Model Engine Maker
Engines => From Kits/Castings => Topic started by: Florian Eberhard on November 04, 2012, 05:16:55 PM
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Well, I wasn't very active in the last time. That's because of my studies (mechanical engineering; 5th semester now...)
However, I started a new project this summer.
I recently ordered a set of castings for the Stuart steam driven boiler feed pump and well, I started machining and now and then I find some time to continue...
How I received the set (I think my dealer added some more hex material)
The First part to be machined was the upper pump body.
It wasn't easy to do everything only with the lathe, for example here, I first cut a thread into the stub, where the water will come out later. That Way, I was able to machine the outside of the stub to be able to make threads later...: (The internal thread was drilled out later)
Finally, the flange to the lower part of the pump body was finished.
Then I took the lower pump body and the first thing that happened was that I found some bubbles. Well, I bored away all of the material with bubbles and solderd in a piece of gunmetal...
Afterwards, I drilled out the pump cylinder and finally reamed it to size. To machine the outside of the cylinder, I fixed the cylinder on a mandrel and took it in the lathe using a collet. (The mandrel actually is a cylindrical pin and has a quite tight fight in the Pump body. Additionally, I fixed it with some superglue.):
So much for now...
Cheers Florian
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Hey I have a set of these 8). I'll be watching with great interest.
Jo
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I've got some more Progress pictures ;) :
After the pump cylinder outside, I faced down the flange which connects the lower and upper part of the pump body:
Next step was to machine the stub on the suction side of the pump. Unfortunately, there was a small bubble in there as well and finally crashed the drill bit. I then had to repair the stub. I machined it off and made a new one out of gunmetal. That stub was soldered to the pump body with silver solder (second soldering operation on the same part :insane: )
That worked out pretty well and I continued with making studs to hold the two parts of the pump bodys together. Yes, all the hardware is being delievered but I only have metric threading tools and so I decided to make all the required screws and nuts by myself. You can also see that instead of a gasket, I am using an O-ring to seal the connection between the two parts.
Finally, I have put everything together and there we are now.
Next part coming up as soon as its written...
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After almost finishing the Pump body (I need my milling machine to finish it...), I continued with the Pump base.
I first made the Pump end planar with a file and also brought it into a square angle with the supporting face. Then, the center was marked on the opposite side (Steam cylinder side) to set the part on the faceplate. I had to use a piece of steel to bridge the bore in the center of the faceplate.
With the center marked, I drilled a hole with 8mm in diameter. Then I could use the boring bar to expand the hole to the final diameter of 14 mm.
After the bore was finished, I face-turned the steam cylinder side to later proceed with the other side.
I have heard that the most important thing for getting a good running Pump is, to get the Pump-, and Steamcylinder exactly concentrial. I was thinking a lot until I had the ideal solution:
I clamped a piece of steel rod into collets (could also have used the 3jaw but I like working with collets...)
This Piece then was machined so the Base would fit on it with a tight fit.
Next, I secured and fixed the Base with a screw and face-turned the pump side as well as the other side. I first drilled to 8mm and then bored out to the final diameter. Then you can see the finished bore (with some oil on it - I already had some rust where I clamped the base on the rod; so I did immediately put some oil onto the finished surfaces....)
And finally with the pump body in place; The Pump cylinder also here fits tight into the base and needs to be pushed into with quite some effort. I will secure it with a screw from the bottom of the pum base (this detail is not entirely clear on the stuart plans and I think it is even missing.)
Well, this is how far i've got up to now. I can't say when I will find some time to continue; I hope quite soon ;)
Cheers Florian
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Hi Florian, I will be following you as well. Nice save on the pump and looking good. I am purchasing a hand pump from PM Rearch so this may help me to machine mine when I get it. So following with interest.
Don
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Florian, You had some rotten luck with that gunmetal casting but as Don said you have done a really nice repair.
Stuart's castings have been up and down over the years :-\ looks like you got a bad one. Is the cast Iron ok? No nasty hard chilled spots?
Jo
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No nasty hard chilled spots?
No, nothing up to now...
The Problem with the drill bit could have been avoided, I guess I was not gentle enough as well...
However, I see it as a challenge...
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Looks great from here Florian! I hear these pumps are tough to build...and I can appreciate that!
Dave
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It looks like you are keeping well on track, especially fixing that casting. Good job.
Lee
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Nice repair on your mishap. I have found that gunmetal is almost like working with copper and is very grabby. By knocking the edge off of the drill and proceeding slowly usually avoids problems and heaven knows I've had my share. I built and have the Stuart pump on one of my displays but when I built it many years ago all of the castings were gunmetal.
gbritnell
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Nice stuff. Some very good looking parts despite the hardships.
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My experience is, that the material from those canstings is even more grabby than that kind of gunmetal, I have been using up to now.
However, I now got me another drillbit especially for brass and gunmetal (http://www.feinewerkzeuge.de/messingbohrer910050.jpg).
I have seen pictures from sets of casting with all the castings out of gunmetal, I would really have appreciated to get such a set but I guess they are quite rare...
(It wouldn't have resulted in such mess from machining like it does witz cast iron...)
George; how did you make the ball seats? Just a sharp edge?
Florian
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Nice work there Florian, just goes to show this machining castings thing is far from easy. I like the way you are leaving the cast surfaces as cast - as intended. :ThumbsUp:
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If I didn't leave the cast surfaces, I could directly build it from stock material... ;)
I really like the look of cast surfaces on all the mechanical stuff...
I am not sure if and how i am going to paint it in the end...
But there is enough time to find that out :)
Florian
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Exactly, I've seen some people machine or dress all the surfaces - sort of defeating the point of a casting but each to his own I guess.
I was surprised how well gun metal silver solders - one of the few things I've made from castings, probably the only successful thing was a hand pump for Sweet Pea loco which was two castings silver soldered together.
Will be a useful bit of kit this, will you be using this with a boiler at some point?
Nick
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Hi, nice save on the casting :ThumbsUp:
kind regards
frazer
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... will you be using this with a boiler at some point?
Yes, that is the Idea!
I have a scotch boiler that is just the right size for this pump.
Florian
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Some progress here (from the weekend)...:
I continued with the steam cylinder cover towards the pump base. I first clamped it on stub and then premachined the spigot which will center the cylinder so I could just clamp it with a collet. (it has a greater diameter yet than the cylinder bore will be)
Then I rough turned the Part; had some problems with chatter marks on the square end of the cover (It is really thin there and with the interrupted cut, it starts to chatter quite fast)
Therefore, I gound me a HSS tool with a very sharp and thin tip (to get a very soft cut). But the surface still is not work as good as I want it. I guess I will have to finish it with a full surface support on the backside. You can see that also this part has some bubbles; I guess they had a bad day when castint those gunmetal parts... (The original cylinder hat a very big bubble, but It was replaced by the shop where I bought the set of castings)
The Next step was to make the piston bore and the thread for the packing gland. I also machined the threads with the lathe, so the threads and the bore for the piston shaft are running absolutely true to the Outside as well as to the spigot. The stub fits really nice into the pump base, It has to be pushed in with a very small amount of force and therefore is absolutely in Line with the Pump on the other end.
I can already imagine what it is going to look like!
Greetings from Switzerland
Florian
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Good choice cutting the internal thread on the lathe :ThumbsUp: I would have cheated and got out a tap. No doubt later wondered why things didn't line up.
Jo
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Looking good Florian! That is what gets people I'm told on that pump...the concentricity, and the spool valve.
Sounds like you got one licked! You'll get the other....Great Job!
Dave
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Hello Florian
I have been looking at the Stuart Steam Boiler Pump which have made (I assume it is now finished) very well done.
Although it does not appear difficult to build it is not an easy unit to build and lot of mistakes can be made.
I have built a couple in the past and have one in workshop at the moment, I did not build it and it needs some work on
it to get it run well and slowly as well as fast which they mostly only do!
As I have said your machining is very good, the best of luck with your engineering career (I did my training here in the UK over forty five years ago)
regards
Peter
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I assume it is now finished
No, it is not. I had to concentrate on my studies since my last post. Therefore the pump is waiting to be taken care of.
BUT: I have graduated and got my bachelor of science in mechanical engineering :whoohoo:
Furthermore, my milling machine ist getting ready to be used (acually can already be used but i will have to change the electrical part to a final solution.)
With other words, the project shall be continued soon! (Is almost on top of my to-do List, right after finishing the refurbishment of my vertex rotary table)
Cheers Florian
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I assume it is now finished
No, it is not. I had to concentrate on my studies since my last post. Therefore the pump is waiting to be taken care of.
BUT: I have graduated and got my bachelor of science in mechanical engineering :whoohoo:
Furthermore, my milling machine ist getting ready to be used (acually can already be used but i will have to change the electrical part to a final solution.)
With other words, the project shall be continued soon! (Is almost on top of my to-do List, right after finishing the refurbishment of my vertex rotary table)
Cheers Florian
Congrats Florian!.....That is definitly something to be proud of!....
