick
Post by: Craig DeShong on October 11, 2020, 11:32:48 PM
Very interesting Brian, can’t wait to see it run.  It’s going to be a gangly looking thing with that cross head sliding in and out in front as it moves along!
Title: Re: Trevithick
Post by: Brian Rupnow on October 11, 2020, 11:39:16 PM
Sometimes the game plan changes in the middle of the game. I originally did not intend to have flanges at either end of the boiler. Last week I decided I actually did want them, as separate rings that I could slide over the ends of the boiler and attach with small bolts. The only fly in the ointment was that I had already dedicated the space at one end of the boiler to support a guide rod mechanism for the slider that moves the valve. Today, I turned up some plate on my faceplate to get a curvature identical to the o.d. of the rings (one of the rings is leaning against the headstock in the picture), and then welded the resulting pieces to the rings. My tig welding is improving, but it is not very artistic. So, at this point the pieces are welded to the rings, and the resulting welds are slathered with J.B. weld which won't be dry until tomorrow. When they have dried, I will work some artistic magic on them and then attach the rings to my boiler.
(https://imagizer.imageshack.com/img924/430/yzw05X.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on October 12, 2020, 04:17:40 PM
No real machining work this morning, but a couple of hours spent updating the 3d model to reflect what was actually built. Here you can see the heavier connecting rods and the updated boiler rings which have the guide rod supports built into them.
(https://imagizer.imageshack.com/img922/1558/Wq947w.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on October 12, 2020, 09:19:50 PM
Spent a very large part of the day working out tight spots and freeing everything up. This is a finicky kind of job, and it can't be done until everything is almost finished and assembled. Also got a start on the valve valve actuator rod. The two rings which go on the ends of the boiler are leaning up against the engine.
(https://imagizer.imageshack.com/img923/2066/mtTSNc.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on October 14, 2020, 12:16:08 AM
Elvis has not left the building. Elvis is up to his neck in adding the flanges to the boiler and adding the valve linkage. I really, really hate making changes part way thru a job. I can make it end up pretty, as if I'd planned it this way all along, but it adds a whole page to my frustrations list. Oh well, one end is finished. Tomorrow, who knows?--The canary may sing for me!!
(https://imagizer.imageshack.com/img924/4003/yposWV.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on October 14, 2020, 09:21:22 PM
Mechanically, I'm at about 99%. I can tell, after playing with it half the day, that it wants to run. It is proving very difficult to set the 4 way valve so that it reverses the action of the cylinder at the end of the stroke. I've about had it for today, but wish me luck for tomorrow.
(https://imagizer.imageshack.com/img923/8572/qta4zI.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on October 14, 2020, 11:06:06 PM
Game plan for tomorrow is to broach keyways in the flywheel, bronze gear, and crankshaft. Right now they are only connected with set screws, and the two offset pinions keep getting out of synch and locking things up.
Title: Re: Trevithick
Post by: Art K on October 15, 2020, 02:57:30 AM
Brian,
That makes a lot of sense so much of that thing is interdependent. Anything could throw off the whole works. What do you figure that Mr. Trevithick had the same problem timing the original?
Art
Title: Re: Trevithick
Post by: Brian Rupnow on October 15, 2020, 01:51:50 PM
Art--probably not so much. Mr. Trevithick's engine weighed over 5 tons. the members which made up his engine could take a bit of off-center loading and not even notice it.
Title: Re: Trevithick
Post by: Brian Rupnow on October 15, 2020, 05:51:53 PM
Keyways have been added to the flywheel, bronze gear, and to the crankshaft. It helps, but still doesn't let the engine get "over the hump" at each end of the stroke and continue running. Once an engine like this runs, it quickly wears down any "tight spots" and the longer you run it, the smoother it gets. Of course, the magic is in getting it to a point where it will run under it's own power. There really aren't any more changes I can do mechanically to get it running. This leaves me with two options. Make a bigger, heavier temporary flywheel to get it running, or hook it up to an electric motor and let it run for a couple of hours to get rid of any remaining tight spots. The electric motor method is the cheapest, since I don't have to buy any material, but this is not an easy beast to hook an electric motor to. I am going to call my metal supplier and ask about the price of a 8 1/2" square plate x 1/2" thick to make a much heavier flywheel.
Title: Re: Trevithick
Post by: Charles Lamont on October 15, 2020, 08:55:13 PM
Brian, I can think of a couple of things you could try before having to make a new flywheel. Have you yet got it to the state where it will rock backwards and forwards by itself through a (not quite) half turn?
Title: Re: Trevithick
Post by: Brian Rupnow on October 15, 2020, 09:48:16 PM
Too late Charles. Now you know how I spent my afternoon. This started life as a piece of 1/2" x 8 1/4" x 10" hot-rolled flatbar. There is no center hole in it yet, just a good center-punch mark. It has double sided tape on the side facing the lathe jaws and is held in place by a live-center in my tailstock. I cut the 4 corners off with my bandsaw and then spent the afternoon nibbling away at it until it is perfectly round. This method always works well for me, but you can only take about 0.010" depth of cut or the tape slips.  I'm not going to put a lot more time in this flywheel. Tomorrow it will get a centerhole and keyway and set screw, and have  a #10-24 thread put in 1 1/2" off center for the  shoulder bolt which connects the con rod. If the heavier flywheel does the job and makes the engine run, I'll worry about doing some cosmetic work on it later.(https://imagizer.imageshack.com/img923/1151/m8dVX3.jpg)
Title: Re: Trevithick
Post by: Charles Lamont on October 16, 2020, 07:54:31 AM
Too late Charles.
