Model Engine Maker
Engines => From Plans => Topic started by: JCvdW on October 29, 2020, 09:47:59 AM
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Being inspired by the MEM Corliss steam engine build threads of Arnold (http://www.modelenginemaker.com/index.php/topic,1333.0.html (http://www.modelenginemaker.com/index.php/topic,1333.0.html)), Vince (http://www.modelenginemaker.com/index.php/topic,1526.0.html (http://www.modelenginemaker.com/index.php/topic,1526.0.html)), and others, I decided to give it a go.
I will be using the 24mm to 1 inch metric plans, found here: http://www.modelenginemaker.com/index.php/topic,1285.60.html (http://www.modelenginemaker.com/index.php/topic,1285.60.html)
Thanks to everyone for all the relevant information available on this forum.
Being a novice, and this my first steam engine, this may end up being a bridge too far ...
I decided to start with the flywheel, and to construct it from separate parts for the rim, spokes and hub.
I ordered some hollow bar for the outer and inner rim. The closest sizes I could find were 180 x 150 mm and 170 x 140 mm.
(https://i.imgur.com/BiNsF8B.jpg)
The Myford Super 7 has a capacity of 178 mm, so I had the outer rim machined down to 176 mm by a local engineering shop. The outside had a very good finish, which I hoped I could use as is. I clocked it in as best I could on the four yaw chuck and started boring out all the excess material.
(https://i.imgur.com/be0BoD7.jpg)
As the rim got closer to size, I noticed that the material had warped and that the outside was not running true anymore. By now the rim could fit over the chuck, so I remounted it and turned the outside to be circular again, removing 50 micron at a time. The tool just reaching the width of the rim.
(https://i.imgur.com/zuJbNm9.jpg)
Now to bore the inside to final dimension. I tried to grip the rim on the outside, but found that gripping on the inside results in less distortion of the rim. The best I could clock it to was about 100 micron, with as light a grip as possible. I bored out the inside from both sides taking off 50 micron at a time. I left the inside diameter on one side about 100 micron smaller to create a reference edge for the inner rim to fit against, as suggested by Arnold.
So after many more hours than I expected at the start, the outside rim is complete. Quite pleased with the final result.
(https://i.imgur.com/fsYkWMY.jpg)
Now for the hub and the inner rim. I already made an indexing plate that fits on the outside of the lathe spindle, to use when drilling the spoke holes.
(https://i.imgur.com/Nd2ecIG.jpg)
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Hi JC,
as someone just coming to the end of a Corliss build here's to wishing you well with yours. The MEM design is a nice project and a fine runner - Good luck with your endeavors :ThumbsUp:
Regards - Ramon aka 'Tug'
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Hi JC,
as someone just coming to the end of a Corliss build here's to wishing you well with yours. The MEM design is a nice project and a fine runner - Good luck with your endeavors :ThumbsUp:
Regards - Ramon aka 'Tug'
Hi Tug
Thank you very much. I had a quick look at the video of your tandem Corliss. Beautiful! Well done! Workmanship that I can only aspire to!
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Good luck JC. I am sure you will enjoy the build. Pulling up a chair and some popcorn.
Vince
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Started on the hub. Mounted my hand drill on the cross slide to drill the spoke holes. Clocked it in to be perpendicular to the hub.
(https://i.imgur.com/RVjzKTZ.jpg)
Setting the height of the drill, using an old drill bit with tip ground to a point.
(https://i.imgur.com/HFB70rm.jpg)
Tapping the eight M6 spoke holes with a spring loaded tap holder in the chuck.
(https://i.imgur.com/UT2FSXl.jpg)
All spoke holes done. I took Arnold's idea and also drilled and tapped M4 holes for two grub screws to secure the flywheel to the crankshaft. Shaft hole drilled 1mm undersize, to be accurately bored later once the flywheel is assembled.
(https://i.imgur.com/o4SWJ7L.jpg)
Hub complete.
(https://i.imgur.com/RLq6oiP.jpg)
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Good luck JC. I am sure you will enjoy the build. Pulling up a chair and some popcorn.
Vince
Thank you Vince. You are one of the reasons why I decided to give this a go. :D
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Hmm... JC, for some reason I'm not seeing your pictures. Is anyone else having this problem? Or is it something specific on my end?
Kim
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Hmm... JC, for some reason I'm not seeing your pictures. Is anyone else having this problem? Or is it something specific on my end?
Kim
Not seeing the pictures here either. :(
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The photos were visible this morning but not now.
Vince
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Haven't seen any images so far - logged in or out :(
Tug
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Hi JC,
Sorry about the photo problems :(
I'm betting that it's a permissions issue with wherever you have them hosted. When you upload the pictures, you're logged in, so you can access them and see them in your posts. But nobody else is logged into your account, so we can't see them.
There's probably a way to change the permissions on the photos to allow other people access. I don't know what service you're using, so I can't give you more specific info. But I'm guessing if you poke around in permissions you'll come up with something.
Good luck!
Kim
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Kim & Tug, thanks for the feedback re the photos.
Turns out that the photo links I used were not permanent, and as far as I can tell, permanent links are not available for ICloud images. I am now using Imgur to host the images, and direct permanent links to the images are immediately shown.
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That's much better JC - good photos too. Looks like you've made a good start :ThumbsUp:
Tug
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Thanks JC,
Yes, I see your pictures now! Thanks for taking the time to re-post them.
Looks like you're making good progress on your flywheel!
Kim
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:ThumbsUp:
Nice job! I especially like the cross-drilling set up.
:popcorn:
John
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Great start, always nice to see another build of this engine. Will be watching along!
:popcorn: :popcorn: :popcorn:
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Thinking ahead on how to assemble the flywheel, I decided to also hold the hub in the lathe end stock using a Jacobs chuck, the way Arnold did it. So far the axle hole in the hub is only drilled, and not perfectly straight. I therefor mounted the hub in the four yaw chuck and bored the hole to be straight and concentric, but still slightly under size.
The runout of the Jacobs chuck is about 100 micron, so I decided to turn a temporary concentric arbour for the hub by mounting a piece of scrap in the Jacobs chuck. The MT2 taper of the chuck does not take a drawbar, so I supported the work with a dead centre in the end stock, and turned down the arbour for a snug fit of the hub.
(https://i.imgur.com/cJjyPuO.jpg)
With all the preparation work out of the way, it was time to turn the inner rim of the flywheel. Quite a lot of material to remove! After the warping I saw on the outer rim during bulk material removal, I decided to first turn and bore the inner rim to about 1 mm from final dimensions, before aiming for the final dimensions.
(https://i.imgur.com/sLMhLTK.jpg)
Many hours and lots of swarf later, the inner rim has the correct inside diameter and thickness, ready for the spoke holes to be cross drilled. The outside diameter is still oversize, to be turned down once the spokes are in place.
(https://i.imgur.com/Y26huLx.jpg)
Cross drilling the spoke holes, using the same indexing plate used for the drilling the spoke holes in the hub.
(https://i.imgur.com/QzxDnJw.jpg)
Test fit of the spokes and hub before glueing with Loctite retaining compound. So far so good.
(https://i.imgur.com/dJkC7uz.jpg)
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That's a good start JC, looks very promising :ThumbsUp:
Keep it coming ;)
Tug
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Thanks for the feedback Tug!
Before glueing the spokes, I checked the concentricity of the hub by running the assembly on the lathe, and everything looked perfect. So I disassembled the lot, and cleaned it for glueing. Great was my disappointment after glueing the spokes, that the hub was quite a bit off centre!.
By then the Locktite was rock solid, and I had to use a blow torch to get the spokes out. I realised that I needed finer control to position the hub, and decided to thread the ends of the spokes. With nuts on the ends of the spokes I could then accurately dial in the hub to run true.
(https://i.imgur.com/fu5I0Fb.jpg)
I could then glue the spokes by removing one at a time, glueing and then locking it back into place with one eye on the dial indicator. The end result is a hub that runs true within 20 micron on the one side of the wheel. I eyeballed the hub on the head stock side of the wheel while running the lathe at moderate speed, and it looks ok as well. Final boring of the axle hole should take care of any residual skewness of the hub. Once the glue has cured, I can proceed to saw off the spoke ends and machine the outside diameter of the inner rim to fit the outer rim.
(https://i.imgur.com/zhbtYoN.jpg)
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That is looking great - nice save on the spokes too!
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With the Loctite set, I sawed off the spoke ends and then carefully turned the inner rim down until the outer rim could just slide on, up to the slight ridge left on the inside of the outer rim. I decided to use JB Weld slow setting epoxy to join the two rims. This allowed me ample time to carefully position the outer rim to run as true as possible with the inner in the four jaw chuck. I am quite pleased with the final result.
(https://i.imgur.com/80YTXE0.jpg)
While waiting for the glue to set, I started thinking about the cylinder block, and read through Arnold's and Vince's build threads. Quite a lot of new challenges ahead. First of all getting the chunk of 60 x 60 mm mild steel down to 50 x 50 mm, then getting familiar with terms such as fly cutting, honing and/or lapping of the cylinder. And drilling and tapping lots of M2 and M3 holes. In anticipation of the latter, and seeing that the raw material is oversize, I carefully drilled a shallow 1mm hole with the milling machine to get a feel for what is possible.
(https://i.imgur.com/JgPPbCh.jpg)
Any general advice on any of the above will be much appreciated. I do have a spare block of raw material, just in case :LickLips:
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Terrific job on the flywheel, looking forward to seeing the cylinder shaping.
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It will end up looking like Swiss cheese - full of holes. :D :D
Vince
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I cheated on my Corliss by boring out the block to just oversize then pushing in a thin brass tube liner. The finished bore was slightly undersize to drawing but it meant I did not have to worry too much about the surface finish during boring or having to hone it. The brass tube had a polished id quite acceptable for use with a piston using an O ring without any further work.
Of course you might be relishing the boring and honing challenge...
Andrew
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Thanks for the encouragement crueby!
Andrew, the liner idea is interesting. Will keep it in mind as plan B. Would like to learn a bit about lapping though. I read Tug's thread on lapping today (http://www.modelenginemaker.com/index.php/topic,1908.0.html (http://www.modelenginemaker.com/index.php/topic,1908.0.html)), and would like to try some of his techniques. Thanks Tug!
My power hacksaw, which I built as my first metal work project earlier this year during the lockdown, earned its keep today. It is based on plans I purchased online from myfordboy (https://myfordboy.blogspot.com/p/compact-power-hacksaw.html (https://myfordboy.blogspot.com/p/compact-power-hacksaw.html)). Within 90 minutes, it reduced the 60 x 60 mm cylinder stock to 51 x51 mm. I was not sure if it will be up to the task. And I am really impressed with the bimetal hacksaw blade. It would easily cut another mild steel block down to size.
(https://i.imgur.com/noOEpk9.jpg)
(https://i.imgur.com/LBmjgsS.jpg)
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After some distractions I finally managed to complete the flywheel by boring out the axle hole to 9mm using one tip of a 5mm end mill.
(https://i.imgur.com/Jlzl5TJ.jpg)
(https://imgur.com/Jlzl5TJ)
I also turned the shaft, and with the flywheel off the four yaw chuck for the first time in a long while, I am quite pleased with the final result.
[youtube1]https://youtu.be/3VCCpnVdjnQ (https://youtu.be/3VCCpnVdjnQ)[/youtube1]
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Looks like you got it to run very true :ThumbsUp:
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Nice work on the flywheel!
Dave
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:ThumbsUp: :ThumbsUp:
Vince
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The 8mm HSS tool bit for the fly cutter arrived a few days ago. I watched the Youtube video 'Use of the fly cutter on the milling machine' by Tom's Techniques and studied his drawings on how to grind a tool bit for fly cutting. With my newly ground fly cutter, I squared up the cylinder block and brought width and height to final dimension. I left the length 2 mm too long, to be faced off later when boring the cylinder on the lathe. Quite happy with the result.