Dave
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Well done Florian :ThumbsUp:!
Whats next? A Masters? or have you entered the big wide world of work :) :( ;D?
Jo
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Hey Jo
No, I am going to work. (am just looking for a job). Maybe I'll start with a masters later but not right now.
Cheers Florian
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Yeah nicely done, screwcutting is something I should practice. Not much excuse with the gearbox on the harrison there are many threads it can do just switching levers around. :ThumbsUp:
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I assume it is now finished
No, it is not. I had to concentrate on my studies since my last post. Therefore the pump is waiting to be taken care of.
BUT: I have graduated and got my bachelor of science in mechanical engineering :whoohoo:
Furthermore, my milling machine ist getting ready to be used (acually can already be used but i will have to change the electrical part to a final solution.)
With other words, the project shall be continued soon! (Is almost on top of my to-do List, right after finishing the refurbishment of my vertex rotary table)
Cheers Florian
Congratulations!!! You have passed a big milestone and with your solid thinking and methodical approach, you will surely find a satisfying job and go on from there.
Jerry
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Gentlemen, after quite a while of not taking care of the pump, I would like to announce to you, that i am now continuing with the build. ;D ;)
Well enough talked, here's some pictures:
The cylinder is (by chance or with intent???) designed, so it can be hold with a 3 jaw chuck and getting the cylinder bore at exactly the middle of the cylinder. First, I faced the cylinder and center drilled it. After this, I drilled with a 12mm drill to get close to the 14mm bore that I am intending to reach.
And finally, I bored the cylinder to 14 mm. After boring out the cylinder,I finished the cylinder bore by lapping (using an expanding mandrel and lapping compound). Though I had to find out that copper is not a good Idea to use on a copper based alloy. Some of the rubbed off material caused little grooves in the bore wall after getting stuck on the copper mandrel. So I afterwards had to repeat the lapping with an aluminum mandrel (which turned out like I expected).
I am going to build the pump with some modifications to the Stuart Version. To get the modifications visible before doing it to the castings, I modeled the Steam cylinder side of the pump in my cad system.
The most remarkable difference will be that I am going to use d slide valves instead of the piston valves.
The Idea behind is to get it as tight as possible and therefore to have the smallest possible amount of leakage steam. It would also be easier to revise the valves if they are worn.
So much for now - more to come later ;)
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Nice to see the update on this fine project Florian, and I would like to add my congratulations also for completing your ME degree. Best wishes in your search for a job also.
Bill
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Yes, nice job on the pump and the degree Florian!
Best wishes
Steve
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Thanks guys for all those wishes and congratulations! :)
After face turning the second side of the cylinder, I machined the fastening threads and steam ports of the cylinder casting
Then face milling the valve bearing surface (how is this suface actually called!?)and drilling holes to cut threads afterwards.
Milling steering ports took quite a while and had to be executed really carefully since there is not much room for the endmill to move when disengaging the cut.
All the steering ports finished. Also the cylinder is almost finished, only the drain cock threads are yet to be machined.
Then I cut two pieces of gun metal rod and milled them to size for the d-valves. The bigger one is the valve which is going to control the steam for the working piston. And the two finished d-valves. The smaller one will control the steam for the spool valve piston.
So much for today - Ill continue tomorrow.
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Comgratulations on your degree :cheers: and keep up the good work on the pump.
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Pump is looking excellent, great cad modelling and well done with the degree.
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Nice going, Florian, and interesting to see your modifications to the original design. :ThumbsUp: :ThumbsUp:
Simon
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Nice work and great pics Florian. That degree is yours and it is never going anywhere now. Enjoy a little "life" mate. You are only young once, just ask most of us old farts :cheers:
Whiskey
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Then face milling the valve bearing surface (how is this suface actually called!?)and drilling holes to cut threads afterwards:
(https://dl.dropboxusercontent.com/u/21771006/Hobby/Stuart%20Pumpe/IMAG0299.jpg)
Florian,
In my Double Tangye articale Edgar Westbury referred to that as the "steam chest face".
Jo
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Congrats on your degree Florian and nice work on the pump. I have a concern with your D valves. Your cylinder is brass and you D valves are brass. Brass on brass will cause galling if rubbing for long periods. Stainless would be a better choice. Ask me how I know? :facepalm:
Don
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Hi Don
Yes, I know that the material combination is far from ideal. I have been thinking about that problem aswell and what I have decided to do it anyway.
My thoughts were:
1. The castings are made from gun metal - I have used gunmetal as well for the valves. (though the cast gun metal may have slightly different material propertys.
2. There is a german locomotive manufacturer (Regner) who uses brass cylinders and brass valves. That also works for quite some time until there is wear which affects the functionality.
And if there was wear, I could fit a piece of stainless sheet (0.5mm thick) to prevent from furhter wear on the cylinder.
So, I will see what happens and then decide whether I have to modify it or just leave it the way it is.
Cheers Florian
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As an old friend and respected model engineer used to say - 'Slide valves wear IN, not OUT'
Nice work!
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So - I thought I'd write the next part earlier. But anyway, here it comes:
Next part to machine was the valve chest. I first face milled all the sides except the one opposite to the one with that little stub.
I used my wohlhaupter to machine the stub for the valve rod and to face the surface around the stub.
Next part was to mill the cavity. I did that after drilling the holes for the valve rod and the spool valve piston.
After that, I attached the chest to the cylinder and machined the backside of the cylinder after aligning the front sides. Also here, I was using my wohlhaupter and the horizontal feed. (You see - I love that tool :D ) The surface turned out quite nice.
So much for now, see ya ;)
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Hi Florian
I have just recently signed up to the forum but have been following your build of the Stuart pump and I do admire your workmanship.
I have over the years built and repaired about 9 - off these pumps but never considered converting to slide valve.
I have great reservations that your pump will not work.
Do you know that single cylinder double acting steam engines are not self starting and when running rely on the flywheel inertia to keep it going and if it stops at T.D.C. or B.D.C or the crank horizontal to the plain covering all ports it will not start.
In your pump like the single cylinder engine if the pump stops with the valve at Top or Bottom the inlet ports will be closed, likewise if it stops at mid stroke all the ports are covered and no steam will get thro' to activate the shuttle valve, hence no self starting.
If you study the Stuart arrangement you will see that the auxiliary valve, the 5/32" dia one , always has a port open for steam to the shuttle valve and makes the pump self starting.
I may be off the mark here as you may have thought of a way to get steam to the shuttle valve if all the ports are closed, if so I will be very pleased to here how as you may have solved the age old problem of a single cylinder engine being non self starting.
George.
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I have great reservations that your pump will not work.
Hi George
Well, there could theoretically be a case where all the ports are closed. But the probability is very small because the auxiliary valve will have to get over the point where the ports are equally closed until the shuttle valve is going to move.
To describe it with an analogy: It is like having a pendulum stopping with the mass above the bearing point.
It is possible because of friction but the probability is very small and the stability at this state is very low.
I have attached a scheme of the principle of my pump:
If you look at it carefully you will find out that it wouldn't work that way, the piston would drive the auxiliary valve to the wrong direction.
But I have drawn the ports this way to make it clearer when looking at it.
If it should happen, that I am really gonna have problems, I will see what I can do.
Greetings Florian
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Florian ,
Thanks for the reply, it will be interesting to see the final result, I am still doubtful but only too willing to be proven wrong.
We all need you young guns to to experiment to change perceptions that us old hands have lived with for years.
Keep posting, I love your machining skills .
Regards
George.
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An excellent discussion Gentlemen....you both deserve credit for that. :praise2: :praise2:
I too am following along and although I haven't made one of these pumps, I have heard horror stories of their difficulty to get to run consistently. That said...I give you great credit Florian, as if we always do what we've always done we will always get what we've always got.....
Let the chips fly!
Dave
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Oh, George, when im already having such an old hand with those Pumps reading my thread:
How do you fix the water pump body to the cast iron base? The Stuart plans just "forget" about and I haven't seen any hints on how it was intended.
Am I just blind...?
Also on the internet, i wasn't able to find any hints.
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Hi Florian,
Your diagram looks like a variation on the Weirs Glissard Valve. If bypass ports are fitted the steam can be supplied for the whole length of the stroke to either end by rotating the auxilairy valve which, whilst not 100% fool proof, usually manages to get the pump restarted should it stop on the top or bottom of the stroke, where the main valve has closed off all the ports.
Solution 2 is a bloody big crowbar and a large block of wood under/over the X head. :hammerbash:
Food for thought maybe?
Best Regards
Bob
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Hi Bob
I will see how it runs and modify it if it doesnt run nice.
It wouldn't be so bad for me if I had to move it to the right position before starting (auxiliary valve or piston)
But as I said, I will first let it run and see what happens.
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Florian
I'm with you on this one. Your modification does not change the way that the valve works. It only replaces two piston valves with two slide valves and I think your reasoning for that is valid and also interesting. Your doubters seem to forget that steam is supplied to the piston by the shuttle valve, which is not directly linked to the eccentric but is more of and either/or device controlled by the primary valve and as you state, is highly unlikely to come to rest between states. If you have any problems getting regular cycling, i would bet that fine tuning the primary valve will resolve them.