It's hard to keep up with you, Brian. So, have you got it to the rocking stage?
Title: Re: Trevithick
Post by: Brian Rupnow on October 16, 2020, 01:41:07 PM
I have it to the stage where the piston will go to one end, trip the 4 way valve, then travel back the other direction and stall out before tripping the valve to go the other way. that is why I'm trying a newer heavier flywheel
Title: Re: Trevithick
Post by: Brian Rupnow on October 16, 2020, 03:50:33 PM
Okay Charles---Big changes with the heavier flywheel. The flywheel is rocking back and forth like crazy between top dead center and bottom dead center under air pressure.  This is very promising. Based on what it's doing now, it should just require some adjusting of the valve actuators on the slide bar. I have just blown an internal hose and have to tear things down to reconnect it. Is there any kind of liquid glue that I can permanently glue the neoprene hoses to the brass or steel tubes on the 4 way valve ? I do have some small spring wire clips from the hobby shop, but at higher air pressure the hoses keep blowing off. Crazy glue sets up so quickly that I wouldn't have a chance to put some glue on the steel tubes and then slip the neoprene hoses over them. Is there something like a "delayed action" super-glue?
Title: Re: Trevithick
Post by: Charles Lamont on October 16, 2020, 05:46:47 PM
Brian, do you have barbs on the pipe ends? I think they would be more likely to hold the hose than glue.

If you still have trouble getting it to go over the dead centre, even with more pressure, then I suggest you have another look at my earlier posts:
http://www.modelenginemaker.com/index.php/topic,9902.msg225576.html#msg225576
http://www.modelenginemaker.com/index.php/topic,9902.msg225580.html#msg225580
I suspect that once you do get it to run, you may need a regulator (throttle valve) to stop it going into orbit.

Charles
Title: Re: Trevithick
Post by: crueby on October 16, 2020, 07:13:49 PM
I always need to turn barbs into the ends of the pipes for the plastic hose, then put either a hose clamp or for smaller tube I just twist some bailing wire around it.
Title: Re: Trevithick
Post by: Brian Rupnow on October 17, 2020, 12:03:56 AM
I learned three new things today. #1--There is a type of crazy glue that doesn't dry instantly--it gives you about 15 seconds between when it is applied and when it dries. This is enough time to coat a hose barb (actually a piece of 0.185" diameter brass tube) and slip a neoprene hose over it before it becomes absolutely immoveable.---If you're quick!!
---#2--If you have a bunch of air connections inside something else that requires an hours work to take it apart, then never, ever, ever use neoprene tubing  pushed onto metal tubes for connections.--Make them from metal tubing and solder them in place.
---#3---Engines which have wheels on them are as suicide prone as lemmings, which jump off cliffs into the sea. I've probably grabbed this damn thing out of the air half a dozen times today when it jumped off my desk. I haven't moved so fast since my wedding night.
Title: Re: Trevithick
Post by: propforward on October 17, 2020, 12:11:41 AM
That thing about Lemmings was a falsehood perpetuated by Walt Disney studios. Tell your engine! Maybe it will stay put.
Title: Re: Trevithick
Post by: crueby on October 17, 2020, 12:23:03 AM
Three very good lessons!    :Lol:
Title: Re: Trevithick
Post by: Brian Rupnow on October 17, 2020, 01:18:06 AM
Propforward--I knew that--but it fits the story I was telling.
Title: Re: Trevithick
Post by: propforward on October 17, 2020, 02:07:37 AM
I enjoyed it almost as much as following your engine thread. All good fun.
Title: Re: Trevithick
Post by: Robert Hornby on October 17, 2020, 03:54:20 AM
Okay Charles---Big changes with the heavier flywheel. The flywheel is rocking back and forth like crazy between top dead center and bottom dead center under air pressure.  This is very promising. Based on what it's doing now, it should just require some adjusting of the valve actuators on the slide bar. I have just blown an internal hose and have to tear things down to reconnect it. Is there any kind of liquid glue that I can permanently glue the neoprene hoses to the brass or steel tubes on the 4 way valve ? I do have some small spring wire clips from the hobby shop, but at higher air pressure the hoses keep blowing off. Crazy glue sets up so quickly that I wouldn't have a chance to put some glue on the steel tubes and then slip the neoprene hoses over them. Is there something like a "delayed action" super-glue?
I have found that keeping SUPER GLUE in the fridge provides two benefits. Firstly it seems to last quite a long time before "going off"  in the tube. I have had it last 2 months. Secondly when using it I have a bit more time to position/adjust the components before it sets, say around 15 seconds rather than instant.
