I use a similar system to fit the flywheels to my engines but drill through the collet and into the crankshaft a bit and fit a silver steel pin. Then when you want to take of the flywheel the collet stays on the crankshaft. The pin is drilled and tapped so a screw may be fitted to remove it. The taper is a good idea fitting a key to a parallel shaft often makes for a wobbly flywheel.

Edited By Engine Builder on 05/08/2012 13:59:58

Hi. I am just about to start on building this engine from the Hemmingway's Kit. Can you give any advice on if you have run into major difficulties or problems? It's the first IC engine I have built, having done a couple of steam engines from bar stock.

Cheers Andy

There's a description of building this engine here:-

**LINK**

It's not my engine. I've just been following the thread on the other forum with interest.

Admittedly re-awaking an old thread, but I have the same question as Terence. It looks like ‘Engine Builder’ has supplied the solution, but I don’t understand what is being suggested. I’d be grateful if someone can explain again.

i.e. I don’t understand:

‘I use a similar system to fit the flywheels to my engines but drill through the collet and into the crankshaft a bit and fit a silver steel pin. Then when you want to take of the flywheel the collet stays on the crankshaft. The pin is drilled and tapped so a screw may be fitted to remove it. The taper is a good idea fitting a key to a parallel shaft often makes for a wobbly flywheel.’

David

I see. Thanks Jason – it looks like you went to a bit of trouble drawing that for me. It’s really appreciated.

David

I am not Rod, but this method may help. I first "loctite" the crank pin into the webs with a piece of shaft material through the other holes for alignment, then leave it to cure. Meanwhile, I clamp a piece of ground bar into a matching pair of Vee blocks that are sitting firmly on a ground surface, with a gap between them, a little larger than the width over the finished webs. I then lift the whole thing and put a little "thread lock" on the underside of the Vee blocks, and temporarily "glue" them to the ground surface they were sitting on. When the thread lock has cured, the round ground bar is removed, and the two shaft parts of the crankshaft are inserted into the web assembly, and the whole thing clamped into the glued down Vee blocks. When all has cured the crankshaft is removed, and a light tap with a small hammer(with a piece of brass interposed) will remove the Vee blocks from the ground surface. Any thread lock on the Vee blocks is easily removed with a sharp blade.The last crankshaft that I assembled like this, I held in a collet at one end and clocked the other end for runout. It was less than half thou.

Like Maurice I make up the "U" shape of webs and pin first then when that has cured slip it onto the crank stopping just short of its final position. Apply a couple of rings of Loctite to one side of each web and then slide it into position while twisting the main rod. That way you don't smear it all down the rod.

Having said that I solder all my IC engine cranks and keep the Loctite for small steam engines

A rough sketch of the assembly of a simple crankshaft. If you want it can be silver soldered instead of Loctite. The only motor I have with this form of crankshaft is a small beam hot air engine, the diameter of the shaft and pin is 3 mm, the webs are 2 mm thick, and shaft lock is holding up well.

Ian S C

Edited By Ian S C on 18/09/2017 13:06:30