(https://i.imgur.com/ohvvoLn.jpg)
My newly acquired 2mm and 3mm taps and related drill bits are now waiting to turn this block of steel into a Swiss cheese ...
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Got an excellent finish with the fly cutter!
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After a bout of Covid 19, it was time to do something in the workshop again. I decided to bore the cylinder. Up till now I had better results on the lathe with HSS tool bits compared to carbide inserts. So I had to make a HSS boring bar. I like the boring bars made by Stefan Gotteswinter (https://youtu.be/O9d_I0A4kzg (https://youtu.be/O9d_I0A4kzg)), so I first had to make a tool to make a tool - a slitting saw arbour (also according to a design by Stefan) to cut a slit for the boring bar.
Unfortunately I only had 10mm round stock for the bar, and all the suppliers are closed for the summer break. Would have preferred it a bit thicker.
(https://i.imgur.com/XuiJbfs.jpg)
After facing the cylinder block on the lathe, I drilled out the cylinder to the maximum diameter drill I have, and then started boring with a carbide insert (lots of chatter) until the hole was big enough to accept my brand new boring bar with its freshly ground 4mm HHS bit.
(https://i.imgur.com/IhZgx54.jpg)
(https://i.imgur.com/EypQR9A.jpg)
Roughing out went smoothly, my boring bar is working! No chatter. As I approached the final dimension, I rounded the tool bit a little bit with a stone, reduced the depth of cut, and decreased the feed rate, expecting a very smooth surface finish as the result. Big mistake! Steep learning curve! The tool immediately started to chatter. Being close to final dimension, I had to stop boring. Should have started experimenting earlier! Due to the small depth of cut, the chatter marks are relative small though. I am now curious to see if lapping will remove the chatter marks and leave a smooth finish. As soon as I can find a 3mm sheet of copper I will attempt lapping by following Tug's thread http://www.modelenginemaker.com/index.php/topic,1908.0.html (http://www.modelenginemaker.com/index.php/topic,1908.0.html).
But before lapping, I first have to drill the inlet and exhaust holes.
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I decided to follow Vince's approach to drill the port holes. But first another tool had to be made - a lathe stop. I followed Joe Pieczynski's design (https://youtu.be/LrCS_-3Gh0Y (https://youtu.be/LrCS_-3Gh0Y)). I also made a 15 deg reference plate for the vice, and then proceeded to mill 3mm flats for the drill bit to start on.
(https://i.imgur.com/xfJKOYp.jpg)
Then it was time for the first 1.5mm hole. I spot drilled with a 90deg spot drill, held my breath and started drilling. At about 8mm depth, the drill broke.
(https://i.imgur.com/A2WTfyd.jpg)
This is not going to work. The maximum speed of my mill (Rong Fu 45 clone) is only 1600 RPM, the total runout is about 30 micron, and of course there is no feel for what the drill bit is doing. And the required depth of a hole is more than 12 mm.
So what to do? At this point I think it will be better to first drill the valve holes, mill the steam pockets, and only then drill the small holes, which then only has a depth of about 2mm. I am also contemplating to buy or make a micro drill adapter which allows feeding the drill by hand while still being driven by the mill, as demonstrated here (https://youtu.be/PqU5wS0J4MU (https://youtu.be/PqU5wS0J4MU)). Another alternative would be to use my home made CNC router (which has so far only been used for milling wood). It has a variable spindle speed from 5000 to 20000 RPM.
I do not think it will be possible to remove the broken drill bit. On the bright side - at least now I have a cylinder block to try out different drilling strategies, and also practise lapping.
Any advice will be much appreciated.
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Hi JC,
Commiserations on that broken drill - not the best place to be at any time. Still it looks recoverable.
My thoughts would be to forget the broken drill and use a slightly larger drill to do the remaining holes within the limits of the slot - 2 -2.2mm maybe and drill slowly (feed) at your max revs. 1600 rpm may not be text book but should be more than sufficient. Lots of small pecks and withdrawal to clear the swarf is needed on this situation. It doesn't take much swarf to jam a small drill and that's a deep hole relevant to diameter. Keeping the swarf clear is something to keep in mind at all times here
You could use a carbide drill to try to remove the broken one but given where it is and the little effect it will have on the final running personally I wouldn't bother - you could end up making things worse which is always a risk. Increasing the diameter of the holes will easily make up for any loss of flow. Annoying to think it's there though but once covered - 'out of sight out of mind' soon makes it forgotten about ::)
Your mill looks very similar to my Amadeal so I assume you have a drill spindle function. It has to be said that mine is 'heavy' in feel compared to my drill which does affect feel on using small drills but with care this op should be manageable as set up.
Hope that's not teaching granny etc -
Good luck with it - and that lapping ;)
Tug
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I drilled out the valve holes and milled the valve chambers before drilling the valve passages. However it was still a fraught operation as the drill then starts on the curved surface of the valve hole and starts to dance unless extreme care is taken. A very light touch is needed to allow the drill to centre.
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Tug:
Thanks for the feedback. It made me realise that the cylinder block is not lost, and I should be able to recover from the broken drill bit. I also realised that it should still be possible to dislodge the broken bit when machining the steam pocket.
astroud:
Thanks for the info. I will never have a light touch with my milling machine. I therefor decided to order a sensitive drill attachment from LittleMachineShop in the USA, which allows one to feed the drill by hand. Hope this will solve my problem. It is just frustrating that none of these more specialised tools are available in South Africa.
In the mean time I found some 2mm copper sheet at the local scrap yard, and made a cylinder lapping tool. Thanks again for your info Tug! I am not familiar with silver soldering, so I glued the copper tube to the leading edge of the D-section using two part epoxy. This is working well.
(https://i.imgur.com/RSfMo0g.jpg)
I could not resist trying out the lapping tool even before for the steam ports have been drilled. I used some fine automative grinding paste, and the chatter marks quickly disappeared. I followed this with some polishing compound that I happen to have in the workshop. The cylinder is not perfect yet, but much better than before. As far as I can tell with my telescoping inside micrometer, the bore is as parallel as I can measure.
(https://i.imgur.com/1XmfTc1.jpg)
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Nice work on the lapping JC :ThumbsUp: good to note that epoxy did the trick too. Silver soldering is always a bit fraught in case it runs to far.
Keep it coming
Tug
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Thanks for the encouragement Tug!
While waiting for the sensitive drill attachment to arrive, I made the outrigger bearing pedestal. I treated myself to a rotary table for Christmas and thought the round corners of the pedestal base to be a good opportunity to try out my new toy. I mounted the four yaw chuck on the rotary table to hold the part.
(https://i.imgur.com/TLtEMTc.jpg)
(https://i.imgur.com/lMH4hdR.jpg)
(https://i.imgur.com/QPdIT1w.jpg)
Unfortunately, the corner radii came out too large, so I will have to remake the part. It never the less turned out to be a good practice run with the rotary table and also to practice some filing and sanding to remove machining marks from a milled part. Next time I will machine the corners first, while the part is much more sturdy to clamp in the rotary table. I will also use some shim stock packing to prevent clamping marks.
(https://i.imgur.com/WH6qN2d.jpg)
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The sensitive drill attachment arrived today. Made in China, imported from the USA... There is quite a bit of play in the sliding mechanism, so I was a bit sceptical at first. After successfully drilling ten 1.5mm holes through a 10mm piece of scrap mild steel, I however feel much more confident to drill the cylinder block. One directly feels what the drill is doing. If the drill bit gets stuck as it breaks through, it simply spins in the small chuck, without breaking.
(https://i.imgur.com/JVlT8UH.jpg)
(https://i.imgur.com/O97ppSd.jpg)
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Hi JC,
Something that did occur to me and perhaps worth mentioning before you have another go at drilling the cylinder.
Did you just centre drill on an angled surface with cylinder set at the angle or did you create a flat bottom square to the drill before centre drilling. If the surface was at an angle, despite being centre drilled that can kick a drill off - it would be best to plunge a small cutter in to bring the surface level to the drilling direction before centre drilling.
Good luck with it :ThumbsUp:
Tug
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JC, how does the sensitive drill attachment work - is there a clutch in it, or are you adding pressure with that ring?
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JC, how does the sensitive drill attachment work - is there a clutch in it, or are you adding pressure with that ring?
The attachment has a spring loaded telescopic shaft to drive the chuck from the mill. The external ring is attached to the movable shaft with a bearing. One holds the external ring by hand to apply down force on drill bit. Total available downward movement is about 24 mm.
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Tug, thanks for the suggestion. I did mill a flat surface in the cylinder block with a 3mm end mill before drilling.
Working on the bearing pedestal made me realise that I need more practice on the mill before taking on the more complex parts. So I postponed further work on the cylinder block for a while.
I had another go at the bearing pedestal, with a much more satisfying end result. A coat of primer, and it is ready for storage. I never expected making these parts will take so long, so it will probably remain in storage for quite a while ...
(https://i.imgur.com/pW4sJF4.jpg)
(https://i.imgur.com/qnVnj7K.jpg)
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I decided to make the cylinder feet next. Relatively simple parts to gain more experience with the mill. I have realised by now that starting out with correctly dimensioned and squared stock, makes life much easier further down the line. It also became apparent that I can do with a set of parallels for the vice, rather than the piece of steel ruler that I am currently using.
I went for the split design of the feet, for easier assembly later.
(https://i.imgur.com/GfgwVkp.jpg)
(https://i.imgur.com/tMwwwy4.jpg)
(https://i.imgur.com/QzAxacw.jpg)
(https://i.imgur.com/jdbG8wa.jpg)
A coat of primer will hide any minor remaining machining marks, so I am happy with the feet so far.
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I finally finished the two cylinder feet. I keep on surprising myself with how easy it is to make a silly mistake. I drilled one of the feet mounting holes too big. Rather than remaking the part (for the third time!) I made a plug and Loctite it into the oversize hole.
(https://i.imgur.com/2dkPVvI.jpg)
A coat of primer to keep the rust away, and the feet are ready for future assembly.
(https://i.imgur.com/2IoQCm5.jpg)
(https://i.imgur.com/JwblgkW.jpg)
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Started on the two bearing blocks for the flywheel. I decided to machine both bearings together from a single block of bronze which I had cut from a piece of round bar. I will later separate the two bearings with a slitting saw.
(https://i.imgur.com/AGrfEE5.jpg)
I bored the axle hole on the lathe using a long 5mm end mill as boring bar. I also faced it off to have one side of the block perpendicular to the hole. The axle in the hole then served as reference to machine the base of the bearings parallel to the axle.
(https://i.imgur.com/axlQEDO.jpg)
I now have to create the curved top of the bearing...
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I shimmed the top edges of the milling chuck with the blade of a feeler gauge and then milled the curved top of the bearings by rolling the bearing block on the axle.
(https://i.imgur.com/LclwwaX.jpg)
Using a Magnifying Glass application on my mobile phone, I could accurately position the cutter to mill right into the corners of the curve.
(https://i.imgur.com/Oi3BTQZ.jpg)
After some further sanding with home made sanding sticks, I am quite happy with the result so far.
(https://i.imgur.com/NsZbmn0.jpg)
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great work!
:popcorn: :popcorn: :popcorn:
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:ThumbsUp:
That did turn out nice!
Cool idea about the "Magnifying Glass"!
John
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Thanks John en crueby for the kind remarks!
After drilling the mounting holes, I split the two bearings with a slitting saw, and machined to size.
(https://i.imgur.com/BD8yRlu.jpg)
(https://i.imgur.com/oELxM39.jpg)
Now for the Crankshaft Support to mount the second bearing ...
