Steppers. How to connect a pulley to it?

[Degrom]

Hi.

I want to connect a timing belt pulley's to a stepper.

How do I go about doing this?

The T5 pulley's I am looking at has a 6mm ID and the Nema 23 steppers I have has a 1/4" shaft. (6.35mm)

Do I just press fit them? (If so,how do I do it with a Stepper Motor? )

Any suggestions are welcome.

Best regards,
Bert.

[acondit]

You either (1) find pulleys the correct size, (2) bore out the pulleys, or (3) turn down the shaft on the motor. I would recommend #1.

Alan

[BobWarfield]

Bore 'em out on a lathe. If you don't have a lathe, but you do have a mill, you can try it there too.

Best,

BW

[Degrom]

The T5 pulley has an ID of 6mm and Nema 23 has an OD of 6.3mm.

Was just wondering if that little 0.3mm was for press fitting it...

[chrugel]

The T5 pulley has an ID of 6mm and Nema 23 has an OD of 6.3mm.

Was just wondering if that little 0.3mm was for press fitting it...

0,35mm is not little when it comes to press fitting!
I had a pulley that was a little bit to big and what i did was to shimis it with thin metal plates and then press fitt it. I believe this was in the range of press fitting 0.0~ somethig and it took about 10.000N to get the work done.
I cant imagine what it's going to take to get 0.3 mm done.
If you have access to a lathe is is not hard drilling up the pulley. It is a little bit tricky getting the excact size.
If i is a dual shaft motor it is a lot easier to turn down the motor shaft. I've turned down a couple of motorshafts without even dissassembeling the motors. If it is not a dualshaft it can be rather tricy and you have to take the motor apart.


chris

[irving2008]

Do not take the motor apart if you want it to work after... steppers are very touchy about the magnetics - if you remove the rotor you may find the stepper isnt as powerful as it was before.

Always make the pulley fit the motor... drill it out on a lathe or mill or get a get a 6.35mm tapered reamer and open out the pulley bore that way...

[LeeWay]

If you have several 1/4" drill bits, find the smallest diameter one. They will likely vary a bit. Then just use that to increase the hole size. Easily done on a lathe, drill press and yes, even by hand. You are effectively only reaming to size.
A solid motor coupling to a screw would be more critical, but for a belt pulley, incredible accuracy just isn't needed. Close is good enough.

[johnmac]

If your pulley has flanges to keep the belt on, be careful with it. The flanges bend and breaks off easy.

John

[pescado_loco]

use a hss reamer. $8 from enco

[Degrom]

Thanks for everyone's input.

I will try and get a 1/4" reamer and use it on my lathe.(I might as well buy a reamer instead of a drill bit because I will have to do 6 or more of these pulley's)

I will also remember to be carefull with the flanges...

One last question... Can I just use a normal grub screw to secure the pulley to the stepper motor? (Or is there a better way of doing things?)

Kind regards,
Bert.

[martinw]

Dear Degrom,

If you use a grub screw, just file a small flat on the motor shaft so the grub screw point hits a flat surface. You might want to use a drop of low strength thread locking engineering adhesive so that the grub screw doesn't unscrew in use. That will give you an assembly that can be dis-assembled. Clean all the parts in solvent (eg IPA) before using the thread locking/retaining adhesive. Loctite is a company has a huge range of these engineering gloops.

Be warned....if you use the stronger ones, you will never be able to take your gizmo to pieces.

Good luck,

Best wishes,

Martin

[martinw]

Dear Degrom,

Here is a Loctite link in your part of the world.

http://www.loctite.com.au/cps/rde/xc...8_AUS_HTML.htm

Enjoy summer,

BW

Martin