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Re: Stepper motors

Posted: Wed Apr 18, 2012 8:16 pm
by edwardrford
So, I've tried drilling out a 5mm pulley to fit a nema23. The results are so/so at best. You'd think it would be easy to bore out the original hole and keep everything concentric, but it ends up that it isn't that easy. (at least for me it wasn't)

After many screwed up pulleys (or so/so pulleys as I like to call them), I've resorted to just buying new ones when the situation arises. They run about $5/each and in my opinion, it's worth the price.

-Edward

Re: Stepper motors

Posted: Thu Apr 19, 2012 1:05 am
by kargofab
Hi Edward,

So are you saying there's a larger bore pulley that'll work?? Do you have a pointer to the part?

Thx.

-m

Re: Stepper motors

Posted: Thu Apr 19, 2012 1:15 am
by RedOko
Its actually a 1/4(.250) inch diameter.

http://store.makerslide.com/index.php?m ... ucts_id=16

Re: Stepper motors

Posted: Thu Apr 19, 2012 1:43 am
by edwardrford
RedOko is correct, it's 1/4" pulley for a nema23.

You can find them here as well: https://sdp-si.com/eStore/PartDetail.as ... roupID=218

That's a great site btw for lots of stuff: belting, pulleys, hardware, shafts, bearings, etc.

-Edward

Re: Stepper motors

Posted: Thu Apr 19, 2012 2:28 pm
by sea2stars
Nice link.

I bought some metal ones from these guys in NY though;
Quality Transmission Components

Re: Stepper motors

Posted: Thu Apr 19, 2012 2:53 pm
by RedOko
In order to have a nice hole for these thing, I recommend reaming it out after drilling it a bit undersized. This is basically a 2 step operation and better performed in a rigid drill press. A 1/4" drill bit will almost always create a hole bigger than 1/4".
Here is a nice explanation on the topic in case you need to do a lot.

http://awtarlab3.engin.umich.edu/wiki/i ... ing_a_mill

Personnally for a few timing pulley it will be a lot cheaper to just buy new one, and just save those in case you come across metric sized stepper.

Nema stepper motor mounting hole location are the same for metric and inch. Just the size and thread differ, for the shaft they either have 5mm or 1/4inch diameter shaft for the Nema 17 and 23. The motor I'm using is actually a mix of 4-40 thread for the mounting with a 5mm shaft. :o

Re: Stepper motors

Posted: Thu Apr 19, 2012 9:39 pm
by nogthree
Just a tip, if you're trying to bore out the pulleys you're better off doing it in a lathe. The original pulleys I had were for Nema17 spec shafts and I had to bore them out, doing them on a lathe keeps them centred perfectly.

Just don't do what I did and bore it out with a metric drill instead of the 1/4 in one :oops:

Re: Stepper motors

Posted: Fri Apr 20, 2012 11:35 am
by CptanPanic
So to upgrade x/y to nema23, all you need is new pulleys?

Re: Stepper motors

Posted: Fri Apr 20, 2012 1:18 pm
by Aaron Seltzer
CptanPanic wrote:So to upgrade x/y to nema23, all you need is new pulleys?
Nema23's attach with M5 not M3 fasteners. Not clear if either are included in the kit.

Re: Stepper motors

Posted: Fri Apr 20, 2012 1:40 pm
by edwardrford
The kits from inventables will include the correct M3 fasteners to connect the standard nema17 motors. If you're going to use nema23 motors then yes, you'll have to get the M5 bolts to mount those motors.

If I recall correctly, M5 x 16mm socket head cap screws will work great. When you mount the motors, run the bolts from the inside out (backwards from what you would think). So the nut is on the outside of the motor and the bolt head is on the inside of the plate. This gives enough room for the belt to clear.

-Edward