Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines
The Regular Stuff: Chat, Buy, Sell, Off Topic, etc. => General Discussion - Model & Toy Steam Engines – Stirling Cycle – Flame Lickers – Small Antique Originals => Topic started by: Hassellbear on January 22, 2024, 11:17:57 pm
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Paula is right on target--I've done this successfully on several cranks from different engines using a rawhide hammer.
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Hassellbear, that is a beautiful engine, and I wouldn't mind finding one like it someday!
The problem with the wobble is not unusual for engines that have the flywheel mounted to a cantilevered crank end. This is not an ideal design, especially with the flywheel located right out at the edge of the base where it could be easily bumped or impacted. Here's a similar engine which has a outboard bearing to help support the flywheel:
[attach=1]
As far as fixing, I don't think I would want to try straightening the shaft while still mounted in it's bearings. What I would recommend, if you have a lathe, is mount the unbent end in the headstock, preferably in a collet. An auxiliary support bearing could then be attached to the carriage to support the outboard bearing journal. I would use a split bearing arrangement, whereby it could be tightened down with bolt to secure the shaft.
This arrangement allows you to rotate the crankshaft in the lathe, by hand, until the bent end faces up. A magnetic-based test indicator could be mounted on the carriage to check the degree of runout. Light tapping with a brass hammer should bring it back to straightness. It's not really bent very much. The amount of the bend is exaggerated by the large diameter flywheel. When the test indicator reads essentially zero as the crank is rotated, you're finished.
The above operation could be accomplished with the crank remaining in the engine, but it may end up damaging the outboard bearing. Also, "Woe is me" makes a very good point about disassembling the engine. Make sure every part is identified as to it's exact position, so that everything will work smoothly when reassembled.
Paula
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It was dropped or something was dropped on it. That wouldn't have come out of Doll's doors
like that. What you don't do is try to pry it straight using the flywheel. You'll break
something that you might not be able to replace for a long time, if ever. It's going to have
to be taking apart, and being a twin, that's a lot of parts.
Take apart in an order and put back together in reverse order. Don't just through the parts
in a box and then expect yourself to sort as you go. First part that comes off, set it the
farthest from you with the screws or nuts that hold it on. Nest part, set it and it's fasteners
a little closer. Keep doing this so when it's time to reassemble, it's all laid out for you.
Remember when you put it back together, the closest part to you was the last part to come off.
So now it's the first part to go back on, and so on, and so on.
Hopefully the journals are not to washed out. When you're putting it back together you might
want to shim it.
Have fun and welcome to hobby.(https://emoji.tapatalk-cdn.com/emoji106.png)
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Videos
https://youtu.be/HEkL9DwxFNU?si=pwgN4xSrfbE7B3-v
https://youtube.com/shorts/bfHVQzBxdrE?si=Hx6_7WIk5I2n9mc8
https://youtu.be/r1KRKE8HcrM?si=SAgGRky8FuQCTjsf
https://youtu.be/cfJ_qbVArVM?si=cn7iu-YxakrPN3sY
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I ran it on air. There’s definitely a bit of wobble. I’ll link some videos.
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Nice engine. Straightening old cams is tricky because they can be so brittle. Good luck.
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I second the motion!
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That is a nice engine to have. It would be nice to see a video of it running even on air.
Want to see the wobble. There's some extra solder on the boilers back end cap and not a
good fit. Keep us up to date and shoot that video.
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Hi,
Today I received a 1929 Doll 365/1 which I purchased online from a reputable dealer in the UK. There are a few issues which require a bit of attention, but overall this engine is in relatively good condition considering its age. I suspect it underwent a prior restoration because the base is painted gray instead of dark green, and a couple of machine screws don't match the others.
One issue is a noticeable 0.042" wobble in the outer rim of the flywheel. The seller disclosed the flywheel wobble and thought the cause might be a slight bend in the crankshaft. I tend to agree because I can see a bit of run-out at the end of the shaft. Considering the rarity of the engine, I will have to think quite a bit before I attempt to straighten the crank. I may just live with it as is. Suggestions regarding this are welcome.
Another issue is the steam exhaust tube is missing. The difficulty here is sourcing the the tube solder fitting which threads into the cylinder assembly. I worry the size and threading of this fitting is not standard since it was made years before ISO metric was adopted. Any information and suggestions concerning this steam tube fitting will be greatly appreciated.
The following pics show the engine just as I received it. It needs a light cleaning to remove a bit of grime, but the patina will remain untouched (with the possible exception of the base which I may repaint a dark green).