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I started making the Crankshaft Support by machining the rounded corner. Not having a cutter for this, I used a ball nose cutter the same way a CNC machine would do. I calculated the incremental X and Z coordinates that will result in a rounded corner. It certainly worked better than trying to round the corner with a file.
(https://i.imgur.com/RKO9KVX.jpg)
(https://i.imgur.com/ZhlRK9l.jpg)
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Finished machining the Crankshaft support today. Motivating to see the first bit of a subassembly!
(https://i.imgur.com/OoVy8EX.jpg)
(https://i.imgur.com/sKBlQKe.jpg)
(https://i.imgur.com/tPArNk9.jpg)
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Nice.
Starting to take shape.
Vince
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Thanks for the comment Vince!
I started on the Guide, by fly-cutting some mild steel stock, and soon realised that the smooth finish I obtained when fly-cutting the cylinder block was beginners luck!
(https://i.imgur.com/6GEXlUp.jpg)
This provided the perfect excuse for a diversion - to build a power feed for the X-axis of the mill. https://www.modelenginemaker.com/index.php?topic=10327.msg235437#msg235437 (https://www.modelenginemaker.com/index.php?topic=10327.msg235437#msg235437)
The power feed is now complete. I am very happy with the fly cutting results (after also realising the importance of grinding the correct shape on the high speed steel cutter!).
This inspired me to have a second attempt on the cylinder block. The result is a block of mild steel with much more accurate dimensions compared to the first one, and with a much smoother cylinder bore prior to lapping. I am now at the point where I can drill the steam ports again. Holding thumbs!
(https://i.imgur.com/0qjlsSs.jpg)
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This weekend I successfully drilled the 20 1.5mm steam port holes in the cylinder block using my sensitive feed micro drill chuck. What a relief! I used three new drill bits on the 20 holes, just to be on the safe side. The micro drill chuck is tightened by hand, allowing the drill bit to spin in the chuck if it catches when breaking through.
(https://i.imgur.com/i1dl56x.jpg)
(https://i.imgur.com/2q65XPQ.jpg)
I then drilled and reamed the four 6mm holes for the steam valves. I was not aware of the difference between a hand reamer and a machine chucking reamer, and started out using a hand reamer in the milling machine by mistake. I reamed a test hole in my discarded first cylinder block and obtained a smooth and straight 6 mm hole. So far so good. But as Murphy would have it, when reaming the first hole in the second cylinder block, the reamer broke. Fortunately without too much damage to the hole.
This forced me to read up on reamers, and to watch some Youtube videos (which I should have done earlier!). I bought the correct machine chucking reamer today, and reamed the remaining three holes without incident. Nerve-racking, but I guess this is the whole purpose of the exercise - to learn.
(https://i.imgur.com/eVrLxGs.jpg)
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Gotta be a big relief to have those holes done, that engine has a lot in the block. Time to sit back and admire it!
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Top work. Fly cutting is immensely satisfying for some reason, but also really nice and precise work porting that block, you must be pretty happy with that. Off to look at your power feed now.
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Nice one JC. A lot more holes needed in that cylinder block. It will end up looking like Swiss cheese.
Vince
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Splendid, I liked the CNC (count number of cranks) rounding method :praise2:
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Thanks for checking in Crueby, Stuart, Vince & Roger. Words of encouragement are always much appreciated!
I made a small M2 tap wrench and tap depth stop as suggested by Joe Pieczynski:
[youtube1]https://youtu.be/XNmd1-v62tw[/youtube1].
After a few holes in my practise cylinder block, it was time to tackle the real one.
Four holes tapped. Twenty eight more to go ...
(https://i.imgur.com/yQi1XLC.jpg)
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Great work! Thanks for posting Joe Pie's video too. Now I know what new tools I need to make to help with my tapping struggles. :whoohoo:
Eric
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Thanks Eric. The small tap wrench certainly helps to feel the tap resistance, and when to clean out swarf. I magnetised a 1.5 drill bit for this purpose. However, I still managed to break an intermediate M2 tap! With this particular make of tap I could not really use the first tap in the set, and I think the intermediate tap was getting blunt and fatigued.
After some agony, I managed to mill out the broken tap with a carbide 1.5 ball nose cutter, without causing any noticeable damage. Disaster averted!
I then bought a German set of M2 taps, which is definitely of a better quality. With this set I can use all three taps, with less strain on each tap.
Today I finished drilling and tapping the 32 M2 holes for the valve bonnets. With all the M2 holes out of the way, I feel a bit more confident about all the remaining holes in the cylinder block.
(https://i.imgur.com/2Xm0sm1.jpg)
It is time to lap the cylinder and then make the front cylinder cover.
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I tried to lap the cylinder as before, using the lapping tool described previously. But try as I might, I could just not get the same finish on the cylinder bore again. After a lot of fiddling around, I decided to look back at my previous post. The secret was a bit of polishing compound!. Applied polishing compound - and the finish is much better. I am going to assume that this will be good enough for teflon piston rings.
(https://i.imgur.com/0BbxbFC.jpg)
After studying the excellent build threads of Arnold and Vince (again!), I drilled and tapped the holes for the front cylinder cover using the PCD function of the DRO.
(https://i.imgur.com/rlol5e9.jpg)
I then turned the front cylinder cover, making sure that it fits snugly in the cylinder bore.
(https://i.imgur.com/3LKb5Z9.jpg)
I located and drilled one of the 3mm through holes and then bolted the cover to the block to spot drill the other seven holes.
(https://i.imgur.com/VMjfgCi.jpg)
Quite happy with the final result. I always find a completed subassembly very motivating to carry on...
(https://i.imgur.com/75zMsSt.jpg)
Looking ahead, I am wondering what the purpose is of the gland nut that screws into the rear cylinder cover?
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Great results on the lapping, that should do very well. Excellent progress overall!
:popcorn: :popcorn: :popcorn:
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Looking ahead, I am wondering what the purpose is of the gland nut that screws into the rear cylinder cover?
The gland nut holds the seal in place for the piston rod.
Eric
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Thanks for the feedback crueby & Eric!
Vince mentioned in his build threat that he adjusted some of the M3 hole locations on the cylinder block to allow for better nut placement. I followed his approach and modified the size and hole positions for the front cylinder cover. He mentioned similar changes for the cover plates.
All these small changes to the original metric plans started to bother me. After all the machining already done on the cylinder block, I want to avoid drilling a hole in the wrong location at all cost.
So I decided to first model the cylinder block and all its attachments in Autodesk Fusion 360. A software model is after all much more forgiving when putting a hole in the wrong place! The model also allows me to see how the engine will eventually look with standard M2 and M3 nuts and washers.
(https://i.imgur.com/ADj4LdS.png)
An interactive version of the model can be found here: https://a360.co/3p3kaKt (https://a360.co/3p3kaKt)
I hope that I can find the correct size DIN 433 M3 washers locally. The freely available M3 washers are a bit oversize, with an outside diameter of 6.8mm, in stead of 6.0mm.
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Hi JC
I received your PM. I have a habit of changing the size of the nuts and bolts primarily because I think they might look better. At that time I used standard size nuts and bolts but now I know that there are model size nuts and bolts which look even better.
https://knupfer.info/shop/index.php/deutsch/modellmuttern/va-a2-niro/402-30.html
As for washers, I used DIN 433 washers which are smaller than standard size washers which I got from the UK.
https://www.westfieldfasteners.co.uk/Metric-Washers/For-Cheesehead-Washer-M3-A2-Stainless.html
I don't remember exactly why I might have changed the position of the bolt holes. If it was for an important reason I might have mentioned it in my build log. The only reason I can think of is that I might have been worried that some of the bolt holes would be breaking into the valve holes.
That's a great looking 3D model of the cylinder. I have 3D modelled my Kiwi and also the Monitor steam engine in Fusion 360 but for some reason not the Corliss.
Sorry if I wasn't a great help in my reply to your PM.
Vince
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Hi Vince
Thanks very much for your quick response to my PM!
You helped me a lot. Using the Knupfer nuts certainly looks much better.
(https://i.imgur.com/udJyzod.png)
Now I have to deal with the EUR/ZAR exchange rate! :'(
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I think on the knupfer homepage they are saying that they will be on holiday from the first of June till the sixteenth of June.
Vince
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All 84 holes in the cylinder block drilled and tapped! :whoohoo:
(https://i.imgur.com/xw9MTC2.jpg)
Now only the steam pockets left to mill, then the cylinder block will be complete. But somewhere in the future there are still 84 studs waiting to be made...
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That is a major milestone - all those holes and threads in the right places and no major mishaps :ThumbsUp:
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Terrific! Great spot to sit back and admire your work!
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Thanks Crueby and Admiral_dk! I thought I should first complete the engine block before sitting back, so today I milled the two pockets for the steam ports. Now the cylinder block is truely complete!
I started by plunge milling with a 10mm cutter, and then finished off with a new 7mm cutter that I had. Really enjoyed my X-axis power feed on the mill today.
(https://i.imgur.com/yylRsin.jpg)
(https://i.imgur.com/28gMD6i.jpg)
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That is one serious hunka metal. Obviously lots of work, and very nicely done.
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Thanks Roland! Yes at some point I started to doubt whether I will ever see the cylinder block completed!.
I started on the steam port covers by squaring off two pieces of 6mm BMS, making sure that both are exactly the same length as the cylinder block.
(https://i.imgur.com/DqDH4FK.jpg)
Not sure yet if this is a task for the lathe or the rotary table on the milling machine.
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I decided to machine the covers on the lathe.
To support the material in the four yaw chuck, I first machined a plywood insert of appropriate thickness for the chuck, using my 3 axis cnc router.
(https://i.imgur.com/SXkXQEp.jpg)
With the material clocked into position in the four yaw chuck, I drilled a centre hole to use the live tail stock centre as extra support.
(https://i.imgur.com/nHm8Ehf.jpg)
Probably not the fastest approach to do this on the lathe, but it worked out well in the end.
(https://i.imgur.com/RRLrGCC.jpg)
With all the holes drilled, I could not resist assembling all the bits and pieces to see what it looks like so far.
(https://i.imgur.com/URpJqZY.jpg)
Next will be the crosshead guide. This will give me all the reference diameters for the front cylinder cover, to hopefully ensure accurate alignment between the crosshead guide and the cylinder.
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Congratulations on the engine block - looks terrific!
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Thanks Crueby!
I started out with a a 50mm diameter chunk of mild steel for the crosshead guide. I first bored out a large enough hole for the chuck side, so that I will not have to deal with a blind hole when boring the through hole.
(https://i.imgur.com/2oF7tRX.jpg).
I then turned the workpiece around and step drilled and bored the through hole leaving it about 1 mm undersize. Fortunately the boring bar I made for the cylinder, is just long enough to bore the guide.
(https://i.imgur.com/HN3bQlp.jpg).
I then turned the OD 1 mm oversize, to allow for any movement in the steel, as was suggested to Vince many moons ago.
(https://i.imgur.com/09TSK8E.jpg)
After bringing the ID, OD and flange diameter to final dimension, the guide was parted off. I then turned it around and clocked it in the four yaw chuck, before carefully finishing the flange.
(https://i.imgur.com/azAVyy5.jpg)
The bore was quite rough and measurably tapered, so I made a lapping tool similar to the one used for the cylinder, and lapped the bore to be smooth and parallel.
(https://i.imgur.com/0joj0S1.jpg)
(https://i.imgur.com/dhu3pbH.jpg)
I also made a small brass test piece to check the bore. It slides smoothly from side to side. I will use the test piece again once the guide is complete.
(https://i.imgur.com/IQ7CyhG.jpg)
The four yaw chuck was used to hold the guide on the milling machine, and the PCD function of the DRO used to drill the eight mounting holes in the flange.
