[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

[Degrom]

Thanks Martin,

I am excited to get the items fitted.

Thanks for everyone's help,I should be able to get the job done now.

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

[Mike Nash]

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.

Maybe, but on my X2 mill, the pulleys were not concentric with the shafts/screws due to a slightly loose fit. (I bought the mill already CNCed so I don't know whether the pullies were drilled/bored.) Anyway, that was the source of the 0.001" "drunken thread" symptom I was having. I had thought it was the ballscrew, but it was the pulley on the ballscrew.

[Pader]

I do not know whether I am off the mark here but I have come across this difference in Asian built motor shafts. They nearly all use inches instead of metric for the US market. 6.3mm equates with 1/4" imperial. Why not drill out the pulley using a 1/4" drill which is easily obtainable?

[vger]

On method I have used to enlarge the bore in a hole is to use sand paper. In your case, take a small shft about 1/8" (a small drill bit will work) use a short piece of tape and wrap the tape around the end of the shaft just over 1 wrap. Take a small strip of fine grit sand paper (320 or 400 grit) and use the tape to attach/wrap it to the shaft with the abrasive side out. Wrap just enough sand paper so that it just fits into the pully bore. Chuck the small shaft into a hand drill and sand the bore of the pully. It will be slow going and you may need to replace the sand paper several times as it loads up, but it works. I have changed press fit to slip fit several times with this method.

Steve

[ger21]

If you haven't purchased the pulley yet, you should be able to find them with a 1/4" bore.
http://www.econobelt.com/Q460/RFQ/de...g_1-209_1.html

[UUU]

I've rebuilt my machine with new steppers so was faced with mating existing pulleys to new motors. I was fortunate in finding some steppers with a 6mm shaft, so that part of the problem didn't exist.

I cross-drilled the pulley and through the shaft and fitted a roll-pin.