Jerry
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No nay sayers Jerry....just a polite discussion of the attributes involved. :ThumbsUp:
The way is should be.
Dave
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Oh, George, when im already having such an old hand with those Pumps reading my thread:
How do you fix the water pump body to the cast iron base? The Stuart plans just "forget" about and I haven't seen any hints on how it was intended.
Am I just blind...?
Also on the internet, i wasn't able to find any hints.
Florian,
I make the water pump casting a hard push fit by hand into the casting and leave it as such until the pump with the piston is complete and with your machinenery and skills you probably will not need to do the following.
You mentioned earlier that one of the main things to get this pump to work was that the 1/4" dia ram had to be directly in line with the piston in the cylinder and I will confirm that this is so.
I have been given many pumps that wouldn't work because of this so what I do is make the water pump gun metal casting a loose fit in the main frame .002" - .003" undersize I machine annular groves with a parting tool on the dia, (3-off,) push the piston fully towards the water pump end, coat the undersize water pump grooves with Loctite 603 and push it on to the cast frame, stand it vertical over night and I have never had any further trouble.
A bit unconventional but effective,if you don't need to do as described if you can push the pump ram back and forward by hand when you have the auxiliary bracket fixed to the shaft I would still run an annular groove on the pump casting and fix with Loctite, after all once on there is no need for it to come back off.
George.
P.S.
I also always fit a Silicone "O" ring to the 1/2" dia piston
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No nay sayers Jerry....just a polite discussion of the attributes involved. :ThumbsUp:
The way is should be.
Dave
Thank you Dave.
George.
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Thank you George!
Ya know....it ain't easy. We as a team try to keep is cool and civil. We all don't have to agree....as a matter of fact disagreement is encouraged to a certain extent....but doing so politely...and most importantly...respectfully is the key.
If as a group we figure that one out....we're golden...and from what I've seen we're doing just fine!
So keep it talking guys....and gals....keep talking.
Dave
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I have great reservations that your pump will not work.
Hi George
Well, there could theoretically be a case where all the ports are closed. But the probability is very small because the auxiliary valve will have to get over the point where the ports are equally closed until the shuttle valve is going to move.
To describe it with an analogy: It is like having a pendulum stopping with the mass above the bearing point.
It is possible because of friction but the probability is very small and the stability at this state is very low.
Here is a scheme for the principle of my pump:
(https://dl.dropboxusercontent.com/u/21771006/Hobby/Stuart%20Pumpe/Ventilprinzip.JPG)
If you look at it carefully you will find out that it wouldn't work that way, the piston would drive the auxiliary valve to the wrong direction.
But I have drawn the ports this way to make it clearer when looking at it.
If it should happen, that I am really gonna have problems, I will see what I can do.
Greetings Florian
Florin,
May I go back to your post with the C.A.D. and ask the question.
If the auxiliary valve is operated by the pump rod this means that they are both going in the same direction, as the original Stuart pump.
In your drawing it shows the piston in mid stroke and the Shuttle valve covering both ports, is this a small mistake, if not how does the steam get into the L/H. side to blow the piston to the bottom and as the shuttle is hard against the R/H side how are you to move it to get steam behind the piston to blow it to the top. ?
George.
Pic of the Stuart pump with the auxiliary valve driven by the pump ram.
Florian,
May I go back to your post with the C.A.D. and ask the question.
If the auxiliary valve is operated by the pump rod this means that they are both going in the same direction, as the original Stuart pump.
In your drawing it shows the piston in mid stroke and the Shuttle valve covering both ports, is this a small mistake, if not how does the steam get into the L/H. side to blow the piston to the bottom and as the shuttle is hard against the R/H side how are you to move it to get steam behind the piston to blow it to the top. ?
George.
Pic of the Stuart pump with the auxiliary valve driven by the pump ram.
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Florian
I'm with you on this one. Your modification does not change the way that the valve works. It only replaces two piston valves with two slide valves and I think your reasoning for that is valid and also interesting. Your doubters seem to forget that steam is supplied to the piston by the shuttle valve, which is not directly linked to the eccentric but is more of and either/or device controlled by the primary valve and as you state, is highly unlikely to come to rest between states. If you have any problems getting regular cycling, i would bet that fine tuning the primary valve will resolve them.
Jerry
Jerry
If you look at the pic Florian posted and the pic that I have posted you will see that no eccentrics are used.
The auxiliary valve is driven in the same direction as the pump ram.
Also there will be no way to fine tune the valves as Florian is cutting a steam space on the underside of the top steam chest with no way of access to see what is happening, not like a valve chest that has a bolt on cover, so I still have my doubts but willing to be shown how it can be done, never too old to learn.
George.
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My apologies to anyone that I offended with my remarks. I am a little confused as to what was offensive as it was not intended to be. Several of my recent post seem to have caused ill feelings so it must have something to do with my general attitude which, I must admit, has not been good lately. I will refrain from posting until I have a better outlook.
Jerry
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I saw nor construed nothing offensive Jerry....Deep breath everybody....hmmm.
Dave
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In your drawing it shows the piston in mid stroke and the Shuttle valve covering both ports, is this a small mistake, if not how does the steam get into the L/H. side to blow the piston to the bottom and as the shuttle is hard against the R/H side how are you to move it to get steam behind the piston to blow it to the top. ?
As I said, the drawing (made with paint) is not correct.
I only made it for showing ports and valve arrangment.
The auxiliary valve would of course have to be on the other side so the piston ram could move it to where it already is in my drawing.
This would then cause the shuttle valve to switch position as well and the piston would go into the wrong direction.
BUT:
On my Pump, the ports between the auxiliary valve and the shuttle piston are crossed. And that would then make everything right.
As you see, my drawing can not be drawn correctly but I did chose to draw it that way because crossed ports in that drawing might confuse someone.
Cheers Florian
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That seems understandable and reasonable Florian. Please proceed. 8)
Dave
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I am intrigued by this discussion, you both have some very good points and I will stay tuned in the see how it all works out. I can see both sides of this and can't make up my mind who is correct. Florian you are showing so great engineering skills.
George your pump is gorgeous and thanks for starting the discussion.
Regards Don
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In your drawing it shows the piston in mid stroke and the Shuttle valve covering both ports, is this a small mistake, if not how does the steam get into the L/H. side to blow the piston to the bottom and as the shuttle is hard against the R/H side how are you to move it to get steam behind the piston to blow it to the top. ?
As I said, the drawing (made with paint) is not correct.
I only made it for showing ports and valve arrangment.
The auxiliary valve would of course have to be on the other side so the piston ram could move it to where it already is in my drawing.
This would then cause the shuttle valve to switch position as well and the piston would go into the wrong direction.
BUT:
On my Pump, the ports between the auxiliary valve and the shuttle piston are crossed. And that would then make everything right.
As you see, my drawing can not be drawn correctly but I did chose to draw it that way because crossed ports in that drawing might confuse someone.
Cheers Florian
Florian,
Gotcha !!
Yes you will need to transfer the ports to get the shuttle to work.
I have made a small 3" high vertical WEIR type pump from stock material and from the drawings by Southworth pumps and there is a plate between the steam chest and the cylinder face which has the steam ports transferred to get the shuttle to work, I hope that it's visible on the enclosed pic.
This little pump is very reliable and works down to about 5 p.s.i and is self starting every time, pics enclosed and I hope you can see the groove to transfer the steam.
I have also made a vertical WEIR type pump 6" high from a set of castings and it transfers the steam by various galleries to get the steam transferred, both of these pumps are slide valve operated.
I didn't quite understand your C.A.D. drawing but thanks for explaining, technology has passed me by I am afraid to say and I still rely on sketches on a pad, unfortunately I didn't take any pics of the slide valve arrangement but I could scan and post them to you by e-mail if you wish, just P.M. me with your mail address.
Keep up the good work and I look forward to seeing you complete the project.
George.
This is the 6" high pump.
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I think that my pics are too big so I will post the others individually until I have the time to explore what I am doing wrong.
George.
3" high steam pump.
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The sight is only allowing 1- pic at a time but you have them now, perhaps I could have suggestions on how to resize my pics.
I use a MAC and it will not recognize Photo Bucket.
I like the pumps, George!
George, if you have the photos in iPhoto, you can select the photos you want to export, then choose Export on the File menu, and in the "File Export" tab choose to export "Medium" quality JPEGs, size "Large". That should give you images of about the right size.
Otherwise you can open the individual image files in Preview, choose Tools -> Adjust Size, and choose to "fit into 1024x768" (if you want to preserve the original, be sure to "Save As" not "Save" otherwise you'll overwrite it).
Simon
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Glad you sorted it George!.....
