eccentrics...how to?

[MrTin]

Hi all,
I am thinking of making a set of reversing gear for my Stuart D10, but it suddenly occurred to me that I had no idea how to turn eccentrics!

Any tricks, advices, thread links?

Thanks,
Martin

 

[dnalot]

Basicly you just turn the outside form on the lathe and then drill the center hole off center the desired amount.

Mark T

 

[MrTin]

But if it needs a collar round the eccentric hole for fixing the eccentric to the shaft??

Martin

 

[xpylonracer]

Martin
If you have a 4 jaw independent chuck you offset the centre of the stock off centre by halve the amount of eccentricity you require, you can turn the boss at the same setting.
If you don't have a 4 jaw then by using a packing piece under 1 of the jaws of a 3 jaw chuck you can achieve an offset to the rod, I don't have the formula in my head or to hand but the packing thickness can be accurately calculated.

Emgee

see this page http://www.steves-workshop.co.uk/tips/lathetech/eccentrics/eccentricindex.htm

 

[Jasonb]

For the twin eccentrics needed for the stevensons reversing gear drill and ream the blank first including forming the collar and tap for the lockscrew

Then make an arbor to hold the blank that is offset in the 4-jaw and slip the blany onto it, held by the lockscrew. Turn one eccentric and its groove then rotate the part made eccentric on the arbor and then turn the second eccentric and groove.

J

 

[MrTin]

Many thanks, gents, for your help. I get the idea now.

Cheers,
Martin