Detail view of linkage showing connection of piston rod, connecting rod to guide arms. A touch of Loctite on the screw threads should hold everything nicely in place on assembly.
With the cylinder and steam chest completed the next stage was the fabrication of linkages, eccentric and flywheel. Most of these items are relatively straightforward though it pays dividends to take your time and make each component as precise as possible. It’s tempting to rush the final stages but to me this is a mistake. Hurried workmanship now can so easily result in hours of frustration when your engine refuses to run.
One problem with Elmer’s plans is the quality, or lack of, of the pictures featured in the build notes. At first I had a struggle trying to sort out the detail of the linkage relating to the connection of piston rod and connecting rod. I think I have resolved the dilemma and the picture on the right shows my final result. I hope this is of some help to those of you following this build. I was also unsure on Elmers method of retaining the connecting links to the arms and you will see my solution in the gallery of build pictures.
By the way, with building my engine 50% up on Elmer’s plans I had to source a 4.5″ flywheel. Surfing the net took me to martins models I can highly recommend these top quality flywheels, beautifully cast with an excellent selection of styles and sizes. At the moment the $20 flywheels come into the country without attracting customs and excise duty which currently applies on items exceeding £18.00 in value.
So with a glimmer of light at the end of the tunnel I set about the final stages of completing Elmers #32
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- Studs were made for both guide arms from 3mm stainless and threaded M3 at both ends. After silver soldering the centre piece was cut away.
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- As I din't have a convenient piece of 50mm dia. brass the crank wheel was fabricated from aluminium plate and rough cut by hacksaw.
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- The 'Flinstone' styled wheel was clamped up in an arbour and turned down to size. Note 'rough cut' index cutter in toolholder.
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- Over to the mill for shaping the crankwheel. A large diameter end mill provided the profile I needed.
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- Switching from horizontal to vertical was the best way of arriving at the final shape for the crankwheel.
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- After cleaning up the spokes with a hand file the flywheel was set up in the three jaw for final finishing.
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- A drill bit holds everything in place during trial assembly of linkage. This is the pic that is hard to decipher from Elmer's build notes.
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- Trial set up of crankwheel and flywheel on crankshaft. Everything checked for smooth free running.
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- Testing the motion of the running gear. Care and accurate maching will have paid you dividends when you arrive at this stage.
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- Any slight stiffness in the running gear will disappear during the running in process. More serious binding needs to be sorted before proceeding.
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- My final machining job was the eccentric. You need a 4 jaw independant chuck for this - simply follow Elmer's build notes.
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- The completed eccentric turned from mild steel bar - the final piece in the jigsaw.
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- An overhead view of the crankshaft, flywheel and linkage down to the cylinder and steam chest.
It was at this stage in the proceedings that I couldn’t resist putting some air through the engine to see if there were any signs of life and I am pleased to report that after just a few minor adjustments my new creation burst into life !
A superbly crafted and informative site, and a joyful experience. I had decided beforehand to build the tall vertical, and spent today studying Elmer’s plans. I had not, of course, realized that you had chronicled your own efforts, so I was delighted to stumble on it this evening. My boring and lapping experience extends to one previous engine, but I learned quite a lot about the process, the hard way. I’m looking forward to starting!
Hello Brian, Thanks for your kind words - it’s always good to receive feedback, it makes the whole process worthwhile. I was particulalry interested to hear you are about to build Elmers Vertical mill engine. If you feel I can be of any help during the process simply drop me an email somers.john(spam)@start-model-engineering.co.uk - take out the anti-spam bit from my addy. I would be very interested to receive progress photos during your build and maybe a video at the end !
John