Dave
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Oh oh - you are getting off the original topic a little (with the how to post pictures thing)
George, I have asked a moderator to merge your posts into one (as far as it makes sense)
So please let me continue my report:
I forgot about the front cylinder cover which has been finished before the valve chest:
You may remember that I had a problem when I was machining the front cylinder cover plate. I took a disc of aluminium into the 3jaw. Then I first face turned it and then made little grooves every 5mm (radial). Finally, I bored the center so the stub of the front cylinder cover could be pushed in with a tight fit.
Then I used some instant adhesive to secure the cover to that disc.
It worked really well, with the whole surface supported there wasnt any chattering.
After finishing that surface, I had to drill the hole for the stub on the valve chest. To get the hole at exactly the right position, I clamped the cylinder on the milling machine with an expanding mandrel. Then I attached the valve chest and aligned the spinlde with that stub by moving the crosstable to the right position.
Afterwards, I removed the valve chest and fixed the front cover to the cylinder.
The bore is exactly at the right place. All the same, I took a drill which is 0.2mm greater in diameter than the stub to allow a little difference in position (probably caused by the liquid seal I want to use to assemble it)
Thats it for now, I'll continue soon ;)
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Yes Florian you are quite correct and I apologize for high jacking your thread it was not intentional and the moderator can delete them from your thread.
Please continue with your post.
May I ask why the threaded spigot of the auxiliary valve that you have just explained how you marked the hole for it in the front plate looks as though it has been burned ?
George.
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Yes Florian please proceed. That's a cool looking pump!
Dave
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May I ask why the threaded spigot of the auxiliary valve that you have just explained how you marked the hole for it in the front plate looks as though it has been burned ?
Because I had to solder a plug into a wrong positioned center hole :embarassed:
I could have left it because it would have been under the whasher finally but that would have kind of annoyed me. (Just do know that it is not as it should be)
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Gentlemen
I have just spotted a set of stuart boiler feed pump from the old times where the whole casting was made from bronze:
http://www.ebay.com/itm/STUART-STEAM-BOILER-FEED-PUMP-CASTING-SET-/271326791647?pt=Model_RR_Trains&hash=item3f2c5647df
One of you may be interested in it..?
Cheers Florian
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Damn, I was watching that already >:D
Simon
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Damn, I was watching that already >:D
Simon
Simon,
Way back in time Stuart made the steam pump with the frame and the water pump all in one from Gunmetal.
I was told that they stopped producing it this way as there was so many complaints that it was so difficult to hold and machine the water passages on the pump and to hold the whole caboodle for machining and get the pump ram in line..
I do know it's difficult to hold so it may well be that you wait for the modern one as per Florians.
I hope that this is of help to you.
George.
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Damn, I was watching that already >:D
Simon
whooops. Sorry about that :embarassed:
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I might know a man :embarassed: who can point us in the direct of a couple more ;).
Jo
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I guess I've had you waiting long enough... ;) :
Next, I had to drill the steam ports for the shuttle valve. They are angled in two directions and so I had to use the vise in vise technique to get the right angle. Works quite well!
Then I machined the cover for the backside of the cylinder, already finished on the picture.
Sadly, there are some blowholes in this casting as well. But I simply ignored it because I didn't want to order a spare part and the holes are not very big.
Thats it for tonight - I'll continue soon (hopefully sooner than this time... ;D )
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Looking good Florian
Steve
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Florian,
Over the past 20 years I think that I have made and refurbished about 10-off these pumps.
One of the things I always found difficult to get correct was drilling the hole in the front cover to take the screwed spiggot of the steam chest.
It never occurred to me to use the method that you describe in your No 63 post, the only difference was that I used my center finder to find the center of the auxiliary valve hole, locked the "X" and "Y" tables, removed the steam chest and drilled the hole .015 O/Size and it's a perfect fit, that is after I had to fill in the oversize hole that I made before reading your post.
So thank you for the method, just lets you see that your posts are appreciated and that you are never to old to learn.
George.
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that is after I had to fill in the oversize hole that I made before reading your post.
Hey George
That sounds like you are working on a stuart pump just right now..?
If so, would you maybe put some pitures up here aswell? I would be interested for shure!
Florian
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After finishing the valve chest (almost...), I machined the shuttle valve piston from a 5mm dia stainless steel rod.
As you can see, I had to start three times. :insane:
The first one got one mm to short, I still have no idea why.
The second one had the correct length but I have cut the groove for the o-ring a little too deep so the o-ring was not pre-loaded a little (as it should to get it steam tight).
And finally the third one came out right. (though i had to replace it aswell - but more about this when I get there) One of the pictures shows the steam chest with the shuttle piston and valve installed.
I already machined the first piston shaft / pump ram some time ago. I decided to use a lapping ring to finish the surface.
But I had to find out that i had used the wrong grade of stainless because this one tends to bite (its 1.4301 if you are familiar with that notation).
This also happened during the lapping process and so I got a quite deep helix formed groove in my almost finished shaft. That really pissed me of because the pump ram was already finished. You will notice that the pump ram is bigger in diameter. It has 8mm, thats 2mm more than the piston rod which has 6mm.
I have by the way also increased the cylinder diameter from 12mm to 14mm so the cylinder should be able to deal with the greater amount of force required for that pump ram. Well - now I made another attempt using another grade of stainless now (1.4021) You can see the cylinder shaft side being machined. The stub at the live center side is where the cone and the thread will be machined and I have already turned them to in about 5.98mm so that is slightly smaller than the 6.02mm I am heading for to enable 0.02mm being lapped away for a perfect finish and cylindricity.
Lapping took quite long, in about 1 hour for the cylinder shaft and 30 minutes for the ram. I was rotating the shaft with an cordless screwdriver. ( I used some brass sheet metal stripes bent around the shaft to protect it from the hard drill chuck jaws)
Mission accomplished! The shaft came out quite nice. For comparison, the last picture shows it right next to the one that went bad during the lapping process.
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Looking good Florian and I love your Techniques.
Don
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Very nice, Florian, and I like the lapping ring. :ThumbsUp: :ThumbsUp:
Simon
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Florian.......
The original shaft [1.4301] being a 300 series grade is austenitic & shall we say non rusting...however with poorer machining qualities
The second shaft [1.4021] being a 400 series grade is martensitic & although it has slightly superior machinability qualities is technically not capable of being rust resistant
1.4571 material is readily commercially available & has marginally superior machining qualities over 1.4301......
1.4571 also has the advantage of being from the 300 series family with totally rust free substrate
A consideration could be to use 1.4571, then followed by grind, chrome & regrind which would provide a totally rust free substrate & surface hardness to 65Rc and to say 0.3 umRa surface roughness
The 65Rc & the 0.3 umRa being the optimum considerations for superior design.......Derek
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Hi Derek
Thanks for bringing that fact to my attention.
Chrome plating, grinding and more would be a little over engineerd though I am shure it would result in a perfectly running pump. However - I don't have the possibility to do it by myself and therefore It would also cost some money. (I guess more than I want to spend for it)
I will see what happens with 1.4021 in that little pump. Polished surfaces are as far as i know good if its about preventing corrosion.
The reason for using 1.4021 is not the machinability but the fact that it seems to wear with a better surface than 1.4301 (I don't know it yet but I have been told it would be that way. So I will see how it turns out) and of course that i had it around (Ordered it for some parts that I wanted to harden and that should not corrode fast)
Florian
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that is after I had to fill in the oversize hole that I made before reading your post.
Hey George
That sounds like you are working on a stuart pump just right now..?
If so, would you maybe put some pitures up here aswell? I would be interested for shure!
Florian
Florian,
Yes I am making a boiler feed pump at present and although I have made a few I have tried some of the methods that you have posted.
Unfortunately this set of castings are the poorest that I have ever tackled. the casting at the water pump end is very out of line and difficult to grip in the 4- jaw to enable me to machine the steam engine end which is the method that I have always employed and then bore straight thro' after drilling out with a 29/64" drill.
I tried your method of clamping on the face plate but even though it was clamped up tight the casting moved when I started machining the end for the engine. so it was back to my old method but you can see in the pic that when I bored thro' it was off center, not much that I could do even though I had tried to square up the water pump end of the casting before boring.
I have also found out the the holding down bolt feet on the casting is out of line so the bolt pitches will be different to each other.
Apart from these miss aligned parts I am please that on following your post on drilling for the Auxiliary valve has worked out perfect.
Thanks again.
George.
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Florian,
Having just completed the piston and shaft on my pump it has raised a question on your post No 76 where you have the piston rod shaft at 6 mm ( 1/4" ) and the water pump at 8mm ( 5/16" ).
Why have you done this as the designed dia of the water pump is 6 mm ( 1/4" ) and it pumps copious amounts of water at that dia ?
It also means that you will have to feed the shaft in from the water pump end and thread thro' the seal and the gland nut, slide the auxiliary valve rod actuating arm on and then slide it thro' the next gland nut and then thro' the seal on the engine with the steam cylinder bolted on and finally screw on the piston.