(https://i.imgur.com/lrgCx1V.jpg)
I mounted the vice sideways on the milling machine, and then clamped and clocked the guide to mill the slots with the aid of my X-axis power feed.
(https://i.imgur.com/AbidWG3.jpg)
After step drilling the two 15 mm holes at the ends of the slot, a 15 mm slot drill was used. The material in between the two holes was then removed with a 10 mm end mill. I was so absorbed by the whole operation that I forgot to take any pictures!
After a bit of deburring, filing and sanding, the crosshead guide is ready to receive the crosshead! And the brass test piece still slides smoothly backwards and forwards. Hopefully the crosshead will do the same!
(https://i.imgur.com/llE5ogq.jpg)
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I was so absorbed by the whole operation that I forgot to take any pictures!
Hah! - I do that more often than not! I suspect others keep a camera taped to the forehead with the shutter linked to their eye blinks.
Multi step operations like that are often the most fun and interesting I think, both to do and to read about. That guide looks like it came out very well, and your photos and descriptions are really quite clear and concise.
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Nice work on the cross head guide! It looks terrific! :ThumbsUp: :popcorn:
Kim
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Awesome work ……… :Love:
:cheers:
Don
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Thanks Ron, Kim & Don for the kind comments. Much appreciated in these times of lockdown and social distancing!
With the crosshead guide completed, I decided to make and fit the crosshead. I turned it to the same diameter as the previous test piece, drilled and tapped the hole for the piston rod and then finished it off on the milling machine.
First time I could use one of my newly acquired collet blocks.
(https://i.imgur.com/wA6aunl.jpg)
(https://i.imgur.com/558k3Rp.jpg)
(https://i.imgur.com/smDV4ky.jpg)
(https://i.imgur.com/PIcat7v.jpg)
Quite happy with how the crosshead slides in its guide.
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The design of the rear cylinder cover was modified slightly for an o-ring as gland packing.
(https://i.imgur.com/ibt71SO.jpg)
Note the bosses on both sides of the cover, for precise alignment of the cylinder and the cross head guide.
The gland nut was made first. Since a standard M10 thread is quite coarse, I decided to single point cut a finer (non standard) thread on the lathe. I have never done any thread cutting before, so some Youtube research was in order.
I like the idea to turn the lathe by hand, as suggested by Steve Jordan:
[youtube1]https://youtu.be/ksCd9FfjUFQ[/youtube1]
So I first had to make a crank handle. A few trial external and internal threads were then cut using carbide inserts. The top slide was set at 60 deg, and a DTI used to monitor thread depth, as suggested by Blondihacks:
[youtube1]https://youtu.be/q7scadYptTI[/youtube1]
After also watching some of Joe Pieczynski's excellent videos on thread cutting, it turned out to be a fairly straight forward operation.
After preparing and cutting the gland nut thread, the hex head was milled using a hexagonal collet block.
(https://i.imgur.com/ffTbBPQ.jpg)
(https://i.imgur.com/G8WZTA6.jpg)
(https://i.imgur.com/xI1H7yC.jpg)
Next up was the rear cylinder cover. The internal thread for the gland nut was cut after turning the undercut for the o-ring.
(https://i.imgur.com/bTENCB1.jpg)
The internal thread was enlarged gradually until the gland nut screwed in snugly.
(https://i.imgur.com/nfzJFxn.jpg)
The gland nut was then parted off and the outside of the rear cylinder cover completed. The 6mm hole for the piston rod was bored out using one tip of a 4mm end mill. The hole was bored slightly oversize to allow free movement of the piston rod.
(https://i.imgur.com/0UrEcNK.jpg)
The cylinder cover was then parted off and turned around in the four yaw chuck to machine the cylinder boss.
(https://i.imgur.com/9u44nVa.jpg)
With the eight mounting holes drilled, it was time to assemble everything and see how well the crosshead slides with the stainless steel piston rod in place.
(https://i.imgur.com/0bjb7Gq.jpg)
The crosshead slides smoothly! Everything seems nicely aligned. I hope I can say the same once the piston and o-rings are also in place!
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Coming along fantastically - great work!
:popcorn: :popcorn: :popcorn:
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Looks great!
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That's really looking the part! :ThumbsUp:
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Excellent work here. Great job.
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Thanks for the encouragement and kind words guys!
The piston was made out of mild steel, as the O-ring should prevent it from touching the cylinder. The piston has about 50 micron clearance in the cylinder.
After researching O-rings a bit, I decided to go for about 10% compression of the ring between the OD of the groove and the ID of the cylinder, and about 20% clearance for the width of the groove. The O-ring has a cross-section of 1.5 mm, with 24mm ID.
I started by machining a sacrificial outside groove to the the same depth as the final groove, as it is easier to measure with a micrometer. Noting the DRO reading of the cross slide, I could then easily cut the actual groove to the same dimension.
(https://i.imgur.com/r9vExZw.jpg)
After drilling and boring the hole for the piston rod, the sacrificial groove was removed and the piston parted off. I flipped it around in the four yaw chuck, and cleaned up the face. A small groove marks this side as 'inaccurate' relative to the hole, and hence to be the side for the piston rod bolt.
(https://i.imgur.com/pfCKzfy.jpg)
The piston rod was clocked up in the four yaw chuck and machined down to match the hole in the piston. After threading for an M4 bolt, the piston was mounted. With less than 20 microns run-out, I am quite happy.
(https://i.imgur.com/KlCNx2O.jpg)
(https://i.imgur.com/qYEjSPM.jpg)
Time to check the alignment of the piston, rod and crosshead relative to the cylinder and cross head guide. I fitted the piston O-ring and installed the piston assembly. The motion is smooth, with constant resistance throughout the stroke, so the alignment seems good!
The O-ring has quite a bit of friction inside the cylinder though. I cannot move the piston by simply blowing on one side of the cylinder while closing the relevant steam ports. Not sure if this a valid test. I will increase the O-ring groove depth later if needed once I can apply compressed air to the engine.
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The O-ring has quite a bit of friction inside the cylinder though.
I guess that is a side effect of using an O ring. I used a graphite impregnated yarn (can't remember the proper name for it) instead. I remember that when I did my first run this yarn was not used (also no gaskets) but the Corliss still ran beautifully.
https://www.youtube.com/watch?v=GjaW1frBMk0
Vince
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Some oil will let the o ring slide easier too.
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Thanks for the feedback Vince. The smooth motion of the brass crosshead inside its guide makes me think that a brass ringless piston may well be a better solution. Your video also serves as much needed motivation to carry on!
Crueby, I oiled the O-ring but it is still a bit 'sticky'. It makes me wonder if the cylinder is really as smooth as it feels/looks. I will just have to experiment a bit more with different groove dimensions and perhaps ring material.
In the mean time I resumed work on the crankshaft and guide support. A base plate was made out of 3mm flat stock and the crankshaft support machined down the thickness of the base plate. Holes were drilled and tapped and the subassembly bolted together. Bolt holes will be filled with epoxy later. I also drilled a 5mm hole to later mount the lever support.
(https://i.imgur.com/ddMrFSK.jpg)
Before making the hole for the crosshead guide, I measured the hight of the guide. The quill DRO of the milling machine together with a DTI make an accurate height gauge.
(https://i.imgur.com/AL3x9X0.jpg)
It turns out that the two cylinder feet were not exactly the same height, and (fortunately!) also a bit too high. The cylinder block was mounted upside down in the mill and the two feet milled down to equal and exact dimensions.
(https://i.imgur.com/KMXboBZ.jpg)
With the crosshead guide at the correct height, I used the X and Y DRO's on the mill to locate and mark the center of the guide hole in the guide support. The guide support was then mounted in the four yaw chuck and centered using a dead centre and DTI.
(https://i.imgur.com/sQCYkqZ.jpg)
The hole was then step drilled and bored in the lathe. I am very glad I took some time to check all dimensions beforehand. The guide aligns perfectly with the hole and fits like a glove.
(https://i.imgur.com/2do6PxN.jpg)
(https://i.imgur.com/TkXIoU0.jpg)
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The o ring groove dimensions can effect it a lot, very small change can make a big difference. The percentage way will get you close, then its a matter of a little experimenting. The width of the groove needs to be slightly wider than the ring to give it room to squish down, but not so wide that it moves side to side.
That crosshead guide assembly is coming out great!!
:popcorn: :popcorn: :popcorn:
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have gone back to your 1st page here, but cannot see if you intend to steam, or display the engine on compressed air?
There is a principal difference, as if steamed, the sealing elements will need to be Viton, Siliconeor your trialled Graphite impregated twine as these are suitable for our model steam temperatures of say 150 degrees C
Nitrile elastomer [Buna N, Nitrile Rubber etc., ] is not suitable above say 90 degrees C in dynamic applications [piston & gland],
The image of your polished cylinder bore appears smooth, however this is subjective as a smooth bore can be a group of shiny razor blade bands
You mention trialling Graphited Twine in the piston [there are many Brands, Walkers or Chesterton are 2 of the better-known Trade names, and this material is absolutely suitable as a pressure energised seal element for not only trial use on steam or compressed air, and for continued full time use
The degree of surface roughness in the cylinder bore will be cross mated to the visual surface of the twine, if after use, the twine displays a shiny surface, you can be assured the bore has a reasonable lever of surface roughness, it the twin has longitudinal lines, this would indicate a questionable surface roughness
As a downside, both Viton and Silicone have a far lower abrasion resistance over Nitrile, so this then dictates a lower level of surface roughness in the bore
Derek
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Thanks Crueby for the feedback. As soon as the flywheel is connected to the piston, I will experiment a bit with O-rings.
Derek, thanks very much for taking time to share your experience. The plan is to run the engine on compressed air only. The current O-ring is Viton. This is all new to me, so your advice is much appreciated. If I can lay my hands on some graphite yarn, this will definitely be included in the experiment. A quick search on the internet showed that 3mm yarn may be hard to find in South Africa. The thinnest I came across so far is 4mm, in lengths of 8m!
Today I finished the guide support on the rotary table, using a sacrificial piece of aluminium as spacer. It took quite a while to set up.
(https://i.imgur.com/UtBoTUp.jpg)
With the rotary table already set up, I also made the lever support, to be epoxied to the guide support later.
(https://i.imgur.com/ESNZCoj.jpg)
(https://i.imgur.com/21yzJLQ.jpg)
Very happy with the end result.
(https://i.imgur.com/jCCBAng.jpg)
I ordered some 303 stainless steel round bar for the connecting rod and crank shaft. Looking forward to seeing the flywheel moving the piston!
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If I can lay my hands on some graphite yarn, this will definitely be included in the experiment. A quick search on the internet showed that 3mm yarn may be hard to find in South Africa. The thinnest I came across so far is 4mm, in lengths of 8m!
My experience with graphite yarn is rather limited, but what I've seen it is stranded and I was able to pull out a few strands and use that as smaller graphite yarn. I wouldn't be surprised if your 4mm could be used just by removing a strand or two to make it slightly smaller in diameter.
Just a though.