Robert
Title: Re: Trevithick
Post by: Brian Rupnow on October 17, 2020, 03:05:33 PM
After a full day of fixing disconnected tubing and taking things apart and then putting the parts all back together again, it was time for some analysis as to what was happening. Right now, as things set, the valve is set so that it is fully opened at the end of the piston stroke in either direction. Now, in a perfect world, where the flywheel really was doing it's job, the inertia of the flywheel should carry the crankshaft "over the top" before the piston begins to travel in the opposite direction. Since the flywheel is bouncing back and forth between the top and bottom dead center, the conclusion is that the valve is being actuated just a tiny bit too soon. If the opening was delayed for another millisecond, the crankshaft would have that space of time to get "over the hump" and  make complete revolutions rather than bouncing back and forth thru partial rotations.  So yes Charles, I do agree with what you are saying and what you show in your diagram.  With everything "as designed", I can adjust the sliders so that the valves begin to open a bit later in the cycle, which in theory mean they would close a bit later in the cycle. That would be a "best case" scenario. If that doesn't work, then as Charles suggested, shortening the radius arm on the valve would allow the valves to operate closer to the end of the piston stroke and hopefully allow the flywheel to get "over the hump" before travelling back in the opposite direction. I have the capacity with my current design to shorten up the radius arm with no other changes.
Title: Re: Trevithick
Post by: Brian Rupnow on October 17, 2020, 06:42:00 PM
Bah!! Humbug!!--The easy fix (repositioning the valve actuators)  didn't work. I have never had an engine so close to running that didn't actually take off and run. I can see a number of things which I could do to fix this, but they are all progressively more and more difficult. The next easiest fix is to shorten the radius arm on the valve. Of course this will make for an extended  cantilever on the sliding brass actuator. I have a small (3mm) ball bearing that I think I can work into the equation to take a bit more friction out of the valve action. Oh well, thanks to Covid there is damn all else to do anyways.
Title: Re: Trevithick
Post by: Charles Lamont on October 17, 2020, 08:53:56 PM
So far we have only ever had the Catch Me Who Can replica at Bridgnorth running jacked up, as a stationary engine. (I am hoping to get back to work on the brakes in the next couple of weeks.) In that state it will run down to about 20 rpm, and we have had it do so on as little as 5 psi. The limiting factor is not so much the valve advance as lifting that hefty crosshead over the top. In this it is helped by our use of 'modern' wheel and tyre standards rather than the much lighter ones Trevithick would have had. Each of our driving wheels weighs in at over half a ton, so they act as pretty good flywheels. Even so starting takes a bit of practice to avoid the backwards and forwards rocking motion that Brian has at the moment. On the road it will be quite different. The all-up weight is going to be not far short of 9 tons, and that amount of inertia should smooth out the low-speed motion a lot.

Brian, connecting the wheels up and putting the engine on the floor might help a bit, especially if you could fill the 'boiler' with lead. 
Title: Re: Trevithick
Post by: Brian Rupnow on October 17, 2020, 09:08:38 PM
Charles--I'm just trying to get the engine to run without having any of the gears in place.(except for the one on the end of the crankshaft.) In the next five minutes I'm going to start making a shorter radius arm on top of the valve.
Title: Re: Trevithick
Post by: Brian Rupnow on October 17, 2020, 11:55:58 PM
Charles---A little math for you.  The radius on the arm which sets above the 4 way valve was 0.900" long. I shortened it to a radius of 0.775" long. If you assume that the included angle is 90 degrees then the chord length of the smaller radius is 13 % less than the chord length of the larger radius. Will it make a difference in how the engine responds?---I don't know. I have made the new pieces but haven't installed them on the engine yet. That will be tomorrows job. ---Brian
Title: Re: Trevithick
Post by: Charles Lamont on October 18, 2020, 07:09:05 AM
Charles---A little math for you.  The radius on the arm which sets above the 4 way valve was 0.900" long. I shortened it to a radius of 0.775" long. If you assume that the included angle is 90 degrees then the chord length of the smaller radius is 13 % less than the chord length of the larger radius. Will it make a difference in how the engine responds?---I don't know. I have made the new pieces but haven't installed them on the engine yet. That will be tomorrows job. ---Brian
Qualitatively, yes, it should make some difference. To do timing diagrams one would also need to know the piston stroke and details of the valve and ports. But timing diagrams won't tell you if it will run anyway. Today I am off to Bridgnorth and will see our replica for the first time since the start of viral lockdown. 
Title: Re: Trevithick
Post by: Brian Rupnow on October 18, 2020, 04:08:22 PM
Wco5RXN3cXcThis is my Trevithick engine doing something I haven't seen before. It has a unique 4 way valve mounted on top of the boiler, and the valve swings back and forth under the influence of the sliders which contact the valve arm. I don't have things set up quite right yet, so the engine is "stuttering"---The valve is being reversed before the piston gets far enough in it's linear travel to get the crankshaft over dead center and complete a full revolution. This is not what I am ultimately aiming for, but I hope that with some adjustment to the sliders I can coax it into full revolutions.---Brian
Title: Re: Trevithick
Post by: crueby on October 18, 2020, 05:29:25 PM
As is, it would make a good sawing motion, but hopefully there is a sweet spot on the slider rings.