This is going to take up quite a bit of time if you have to take the shaft back out, whereas if you stick to the design size of 6 mm ( 1/4" ) with the piston fixed on you can feed in from the opposite end of the steam cylinder, which is much easier.
It's just a thought but maybe you could let me know how you are going to do it as I can't see any advantage in your design change..
George.
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Hi George
I wanted to increase the bore of the steam cylinder and of the water pump aswell (to prevent the pump from going "too easy")
But I simply didn't want to have a 8mm cylinder shaft as it seemed a little too big for me (and wouldn't have worked with the tappet because that would have not enought diameter/width on the lower end)
I will assemble the pump likewise:
1. fix the pump body to the cast iron base
2. add the cylinder cover on the ohter end
3. insert the pump/cylinder shaft from the pump side, add the tappet in the middle
4. fix the piston to the shaft
5. add the rest of the cylinder.
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Hi Florian,
It really is the only way to assemble the pump, but how are you going to fix the 2- C/Sk screws that hold the bottom cover to the cylinder.
This means that you will have to fix them and then offer the piston to the rod from the top of the cylinder while the cylinder is affixed to the bottom cover.
It would have been so much easier for assembly and maintenance if you had left the pump ram at 6 mm ( 1/4" ) which means that you could assemble everything and then offer the piston fitted to the 6 mm rod from the back end of the cylinder.
Must compliment you on your machining, first class.
George.
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This will be one of those.....Let's give it try projects.....though knowing Florian as I do, I am sure he can give it the "business" necessary to make it work the way he wants.
Love the build Florian!....please continue!
Dave
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Hey George
Instead of using 2 screws to fix the cylinder unit to the cast iron base and 2 screws to connect the cylinder with the cylinder cover, I will not have any screws which connect cover and Cylinder before mounting it.
I will have 4 Screws connecting the cylinder with the cast iron base though the lowest screw - actually I have to talk about stays - the lowest stay will go all through the cylinder and will have a threaded end in the cast iron base and the other end at the cylinder cover at the end of the pump.
But you will see that when I am going to make the studs.
Florian
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Hi Florian,
I am a bit like a skier going off piste and not knowing what to expect, I am used to working with the Stuart drawing so it's good to hear that you have designed a way around the original design and I look forward to seeing how.
I keep saying " you are never too old to learn " and you have certainly got the old gray matter working.
Do you intend to feed a steam boiler with the pump or just to run it on air ?
George.
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I will use it as a pump in combination with my scotch boiler I guess. (Or probably with a vertical one I got recently)
But definitely under steam!!! ^-^
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I think its time, istn't it :Lol:
Well, here I go:
Next was the piston. I first parted off a piece of the chunck of material that was delievered. This piece was then held in collets and the inner contours were machined. First the conic bore and then the other side where I had to make room for the nut. The outer diameter was finished by holding the piston with its shaft and taking the shaft in collets. I usually do this to get minimal runout. (And I am shure many of you also do it that way). After finishing it, I have put it into the cylinder (still using the machining nut) Then I also made the final nut and assembled everything.
Next were three gland nuts. They were all made the same way (more or less)
You may remember my thread about thread milling. This is what I used it for. I first machined the thread and the whole inner side of the gland nuts. Then switched over to the milling machine to mill the slots.
That was followed by parting off and finally finishing the ohter end. The Radius has been hand made with a little file (and thats why there are no pictures of this - I only have two hands and needed them both... ::)
However, the last picture shows what they look like:
Thats it for now - Ill continue soon (tomorrow maybe..?)
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Florin,
I am really intrigued as to how you spot the casting to take the Cap head socket screws, it's one of those things that I have never had explained or shown, so perhaps you would explain.
George.
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Hi George
You are talking about how to countersink the screw, right?
(By the way - the cap screw is only temorary - I will of course use washers, nuts and studs in the end.)
Be right back with a picture ;)
Here I am:
I have made a "reverse countersink" d-bit. Its ground free hand so you see its not looking so nice :embarassed:
However, the trick of it is to use the bore as a guide for countersinking. For this, I have turned the shaft near the "head" of the tool to the drilled hole size (Thats the shiny part).
How I used it:
I have taken the d-bit into the collet chuck of the milling machine and then moved the tool up slowly. I had to lower the table for this. It is imortant not to use the quill if you do not have a fine-feed for it (often realized with a worm gear reduction drive) because the surface is not straight. This could get dangerous for the tool and for the cast part aswell! (And maybe also for yourself if you do not watch out!!!)
The last picture is only for demonstration.
Florian
ps: I wanted to write about how I did this but it looks like I forgot about. Good you did remind me on it!
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Brilliant stuff Florian.
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Nice one Florian!
Dave
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Hi Florian,
Thanks for taking the time to show your method of counter boring on the Casting.
I have always thought that it would have to be done from behind but couldn't think of a way to do it, "D" bits are no problem to make I think that I have one for every size that I have ever needed.
It's a pity that you hadn't posted this earlier as yesterday I lashed up a method and as you know the problem is getting past the water end part of the casting to get a straight line to mill the spots.
I used a tool like an end mill with very rough teeth on the dia 3/8" , I don't know what you would call it, I fixed the shank into a piece of Mild steel and machined the mild steel rod as small as possible in order to get past the water end casting.
This allowed me to fix it into the collet chuck on the mill , tilt the casting by using a piece o 1/16" thk packing which allowed me to get down to the casting.
It did the job but not very pretty but as it will eventually be painted it may not be so noticeable.
No 1.
The modified tool.
No 2.
Spot face on pump casting.
No 3
Piston fitted with Silicone "O" ring.
No 4
Progress of pump to date, the 5/32" rod is only there to mark off the center for the end stop/adjusting screw.
I have an old casting which I made a mess of but it will be good enough to make a tool as you described and see how I get on.
George.
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Nice job on the upside down spot facing Florian. Always nice to see a home made tool getting the job done.
Steve
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Again "soon" turned out to be more than one day... :stickpoke:
The tappet followed being machined. First, I drilled and reamed the hole for the shaft. That was followed by milling the sides and the lower radius with the rotary table. The tapped was held with a simple mandrel. The tapped has a 6mm bore and goes on a stub on the top of the mandrel. That fit is quite tight (But you can still put them together by hand) and then secured by a M4 screw.
Then I had to drill the cross hole for the clamp (Is that called like that?)
Afterwards, I machined the clamp from a piece of 4mm rod.
Done - the clamp is finished and the tapped also (almost at least - still needs some filing but thats gonna come later)
Also, I had to make the "set collars". I never liked the look of them and so I decided to do it slightly different here aswell. I decided to make two clamp collars.
Cut off and chamfered. The screw in front of them is a M1.2 screw.
Milling steps, center-drilling (The final hole was drilled on the drill press as I have no good drill chuck for the machine - need to get me one...) and finally slitting the collars.
So much for now. Till next time (whenever that will be ;) )
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Not thats is the point where all the parts are ready to try let the pump running.
I have a so called "lapping film" (It is actually abrasive paper which is water- and oil resistant and has a very precise thickness) which I used to get the surfaces plain and nice:
There are different grain sizes and with the smallest one, the surfaces can be polished mirror-like (look at the d-valve!)
I assembled all the parts and tried. The pump did not move for a single stroke. :hammerbash:
Disassembled all the things, checked everything and considered again my thoughts about the principle. I had everything right but why didnt the pump move!?
The first thing I have seen was that the surface on the shuttle piston bore was not as good as it should be and the piston was running rough.
I then took a 5mm lapping mandrel (which I had from another project) and tried to improve the surface so the O-ring wouldn't stick on it.
Reassembled and the pump moved for a few strokes but then again stopped doing anything.
I disassembled again and found that the O-ring groove on the piston was not deep enought, the shuttle piston was still not moving as free as it should be. (somehow I didn't notice that before)
However, I made the grooves deeper and tried again.
AND THE PUMP IS DOING WHAT IT SHOULD: :whoohoo:
https://www.youtube.com/watch?v=5OxhSaGZZRk
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Now that is of course only actuated by hand and therefore the next step was to let it run by itself:
Still, I was having problems because the pump stopped when reducing the pressure and then I was not able to start it again by itself.
I first was really helpless and then had the Idea that the shuttle piston might be too small.
I then made another shuttle piston (that is the 4th one :insane: ) now with 6 mm diameter.
The bore in the valve chest was extended using a new 6mm endmill:
The bore turned out to be very smooth. Here you can see why I had to use an endmill:
And finally the new shuttle valve piston beneath the old one.
And the pump is running!
https://www.youtube.com/watch?v=BuEWxvJh79Y
BUT: There is still the Problem that the pump "gets stuck" - I was really going to be pissed off and couldn't think of any reason at that moment. :rant: :headscratch:
That's it for today - the solution to this problem (there was a solution) will come soon ;)
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Nice Job Florian!
I'm sure that you will get it sorted out and running just the way you want.
Dave
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Looking good Florian. You'll get it sorted
Steve
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Florian,
Do you have any lubrication on your air line to the pump ?
If not it could be the "O" rings drying out and stopping the pump.
