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Y motor coupling

Posted by Andromodon 
Y motor coupling
June 14, 2008 07:29PM
Hello. I am in the need of a Y-motor coupling. It seems my kit is missing one. Can you print one out for me? How much would it cost? Thank you.
Re: Y motor coupling
June 14, 2008 07:35PM
Re: Y motor coupling
June 15, 2008 06:43AM
I am about to make one for myself so doing another is no problem. The plastic will only cost a few cents, postage is the only significant cost for a part this size. Where are you located?


Re: Y motor coupling
June 15, 2008 08:11AM
This the same story as the one with the Z Pulley, isn't it?
I think there is only one part, a combined pulley + coupling, similar to the one on the Z-axis...
Re: Y motor coupling
June 15, 2008 07:41PM
Hey Chris,

Thank you very much! smiling smiley My zip code is 55416 (USA).

I am going to first check with Bits From Bytes to see what Ian says. I suspect he'll reply by Monday sometime.

Re: Y motor coupling
June 15, 2008 07:43PM

Yeah, this is the same story as the z-axis post. I did a count last week and saw that I didn't have enough toothed (like a gear) parts to finish the project. I think having a Y motor coupling will fix the problem and get me going again. smiling smiley

Re: Y motor coupling
June 15, 2008 08:05PM
Yes it makes sense with molded parts to combine couplings with the adjacent toothed pulleys. They have to be separate when made by an extruder because it cant do the teeth. The pulleys are made from PCL using a mold made by RP and lined with belt.

Re: Y motor coupling
June 18, 2008 07:14PM
Dear Chris,

Ian hasn't responded yet. He's probably on vacation or something. Can you please print a y motor coupling & toothed pulley setup like in this picture?

If you can thing of something easier to print that is equivalent, that's fine. Thank you so much for this!

Do you have a paypal account that I can put some money into? I'll give you my address in the paypal transfer comment.

Re: Y motor coupling
June 19, 2008 12:21PM
Hi Andy,
I can't print the toothed pulley, the teeth are 0.9mm which is below the feature size of the machine and they need sharp corners. Also there is no model for the toothed version.

The printed y-motor-coupling looks like this: -

The instructions are then to mold a separate pulley using an RP mold lined with some belt. Here is the mold and a picture of my first attempt: -

As you can see it does not look practical. I think the mold is too small. I calculated it should have 16 teeth at 2.5mm which gives 40mm / turn and 0.1mm per half step but I only got 13 teeth.

I bought some metal pulleys, which are expensive:

open | download - metal pulley.JPG (159.7 KB)
Re: Y motor coupling
June 19, 2008 08:41PM
Wow, that would be great!

Yeah, I think I am actually missing a part. It is my understanding that the Bits from Bytes kit is supposed to come with two of the parts in the picture I supplied, but mine only came with one.

At [forums.reprap.org], nophead said:
"I think the z-motor-coupling has been combined with the pulley in the BitsFromBytes kit."

And Ian Adkins said in an email to me:
"The Z motor coupling is part of the Z drive pulley..."

It's possible that I'm making a mistake by using the "Z-motor-coupling/pully piece" as just a coupling right now, and am not using the pully part. Even then, though, I would be missing a Y-motor coupling. Plus, since the pully on the "Z-motor-coupling/pully piece" is of a much smaller radius than the pullies used on the rest of the vertical z-bars, I don't think they would all spin at the same rate, making three legs go up faster than the fourth, and causing total havoc and destruction.

As far as I can see, I think I am missing a "Z-motor-coupling/pully piece". smiling smiley

Thanks so much for your help!
Re: Y motor coupling
June 20, 2008 04:13AM
So do you have three larger pulleys for Z and one coupling with a small pulley?

In that case I would guess the coupling is the y-coupling and you are indeed missing just a z-coupling as you first suspected!

Looking at the picture from Reece again it also looked like he had a y-coupling on the z-motor so I am totally confused.

I will print a z-coupling this evening and post a picture to see if that is what you need. If that is the case I can send you the z-coupling but not the pulley as I am planning to use four small steppers on my z-axis so I don't have any large pulleys.

Re: Y motor coupling
June 20, 2008 11:21AM

I actually have four larger pullies for the Z axis and one coupling with a small pulley.

Thank you soo much for your help!!! smiling smiley
Re: Y motor coupling
June 20, 2008 03:12PM
This is what the RP z-motor-coupling looks like: -

Similar to y-coupling but longer. If this is what you need PM me your address and I will try to post it tomorrow.

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