Title: Re: Trevithick
Post by: Charles Lamont on October 18, 2020, 06:10:05 PM
COOL!
Title: Re: Trevithick
Post by: Charles Lamont on October 18, 2020, 06:21:32 PM
That seems well short of going over dead centre, with about another 30° of crank rotation to go at each end. I would like to see the valve and port dimensions, but for now I suggest gradually spreading the tappets further apart. This will delay the valve motion, but of course if you go too far the ports won't open enough. It looks as though the valve is not going through a full 90° anyway. If not, strangely, spreading the tappets a bit might give more valve movement.
Title: Re: Trevithick
Post by: Jasonb on October 18, 2020, 06:42:51 PM
Brian, looks like you are well on your way to your next project of a steam saw ;)

Title: Re: Trevithick
Post by: stevehuckss396 on October 18, 2020, 07:30:45 PM
I have no doubt that you will get it squared away and running slicker than spit on a door knob.
Title: Re: Trevithick
Post by: crueby on October 18, 2020, 08:10:07 PM
Brian, looks like you are well on your way to your next project of a steam saw ;)

Ooh, love that saw! Do you know what model/plans it is? Your build?
Title: Re: Trevithick
Post by: Brian Rupnow on October 18, 2020, 11:21:37 PM
I've tried all of the tricks in the "Rupnow Magic Hat" and I am not able to get this thing to run using the 4 way valve. It is one of those engines that wants to run so badly that you can almost taste it, but it isn't happening. I have tried all of the different settings that I can think of, and have pinched my fingers so badly that I cried like a baby, but this just isn't going to run for me. This is not to say that the project is abandoned--Just that it isn't going to run with this 4 way valve. I can salvage most of the parts and make a Trevithick engine that runs with a more conventional slide valve. I hate to admit that I haven't been able to get this to work, but I have tried everything I can think of. Weirdly enough, I can make the model look more like the original Trevithick by using a conventional slide-valve than I could of if the 4 way valve had done the job.
(https://imagizer.imageshack.com/img923/8941/i8oJXi.jpg)
Title: Re: Trevithick
Post by: crueby on October 19, 2020, 03:39:20 AM
Thinking through the valve motion, and remembering some things from the videos of the full size engines - had an idea. The way the driver had to manually run the valves during startup makes me wonder - if the motion of the piston rod and the slider is not quite enough to run the valve all the way to admitting steam in the other direction, but it depends on the speed of the hit from the tappet to drive the valve farther along to open the steam port in the other direction.... That would give you just that little bit of lag in the operation of the valve to let the crank go past the TDC/BDC positions....
Does that make sense? Need to go back and watch the video of the reproduction full size engine again to see the stopping point of the slider/tappet against the valve crank.
 :thinking:
Title: Re: Trevithick
Post by: Jasonb on October 19, 2020, 08:19:41 AM
Ooh, love that saw! Do you know what model/plans it is? Your build?
[/quote]

It's one of Torsen's designs, though photos not showing at the moment
https://www.ts-modelldampfmaschinen.de/gussteilesaetze-modelldampfmaschinen/modelldampfmaschine-dampfsaege.html
Title: Re: Trevithick
Post by: Zephyrin on October 19, 2020, 09:27:46 AM

I would say that the valve is not involved in this reciprocating movement, but it seems to me from the video (post #204), that it's the stroke of the connecting rod that is too big for the length of the cylinder...and can't go through the dead points. With a shorter piston or a shorter crank it will do it ...

I like the mood of your posts, very pleasant to read, thanks to share.
Title: Re: Trevithick
Post by: Brian Rupnow on October 19, 2020, 03:39:20 PM
Boys, we're going to start down a new path today. I'm very disappointed that I didn't get this engine to run with the 4 way valve and I really, truly thought that I would. Ah well, so much for unbridled optimism.  The change of course is going to involve a more conventional steam slide valve on the cylinder. Due to restrictions based on everything having to fit inside the boiler, I am going to have to gear the crankshaft to a "camshaft" and mount the eccentric strap and eccentric on the camshaft. (it will revolve at the same speed as the crankshaft.) This means that the steam-chest will hang from the underside of the existing 3/4" diameter x 3" stroke cylinder, similar to the way it did on the Stephenson's Rocket. I will be getting rid of all of the exterior valve control rods and guides, and the rings with built in rod guides will revert back to being just simple rings around the ends of the boiler. The only visible difference is going to be at the smoke-stack end of the engine, where it will be possible to see the extra set of gears to operate the cam shaft, and different method of mounting the crankshaft and cam shaft. If this sounds like a lot of extra work, well, yes, it will be.-However, it's Covid time. Can't visit friends, can't go out for entertainment, can't even see my grandchildren nor take out good-wife for a restaurant meal. I'm just happy to have something fun to do!!!
