Re: Strype's Makerslide camera rail project.

[Duane Johnson]

Chris,

I think this is the best shot I have of the idler until I get another one built:

https://www.dropbox.com/s/o0urk03f7ppl37j/2013-01-20%2013.30.31.jpg

Comments interspersed below...

On Tue, Mar 12, 2013 at 8:39 PM, Strype <strype...@gmail.com> wrote:

Idler assembly: where you using a spring loaded m5 screw and nut to kick the "U" piece away from the "Forks" to apply tension to the belt?

There is nothing spring-loaded in the design--the timing belt pulls the bearings ("U" piece) toward the slider, and the M3 (not M5) screws push the "U" piece away.

 

I have some redesign suggestions(or at least things I'm probably going to do for me) for your printed pieces now that I am putting this together:

1. For continuity purposes and ability to limit various parts and simplify assembly in the field.... I would redesign the CAD files so all attachment holes are a uniform 20mm from each other. This will allow a single double tslot nut for every two screws. This is quicker for assembly and more uniform to the 20mm rail standard. 

Interesting. I don't think I've used double tslot nuts before--what do they look like and how much do they cost?

 

2. Is there a design reason that you made you decide to only have 3 attachment holes (to the rail) on the motor mount?

The only design reason is that I started with 2 holes, and realized that leaves room for it to twist. So 3 holes was incrementally better :) I guess the reason I didn't immediately up it to 4 holes was the time to print more plastic (and it seemed unnecessary).

3. Is the motor securing holes on the motor mount set up as a Nema23 standard? Mine is a Nema17 but does not align. Do you think it is possible to have both hole standards in the mount without significantly weakening it? 45 degree offset?

It should be NEMA17 standard. I'm surprised it's not lining up for you. Can you send a picture to show what it looks like for you? It would be especially helpful if you could measure the distance between the holes, either orthogonally or diagonally, and let me know what distance you're seeing. I've tried it on 2 different NEMA17 motors (RATTM and Kysan) and it seems to fit both.

 

4. Idler "U" Bracket.... For me I think I going to redo it wider. The idler from inventables.com fits but the new one I got needed me to sand it out to keep it from binding.

I used bearings directly since the "U" acts as a nice container for the timing belt. Any reason in particular that you decided to use the full idler plastic part?

 

Let me know what you think.

-Chris

It's great to get feedback like this! Thanks for sending it along.

Duane