Southworth make steam boiler pumps in WEIR vertical style with slide valves and shuttle vales but no "O" rings on the shuttle so could you try the pump without the "O" rings.
I have made the WEIR type by Southworth, the 6" high vertical one and the latest one that I have made is the small 3" vertical WEIR type pump.
Both are self starting at very low speeds and the only "O" rings that I use are SILICONE on the pistons.
Just a thought.
George.
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Congratulations :ThumbsUp: :ThumbsUp: It always feels good when something you have made works.
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Thanks Guys
I already have sorted out that problem - I just didn't write here what the solution to it was ;)
Florian
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Brilliant Florian, seems to work really well that, have you tried it pumping anything yet?
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Gentlemen - I guess I owe you the solution to the reason of the pump not running properly:
After thinking about what could cause the problem and listening to the Pump, I found out that the d-Valves were too short. They were just as long as the distance was between the outer edges of the cylinder ports. Theroetically. In fact, the ports were a little wider than they should have been and so there was a position where the d-Valve couldn't cover them completely and in the same time let the steam in to both of them.
This alone wouldn't be a problem but the ports are wider than the d-valve wall. That results in a "short circuit" for the steam which was enough to get the pressure dropping below the required level for moving the shuttle valve.
So I had to make another pair of d-valves. The old ones in front of the raw material:
And that is it. The new ones on the left and the old ones on the right.
That was then also the cure for the problem of the pump getting stuck. The pump still gets kind of stuck but it will restart by itself if I increase the pressure.
I will have to exchange the o-rings aswell because at the moment I am using nbr o-rings but silicone would be better for this (which I don't have in stock that is why I first took some nbr rings)
However, here you can see what I am talking about of "getting stuck":
https://www.youtube.com/watch?v=OlVJvIKo4lw
Well - I am confident that the steam also will help to get the pump running smoother. We will see. ;)
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Florian....as George has suggested....Silicone [MQV] rubber O-rings will provide superior service
This MQV material is rated to 220 degrees C and a similar 85 Shore hardness [to NBR]
NBR material is only rated to a nominal 100 degrees C....but at this temperature [or above] swells & becomes sticky & natural lubricity diminishes greatly
At say 3.5 Bar WP....you are feeding steam @ say 140 degrees C into the pump........which certainly could have contributed to NBR swell & the issues you experienced......Derek
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Hi Derek
Yes, I know that nbr is not suitable for that use. I only used the nbr rings to start and I have to order silicone rings.
Florian
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Now the pump is running, I'll have to make all the rest:
1. making studs, nuts and washers
2. fixing the pump to the cast iron base
3. milling the outside of the cylinder covers (and the cylinder ends aswell)
4. making the gland packing from teflon for the water side
5. making drain cocks
6. making the plug screw for the pump backside
7. making the check valve plunger (I am not going to use the balls - I will make them from brass and use an o-ring for sealing)
8. making the cylinder cladding (I will not use that aluminum sheet piece delievered with it - I don't like its color - doesn't fit together with gun metal I think...)
9. making main steam valve with oiler aswell as steam exhaust pipe
So you see its quite some work left though some poits will be done within one or two hours.
But lets start with the first task.
I began with the undercut for the threads. Then the chamfer for the thread start was cut, followed by cutting the thread using the tailstock as support.
And the same procedure was repeated on the other side.
The washers were cut off from a bar which I drilled with the required diameter first.
I just noticed I didn't take any pictures when making the nuts :o
However, on the last picture, you can see the finished nuts.
One point done then ;) ;D
Thats it for now - 'till soon.
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Florain......I am unsure of your philosophy in using a square undercut for the inboard side if the stud & a radiused undercut for the fastened or outboard side
In a perfect world...would you not have a greater stress riser with the square undercut?........Derek
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would you not have a greater stress riser with the square undercut?
If I had a square undercut yes.
But my undercut has a radius which is quite small (too small maybe...?).
However - those studs are not under such big stress that it makes any difference I think. The Undercut is in this case only to have a clean end of the thread and not for optimizing force flow.
Cheers Florian
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Florian...I am sure that the pressures & stresses being applied to these studs are within the design requirements .....and would have been calculated many years ago by Weir or Stuart etc
It was simply when we see a generous radius undercut being applied to one section of the stud......& then a near visual square edge undercut being applied to the other section of the stud that prompted my question
Mind you....as far as I could see.....there is no nomination of the material grade used........this subject [material grade for studs] was discussed however became shall we say WARM & at one recent stage locked
Without contravening the previous thread assurances.......the selection of different bar stock here for your studs could range from say 500 to 850 MPa which is a tremendous variance....Derek
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It is 1.4301 that was used for the studs wich has in about 660 MPa typically (can be between 500 and 700)
And yes you are right - I should make the radius as big as the one on the front.
However - I've been making the radius with a honing bar and I thought it might get bigger than it actually got. :embarassed:
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Let's also keep in mind that these are models, that the stresses from load go down dramatically with scale.....
Please proceed Florian....you're doing fine.
Dave
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Hello Hello - its me again ;D
I am now happy with how the pump runs:
https://www.youtube.com/watch?v=266v_ZgGt6s
I guess that is quite good (though still running dry)
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And yes - I also continue with the report:
Next, I milled the sides of the cylinder covers and the cylinder as well. I again used the expanding mandrel held in the 3-jaw chuck of my rotary table.
And I made a terrible mistake, I didn't tighten the mandrel tight enough. And this is what happens then: :hammerbash: :Mad:
So I ordered another cylinder cover casting. Unfortunately, my dealer said it is going to take in about one month as he had to oder it from england. Well - what could I do - I just had to wait.
I then continued with mounting the pump to the cast iron base. For this, I had to drill a hole into the base and also cut a thread.
The Idea is to make a tapered bore into the pump body (which sits in the base with a tight fit) and to fix it with a setscrew that has a taper on its tip as well. To get a tapered bore, I had to make a tool (d-bit again) and as the compound slide was set to the angle I directly continued to machine the set screw. That "pocket" in the pump body you can see on one picture is actually tapered.
I am going to try using a teflon seal for the pump ram. So I had to machine a ring that fits into the gland. That thin part of the seal will go into the gland nut. The Idea is to seal and guide the pump ram with teflon in order to prevent the ram from wearing.
One and half a week after I ordered the spare cylinder cover it arrived. I machined it and it all went well Phew!
Looks like my dealer had a cover laying around somewhere in his shop. :whoohoo:
The Stub was machined slightly different as I was a little unsatisfied with the look of it. The new version looks more pleasant to me. However, i should not get used too much to get a second chance though O:-)
I also added screws beneath the shuttle valve bore to support the cover (you can see them on the picture just above)
Thats it for today. See you soon :cheers:
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Looking good Florian, and it's running very smooth in the video too
Cheers
Steve
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Hi all :happyreader:
Next time in the shop, i machined the cylinder drain cocks.
I have once ground me a straight edge tool for making the tapered plugs. Instead of needing around 30 seconds to get a good finish, I now need somethink like 4 seconds to get the taper done cleanly.
Also for the cock body and the spheric head of the plug. Here the time saving is even more - I now need in about 10 seconds to finish the ball head of the plug - with a ball turning attachment that was something around 2 to 5 minutes!
For giving you an impression how this works, I have made a short video of the ball end being machined. The interrupt cutting is due to me holding the cam in one hand and feeding with the other one (so its going even a little faster if I am not recording):
https://www.youtube.com/watch?v=xU4j4zzR2xI
The tapered Plug has got a square on the lower end for driving the washer. To make a square hole, I used a square punch which i had made some time ago.
Then the handle bars are pressed into the ball head of the tapered plug.
The handles were made from boxwood wich machines extremely well and also looks good in my opinion.
That is now where the project ACTUALLY is in my shop. Next time I will write as I continue. ;)
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Beautiful work Florian!
Simon.
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Nice video Florin, beautiful job all around. :ThumbsUp:
Don
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Hi Florian,
It's interesting to see that you are making gland packing from Teflon, I can't see any great wear on the pump shaft as all the forces are in line.
I have often considered using this method but have stayed with the Graphite yarn, some years ago there was an imported twin cylinder double acting engine from India, I think it was, modeled on the Stuart D10 and had the pistons made from either Teflon or P.T.F.E..
A friend of mine in England was the importer but had so much trouble with them that he had to make and replace the pistons made from Bronze and fit Silicone "O" rings, he eventually abandoned their import as he had too much trouble with other parts of the engine.
I have just completed my Stuart pump and it runs very well on steam but must say that it doesn't have the control that yours has.
Mine is very greedy on steam but I haven't had it pumping under working conditions yet, so it may well be much better when it has some work to do.
May I congratulate you on your workmanship and the ball turning tool is the same as one that I made to turn the ball joints on my Flash Steamers prop shaft.
You are quite an insparation and it only makes me try harder with my machining.
Great job keep it up.
George.
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Hey George
Thanks for applauding me! I am always happy if I can give something to the forum because I have (earlier more than now) been finding lots of good information, hints and tricks here in the forum too!