(https://imagizer.imageshack.com/img922/5900/UtY65M.jpg)
(https://imagizer.imageshack.com/img923/2415/TTqvnN.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on October 19, 2020, 08:21:52 PM
Just finished the big three hour "clean-up, slick-up, put all my tools away in the correct place" dance. I try and put my tools away as I use them, but when I get into the final lap of building something I get so excited that nothing gets put away properly. When I walk into my little machine shop and the floor "crunches", I know that it's about time for a sweeping and vacuuming.  My apologies to everyone who hoped to see this run with the 4 way valve.---I did too. My apologies to anyone who I may have snapped or snarled at on the forums. I'm not normally like that. This project hasn't stopped. Very little of my work will be lost, even the cylinder will remain the same. The 4 way valve gets tossed, and I gain a cam shaft and conventional slide valve to control the cylinder. Don't go away please. There is more to come, and I promise, it will be interesting.---Brian
Title: Re: Trevithick
Post by: Brian Rupnow on October 19, 2020, 11:18:58 PM
Two 25 tooth gear blanks turned and that's all she wrote for today. O.D. and hubs are turned to size from 1144 stress proof steel. Center hole has been drilled and reamed to 5/16" diameter. Next time you see them they will have teeth cut and be mounted in place.
(https://imagizer.imageshack.com/img923/4623/DJ0WDn.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on October 20, 2020, 03:34:30 PM
Doing something a bit new and different. Normally, when steam-chests are used with a cylinder they are either both machined as one part from the same piece of material or soldered together, and all of the steam passages are internal inside the walls of the cylinder. In my case, I am retrofitting a steam-chest onto a cylinder which was previously operated by my 4 way valve. The steam lines are going to be external to the cylinder. I will solder brass "hose barbs" into the steam-chest and run flexible neoprene lines from the steam-chest to the cylinder ports. ( I know I cautioned against doing that but needs must.) I have never seen that done, but I can't think of any reason that it won't work.
(https://imagizer.imageshack.com/img924/3049/47oWRt.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on October 20, 2020, 09:43:08 PM
It feels like I must have been taking "slow pills" today. I managed to work all day and make only one part. This is the sub base for the new slider valve. The four shcs in the corners attach it to the cylinder. The four tapped holes are where the steam-chest bolt to it. The tapped holes in the ends are drilled galleries that needed to be plugged after the fact, so they were tapped and #10 set screws threaded in to act as plugs.   There will be three tubes soldered into the block, two on one side and one on the other side.
(https://imagizer.imageshack.com/img923/4804/olhlxL.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on October 21, 2020, 06:26:02 PM
So far today, I've got a stem-chest and a steam-chest cover. I might have the internal slider by the end of the day. I'm anxious to see this controlling the cylinder.
(https://imagizer.imageshack.com/img924/1064/FEUrWc.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on October 22, 2020, 12:12:23 AM
I did finish all of my slide valve business today. This is the slider, the nut, and the actuating rod. The brass steam-chest is not shown in this picture, because I managed to drill four holes in the wrong place. The holes are not in a critical area, and brass is about the same price as gold around here, so they have been filled with J.B. Weld and the steam-chest has been set aside to cure for 24 hours.  Tomorrow I will make the eccentric and it's mount.
(https://imagizer.imageshack.com/img924/4069/QDYdwB.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on October 22, 2020, 01:59:32 PM
Last night I lay in bed reviewing what I had done yesterday, and came to the realization that I needed to get steam (air) into the new steam-chest. It already has 3 outlet tubes--One to go to the front of the cylinder, one to go to the rear of the cylinder, and one to go to exhaust. This morning I added an inlet tube to the steam-chest cover.
(https://imagizer.imageshack.com/img923/2433/2rHWCs.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on October 22, 2020, 04:17:39 PM
Okay, we are back up and headed for assembly. One trick I'd like to show. In the center of the brass steam chest you will see two .093" reamed holes. Dowels will fit thru them into 0.093" holes in the adapter plate below, (or it could be into a cylinder). They will not extend up beyond the top of the steam-chest. Why are they there?---Because, when you are setting these engines up to run, it is very important to know just where that slider is in regard to everything else. If you take off the steam-chest cover so you can see the slider, then it all falls apart in your hands and you lose all track of where the slider was in reference to the steam chest. With these dowels in place (loctited into the adapter plate or cylinder) you can remove the steam-chest cover plate and the steam-chest remains in place, so that you can see where the slider is in regard to the steam-chest.
(https://imagizer.imageshack.com/img924/4980/uNvfb2.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on October 23, 2020, 06:54:55 PM
Today we have something to show. I have removed the 4 way valve which I copied from Trevithick's original engine ( I couldn't get the engine to work with that valve on it), and replaced it with a more conventional slide valve which will be driven by an eccentric cam on a countershaft, which is driven at 1:1 ratio by the crankshaft. The attached video shows the operation of the cylinder when I manually move the slide valve control rod with a pair of pliers. This is very encouraging, and I will now move on to the countershaft and eccentric which attach to the engine end-plate right below the crankshaft. The air hissing noise you hear is due to the fact that I haven't lapped the face of the slider to the steel adapter plate it slides on yet. Sometimes you get lucky and don't have to do that, other times you do.