Kim
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So I am not suggesting that a Viton or Nitrile o-ring in a suitably sized cavity will not be anything but suitable for LP lubricated air operation in the appication , however your piston has sufficient meat in height to increase the cavity width
Kim is correct, in that a 4mm sq woven graphited yarn could be unpicked to reveal maybe 6 or 8 strands of ~~ something that when woven and compressed = the 4 mm sq material, however removing 1 or 2 strands then attempting to re tension [or reduce in cross section] the remainder the resulting strands would be a very slippery impossibility :disagree:
Typically, a 4mm sq length of woven graphited yarn section can be gently hammered to eg., a 3 x 5 mm profile, it can easily be cut at a 45 degree angle at each end so as to overlap and compress on the ends....repeated gentle hammering will reduce the cross section by decreasing the air gap between strands, and also have the effect of increasing the length of the woven section
As an apprentice 55+ years ago, when refurbishing vertical pump components, consideration of the surface finish on the faces of the seal cavity were not important, as long as longitudinal float could be achieved and I was using sizes from 1/8" sq to 3/4" sq. These larger sizes had individual strands approaching 1/8" diameter
This woven graphited yarn was used on both the steam side and the water side on water pumps, and was also used in Water Hydraulic systems [soluable oil and water emoulsions] and relatively low pressure to say 300 PSI working pressure
A regular Saturday Overtime shift [at Penality Rates :whoohoo:] for the apprentice was to spend the full day checking gland and piston seals of woven graphited yarn or and replacing if needed
From an historical aspect, mechanical and dynamic fluid sealing with woven yarns [yes :DrinkPint: :cheers: :DrinkPint: alcohols and ale pumping/pulling against atmospheric pressure,] were first used with a Tallow impregnation, 100's of years before Graphite for impregnation became commericially available, and then well before the acceptance of the humble o-ring
Derek
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After researching O-rings a bit, I decided to go for about 10% compression of the ring between the OD of the groove and the ID of the cylinder, and about 20% clearance for the width of the groove. The O-ring has a cross-section of 1.5 mm, with 24mm ID.
That's really too much compression for Model use you would do better starting with 5% compression and seeing how that goes . You don't want to be looking at commercial groove sizing, there are a couple of published sources for model ring compression. I have built a lot of engines with 24mm bore and tend to use a metric Viton ring of 19.4mm ID 2.4mm section. I use a 2.3mm deep groove so that's about 4% compression and 2.6mm groove width as there is very little ovaling of the ring due to the small amount of compression
If you do go down the graphite yarn route then whatch what you buy, a lot of teh modern stuff can be quite dry and does not seem to suit our applications well, the stuff I use in glands does small of tallow and is quite oily to the feel.
In a lot of cases if you are just wanting to run it for display you can simply leave the ring out and run on a couple of psi or 0.1bar air pressure
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Yes, ..all of the published BS, AS or NFPA Hydraulic Standards for Industry and 0-ring applications are for Nitrile o-rings and are based upon either 250 or 210 Bar fluid system pressures
So accordingly all of the recommended diametrical clearances, cavity widths & mirror surfaces etc., are absolutely meaningless for our low-pressure hobby applications
So if you think this was not quite the Standards you need, these Standards :happyreader: also includes dimensional variances in diametrical clearances [extrusion gap] for between 90 Durometer hardness, and 70 Duro, as these are the two Industry Standards for manufacture
Thankfully, Viton elastomer [as your nominated o-rong seal] is universally manufactured as 70 Duro, as Viton does not have the mechanical strength of semi-processed Nitrile
Let us know how you progress with your tests
Derek
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Thanks Kim, Derek & Jason for your replies. Much appreciated! :praise2:
As soon as I have the flywheel connected to the piston, I will get back to this again. It seems that even though 4mm graphite yarn is advertised, there is no stock available. So I will focus on O-rings first.
With the rotary table still setup on the mill, I rounded the corners of the guide support base plate yesterday. I definitely prefer machining to filing! This concluded fabrication of the guide and crank support. All the parts must just be epoxied together at some point.
(https://i.imgur.com/LCdXglQ.jpg)
I bought some 303 stainless steel round bar for the unpainted parts. Available diameters were limited, so the crank was made from a slice of 50 mm round bar. Both sides of a 7mm disk were faced in the lathe. The 9mm axle hole was also drilled and bored using one tip of a 4mm end mill.
(https://i.imgur.com/lZNmWwO.jpg)
The disk was then bolted to a piece of sacrificial aluminium and centred on the rotary table. (Thanks Vince Cutayar for this idea!) A 3mm hole was drilled where the crank pin will eventually be and a piece of 3mm drill bit used as locating pin.
(https://i.imgur.com/xlQBH1C.jpg)
The contour of the crank was then machined using a 6mm slotting cutter. Machining went well, considering that it was the first time I ever milled 303 stainless steel.
(https://i.imgur.com/rqlVqvf.jpg)
The locating pin was removed, and a 4M thread cut for the crank pin.
(https://i.imgur.com/CdhVCLL.jpg)
The completed crank after a bit of filing and sanding to remove machining marks. I did not expect that this small part would take the best part of a day to make!
(https://i.imgur.com/rZsxoe2.jpg)
Now for the connecting rod...
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I see you have a marble table [large flat tile] in your workshop facility for assembly or dimensional referencing, do you have a surface grinder?, or do you use the marble table for this purpose? [shock horror :cussing: for purists]
Is your workshop air-conditioned?, or does it maintain a stable temperature?
That little 18 mm centered link appears to have a lightly cross hatched appearance........ :ThumbsUp: . will this and all of the other larger engine components it be chemically treated for corrosion resistance....flame heating and oil quenching sounds too aggresssive :hammerbash:
[Many years ago, I could not understand :shrug: why I could not achieve a flat lapped surface using a 12" x 12" x 1" thick paine of Float Glass.......it was difficult to measure, but the visual sure gave it away]
Derek
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Porcelain tile has always worked for me as my surface plate/table and not stopped my engines from running and I hear a lot of people get good results with cheap "granite" cutting boards from the likes of Lidl and Aldi.
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Thanks Derek for the feedback and comments.
The piece of granite is from a kitchen top, and the closest I have to a 'flat' surface. I use it mainly as a surface for sanding paper when sanding flat surfaces. Being a beginner in this game, I have just the basic tools, a lathe and a milling machine. No temperature control here! Chasing flatness is perhaps something for the future ...
Thanks for pointing out the cross hatch pattern on the crank. The picture was taken after sanding with 220 grit paper only. I normally go to at least 400 grit, which smooths things out a bit.
Most parts of the engine will be painted, except for the connecting rod, crank, axle and some of the other smaller parts. The plan is to make all the bare metal parts from stainless steel. The outside of the mild steel rim of the flywheel will also not be painted. I was thinking of perhaps using some clear lacquer spray or varnish for this.
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After studying the work of Vince, Arnold and Larry, I started on the connecting rod. Raw material is a 20 mm round bar of 303 stainless steel. I am pleasantly surprised with how well 303 machines!
(https://i.imgur.com/9AMGTPg.jpg)
After drilling centre holes for later turning between centres, the round bar was milled square, the two ends were milled to size and the 6mm holes drilled and reamed. I took a bit of time to ensure that the centre holes remain centred during milling, by measuring face dimensions between centres on the lathe.
(https://i.imgur.com/0bNQmZk.jpg)
The connecting rod was then mounted between centres and turn down to a diameter of 7.5 mm.
(https://i.imgur.com/he0sm3C.jpg)
With the compound slide set at about 2 deg, a taper was turned on one half of the rod. The connecting rod was then flipped around between centres and the other taper turned. I like the rounded ends of Vince's tapers, so the HSS cutting tool was ground with about a 1mm rounded tip for the same effect.
(https://i.imgur.com/2mUIWTS.jpg)
With turning operations complete, the fork was milled.
(https://i.imgur.com/bcyFszw.jpg)
The inside corners of the fork were then milled by mounting the connecting rod vertically in the four yaw chuck on top of the rotary table.
(https://i.imgur.com/uISRzLE.jpg)
A protractor was used to clamp the connecting rod at the correct angle of 8.5 deg to mill the tapers on the fork. The rotary table next to the vice provided a convenient reference to set the same angle for the opposite tapers.
(https://i.imgur.com/ju8z3nx.jpg)
The last operation was the rounding of the fork ends on the rotary table, after mounting the connecting rod onto a sacrificial aluminium plate.
(https://i.imgur.com/SyEJCcz.jpg)
After a copious amount of filing and sanding, the rod is ready to connect! Cant wait!
(https://i.imgur.com/7vPAnyU.jpg)
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I use 303 for all of my stainless steel parts. It's coming along nicely.
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I use 303 for all of my stainless steel parts. It's coming along nicely.
Thanks for the comment! Do you passivate the 303 stainless steel at all?
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Today the crosshead and crank pins were made. The outside faces of the pin heads were faced on the lathe. The MT2 collet chuck was moved from the milling machine for this purpose.
(https://i.imgur.com/jdvNXeD.jpg)
The crosshead pin is made from 303 stainless steel. The crank pin is made from brass.
All three pins ready for the screw driver slot to be machined. The crosshead screw is screwed tightly into a piece of 6mm round bar for this.
(https://i.imgur.com/AlwkcvA.jpg)
Following in the steps of the men who went before me, the slots were cut with a slitting saw. The pins were held in the vice with a square collet block. The saw was centred relative to the collet using the bisecting function of the DRO.
(https://i.imgur.com/GVLibKv.jpg)
(https://i.imgur.com/9Bk1fuW.jpg)
For the first time, the complete drive train can be linked together.
(https://i.imgur.com/41GvAuy.jpg)
A long way to go still, but at least is it starting to resemble a steam engine! :cartwheel:
(https://i.imgur.com/aazwXRV.jpg)
Can't wait to mount the completed parts on the base to see the interaction between piston, crosshead, connecting rod, crank and flywheel. First have to replace the temporary mild steel axle with a 303 stainless steel axle though.
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Following in the steps of the men who went before me, the slots were cut with a slitting saw.
That picture really caught my eye since I was doing virtually the same thing yesterday and have more to do today once I get to it. 304 SS in my case.
Anyway, I'm continuing to enjoy following along!
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Great progress, its all looking very good!
:popcorn: :popcorn: :popcorn:
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Nice family shot.
Nearly finished.
Vince
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Looks great. Have been following along. I still need to finish my base plate.
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Thanks guys for following along!
The 303 stainless steel shaft took two attempts to get right (First attempt was too short!).
Then the tolerance between the flywheel hub and axle was too tight. After sliding on nicely, the hub jammed solidly on the axle. Probably due to some debris in the grub screw holes. It took assistance from an engineering shop to remove the axle without causing any damage. Sanding down the axle diameter by about 10 micron solved the problem.
With the axle complete, all the parts were bolted onto the baseplate. The bearings were mounted first with flywheel and crank fitted to the axle. The crank was then connected to the piston inside the cylinder block. The crosshead guide and cylinder block assembly was then moved around slightly to find the smoothest action for the connecting rod and crank.
The location of the resulting mounting holes for the cylinder feet are slightly off compared to the drawings - clearly all the component dimensions are not as accurate as I thought.
With everything bolted down, the friction of the Viton piston o-ring inside the cylinder could be assessed again. By pushing on the piston from one side only during the out stroke, the flywheel could be made to turn. This implies that the momentum of the flywheel is sufficient to overcome the o-ring friction during the return stroke. Once the valves are installed and pressure is applied on both strokes, o-ring friction will definitely not be problem. I think I am good to go as far as the o-ring is concerned.
[youtube1]https://youtu.be/RN6FWzQDnoY[/youtube1]
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Excellent!! :popcorn: :popcorn: :popcorn:
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your engine turns very smoothly with thumb pressure. Looking great!
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Oh I promise you. Bob (Maryak) would approve!
Dave
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Looking good. :ThumbsUp:
Vince
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Thanks guys for the encouraging words!
I decided to start working my way back from the eccentric to the valve gear. First up, the eccentric sheave. I like the oilers that Vince added to his Corliss, so space will be provided to mount one.
A bronze disk was turned on the lathe, and split into two with a slitting saw.
(https://i.imgur.com/VKcrkMO.jpg)
The two sawed surfaces were skimmed on the milling machine, the ears were machined, 2mm holes drilled and the 3mm thread for the eccentric rod was tapped.
(https://i.imgur.com/aOr5ggY.jpg)
The two halves were then bolted together, the centre was found and marked on the mill using the mill DRO.
(https://i.imgur.com/SyXDKDq.jpg)
(https://i.imgur.com/9mOLfzY.jpg)
With the sheave centred in the four yaw chuck, the hole was bored on the lathe.
