Armortek

Hello,

I'm having trouble fitting the main sprockets. The bush/sprocket fit nicely onto the shafts but the keys are very tight.

Should I need to use force to put the keys in? Definitely put the keys in last? Possibly file down the keys so they go in most of the way nicely?

Thanks

Sam

Is it tight in the bush, the shaft, or both ?

Adrian.

It is a perfect fit in the bush but difficult/impossible to get it into the shaft.

Thanks

Sam

In that case I would say that the key and the bush are the correct size and the slot in the shaft is the problem. I wouldn't remove any metal from the key, or you risk making ruining the fit in the bush.

You can find that the original machining of the slot in the shaft leaves a little excess metal along the top edges, which then get bent over by the bush to reduce the width of the slot.

Try taking a small file to the top edges of the slot in the shaft, just enough to make a slight chamfer. Then if the key still won't fit, try shaving small amounts from each side of the slot until it fits snugly.

As you remove metal, keep renewing the slight chamfer on the slot edge, so that it can't catch on the taper bush.

Adrian.

^^ As Adrian says but one thing I would try first is to slightly chamfer off the edges of the leading end of the key. It is amazing how a tiny malformation of one of the edges can prevent the key being inserted. Also I add a tiny bit of copper grease to ease the keys in. You need to invest £10 in a digital micrometer so that you can easily identify whether components are the correct size.

Many thanks. I'm trying slow and steady fettling of the shaft.

My cheap micrometer (not as good since my dad borrowed it) shows 4.95 for the key and the shaft BUT 5.00 for the bush. Not sure I trust the gizmo to be that accurate though.

Cheers

Sam

If that's the right way round then there is no reason why the key won't fit. As above chamfer the leading end - IIRC the keys on later kits had fully rounded keys at one end.

Thanks,

Got one side to fit nicely. For the other side having to file the sprocket so the bush fits nicely. Sigh.

Cheers

Sam

My cheap micrometer (not as good since my dad borrowed it) shows 4.95 for the key and the shaft BUT 5.00 for the bush.

Whatttt !!!

Busted !!!!

Adrian.