Advice on turning a part

[mekanik]

Hi Charlie
was just having another look @ your wee jobby, the dia of the boss looks smaller than the one shown with the key in it, what sort of wall thickness would you be left with if you opened it up to 1/2" ?
Mike

[charlieuk]

no they are the same size just one is a fraction shorter.

[mekanik]

Try to run a file in the bore of the gear to see if it is possible to machine it, i think your best option for the pin would be to remake from silver steel, harden/ temper and polish the shaft.
Mike

[charlieuk]

is there any one that may be interested in doing this for me before i go and find some company to do it? Its literally the last part to get my machine up and running!

best regards

[mekanik]

Charlie
Need to know if the gear can be bored, do the file check and if it's possible and you supply a piece or two of silver steel(extra for F**K up) for the shaft, and 4 pieces of smaller dia silver steel that will fit into the space between the gear teeth i will give it a try. Can't promise it will be a success but will give it my best shot before you have to spend silly money on the professionals.
Mike.
Get the file out

[m_c]

The chances of the gear being hardened are somewhere between slim and nil.

If all you have is a three jaw, then make a soft collet.
Easiest way is get a bit aluminium wide enough to cover the gear width, and about a couple mm larger diameter than the gear. Clamp it fairly lightish, then bore it out so the gear will slide in, then tighten the chuck and the aluminium will deform onto the gear.
Alternatively, get a thicker and bigger diameter bit, bore it out deep enough for the gear but leave it a couple mm undersize, remove and cut three slots in, place suitable bits of material to hold the slots open, reclamp, bore to size so the gear slides in, unclamp slightly, remove spacer bits, and clamp onto the gear. Think http://www.arceurotrade.co.uk/Catalo...C-Step-Collets but held by jaws and not a collet holder.

The bolt may be hardened, but probably not hard enough that a decent carbide insert won't handle it. If it is hardened, it's not likely to be through hardened, so once you're throught the skin it shouldn't be a problem. However picking up the thread accurately to extend it using a single pointed tool will be a bigger problem, so it would be easier to do with a die.