Re: [CAD_CAM_EDM_DRO] Adding a Tail shaft to servo's with no tailshaft

I have added tail shafts to quite a few DC motors for use with encoders.
First it depends on the motor. If the rear end of the motor is visible then you should be able to chuck the front shaft into a lathe .
Ensure the motor leads are insulated so they don't generate current while being rotated. use a stready rest to support the body on center.
Center drill the rear end then drill and ream and insert a stub shaft with a good tap fit.
If using US digital encoders you will need to drill 2 and tap 4-40 holes on a 1.812D bolt circle. If drill the rear end cap with the armature installed then you could epoxy the encoder base to the motor end cap if the end cap is flat. You will need a centering tool to ensure the encoder mount is center to the newly installed stub shaft.
Some motors have a hardened shaft so it may not be possible to drill and add the stub shaft.
Dan Mauch
economical 3D scanner software and kits
low cost stepper and servo motors.
cases for Gecko drives
kits and assembled 3-4 axis drives
www.camtronics-cnc.com
www.seanet.com/~dmauch

----- Original Message -----
From: Wayne Weedon
To: CAD_CAM_EDM_DRO@yahoogroups.com
Sent: Thursday, April 26, 2007 3:27 PM
Subject: Re: [CAD_CAM_EDM_DRO] Adding a Tail shaft to servo's with no tailshaft


jerryflyguy wrote:
> I remember someone posting a process they went through to add a tail
> shaft to a DC motor, thus making it possible to put an encoder on it. I
> can't find the site in my huge pile of favorites, anyone ever done this
> or remember the site I'm thinking of?? I've got my hands on some great
> DC motor's but they don't have the tail shaft..

I've done it a few times. I take the armature out of the motor, chuck
it up in the lathe and support the end you need to fit the shaft with a
fixed steady.

Drill, ream, bond a shaft in with a high strength loctite. If you need
to you can make the new shaft slightly oversize, and true to size in the
same setup as soon as the loctite has gone off.

If you are trying to use a standard DC motor, try to use one with a
skewed rotor, they work better as servo motors.

Wayne....

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Wayne M Weedon Email: wayne@...
Fdos Design Poole UK
Tel +44-1202-677025 Fax +44-1202-770515 Mobile: 07774 439915

Specialists in small batch & Production Mechanical/Electrical Engineering
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