(https://imagizer.imageshack.com/img923/334/eqvZpe.jpg)
kWgNeR_SWhQ
Title: Re: Trevithick
Post by: Brian Rupnow on October 24, 2020, 02:05:57 AM
The way that the 1/8" control rod attaches to the brass slider is somewhat complex. The rod is threaded into a rectangular "nut" that "floats" inside the towers on the back side of the slider. It has to be a tight enough fit that the nut doesn't rattle around, but loose enough that it doesn't bind on the slider. If it does bind at all, it may be enough to keep the face of the brass slider from making a perfect seal against the steel face with the ports milled into it. This can be one cause of air escaping past the slider. That is easily  corrected by a little creative file work on the nut or the slider.---or---It could be passing air because the face of the slider wasn't lapped against the steel. I find that I don't generally have to lap the faces, and if it is only a very small air leak, then running for half an hour will generally correct any differences in the faces. That video was made about five minutes after I had first assembled things and they were operating okay.  I will do a bit of detective work tomorrow and see what is causing the air leak.---Brian
Title: Re: Trevithick
Post by: Brian Rupnow on October 27, 2020, 04:07:09 PM
Today I completely disassembled the slide valve on the cylinder, and lapped both mating surfaces on a sheet of glass, beginning with 400 grit and finishing with 600 grit. It worked !!  I have never had to do that before on any of my engines. It's one of the ten thousand things I know about but haven't actually done before. The air leak is gone---or at least so gone that it is no longer audible.---Brian
Title: Re: Trevithick
Post by: Brian Rupnow on October 27, 2020, 06:58:36 PM
You don't have to be crazy to work here---but it helps!! Actually, what you see here is setting up the motor to run without the boiler. Since I can't get at any of the valve linkage when it is all inside the boiler, I will set everything up here and make all the adjustments required, then tear it down and reassemble it inside the boiler. --Sorta kinda like building a ship in a bottle.
(https://imagizer.imageshack.com/img924/2474/eYcxS4.jpg)
Title: Re: Trevithick
Post by: crueby on October 27, 2020, 07:09:34 PM
Getting close, looking forward to seeing the TreviBrian engine going!
Title: Re: Trevithick
Post by: Brian Rupnow on October 28, 2020, 05:23:49 PM
All things cometh to he who waiteth---If he worketh like Hell while he waiteth!!! This is the Rupnow-Trevithick engine on it's very first run with the new slide valve. The 1 1/4" square aluminum bar and the two vices are there just to hold the end-plates securely so that I can run the engine without the boiler in place in order to make adjustments. I think my waterjet cut flywheel is too light, but I can alter that. It is very gratifying to me to see this engine run for the first time.----Brian
BhVR7tLgEJ8
Title: Re: Trevithick
Post by: propforward on October 28, 2020, 05:50:40 PM
Nice work Brian, great runner!
Title: Re: Trevithick
Post by: crueby on October 28, 2020, 06:56:57 PM
Great runneth!   :ThumbsUp:
Title: Re: Trevithick
Post by: Craig DeShong on October 28, 2020, 09:15:00 PM
 :ThumbsUp:  :popcorn:  :popcorn:

Wow!  Nicely done.  Anyone standing in the track is going to take a thrashing just before they’re run over   :Lol:
Title: Re: Trevithick
Post by: Brian Rupnow on October 28, 2020, 09:52:22 PM
Hi Craig--I feel a bit like I've taken a thrashing myself just getting to this stage. Some engines just go together and run without a lot of drama. This one has been ahhh---difficult. It's going to look neat when I'm done, and I think I'm going to paint this one like I did the Stephenson's Rocket, but a different color.---Brian
Title: Re: Trevithick
Post by: Mike Bondarczuk on October 29, 2020, 10:45:16 AM
Hi Brian,

Have been watching this build from the outset and despite some initial stumbles you have persevered and finally arrived at a working solution, so full kudos for all of your efforts and also the descriptions of the various steps.

I shall be starting a build of one of your earlier works which is the simplified beam engine I believe based on Julius's drawings.

Mike
Title: Re: Trevithick
Post by: Brian Rupnow on October 29, 2020, 02:24:25 PM
Hi Mike--Good luck with the engine. it was based on an Elmer Verbourg design.---Brian
Title: Re: Trevithick
Post by: Brian Rupnow on October 29, 2020, 08:13:39 PM
Todays game plan got changed a bit. My waterjet guy was able to make my two steel rings yesterday afternoon, so today I drove over and got them, brought them home, drilled and tapped them and mounted them to the existing flywheel. It's been a cold dreary, rainy day here, but I was glad to get out of the house for a while. The flywheel was originally a piece of 3/16" mild steel plate. I have added a 1/8" steel plate to each side of the rim to make it a little heavier, in hopes that this will let me run the engine slower.
(https://imagizer.imageshack.com/img923/818/0ikNZQ.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on October 29, 2020, 08:29:58 PM
This video shows the engine running with the extra plates added to the flywheel. I'm very happy with this result. The engine will run much slower now.---Brian
Bwn5rP4Oxwo
Title: Re: Trevithick
Post by: crueby on October 29, 2020, 08:33:57 PM
Very good!!  I wonder what it would do with the same pressure but putting a needle valve inline just before the steam chest to restrict the flow - have gotten good results with that on some engines to slow them even more.