As far as i know, "Teflon" is DuPont's brand name for P.T.F.E. So it is acutally the same.
The reason for using it is: Teflon has the lowest coefficiant of friction of all plastic materials. Especially it does not require a certain breaking loose force like most of the O-rings do!
The seal is yet going a little tight and that is why my pump is running very slow. It wouldn't without any load (because the pressure somewhen would drop under the required amount for moving the shuttle)
Your friends problem is the very great coefficiant of thermal expansion that teflon has. So if you have the piston fitted in cold condition(like 20°C), the piston will expand around half a millimeter when you heat it up to lets say 120°C!!
I did not run mine on steam yet, but I just came from the shop and had it running with pressurized air and pumping water. It can bring 11.5 bar water pressure with 4 bar on the steam side!
Next up will be building an oiler and then I can test it on steam.
For your pump: You may want to try putting silicone O-rings on your shuttle valve as well (possibly with making another shuttle valve?).
You will find out that the pump then has a lot more force than without!
If you are going to try, I would recommend to make the O-ring grooves only slightly less deep than they would have to be to get the o-rings flush with the valve (I use something like 0.1mm less in depth but 1,2 times as wide as the o-ring is).
The O-rings also dont get damaged by the ports (even if they are sharp) if the O-rings are only very few more than flush with the outer diameter of the valve.
:cheers: Florian
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Ive had good luck with teflon piston rings in my launch engine
At 165 psi saturated.
Dave
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Hey Dave
Rings are different! They are quite thin and the expansion with hight temperatures is therefore smaller than the one of a full piston. (the expansion over all of course - the coefficient is the same for both - pistons or rings)
Florian
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Florian........raw PTFE certainly does have a low CoF & a high temperature range & so is suitable for out model steam applications .......but the same material has near ZERO memory + low strength
If you use this virgin PTFE material for piston rings ...they will expand @ 10 Bar & 150 degrees C & stay there at this new size/profile/dimension
To counter the strength, manufactures add MoS, or glass or bronze powder which significantly improve the characteristics
With respect to memory, one option is to use a Viton o-ring energiser [whilst dynamic, however is essentially a non wearing elementt] to energise the PTFE seal element
Some very interesting reading here ....www.economos.st .....
I have been using the Economos philosophy in industrial hydraulic sealing applications here in Port Kembla for 20+ years........... Derek
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Well...make it how ever you like....Mine have been of TEFLON and have been pushing my boat around for a number of years.
Mine were machined like this
(http://i164.photobucket.com/albums/u27/mcandrew1894/Steam/teflonpistonring.jpg) (http://s164.photobucket.com/user/mcandrew1894/media/Steam/teflonpistonring.jpg.html)
Dave
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And to your point Florian....the lap joint allows for the expansion.
Dave
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steamer....I do acknowledge that the single L stepped cut seal profile you show is an excellent choice...having a few advantages
1. it does not require a piston of demountable construction to install within a fixed piston seal cavity
2. it also will compensate for linear, axial & volumetric expansion
Raw PTFE is a difficult material to CNC machine.........with your compound step cut I assume the material is reinforced??........Derek
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My Post No 120.
May I clear up the statement regarding the Teflon piston on my friends imported engines.
The piston were machined from a Teflon bar and they seized under steam,that is why he had to replace the pistons ( pistons as per pic )
Dave,
I see no reason as to why you shouldn't make rings from Teflon and as you have proven they work well, some of my club mates with small Oscillating engines roll up Plumbers P.T.F.E. tape to pack their pistons and although they work but only for a season and then have to be replaced.
George.
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steamer....I do acknowledge that the single L stepped cut seal profile you show is an excellent choice...having a few advantages
1. it does not require a piston of demountable construction to install within a fixed piston seal cavity
2. it also will compensate for linear, axial & volumetric expansion
Raw PTFE is a difficult material to CNC machine.........with your compound step cut I assume the material is reinforced??........Derek
Nope.....straight teflon. A friend of mine with another successful steam launch uses the bronze filled version. Like I said....that's how I made it.
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Florian regarding your post No121
For your pump: You may want to try putting silicone O-rings on your shuttle valve as well (possibly with making another shuttle valve?).
You will find out that the pump then has a lot more force than without!
If you are going to try, I would recommend to make the O-ring grooves only slightly less deep than they would have to be to get the o-rings flush with the valve (I use something like 0.1mm less in depth but 1,2 times as wide as the o-ring is).
The O-rings also dont get damaged by the ports (even if they are sharp) if the O-rings are only very few more than flush with the outer diameter of the valve.
:cheers: Florian
I had considered using Silicone "O" rings on the shuttle but on viewing the drawing there are 2- holes that the ring would foul.
Now this is where I disagree with you, you should never allow a Silicone "O" ring to pass over a port.
Silicone "O" rings expand under steam, some people say 100% which I can accept as the grooves are in excess of the "O" ring cross section.
A number of years ago when I started using Silicone rings I did not believe the makers dimensions for grooves.
As an example , for a 1/2" dia piston the recommended groove for the .070" cross sectioned ring is Min depth .057" - .060" and the width is .094" - .102"
Now I just did not believe these dimensions so in my wisdom I machined the groove with min clearance with the result that the engine ran well for about 5 mins and then stopped, after cooling it would start again with the same result.
So after some thought I machined the grooves as per the instruction dimensions and to this day I still do so and have never had any trouble, on further discussions with some of my steam loco model maker friends, who do exactly the same agree that the "O" ring under steam completely fills the groove due to the expansive nature of the Silicone ring and when cool take up the original round shape of the ring.
George.
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Hi George
Yes, it is not the best thing to have the o-ring sliding over a port. And that was my point of view aswell before a friend told me it works quite well in small scales. I tried it out and in fact it does work quite good - at least they last for quite some time and may get damaged after a while but not so fast.
Regards Florian
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Good evening Lady(ies?) and Gentlemen
Another step has been achieved, the drain cocks were completed.
I also had to get the threads into the cylinder - did it without taking any pictures. However, the drain cocks look like I imagined and I am happy with them except the wooden handles - i would rather like them to be a little darker (in about like pearwood - but I don't have any around. I will see, maybe Ill get some...)
I also made another plug for the pump bore (I only made the one for the top when I was machining the pump body):
To get the pump working really well, I decided to use plungers with o-rings instead of the balls.
The plungers have three cutouts to let the water pass through while guiding themselves with the cylindrical extension on the lower side. I milled those cutouts directly in the lathe.
With the finished plungers, I could testrun the pump for the first time! I was using pressurized air instead of steam though but I guess if it runs well on air it will at least run on steam too.
The Pump can do 11,5 bar with 4 bar air pressure! :cartwheel: I would say that is a SUCESS!!! :whoohoo:
So whats left:
- Cylinder cladding (I am still not shure how to do it)
- building a displacement lubricator
- building a main steam valve
- probably painting it (or blacken part of it?)
I started with the lubricator:
I have found an old drawing of a "full size" displacement lubricator which I want to copy in an according size.
I am going to make it from several parts by soldering them together.
So much for now - I'll continue soon (hopefully :agree: )
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That looks good :ThumbsUp: :ThumbsUp: What sort of speed was it running under load?
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That looks good :ThumbsUp: :ThumbsUp: What sort of speed was it running under load?
It was not running anymore then (I closed the valve)
But It can pump against 10 bar (though it is quite slow then...)
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Hi Florian,
thanks for this detailed description. So you replaced the valve balls by that plunger ? I'm wondering about the size of these parts compared to the original balls :thinking:
Greetings
Gerd
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Hi Gerd
Yes, exactly, I used those plungers instead of the original balls.
The balls have a diameter of 5/16 inch which is about 7,9.... mm. Those plungers have 8mm as biggest radius. 5mm on the guiding extension (with the cutouts - they are made with a 3mm cutter by the way) and 6mm on the rear. That extension on the rear does limit the plunger stroke to in about one millimeter.
Florian
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So let me tell you something about that lubricator:
There is a tube in that "cup" so the steam enters it on the top. (just like a "conventional" displacement lubricator) However, the oiler has its connection to the steam pipe at the lower end.
I have to make a bleeding valve as every displacement lubricator needs it. For this, I am going to solder a little piece into that hole, that is just beeing made with an endmill.
Solderd together - I had to solder in two steps. After soldering and pickling, I machined the "oil cup" to get the seam cleaned up.
The bleeding valve spindle is solderd together from two pieces. It is bored hollow until 1mm before the tip to let the water pass through.
The almost finished lubricator with a ruler, so you get an idea of its size.
The handles for the plug on the top and for the adjusting valve have beend made from boxwood aswell. Well - the lubricator is almost done - if not one of those :cussing: handles cracked. So I'll have to make another one... :shrug:
BUT not today - see ya!
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The lubricator looks great Florian. Very nice job
Steve
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The lubricator looks great Florian. Very nice job
Steve
I agree very nice job Florian
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Beautiful job Florian!