(https://i.imgur.com/AZ7d6h8.jpg)
Taking a cue from Vince, a jig was made to securely clamp the two halves, and mounted on the rotary table to mill the outside diameter of the sheave. After removing the bulk of the material with a 6mm end mill, a 2 mm end mill was used to finish the outside surface.
(https://i.imgur.com/CkYyKJW.jpg)
A bit of sanding with 400 grit sandpaper completed the sheave.
(https://i.imgur.com/Do4RhPP.jpg)
Next up, the eccentric disk ...
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Nice job on the eccentric strap!
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Very nicely done - I like your small tap holder. I must make one of those.
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Thanks guys for the kind feedback!
I can't believe that a month has passed already without any progress - life got in the way.
Before making the eccentric disk, I made a wooden base. After cutting mitres for the corners, rebates for the base plate were cut on the milling machine. Probably the most accurate woodworking I have ever done :Lol: .
(https://i.imgur.com/lyLkQEN.jpg)
Sides glued together with corners reinforced.
(https://i.imgur.com/8msN4kb.jpg)
The aluminium base plate is a snug fit. Not sure if it would need to be screwed to the frame.
(https://i.imgur.com/e9YVYGz.jpg)
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i missed your updates JC. Nice to see one.
Vince
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Hey JC....without getting off topic, it's going wonderful I might add, Can you elaborate on that little tap driver you have there? That looks like a nice have for sure.....if you don't want to do it here, and you have the time, drop brief paragraph in the tools section. I might want to make one of those!!!
Dave
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Probably the most accurate woodworking I have ever done :Lol: .
The result speaks for it selv - very good :cheers:
Will you oil the wood or do you have other plans ?
Per
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A lot of excellent machine work going on in this thread. Awesome results JC……l :Love:
:cheers:
Don
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Thanks guys for all the kind feedback and encouragement! It sometimes gets a bit lonely in the workshop!
Vince, my youngest son got married this past weekend, so I was a bit distracted for a while, to say the least.
Dave, the little tap drivers are based on a Joe Pi youtube video you can find here: https://youtu.be/XNmd1-v62tw (https://youtu.be/XNmd1-v62tw). No more broken taps since I have made those!
Per, yes I will most likely oil the wood. Imitation brick work is probably a bridge too far.
I did manage to finish the eccentric disk in the mean time. With only a 50mm diameter piece of 303 stainless steel at hand, quite a lot of material had to be removed. The position of the eccentric axle hole was first marked out using the DRO on the milling machine. The axle hole was then bored using the four yaw chuck on the lathe.
The slot for the strap was then turned to size using 4mm square HSS left hand and right hand bits.
(https://i.imgur.com/xrrKlj1.jpg)
(https://i.imgur.com/cesyUgv.jpg)
The disk was parted off, turned around in the chuck and faced off.
(https://i.imgur.com/wzDdmYe.jpg)
During the past few weeks the scale nuts and bolts I ordered from Knupfer https://knupfer.info/shop/index.php/ (https://knupfer.info/shop/index.php/) also arrived from Germany.
The small M1.4, M2 and M3 spanners are really cute.
(https://i.imgur.com/bsRDepM.jpg)
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Still following along and enjoying the progress pictures.
gbritnell
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gbritnell, thanks for following along!
I managed to make good progress since completing the eccentric disk.
Continuing to work my way from the eccentric back to the valves, the eccentric lever was next. This was made from an off-cut piece of 1.5mm thick 304 stainless steel plate. After machining to size and drilling the three holes, the ends were filed using filing buttons.
(https://i.imgur.com/ffAWhTb.jpg)
Next were the two clevises for the lever. These were made from a single piece of 303 stainless steel. After machining to size, holes were drilled and the part mounted onto a sacrificial piece of aluminium, to mill the round ends using the rotary table.
(https://i.imgur.com/9HvsmtA.jpg)
(https://i.imgur.com/8lCym5j.jpg)
The aluminium block is held in a four yaw chuck on top of the rotary table, which allows for the position of the clevis hole to be dialled in quickly, using a small disk as reference.
(https://i.imgur.com/SESgIQn.jpg)
(https://i.imgur.com/InOcUHz.jpg)
The slots for the lever were then cut on the mill with a saw.
(https://i.imgur.com/ZgUPLUC.jpg)
The two clevises were then separated and M3 holes drilled and tapped for the eccentric rods. One clevis has a left hand thread, to allow for fine adjustment by rotating the eccentric rod.
I am quite pleased with the final result.
(https://i.imgur.com/O4yIQyI.jpg)
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The valve disk was next. This was made from a disk of 303 stainless steel.
(https://i.imgur.com/JQcL6MD.jpg)
After machining a rectangular piece, the locations of all the holes were centre drilled using the mill DRO.
The four corners of the 3mm square centre hole were drilled with a 1.5mm drill, using a micro drill attachment. What a useful tool to prevent small drills from breaking.
(https://i.imgur.com/GaMJGgO.jpg)
The four M2 holes were also drilled and tapped.
(https://i.imgur.com/TzhSsUG.jpg)
Then I realised that I had misread the plans and had drilled the M2 holes in the wrong place. So the whole process had to be repeated ...
All the excess material were then removed with a 6mm end mill for the sides, and a 10mm end mill for the top.
(https://i.imgur.com/qSIDJKS.jpg)
(https://i.imgur.com/G9kbKXB.jpg)
The ends were then mill round using the rotary table, similar to the way the clevises were done.
(https://i.imgur.com/Ygi0Uz0.jpg)
The final result:
(https://i.imgur.com/vepk5Op.jpg)
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The valve disk hub was turned and bored on the lathe from a piece of mild steel.
Then the valve disk spindle was turned from a piece of brass.
(https://i.imgur.com/TtVIpQ3.jpg)
The hub was used to ensure a good fit of the spindle.
(https://i.imgur.com/wAqHAGZ.jpg)
Before removing the spindle from the lathe to mill the square section for the valve disk, I wanted to cut the M3 thread, but realised that I do not own a right hand M3 die, only a left hand one!
So this is it for today.
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Looking good :praise2: :praise2: I also have those tiny spanners from Knupfer :) :)
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VERY nice! I am also following along so do not ever feel alone in the shop. Great pieces of work and thanks for taking us along on this journey... :ThumbsUp: :popcorn: :DrinkPint:
BC1
Jim
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Following on with your build JC, and as you say.....' the Knupfer small M1.4, M2 and M3 spanners are really cute'
Agreed...first class hand tools of the correct scale bolts & nuts for tiny hands and places
Just compliments the excellent range of manufactured product :ThumbsUp: and great people to deal with too :Jester:
..always get a small sealed lolly/sweet :P with each delivery
Derek
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..always get a small sealed lolly/sweet :P with each delivery
Indeed Derek! I also received some sweets, but somehow it got lost in the excitement of all the new goodies!
Thanks Jim & Roger for following along!
After cutting the M3 thread for the spindle, it was parted off and the 3 mm square was milled.
(https://i.imgur.com/2mFiIqP.jpg)
After slightly rounding the corners of the square with a file, the valve disk fits perfectly.
(https://i.imgur.com/hkEnV5j.jpg)
Time to connect the eccentric sheave to the valve disk.
Which begs the question, with the lever vertical, at what position must the eccentric disk be?
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On mine, when the lever is vertical the eccentric is sticking straight up.
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On mine, when the lever is vertical the eccentric is sticking straight up.
Thanks Chris for the quick response! That makes perfect sense, and should also correspond with TDC.
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Eccentric finally connected to the valve disk! :cartwheel:
Eccentric rods were made from 3mm drill rod, and disk swivel was made from brass.
Never thought a piece of metal that slowly oscillates backwards and forwards will be so mesmerising!
(https://i.imgur.com/ElJClWP.jpg)
Valves and valve bonnets next.
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Woohoo! Just wait till the rest of the links are on and moving.... Watch the link... Watch the link.... You are getting sleepy...!
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When I did my MEM Corliss I thought the valve rod to valve disk connection looked a little Mamodesque and went with a threaded rod end and threaded clevis to allow final adjustment.
Andrew
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Great looking linkage there on your Corliss, JC! :popcorn:
Kim
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Thanks guys for the feedback.
Andrew, please share a picture of your linkage. I am curious to see how it looks.
The valves were finished yesterday, and were made from 6mm drill rod. As always I first had a look how Vince made his, and more or less followed his lead.
First a slot was milled with a 6mm ball nose cutter in a piece of scrap aluminium, to securely hold the valves when milling the flat section.
(https://i.imgur.com/8q404pI.jpg)
An M10 and M6 bolt were used to make a stop for the MT2 ER25 collet holder. The M10 bolt screws into the drawbar thread of the MT2 shank. The M6 bolt then screws into the M10 bolt. The stop ensures that the four valves are held at exactly the same depth in the collet, for turning on the lathe.
(https://i.imgur.com/JcP7qNc.jpg)
The final result:
(https://i.imgur.com/Fa8d64r.jpg)
A 1mm ball nose cutter was used to mill a line and a small hole on the end of each valve, to mark the orientation of the flat section of the valve. This will hopefully later assist when setting the valve timing.
(https://i.imgur.com/vdixU3N.jpg)
The original plans for the Corliss show a valve consisting of two separate pieces. What would be the advantage of a two piece design compared to a solid valve?
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Hi JC
here's a picture of my linkage. I Have always thought cranked valve rods don't look right so laid out to allow straight rods
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Thanks for the pic Andrew! That straight linkage looks really good! Too late for me to now make a change though. Can't wait to see my Corliss running!
I made a start on the valve bonnets.
First a piece of 22mm brass round stock was milled into 15mm square bar.
(https://i.imgur.com/YKURXwF.jpg)
After drilling the 2mm holes for the rear bonnets, four of them were sawed off on the mill.
(https://i.imgur.com/dmjg7Ky.jpg)
The four front bonnets were then also drilled and sawed off one by one.
(https://i.imgur.com/DsNRUfe.jpg)
The four rear bonnets were then milled to 1.5mm thickness, and finished off with a bit of sanding.
(https://i.imgur.com/JsWPr3u.jpg)
I now have to make a small jig to finish turning the front bonnets, ala Vince.
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Nice work JC been following quietly and enjoying the built.
:cheers:
Don
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Great progress JC. Not long to go before you put some air in it and see it turning.
Thanks for mentioning my build log but I would like to add that I took some ideas for my build from Arnold who did the same Corliss before me.
Just curious but how can you follow my build log? I thought that the photos in my log were not visible anymore.
Regards
Vince
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Thanks a lot Don!
Just curious but how can you follow my build log? I thought that the photos in my log were not visible anymore.
Vince, thanks again for your detailed log. Your photos are certainly (fortunately!) still visible. Since you have already incorporated Arnold's ideas, I only have to consult your log :D.
A small mandrel was made to hold the front bonnet in the three yaw chuck.
(https://i.imgur.com/SKDG84Y.jpg)
The four front bonnets could then be turned in quick succession. I decided not to use o-rings for now, as the bonnets can easily be bored later if needed.
(https://i.imgur.com/GLjv6HN.jpg)
Now for the fiddly bits. Cannot decide yet how to fasten the valve levers and still have them easily adjustable. I would like to keep the shape of the levers as shown on the plans, as this matches the originals more closely, as shown here: http://www.wkinsler.com/technology/corliss/figures/index.html (http://www.wkinsler.com/technology/corliss/figures/index.html)
Maybe a sholder on the valve stem with an M2 bolt to clamp the lever will do.
(https://i.imgur.com/ZCyRcYf.png)
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Another idea (similar to how Arnold did his) how to clamp the valve lever to the valve stem, seeing that I do have these small M1.4 bolts and nuts from Knupfer:
(https://i.imgur.com/dSRFLKI.jpg)
Anything is possible in a CAD model. Let's see if it can be made from 303 stainless steel...