 :popcorn: :popcorn: :popcorn:
Title: Re: Trevithick
Post by: Brian Rupnow on October 29, 2020, 09:42:39 PM
There are two ways to control the speed of these engines. One is to control the pressure like I am doing. The other way is to hold a high pressure and control the volume of flow with a needle valve. I think the high pressure and needle valve give more control. I have a bank of needle valves here that I used at a steam show to control a bunch of engines about 8 years ago. I may try running my feed hose thru that and see what the results are.
Title: Re: Trevithick
Post by: gbritnell on October 29, 2020, 11:24:50 PM
Brian,
What you have to understand is that if you took any locomotive off of the tracks and ran the engines they would do the same thing, run fast! The flywheel affect is the motion of the locomotive moving on the rails. Steam/air is applied, the piston/wheels start to move and the inertia of the machine takes it past dead center. When we think of flywheels on a steam engine we are generally associating that with stationary engines. I'm not saying that a heavier flywheel wouldn't assist the inertia but I don't think it's truly needed for this application.
gbritnell
Title: Re: Trevithick
Post by: Brian Rupnow on October 30, 2020, 12:07:41 AM
George-I agree with you.---But--this locomotive is never going to run on a track. It will ultimately be a "shelf queen" like my other engines. It may set on a short pedestal so that it can be ran with the wheels slightly "in the air" for demonstrations, just to see all the neat gears meshing.-So for that, it really does require the flywheel. I like my engines to run slowly when I demo them. ---Brian
Title: Re: Trevithick
Post by: Art K on October 30, 2020, 01:28:43 AM
Brian,
Your Trevithick looks really good, the flywheel's extra mass does seem to help slow it down. Great work!
Art
Title: Re: Trevithick
Post by: Charles Lamont on October 30, 2020, 08:43:19 AM
Good to see you finally have something running.
Title: Re: Trevithick
Post by: Brian Rupnow on October 30, 2020, 07:21:08 PM
Making progress here, one gear at a time. This morning I  reassembled the engine inside the boiler, and added the large gear on the side. Nothing is ever quite the same when you move an engine like this, so all of the battles I fought to get the engine running on my desk were repeated to get it running inside the boiler. I have the heavy flywheel on there for set-up but will eventually put the smaller water-jet cut flywheel back on. I just hung the big gear on there to see if the engine noticed any difference in the load, but the engine didn't seem to care whether the gear was there or not.----Brian
BtyPYOiTpGw
Title: Re: Trevithick
Post by: Brian Rupnow on October 31, 2020, 06:07:02 PM
So, here we are!!! Everything goes round and round and up and down like I had planned. I still have to make proper wheels for this thing, and connect the gears to the wheels so the axles will be driven in the finished version. I have a nice color scheme in mind for it. I am really pleased with the results at this stage of the game.---Brian
AG3fBiSYUPo
Title: Re: Trevithick
Post by: crueby on October 31, 2020, 06:51:28 PM
Terrific motion, great!
Title: Re: Trevithick
Post by: Brian Rupnow on October 31, 2020, 09:22:54 PM
Had a visit from three ghostly characters this afternoon. My grandchildren are all getting older. I'm glad they still come across town to Grandpa's house for a visit.
(https://imagizer.imageshack.com/img923/3181/qxTHRo.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on November 01, 2020, 06:26:37 PM
Not really a lot left on the "build" of this engine, but I still had to contend with the hole in the top of the boiler that the actuator arm for the 4 way valve (that I couldn't make work) stuck up through.  I decided that the perfect answer to that hole would be a "steam dome". Steam domes are marvelous things. They can be anything that your fertile imagination wants them to be---a safety valve, a pressure indicator, a speedometer. Most living people under 60 years of age have never actually seen a steam engine. I've been fighting a mild flue all week so I think I'll spend the rest of the day on my couch with a good science fiction book.---Brian
(https://imagizer.imageshack.com/img924/9894/qlyhXa.jpg)
Title: Re: Trevithick
Post by: Craig DeShong on November 01, 2020, 09:32:20 PM
So, here we are!!! Everything goes round and round and up and down like I had planned. I still have to make proper wheels for this thing, and connect the gears to the wheels so the axles will be driven in the finished version. I have a nice color scheme in mind for it. I am really pleased with the results at this stage of the game.---Brian
AG3fBiSYUPo

 :pinkelephant:  :cartwheel:     :cheers: congratulations!  Nothing like seeing all your effort pay off in a well running model.
Title: Re: Trevithick
Post by: Brian Rupnow on November 01, 2020, 10:08:03 PM
Thanks Craig--I'm really chuffed!!!---Brian
Title: Re: Trevithick
Post by: Art K on November 01, 2020, 11:31:53 PM
Brian,
Your Trevethick engine runs really well. That is something to be chuffed about!