I love to see these wonderful silver soldered fabrications.
Dave
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That's gorgeous Florian....want to make one for me? :ROFL:
Dave
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What a great job on the lubricator. Your soldering work is beautiful.
gbritnell
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Thank you everyone! And no, I didn't forget to get you updatet, just needed to find some time to continue writing.
Well, the lubricator is ready, next part was the main steam valve:
After thinking about how to make the valve and the fittings for joining the valve and the lubricator with the steam chest, I decided to make it as one part. And this is the Idea:
I first machined the main body(sorry for the blurred picture - the Autofocus didn't want to see what I wanted to take a picture of :insane: ), everything is coming along well.
I always put quite enough flux for soldering - I learned that this makes soldering a lot easier. After soldering and cleaning it, thats how it looks on the pump now. I also machined the valve spindle in the meantime. And hat is the lubricator-main-steam-valve unit finished.
Here we go, the oiler, main steam valve and therefore the pump are ready for steam!:
Now this is time for the first steam up of my pump!
Went out, heated up the boiler and tried. The pump hesitantly started running. Then I connected it to the boiler and NOOOOOO. The pump did not move :rant: :hammerbash:
Well, there was a "wait a second" in my head. Someone (here?) told me that silicone O-rings will expand under heat. In fact, the pump could only be moved hard, with quite an amount of force.
So I stopped the whole thing, took the pump back to the shop and removed that o-ring. Instead, I made a piston packing with teflon tape.
Went back up and tried again. The pump was running smoother now and semed to be right. But no, the water wasn't pumped to the boiler, no chance. :facepalm: :shrug:
Well, you have to start somewhere and I mounted a pressure gauge to the connection between boiler and pump.
That showed the pump doing 5 bar with only 2 bar boiler pressure. :thinking:
And thats when I immediately had the Idea that the clack valve could be the evil part of the system.
And yes, indeed it blocked somehow (don't ask me how, I still couldn't figure out how).
I modified it and reduced the ball stroke and there we go:
https://www.youtube.com/watch?v=Op6IKp-x9wM
:whoohoo: :whoohoo:
Cheers Florian
ps: Not much left now, Cylinder cladding, valve rod stroke limiting screw, base mounting holes.
Final assembly with using liquid gasket. And maybe a paint job.
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Awesome!.....Well done man! :ThumbsUp:
Dave
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Very nice!
Dave
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Beautiful piece of work Florian! I like.......... :ThumbsUp:
Don
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Hi Florian, very nice and good work. I am lucky that I could see your masterpiece last weekend in full and original size.
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Nice :ThumbsUp:
Oh dear.. now you have me wanting to look at my casting set for one of these :facepalm: Yesterday it was Rod's fault.. I had the Centaur castings out for him and it was difficult to put them away again :embarassed:.
Jo
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Very nice indeed :praise2: :praise2: I am guessing that you didn't take the video yesterday ;)
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I am guessing that you didn't take the video yesterday ;)
Nope ^-^
It was taken on monday the 6th of january. ;)
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:o You made us wait a whole week to see it :(
Jo
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Yes! But it has nothing to do with MEM :embarassed:
There was the "Echtdampf Hallentreffen" in Karlsruhe (Germany) and I was waiting with the upload on youtube because a few guys from the german forums know my youtube account very well and they would have seen the movie before seeing the Pump (they had no Idea I was making this pump...) ;)
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Awesome stuff Florian, fantastic to see it working on steam and actually doing a job. :ThumbsUp:
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Hi Florian,
( quote from your post No 143 .
Well, there was a "wait a second" in my head. Someone (here?) told me that silicone O-rings will expand under heat. In fact, the pump could only be moved hard, with quite an amount of force.
So I stopped the whole thing, took the pump back to the shop and removed that o-ring. Instead, I made a piston packing with teflon tape. )
I mentioned the Silicone ring some time ago that it expands 100% under steam.
You have used Black Viton rings that are not suitable for steam but Pneumatics and Hydraulics, so when the steam hits them they stick.
Also the groove dimensions that you use seam too tight if you were to use Silicone "O" rings.
I must commend you on your decision to make the pump slide valve rather than to the Stuart drawing, it has much more control without the amount of steam loss in the exhaust which is a bit of a pain in a Piston valve set up hence Stuart pumps are renowned for their steam consumption.
It would appear that the "O" rings on the shuttle is a good thing but can't be fitted to the Stuart drawing as they would pass over the steam ports and tear.
I finished my Pump a few weeks ago and it performs well being self starting and can be slowed down, I left out the drain valves as the pump clears itself of condensate every time on start up, the tapped holes for the drains are there with a plugs inserted to fit valves in the future if ever needed.
Good job, well done !!!!!!!!!!
(Enclosed some pics of my completed pump)
George.
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Hi everyone
I am sorry that i've let you wait such a long time! I didn't do anything on the pump for a long time. But there is a good reason why:
I had to do the electronics for my milling machine. That means building up the ontrol cabinet for the frequency converter (1st picture)
Now my milling machine is "independent" and has its own speed controlling unit (2nd picture)
AND I had to do the same for the lathe, so you can imagine id did take some time to do this for both machines!
However, lets get back to the pump!
Next was building the cylinder cover:
I didnt like the anodized piece of aluminium sheet that was delievered by stuart. I thought it was much to thick to look good!
So I took some 0.1mm brass sheet. Though that is not as easy to machine as the aluminium sheet. I started with the metal shears and then milled the edges with the piece of sheet clamped between two pieces of wood.
After the cover had its exact dimensions, I made the little holes to fix it using a 1mm mill. (I was worrying about the sheet to be pulled up using a drill)
I then expanded the holes to 1.3mm using a drill, that worked quite good (after I tested it on a little waste piece) The screws inserted for a first impression.
Then I had to drill the center holes into the cylinder. I started with the row on one end, all the others were done with the pattern of the cover.
First using a center-drill to spot-drill, then continuing with the 1mm drill which is the center-bore for an M1.2 thread. The tape is used to hold the cover tight to the cylinder whilst drilling. I always had to position on one side of the cylinder and then could move the y-axis. That did work really well because I had drilled the cover-holes by coordinates.
Finally cutting the thread. I usually start the thread in the machine but then remove the workpiece from the vice so I can hold tap and workpiece in my hands as it is easier to control the amount of force you put on the tap.
To be continued right away (almost ;) )
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After the screwholes, I had to make three big holes (8mm) for the exhaust and for the two drain cocks.
How I locate the exact position on the cover.
First I put a piece of round material with an according thread into the cylinder.
Then I rise the milling machine's table (with the vice on it) and move the table until the cylinder is just on the fixed jaw.
After clamping, I remove the piece of material and put the cover on the cylinder
Then I made three pilot holes with the center drill. And I had to repeat this procedure for the two other holes.
After removing the cover from the cylinder, I centered the pilot hole under the spindle using a "needle". You may notice the piece of wood held above. With the needle removed, the sheet is clamped with that piece of wood.
Finally, the holes are milled up very carefully with an 8mm endmill.
Three times drilled, three times a sucess (with such a thin piece of sheet...)
Then assembling it to see how it looks. Yes! Came out very nice! :cheers:
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Glad you're back machining metal again :ThumbsUp: :ThumbsUp: That cover looks great :praise2:
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A job I was waiting with (for lack of an end mill which was wide enough): Plaining the bottom side of the pump base.
I also had to drill the holes to fix it to the ground. I drilled them from the upper side because the casting was not very good. And I wanted them to be more or less centered in those "ears" (How are they called??)
I also had to drill another hole for the valve rod stop-screw as well as making it and the counter-nut.
Finally, I replaced the teflon tape packing on the piston with a self-made glyd-ring.
To get the teflon-ring onto the piston, a tapered tool was required.
But after expanding, the piston ring doesn't want to get as small as it was before. So you also need some kind of a funnel to get the piston back into the cylinder:
That's it for the moment. I am waiting for some solution to blacken the cylinder cover. But mechanically the pump is finished now! :jumpingsmileys:
Cheers Florian
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For the fixing ears you could also use the term lugs (which is, however, also English slang for the ears on your head :) )
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Nice work Florian,
Good to see you back at it!
Dave
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Florian........
1. your sizing & resizing tools are perfect to the application for the installation of the Busak style piston Glyd ring........
2. I have never seen the use of two o-ring energisers under the one piston seal, certainly Hallite, Merkel, nor Frudenberg nominate such use....having said this.....I see no reason why this should be an issue
3. because the TEFLON material has such poor memory qualities, we place the Glyd ring in boiling water + a few tea spoons of sugar....then microwave :Mad: for a short period....this actually increases the boiling point of the water by say 5 to 8%
4. this then provides greater elasticity of the TEFLON & less potential for permanent deformation or stretch prior to the resizing process
5. the reason for this is the TEFLON cools quickly when in contact with metal
Derek
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Hi Derek
The Reason for using two o-rings instead of one is just laziness. This way, I didnt have to modify the groove in the piston.
Florian