Re: metric to imperial shaft adapters for stepper motor??

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "rszemeti" <list@r...> wrote:

> Those
> old bridgeport steppers are mechanically massive, Im not sure the
> shaft on a NEMA42 is quite as robust .. IF I was to do this, I think
> I'd go for some nicely turned up adaptor and lock it on with a
> "Trantorque" bush or another similar type of "allround" grippign bush,
> plus make sure I ream the sahft hole to a tight fit. theres a lot of
> potential for extension piece to wobble, I dont think you'll get away
> with a couple of grub-screws on this one.

The bridgeport motors are NEMA42's.
They are just M112's with a heat pot fitted.
If you change to modern drivers you can do away with this heat pot.

My Beaver Mill is fitted with plain M112's and they have all got shaft
extensions from new.
The original shafts are 5/8" diameter and 1-1/4" long. Fitted onto
these are a piece of 7/8" diameter round with keyway. They are bored
internally 5/8" and pushed on and secured with a roll pin drill thru
the extension and motor shaft.
The pulleys then fit onto these extensions with taperlock bushes.
This is how it was produced at the factory and it has never given any
problems.

I have recently converted this from the old Bi level drivers due to
lack of spares to Gecko's.
I did initally have some problems with lost steps but this was using
an early 210 drive.
I then fitted a later series 210 with the four jumper positions, one
for the type 42 motors and it cured all this.
Basic setup is running at 62 volts 7 amps max from the Gecko. Motor is
wired in parallel.
Direct drive onto 0.200" pitch ballscrews.

I have had it running for 3 hours between two clocks on all three axis
in turn, with no lost steps or problems.
A bridgeport should be better off as they will have more torque
running a 2:1 reduction.

John S.

John S.