Art
Title: Re: Trevithick
Post by: Brian Rupnow on November 02, 2020, 09:12:53 PM
Today I'm doing much the same as Crueby---Making wheels with cut-outs in the face. My approach is a bit different, but worth posting a shot of. I have to make four wheels that are identical in the cut out areas, bores, and outer diameters.  I used a caliper and compass to lay out the diameter of the wheels on a sheet of 1/2" thick aluminum, cut out four rectangles, drilled and reamed on center and pushed a size on size rod thru  the holes to keep everything centered, then ran bolts thru two opposing corners (which will become scrap), then stacked all four plates together in my machine vice to drill all of the holes in at once. That way I only have to do the set-up once. Next trick will be to separate all of the plates and cut the corners off, then turn to size in my lathe.
(https://imagizer.imageshack.com/img922/1175/btWFPC.jpg)
(https://imagizer.imageshack.com/img923/449/hTqnUZ.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on November 02, 2020, 11:58:45 PM
This shows the material that will be cut out of the four wheels. The material is 1/2" thick aluminum. Two of the wheels are only going to be 5/16" thick. The two wheels which have gears mounted on them will be 0.408" thick. My next step will be to cut off all of the outer corners and then turn the wheels to be round. Then I will grip them by the round outer rim with my 3 jaw lathe chuck and thin them down to finished thickness and open the center hole out to a finished diameter of 1/4". The windows will be cut out after the wheels are thinned down.
(https://imagizer.imageshack.com/img922/1060/5dAjoQ.jpg)
Title: Re: Trevithick
Post by: crueby on November 03, 2020, 12:16:18 AM
Nice setup!  Unusual to have a 3-spoke wheel - were the originals like that?
Title: Re: Trevithick
Post by: Brian Rupnow on November 03, 2020, 01:32:10 AM
No, the originals were multi spoked like the wheels on the Stephenson's Rocket. I decided to make them three "spoked" because I haven't done very much of this "window cutting"  and I needed the experience. The multi spoked wheels on the Rocket were made of steel so I could weld all of the spokes. These wheels are made from aluminum, and I don't have any experience welding aluminum.
Title: Re: Trevithick
Post by: Brian Rupnow on November 03, 2020, 09:49:49 PM
And we spent a goodly portion of the day on my lathe, making shiny wheels. The two wheels on the right which have raised bosses on the face are the ones which the gears attach to. The wheels are finished now except for cutting the windows in tomorrow on my mill and rotary table.
(https://imagizer.imageshack.com/img923/120/gqrjVO.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on November 04, 2020, 09:56:07 PM
That went well!!!  I still need to do a bit of hand filing, but very little. These four wheels are straight off the rotary table with no other work done on them. Putting in the windows was not difficult, but was time consuming.
(https://imagizer.imageshack.com/img924/9700/E5cTvV.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on November 05, 2020, 09:52:09 PM
I have reached the end. The engine runs very well, and is completely finished mechanically. I started this "design and build" on the last week of August, so it has been about a ten week job. My next step will be to paint the engine and then it goes up on the shelf with all of my other engines. Thank you very much to all of the people that had a look, and thank you for the comments that were made as I progressed with the build. I hope you enjoyed it.---Brian
mSDcE8Jfn2g
Title: Re: Trevithick
Post by: stevehuckss396 on November 05, 2020, 10:56:23 PM
Nice Job! Cant wait to see it in paint.
Title: Re: Trevithick
Post by: Craig DeShong on November 06, 2020, 12:01:34 AM
Very nice Brian
Title: Re: Trevithick
Post by: Art K on November 06, 2020, 03:02:55 AM
Brian,
It looks great, runs great. Glad to have been along for the trip.
Art
Title: Re: Trevithick
Post by: Brian Rupnow on November 12, 2020, 05:22:34 PM
A stinky business!!!--Wish I could have done this painting a month ago when it was warmer outside. As things set, I open my big garage door, set out all the stuff to be spray painted, paint it, then move everything into my machine shop so it will dry enough for a second coat. This comes out to four trips into and out of the garage (2 coats on each side). My house smells like a body and paint shop. I am fortunate to have a very understanding wife!!!
(https://imagizer.imageshack.com/img922/324/KdbOZU.jpg)
(https://imagizer.imageshack.com/img922/6775/hl9n0n.jpg)
Title: Re: Trevithick
Post by: Brian Rupnow on November 14, 2020, 04:38:11 PM
So, the Trevithick is completely finished. The painting was finished 3 days ago, and it was all reassembled this morning and posed for some "beauty shots". I had a few issues with this build which involved the cylinder and the 4 way valve, but in the end I used a more conventional slide valve and finished with a well running engine. Thanks for riding along with me, and saying 'Hi" once in a while. It is a very pretty engine, and now it will go up on my shelf to the place of honour along-side the Stephenson's Rocket.---Brian
(https://imagizer.imageshack.com/img922/8053/ZPoTER.jpg)
(https://imagizer.imageshack.com/img922/1774/5GDdtD.jpg)
(https://imagizer.imageshack.com/img923/2339/puCcCM.jpg)
(https://imagizer.imageshack.com/img924/9980/srQKaa.jpg)
(https://imagizer.imageshack.com/img922/7171/83DUft.jpg)