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JC...thinking that you have 4 of the linkage adjustments to achieve......
I have zero knowledge in the installation of Corliss valving, so does the geometric orientation provide correct timing?, or does each of the 4 valve spools require any +/- positioning?
If you used the same bolt pitch [0.3P] as the M1.4 diameter bolts as the linkage rod, would 0.3P [x .5= 0.015mm per 180 degrees] allow sufficient alignment?....or would you have slip fit & solder both ends of the connecting rod to ensure absolute accuracy in the timing of the arm?
Derek
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Derek, I would think that if all components are accurate, that geometric orientation should provide correct timing. But I expect that in my case I will have to make small adjustments.
On real Corliss valves, the linkages are adjustable, and your suggestion makes for a more realistic model. In fact, this is also how it is shown on the plans. But making adjustable linkages seems really difficult. Hence the attempt to make adjustable valve levers instead.
I started off the adjustable levers by squaring off two pieces of 303 stainless steel.
(https://i.imgur.com/0dChUP3.jpg)
The ears were milled, drilled and then rounded off on the rotary table. The four yaw chuck on the rotary table allows for easy adjustment of the pivot point.
(https://i.imgur.com/aQMNSzZ.jpg)
The M3 holes for the valve stems and the M2 threaded holes for the connecting rods were then drilled and tapped, and rounded on the rotary table.
(https://i.imgur.com/fV6wF7I.jpg)
The 0.5mm slots for the ears were then cut on the lathe. The lever was clamped in a tool holder, with the slitting saw in the four yaw chuck. This way the saw could be accurately centred using the lathe DRO.
(https://i.imgur.com/zJE2sgn.jpg)
The angled sides were then set and milled on the rotary table.
(https://i.imgur.com/OAy8O84.jpg)
The levers were then separated and the connecting rod side also rounded on the rotary table.
(https://i.imgur.com/4eSuThj.jpg)
The final result is not perfect, but will do for now. Next time I will rather use the M3 hole as reference point for all operations, rather than the end of the ears.
(https://i.imgur.com/QjYQV15.jpg)
Only the connecting rods now, and then the engine should hopefully move under its own steam!
(https://i.imgur.com/lVlx5V7.jpg)
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Very nice work, JC! :popcorn:
I found it interesting how you used the slitting saw and held the part in the tool rest on your lathe. I've never seen that done before. Pretty interesting!
Kim
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Thanks Kim for the feedback. Probably a bit of fools rush in where angels fear to tread...
The disk arms were made from 6mm brass rod. First the one end of each work piece was centre drilled.
(https://i.imgur.com/HoPWK00.jpg)
The rod was then held in the vice with a square ER25 collet block. The other end of the rod was supported by a 60 deg pointed tip in the vice stop. The 2mm holes were then drilled, and the arm milled down to a thickness of 2.25 mm.
(https://i.imgur.com/W6lU5hv.jpg)
The arms were then moved to the lathe. 2mm drills in the holes were used to locate the centre of the arm with the DRO. A HSS bit with a 60 deg point was ground for turning.
(https://i.imgur.com/7wdVMlk.jpg)
The end of the arm is supported by a live centre in the tail stock.
(https://i.imgur.com/jSkEivU.jpg)
All four arms turned, and the ends parted off with a slitting saw, ready for the ends to be rounded on the rotary table:
(https://i.imgur.com/DFKNRnP.jpg)
The arm was bolted to a piece of sacrificial aluminium and held in the four yaw chuck on the rotary table to round the ends with a 2mm end mill.
(https://i.imgur.com/90rRGJz.jpg)
All four arms completed, ready for assembly.
(https://i.imgur.com/6q02wJ7.jpg)
I am contemplating using 2mm screws to connect the arms to the valve disk and levers, and to fill the section of thread inside the arms with epoxy. The epoxy will then be turned to form a 2mm rod to prevent unnecessary wear of the brass arms.
Will have to find a supply of compressed air somewhere...
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Well done JC, arms look sharp. How do you center your mill to the rotary table for rounding off? I always find that hard to do and that shows so easily in the part being made..
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Impresive working of very small parts. Nice progress. Terry
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Thanks Terry and Olli-Matti for the kind remarks!
How do you center your mill to the rotary table for rounding off?
I am still a novice, but what I found work best when you have to do rounding around an existing hole, is the following:
First align the axis of the rotary table with the mill spindle. This is done by putting the base of a DTI on the rotary table, with the DTI probe touching the mill spindle. The X and Y tables are then adjusted until a constant reading is obtained on the DTI for any rotation of the rotary table.
A sacrificial piece of material is then used as a mounting on the rotary table to mount the workpiece. With the mounting clamped to the rotary table a hole is drilled and tapped to hold the workpiece. As the mill spindle and rotary table are now accurately aligned, the drilled hole will also be accurately aligned with the axis of the rotary table. If the workpiece is now bolted to the mounting with a bolt having the same diameter as the hole in the workpiece, the hole in the workpiece will also be aligned with the axis of the rotary table.
In most cases, the workpiece will also have another hole somewhere, which can be used to further secure the workpiece to prevent it from rotating.
With the hole in the workpiece aligned with the rotary table, either the X or Y axis can now be moved to set the desired radius. The amount to be moved is the radius of the cut plus the radius of the end mill.
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Today M2 screws were converted into M2 bolts, by putting some quick set epoxy on the top 2mm of the thread, and then turning it down to 2mm diameter once hardened. These 'bolts' connect the disk arms to the valve levers and valve disks. There is no radial play as would be the case when using screws, and the epoxy should also protect the brass disk arms from excessive wear.
After straightening the valves (which curved a little when machining the flats), the whole valve assembly is moving smoothly. The M1.4 nuts and bolts clamping the valve levers to the valve stems allow for easy adjustment of the valve timing.
(https://i.imgur.com/Ac56kPQ.jpg)
Most of the M3 and M2 screws must still be replaced by studs, but only a connection for an air hose is now needed before I can see if compressed air has the desired effect...
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Thats looking fantastic! Not long now till the first air test, and all the fun timing the valves. Fiddly, but so rewarding when it takes off.
Interesting idea with the epoxy over the threads - if I understand correctly that effectively gives you a straight shank just under the screw head, but leaves the threads exposed farther down? Very clever, have to remember that one!
Chris
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Thanks for the feedback Chris! I am a novice, so allowed to think outside the box :).
How satisfying is this:
[youtube1]https://youtu.be/0_EHtaVW23A[/youtube1]
Air supply is the front right tyre of my car, via a regulator set at 2 bar. With the crank set appropriate, the engine starts on its own! No gaskets yet.
A few times during the past year I was not sure that I will ever reach this point!
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Thanks for the feedback Chris! I am a novice, so allowed to think outside the box :).
How satisfying is this:
[youtube1]https://youtu.be/0_EHtaVW23A[/youtube1]
Air supply is the front right tyre of my car, via a regulator set at 2 bar. With the crank set appropriately, the engine starts on its own! No gaskets yet.
A few times during the past year I was not sure that I will ever reach this point!
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Wonderful! Safe to say you can change 'JC attempts the MEM Corliss' to 'JC masters the MEM Corliss'!
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That is an amazingly great first run :praise2:
You should be very happy with that result + you even mention room for improvement ...!!!
So if you manage that too - I can only agree with Chris, that Master of the MEM Corliss, would be appropriate. :cheers:
Per
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Excellent result, JC! It looks and sounds fantastic. Congratulations! :ThumbsUp: :cheers:
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Wow! I'd say that's running beautifully! You should feel great about that!
Just be careful how much you run it or you're right front tire will be flat! :Lol:
Kim
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Congratulations, what a lovely smooth action.
One other mod I did with mine was to have the inlet at the bottom and the exhaust at the top meaning I could bring the air in from under the base and dispense with a pipe coming in at the top which I thought distracted from the appearance and presentation.
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"what a lovely smooth action".......well yes, and the visual and the audible........ :ThumbsUp:
Did you have any issue in the timing JC?....or was it just like ...."adjust to the drawing dimensions & turn on :killcomputer: the oily air?"
One could sit [stand] & watch [& listen[ :DrinkPint: to that slow speed valving changeover action for hours
Congratulations :cheers:
Derek
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Wow that is running great, nice work!
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That looks and sounds awesome JC. Love that puffing sound. A nice slow runner and I'm sure it will run even slower.
Vince
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It's been said, but I have to say as well:
Nice Job! Smooth Runner! Sounds Great!
I also agree that you can take off the "attempts".
Well Done and Thank You for Posting.
ShopShoe
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Here here to all that's been said. :ThumbsUp: I love it :cheers: Terry
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A great result. A good looker and great runner, you can feel proud of that for sure.
Jim
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You are to be congratulated. A little over a year from start to finish. Just amazing. Love it !
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Thanks everyone for the kind words and sharing in my delight! Being able to share the build on this forum makes it so much more rewarding! Even though there is still a lot of finishing work on the Corliss, I am already starting to wonder what the next project should be...
Did you have any issue in the timing JC?....or was it just like ...."adjust to the drawing dimensions & turn on the oily air?"
Derek, setting the timing was basically a matter of adjusting the valves to drawing dimensions. With the piston at TDC, the eccentric disk was first set at 90 deg to the crank using a DTI. This resulted in the connecting rod lever being vertical, as set previously.
The valve disk was then adjusted to be vertical, using a square. The four valves were then set 'just closed' with the flats eyeballed to be horizontal, using the slots in the end of the valves. That was it.
(https://i.imgur.com/IA00Bmp.jpg)
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Very nice work! Really an engine to be proud of!
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Very nice work indeed and a nice runner. Excellent work JC…… :Love:
:cheers:
DON
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Nicely done! I had missed your video and just went back and had a look.
Very nice work!
Dave
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Excellent :praise2: :praise2: :wine1:
As I have said before I do like all the open Valve gear on steam engines :)
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Thanks everyone for the very kind comments!
After admiring the running engine for a few days, and after an extended holiday period, I finally had time back in the shop. All the fasteners were replaced with properly scaled nuts and studs. This took quite a while to complete!
M2 and M3 'studs' were made from M3 threaded rod, and from M2 screws with heads sawn off. M2 and M3 nuts from Knupfer were glued to the studs. The ends of the studs were slightly rounded on the lathe.
(https://i.imgur.com/dTM2AGB.jpg)
M4 nuts for the engine mountings had to made from scratch, by scaling up the M3 Knupfer nut. This forced me to first mount a previously acquired ER32 collet holder to a Myford face plate, and to purchase some ER32 collets, rather than continuously moving my ER25 MT2 collet holder between the mill and the lathe.
A piece of 303 stainless steel round bar was first converted to hex bar on the mill.
(https://i.imgur.com/dMfwKBP.jpg)
The hex bar was then M4 drilled and tapped on the lathe. This was done to a depth of one nut at a time, to prevent a skew hole.
(https://i.imgur.com/wGc2cAW.jpg)
The end of the nut was then chamfered with the top slide set to 30 deg.
(https://i.imgur.com/FWfUFkg.jpg)
The nut was then cut off slightly too long using a slitting saw on the milling machine. I found this to be a much more controlled operation than parting off the nut on the lathe.
(https://i.imgur.com/3AnDo08.jpg)
The nut was then mounted in the lathe using a threaded mandrel, to face and chamfer the second face.
(https://i.imgur.com/2KBIUID.jpg)
(https://i.imgur.com/sMbps5M.jpg)
The engine now looks much more the part, with all the properly sized nuts and studs!
