Prusa I3 dimensions  

Re: Prusa I3 dimensions

All I can help you with is the lead screw (sorry) which is 8mm diameter and pitch (4 x 2mm, T8), similar to this one: http://www.banggood.com/42-Lead-Screw-Linear-Stepper-Motor-1_5A-40mm-300mm-Rod-For-3D-Printer-p-1048041.html (which I bought some months ago for testing).

Peter

Re: Prusa I3 dimensions

Does anyone offhand know the various dimensions of the I3? I'll probably try to preserve some of the dimensions/parts.
I'm away from my printer at the moment, but I have quite good experience with measuring dimensions of existing parts by importing their STL into Sketchup or some *CAD and use its measuring tools. It's way better than messing with SCAD.

Re: Prusa I3 dimensions

Yeah that's what I usually resort to as well.

It kind of looks like 17mm center-to-center.

The lead screw nut is 25mm, with 19mm spacing between the M3 holes.

I have no idea where to find this particular nut that PR uses.

I'm tempted to just print the damn threads into the carrier and forget the business with the nuts. The good thing about the steep pitch is that it makes them far easier to print.

Re: Prusa I3 dimensions

I'm tempted to just print the damn threads into the carrier and forget the business with the nuts.
Don't. At least print them as replaceable smaller part instead of whole carrier at once. They will wear out over time and then they will be easier to replace.

BTW that part you posted before - what is is for? I can't figure out its placement and orientation.

Re: Prusa I3 dimensions

BTW another question: Are you designing parts on a smartphone or is it just a convenient way for you to do screenshot ?

Re: Prusa I3 dimensions

I'm a bit confused how the x-axis belt can squeak?!

Re: Prusa I3 dimensions

It's technically the idler that's squeaking.

I know about the counter-balance screws at the end, but there's only so much those screws can correct for, and ultimately the stock z carriage is just a bad design.

Most of my drafting is done on the desktop, although the mobile app is useful enough to make small tweaks on the go. And for making screenshots.

I've printed 0.9375" UNC threads, M12 fine pitch threads, and even an ACME lead screw threads. I've played with the idea of a separate printed thread nut... but I think for this iteration, I'm going to print them in place.

This is a "split z carriage" design where it's split in two, with the idler toward the outside, in line with the smooth rod/lead screw. The belt is rotated 90 degrees and passes right around both. The two parts are joined by the x-rod strap and now... the coordinated lead screw threading...

Man, I know you guys aren't fans, but printing the threads really, REALLY helps clean the part up. Totally worth at least trying. I'd cut the matching threads exactly as shown in both top and bottom parts.

Re: Prusa I3 dimensions

gz1,

I was having the same issues with a squeal coming from the idler. I finally found a solution that worked for me. Basically I revolved around loosening the tension on my x-axis belt and moving the belt as far back as possible.

First, I disassembled my x axis belt assembly. Then I pushed the spindle which turns the belt on the motor axis (don't know the exact name of it off the top of my head) as far in as I safely could to the motor. Next I reassembled my belt to the extruder frame with less tension and kept the loops as far to the back as possible.

This allowed the bearing in the idler to keep off of the idler piece itself. I hope this helps someone if they ever run into this issue.

Let me know if I can clarify anything for anyone!