Stuart tuner No 9 Crankshaft

Can any body put me back on the right track, have bent and twisted the crankshaft on my no 9, had spent a long time turning the shafts down,, packing piece in place, all's well there, so set about making the throw pieces, spent a long time on these, set it all up in the lathe, checking all the time,, BUT,, IT ALL WENT WRONG, not sure why but I will not be singing up for the local cricket club as not good at catching the crank,, spun out of the lathe and now have a bent and twisted one,, so,

Anybody by chance have a spare under the bench,, long shot that. should I try and repair bent one, make a new one of mild steel as Stuarts sell them in mild steel now, should I make one of parts and silver solder it,,

Am very new to this but working at it, if any body near me to help steer me in this build would be nice, I am between Bromsgrove and Droitwich.

many thanks , and hoping can help me

Edited By Terry olds on 13/06/2015 12:37:09

It would probably be cheaper and easier to make one from mild steel pinned and silver soldered Or even locktite

I personally have not tried Locktite Roy  Provided that you have mild steel in of course

Edited By roy entwistle on 13/06/2015 13:38:01

I would suggest making one from a piece of flat bar thick enough and wide enough for the webs. I have done this for a number 1. I have also made a two throw crank for a double ten from a piece of round bar, and a three throw crank for a Stuart triple complete with eccentrics all in one piece.

I would further suggest that if you have the equipment to do it, you mill as much as possible of the crank between centres. This needs a vertical mill and a dividing head. Well, not strictly dividing, but you need to be able to hold the crank between centres and control its rotation to mill away the material. Some of the material can of course be cut away with a hacksaw before starting the machining. With this technique the crankshaft is much less likely to fling itself past your left ear.You do of course need to finish in the lathe to get a good bearing surface. (Although a larger crankshaft for my steam launch was milled and then ground.)

John

a year or so ago I rebuilt an S9, the crankshaft had a slight bend, so rather than try and straighten it I made a new one from flat steel as John suggested, well I actually made two, the first one just as I was finishing it got caught up , and bent, which was enough to make one say bother, and pack up and do it again the next day.

Unfortunatly this engine got nicked from a public open day display. The origional CS seems to be a forging, the engine was at least 50 years old. Here it is the S9 before anything was done to it

Ian S C

Thanks for the advice guys, have done a four part crank yesterday, and will silver solder it today, but I think a solid bar type one is best, so, I will let you know how I get on.

practice makes perfect, so they say,

Ian sorry to hear you had your S9 stolen. what next.

Just to say 'Stuart Turners ' have come back to me to say, that they are doing a cast crankshaft in the near future, but for now, just supply a steel stock to make one out of.

The S9 used to live in my mates little museum, a couple of doors away from my place, but he took it, along with some of his full size hit and miss engines to a display in Christchurch, about 40Km from here.

At least he still has the last Suart Turner engine that I got going for him, it's a rare one, a ST ProgressSV, it's a little vertical with a slide valve, 1/2" bore, 3/4" stroke, and was available in the 1920/30s. This is as it was, I must have another photo of it as it is. Ian S C