(https://i.imgur.com/1nAZhsS.jpg)
(https://i.imgur.com/dwgHlnM.jpg)
(https://i.imgur.com/4wSdxvS.jpg)
(https://i.imgur.com/acCdw9F.jpg)
The remaining work:
1. Oilers, similar to what Vince did.
2. A few gaskets.
3. Steam supply pipe and fittings to feed steam or air from under the base.
4. Painting - something I still have to learn how to do properly!
5. Buy a compressor, to replace the front right tire of my car as air supply :).
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Nice details.
Saw your 3d model of the Corliss which reminded me that I need to do that also in Fusion 360 to add to my collection. Kiwi and Monitor already done.
Vince
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Personally when a model is as nice as yours in bare metal I would have second thoughts about painting it. Don't get me wrong painting sometimes enhances the work but not always.
gbritnell
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Maryak approved!!!! I'm sure he's smiling!
Dave
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Its looking good :)
Jo
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I agree with George and was thinking a similar thing. It looks awfully nice as is, and the brass against steel make a great looking contrast.
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What a great thread!! I am in the very early stages of building this engine, and it is wonderful to have such a well documented journey to follow. thank you so much.---Brian Rupnow
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It really looks amazing as it is right now :praise2:
... but I really can't say what would be the optimum treatment ... completely painted, partly painted, ferrus parts getting a 'Nickel bath' .... so many options :thinking:
No matter - one to be proud off :cheers:
Per
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Runs like a dream and looks fantastic, you have to be very happy with the result.
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I am in the very early stages of building this engine, and it is wonderful to have such a well documented journey to follow. thank you so much.---Brian Rupnow
Thank you Brian! There are a few well documented threads on this topic. I relied heavily on those by Vince https://www.modelenginemaker.com/index.php/topic,1526.0.html (https://www.modelenginemaker.com/index.php/topic,1526.0.html) and Arnold https://www.modelenginemaker.com/index.php/topic,1333.0.html (https://www.modelenginemaker.com/index.php/topic,1333.0.html)
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Thanks very much everybody for the kind comments! It makes the whole exercise so much more worth while!
I am now in two minds about painting the engine! Apart from the brass and stainless steel parts, the mild steel components definitely will need some rust preventing coating though.
One of the main aims of the model is to serve as a vehicle to learn about machining and processing metal. And I still need to learn about painting...
In the mean time the steam supply and exhaust fittings were made.
To bend the 6mm copper steam supply pipe, a jig was made from scrap wood and metal.
(https://i.imgur.com/CfOcNon.jpg)
Two lengths of pipe were bent after annealing, one filled with salt to prevent the pipe from collapsing. The salt only made a marginal difference, and both pipes turned out acceptable.
(https://i.imgur.com/sdpWEeq.jpg)
Brass flanges were epoxied to the copper pipe (I am still a bit reluctant to silver solder). The exhaust pipe was turned from a scrap piece of brass. A mild steel adapter to be mounted below the base and to receive a 6mm air supply tube was also made.
(https://i.imgur.com/aH2RNw7.jpg)
I am quite happy with the final result. The copper tube will eventually be covered with rope. Now I need some more 3mm studs to mount the flanges... Fortunately there is no deadline to complete this engine! ^-^
(https://i.imgur.com/YE6j7S7.jpg)
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It took a while to find suitable glass tubing for the oilers. I eventually stumbled upon 20mm electric fuses, with glass tubes of just the right diameter and thickness. These were cut to length on the lathe using a cutting wheel on my high speed router, clamped to the cross slide.
(https://i.imgur.com/RBjH6oA.jpg)
The ends of the tubes were then sanded to length. The tubes were held perpendicular to the sanding surface using a piece of mild steel with a hole bored to exactly the right diameter to hold the tube.
(https://i.imgur.com/eCKbxtc.jpg)
After a bit of finicky turning, where my ER32 collet chuck came in very handy, four oilers were ready for mounting.
(https://i.imgur.com/N66KJO5.jpg)
I am quite happy with the final look. An oiler on each main bearing, one on the eccentric strap and one on the crosshead guide. I am just a little bit concerned that the brass oiler caps are going to disappear very quickly!
(https://i.imgur.com/27V1Puk.jpg)
(https://i.imgur.com/JovwbWs.jpg)
This concludes all the machining operations! :cheers:
I decided to use Locktite sealer in stead of paper gaskets, so the only work remaining is to paint the mild steel bits, and perhaps to make a glass display case. Can't wait to connect an air brush to my newly acquired 24 litre air compressor that now powers the engine.
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Those oilers are great!!
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It took a while to find suitable glass tubing for the oilers.
Brilliant JC! Very clever and now committed to memory. :ThumbsUp:
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:ThumbsUp: :ThumbsUp: :ThumbsUp: :ThumbsUp:
Bravo! Excellent job on those oilers. This is a lovely engine, and details like that really enhance it. :NotWorthy:
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And I go through really many Fuses every year in the Repairshop at Work .... and it never crossed my mind to use those glass tubes for anything ...!... In my defense, I never needed an Oiler, nor a Water Height Tube for a Boiler .... but might still not 'have clicked' in my mind :-[
Very nice result on the Oilers too - did you discover that the metal ends on the fuse is easily removed ;) :cheers:
Per
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Isn't it amazing how much useful stuff is hidden in the everyday junk that normally gets thrown away? Those oilers are perfect! :ThumbsUp:
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Great looking oilers but I hope you wiped your ways clean afterwards. I do the same thing when cutting glass tube but I put a piece of paper over the ways between the carriage and headstock when doing it.
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I hope you wiped your ways clean afterwards.
Thanks for the reminder! Not always as diligent as I should be to keep the ways clean!
Here is a short video of the completed engine, prior to painting:
[youtube1]https://youtu.be/s_IDI0ORcl8[/youtube1]
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Runs great! We'll done!
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Great runner
Vince
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One to be proud of - not a simple project :praise2:
A nice runner too :cheers:
Per
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Excellent! Your Corliss runs very well! :ThumbsUp: :popcorn:
Kim
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Terrific!
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Congratulations on a job well done! The Corliss valve dance is mesmerizing! :ThumbsUp: :cheers:
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Awesome results…. :Love:
:cheers:
Don
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That is a really well made and smooth running engine.
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Excellent :praise2: :praise2: :wine1:
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Hi , clever idea using the glass fuses for the oilers. I will remember that and I have a large quantity of these that I have been collecting over the years :NotWorthy: :praise2:
Willy
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In preparation for painting, I am taking my time developing a process that will give acceptable results. The scrapped cylinder block serves as a test piece. Since I now have a small air compressor, I want to spray paint the model.
I started off spraying 2K automative paint with an airbrush, but found the airbrush too small to lay down an even wet coat. A touch-up paint gun gives better results, and I am slowly starting to get acceptable results.
(https://i.imgur.com/EPsrwg1.jpg)
An etch primer is followed by three coats of 2K gloss base coat, with the paint reduced 50/50 with thinners. It is left 48 hours to dry, and then wet sanded with home made sanding sticks, with grits from 400 to 2000. This is followed by hand polishing with an automotive rubbing compound. I found that polishing with a Dremel easily damage the paint on the edges of the cylinder block.
(https://i.imgur.com/D19ZNma.jpg)
Next step is to do the same test on a scrapped valve disk hub, to see how the sanding and polishing goes on round surfaces.
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After lots of trial and error I finally have a satisfactory paint finish.
What I have learned using 2K automative paint (noted here for my own future reference):
1. Use a touch-up spray gun, not an airbrush.The airbrush results in too much overspray. Set the spray pattern to be as concentrated as possible.
2. Take all necessary safety precautions. 2K paint is poisonous!
3. Clean all surfaces thoroughly with a pre-cleaner that does not leave any residue, such as benzine (not acetone).
4. Mask with good quality masking tape. Remove all masking tape residue where tape is removed. Take particular care when masking right up to the edge of a surface, such as for the valve bonnets. The edges to be painted must be perfectly clean for maximum paint adhesion.
5. Wear latex gloves when handling cleaned parts and also while masking.
6. Dilute etch primer 50/50 with thinners for spraying.
7. Allow ample time for etch primer to cure.
8. Dilute 2K colour coat 50 (paint and hardener) / 50 thinners.
9. Spray at least three coats, allowing the required cure time between coats as per paint instructions.
10. When spraying, hold the parts to be sprayed up in the air, away from any dusty surface.
11. Allow at least 48 hours for paint to cure.
12. Rub all painted surfaces with ultra fine steel wool to remove any dust particles and/or orange peel.
13. Be very careful with sanding sticks. It removes paint on small surfaces very quickly.
14. Spray two more colour coats and cure for 48 hours.
15. Lightly rub all surfaces again with steel wool to obtain a smooth surface.
16. Polish all paint surfaces by hand with a lint free cloth, using an automative polishing or rubbing compound.
17. Use gloss clear coat to protect metal surfaces not receiving a colour coat, such as the fly wheel rim. Rub the gloss coat with steel wool for a semi-gloss finish, or polish with rubbing compound for a high gloss finish.
(https://i.imgur.com/7kI32d4.jpg)
And everything back together again:
(https://i.imgur.com/407mw0O.jpg)
The very last bit of work on the engine was to secure the small brass oiler caps on top of the glass tubes, otherwise they will disappear very quickly.
The best solution I could find was to punch out small pieces of double sided tape, normally used to mount mirrors against a wall. The tape is glued to the cap, and fits tightly inside the glass oiler tube.
(https://i.imgur.com/24jGf5s.jpg)
(https://i.imgur.com/WVcOVhM.jpg)
(https://i.imgur.com/Y7s8OSn.jpg)
And that concludes the build!
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Enjoyed following your build JC. Brought back nice memories.
Vince
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Thank you for the recap and useful tidbits :cheers:
Per
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Nice work. Sorry if it has been covered before but what are you using for a milling machine?
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Nice work. Sorry if it has been covered before but what are you using for a milling machine?
I have a Chinese RF45 clone, with an X-axis power feed I made, as described here: https://www.modelenginemaker.com/index.php/topic,10327.msg235425.html#msg235425 (https://www.modelenginemaker.com/index.php/topic,10327.msg235425.html#msg235425)
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Well done :ThumbsUp:
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I am speechless, what a master piece,!!! :praise2: :praise2:
I noticed throughout your build you were using plans that included 3 views etc. I have looked high and low for these in the thread but could not find them. Would you be so kind to link to them. Thank you kindly.
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warrenmaker, thank you very much for the kind words!
In the mean time, the engine has received its own display case, as described here: https://www.modelenginemaker.com/index.php/topic,10902.msg252564.html#msg252564 (https://www.modelenginemaker.com/index.php/topic,10902.msg252564.html#msg252564)
If I remember correctly, I found the original drawings scattered through this thread: https://www.modelenginemaker.com/index.php/topic,1333.0.html (https://www.modelenginemaker.com/index.php/topic,1333.0.html). There were a few corrections to the drawings along the way.
The imperial and metric plans for the MEM Corliss Engine can be found here: https://drive.google.com/drive/folders/1hy8iCIJsRreemegKL2SVauRsrLly8_40?usp=sharing (https://drive.google.com/drive/folders/1hy8iCIJsRreemegKL2SVauRsrLly8_40?usp=sharing) (The pdf files are too large to be attached to this post). I believe these versions include all the corrections that were made.
I also created a 3D CAD model of the engine in Fusion 360 as shown here: https://a360.co/3RV6f7g (https://a360.co/3RV6f7g). I made most of my own shop drawings from the 3D model, but they sometimes had mistakes, which of course I was fully aware of at the time.
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Do you have plans for this? Where can one purchase the plans?
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Do you have plans for this? Where can one purchase the plans?
The post just before yours gives the links... Plans are free and on this site.
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Thank you. I found them just minutes after I emailed you.
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Thank you. I found them just minutes after I emailed you.
Great! Its a great engine, several build logs on the forum so far, hope you add yours!