Machining Drums and Discs - any advice

Status
Not open for further replies.
A mate of mine put the sprocket/drum in the lathe and ground the teeth down with an angle grinder on his big bore gold star
He ran it like that for years no problems
 
hi
Discs, forget trying to machine /turn the discs on anything other than a machine designed for doing this sort of work, I have tried and failed and I am a machinist and mech engineer.
People out there have the correct equipment, and are professionals at what they do, and at the end of the day it costs stuff all.
Blanchard grinding only does one side at a time, and the trick is you need to do both sides at once otherwise you will get pulsations back through the master cylinder/hand lever I know been there.
We have a couple of Blanchard grinders, and the time to setup the correct stones speeds ect would not make it efficient enough to make any money, maybe for a few hundred would be OK.

Drums, I machine my own on one of my lathes, no problem, what is most important is to machine the relined/new shoes to suit the drum after it has been machined to clean surface, I then set the backing plate up on the lathe true to the spindle, shim the cams so the shoes are around 10 to 15 thou bigger than the drum, then machine the shoes so they are a sliding fit in the machined drum, the aim is to get maximum contact of the linings to drum as possible, ie the greatest friction area shoe to drum.

My Penny's worth
Burgs
I to have tried to machine a disc in what I would say a lathe with worn screws and nut.
OTOH, I've gone to professional engineers who have no problem doing it, they keep their lathes in better condition to the one I have.
It all depends on what type of lathe you have, I have a home built one which has taper roller bearings in the headstock , these have to be slighty loose and requires lathe to be run for five minutes to obtain correct running clearance.
 
I've watched this thread with interest
I've machined loads of discs for cars (indeed the local garage uses me for this service when the new disc price is astronomic) The trick is to machine both sides without taking the disc out of the lathe. This means holding the disc on a huge mandrel (approx 5" in diameter, take a slight skim to get a truly flat face) to get the required overhang to do both sides. If the lathe is big enough a right and lefthand carbide tool will do the job. I had to weld a block on the tool to get round the back as the cross slide could'nt get back far enough to do the job. Use a carbide tool that is ground to the correct angle. inserted tooling is not as good as the brazed tip jobs (These need a diamond wheel to sharpen for this kind of work). The sides can be done separately (one after the other)
Commando discs require a different approach. I made a tool post grinding head and using a diamond wheel made for grinding tiles and bricks and the like use that to take whats left of the chrome off. Swap wheels for a specific grinding wheel for finishing. This involved making wheel hubs to carry the different grinding wheels so facilitating quick grinding wheel swops and to get around the disc to grind the back face. Incidentally my lathe is at least 60 plus years old. Its not what you have got, its how you can use the machine.
 
Status
Not open for further replies.
Back
Top