|Pete White||11/02/2019 20:19:09|
|46 forum posts|
Engineering porn, great photos, keep up the good work and posts, much appreciated.
2299 forum posts
Howard; a couple of pics of the cobbler automaton would be nice.
|Howard Lewis||14/02/2019 01:45:53|
|1819 forum posts|
Sadly, was so obsessed with sorting it out that took no pictures. Should have, if only to show the damage and bodges, (likely to make matters worse ), previously present.
Would guess, from the telephone number on the baseboard, that it was pretty old (020 code)
Basically, a geared shaded pole motor drove a multilobe cam. The follower is on a lever which pivots on the left frame. The lever carries three screwed rods, with ball joint ends, which run vertically upwards. The undamaged one nods the head, the two that needed straightening and adjusting operate the right arm, wielding the hammer, and the outer one, a bell crank which drives a horizontal rod at shoulder level, which causes the left hand to sweep to and fro across the shoe on the "anvil".
The fact that the two rods had been bent in compression implied some fairly large forces, (hence the original motor ran, but did not drive the output shaft ).
The cam had been fitted inside out, making the grubscrews inaccessible, which explained why it was loose on the shaft! When fitted with the hub outwards, the cam was running out. It was secured to an arbor, in the lathe and checked with a DTI. The DTi was moved away to allow gentle persuasion, or levering, at appropriate points, until it ran reasonably true again, (1mm+ reduced to less than 0.2mm ) At least the cam now stayed in the groove in the ball bearing follower. Having dispensed with the pack of washers, a solid spacer was turned up to align the follower with the cam.
Adjusting the rods took time, because to make any adjustment meant removing a ball joint, giving it one turn and refitting, before checking the effect of the adjustment.
Once operating satisfactorily, the back was fitted; which promptly stalled the motor! The ball joint on the outer rod fouled. The rod was refitted with the ball joints inboard, but a foul still remained. This was cleared by drilliing a hole in the plastic back, and steadily carving bits away, to extend it, until the foul cleared.
From its state, the shirt was even older than the ones that i wear in the workshop; and that's saying something!
The new owners seemed impressed with my description of the "as received" condition, the repairs,and the "after" operation, that they gave a bigger donation to Club funds than I had expected.
So everyone was happy!
|duncan webster||21/03/2019 15:48:58|
1962 forum posts
Not my idea, Mr Tredenick from Australia, as featured in MEW Feb 19. How to stop the jaw lifting on your Record drilling vice. Only took an hour or so
Edited By duncan webster on 21/03/2019 15:50:36
|Jim Nic||03/04/2019 22:46:43|
168 forum posts
In my last post on the progress of Stew Hart's Overcrank design I had made the valve eccentrics (and the eccentric straps) which had to be fitted to the crankshaft centre section before assembling the shaft. I then thought that making up the shaft would naturally be the next operation. When I came to cut the 12mm dia bar to length for the main part I found that the exact length depended on the width of the flywheel and the output pulley hubs. Sooo the next task was to obtain a flywheel casting from Stuart Models and machine it and make a pulley and, while I was at it, a pulley for the governer belt.
Then I assembled the crankshaft using my usual Loctite method but since this was a twin cylinder engine I also pinned the webs. The pins are fitted through the webs from one end, go through both the "big end" and the shaft section but stop short of protruding from the other end of the web.
And here is an assembly shot of the crankshaft in position before I had cut out the redundant pieces between the webs.
Next up I get to fit the laser cut crank return rods
15042 forum posts
had a try at getting the I F Allman engine going over the weekend and it's nearly there. A few fine tweaks to the gas flow to the actual engine and the position of the burner to get the timing spot on should have it firing a bit more often which should result in some longer runs.
|Ian Skeldon 2||22/04/2019 15:56:08|
|341 forum posts|
Duncan Thanks for the tip, will give that a go.
Jason I love that engine, just to give an idea of the size, what diameter is the fly wheel?
15042 forum posts
10.5" dia and very heavy due to the thick section rim.
|Ian Skeldon 2||22/04/2019 20:08:29|
|341 forum posts|
But what a beauty she is, nice one Jason.
|duncan webster||23/04/2019 12:28:53|
1962 forum posts
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