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Squeaking and or Circles aren't round? Check this! 56k warn!
Looks great!
If the pulley is of a different diameter than the motor pulley, you would have to make sure that the top belt segment remains parallel to the extruder guide rod,
otherwise you will have a geometry change when the carriage moves toward the pulley side and cause the belt tension to change and movement accuracy to be affected.
Aside from that little caveat, it should work great forever.
Quote:I try several designs try to add bearing to X axis idler. I end up using 683ZZ 3x7x3 bearings and reprint the idler holder.
Here is my current V4 design. Looks the printed parts hold up well.. Let me know what you think.

There is the files, include OpenSCAD and DXF drawing file

I print mine in ABS with support. I use Kissicer with 0.25mm layer height , 0.4mm extruding with 50% infill.

Here is the original idler add 683ZZ bearings on both side.

Make sure you have enough grease and put the the idler back to work

I printed your idler holder. One thing I noticed is that you did not add the hole in the side for the locking screw. Do you feel it doesn't need it or did you just forget to put that hole in it? What would be nice is to have a pocket for a nut on the inside so the threads would not strip out. Other than that it seems to be a nice way to add bearings to the idler. If I had a solid works file I'd add a pocket for a nut.

One thing I had to do was do a lot of filing and sanding to get the part to fit. But it looks really nice after cleaning it up and fitting it.
I think the hole is for lock the holder during the shipping. So the belt is not tight during storage and shipping. I don't think there has any use during normal printing. That's why I skip it in the design.
I thought It was like the screws that hold the spring loaded rod mounts. Once the spring preloaded the belt the screw would lock it in place. It could be that it may not be needed. I think I would like to try and mod your design to have a 3mm nut and a clearance hole to let it lock like the original. It looks like there would be just enough room to make it work. I converted your stl to a solid so I can mod it.
@bret4 You are right about the screws for the x idler holder. When I got my used Da Vinci printer I never really check on it. The thread on my original idler hold are all gone that's why no screw come with it Sad .
I fix the model in OpenSCAD now with a screw hole and also one with M3 nuts.
STL and all DXF, OpenSCAD design file are included in the zip file. let me know how it fits if you print one.

V4.1 add screw hole

V4.1 with M3 nuts[Image: v4.1.png][Image: v4.1_M3.png]
Thanks Steven. I printed the one with the pocket for the 3mm nut. A little tricky getting the support right so it can be removed on the pocket but I got it to work. The nut pressed in nice. Only thing I find is that it is a little hard to install the pulley with the bearings on it. It can be made to go in easier with just a little trimming at the top of the bearing pocket.

This is a great design. I'll be using it on my two Da Vinci printers.
@Bret4 I made some changes in the design and add more clearances or the bearing to slide through. Should be easier to install in this version.
Let me know if it works better for you.

V4.2 design, Add more clearance for easier install.

[Image: ScreenShot2014-07-13at10.27.57AM.png][Image: ScreenShot2014-07-13at10.28.22AM.png]

My Da Vinci has just started to develop a squeak but only when going away from home, it sounds to me like it's from this pulley, how do you get the pulley housing out, I noticed a screw on the back of the housing, I removed this but it appears to be clipped in some how, I tried pushing from the handle hole but I was just pushing on the tensioner.


Your right on removing the screw. Your also right on pushing on the tensioner through the handle hole. As you push on the tensioner you lift the pulley up and pull it out of the tensioner. The tensioner will then be free to be removed from the handle hole. There is a spring in the tensioner that can fall out so just watch out for it.
Great, thanks for that. I was pushing and waiting for the snap sound Smile

I have ordered some bearings and am going to try the new bearing housing, looks like a much better solution, you never know after the mod I might actually be able to print items with gaps without everything fusing together.


I just tried installing the V4.1 design, and it was too big to slide into the end structure. I measured the OEM part and compared it to the printed version, and in the critical areas, it's anywhere from .010 to .030 in. oversized.

Has anyone else encountered this? Where can I find the original CAD model, or does anyone know how to convert a .stl file to a solid model?
The one I made was just a little big too. I printed it at 100% fill so I had no problem sanding and filing it until it was a perfect fit. You could also scale it a little before you print it. The thing is that every printer can make things a little different in size due to many factors. Having a little to sand off is a lot better than it being to small. Of corse a perfect fit would be great too.
bret4,, did you have a difficult time installing the bearing on the 3mm shaft. It looks like it is a tight fit.

I checked the dimensions that were on the .dxf file, and they were spot on,,, so it's definitely in the printing where it increases in size. I'm going to sand/file it down to fit.
The bearings are a close fit but we're not hard to press on, on my machine.

I am running repetier firmware on my machine and use simplify 3d to generate the gcode so depending what you use things can be a little different.
FYI, my Da Vinci 1.0 was purchased on the 12th of August and it does come with that pulley lubed from factory. And yet the last few days it was squeaking like crazy... so I took the thing apart, redistributed the grease a little bit and reassembled it, making sure the screw was well tightened and the housing doesn't have any play. It seems to be working well again, fingers crossed...
How tight should the belt be? Only as much as the spring pushes it, or as tight as I can make it? I have the same question for the other belts as well.
I suggest using the spring as a starting point. The belts don't really stretch so just enough to take all slack out is all you should need. Applying excess tension will only wear your printer and steppers faster. In some cases it might actually break parts (pulley/bearing holder).

I'm surprised that 3mm wide bearings are working well for people here.. I'm working on my own custom design of the X tensioner that uses 3x8x3 ball bearings and all is great except that I can't slide the pulley into the carriage structure (not the tensioner) with the bearings on it. It's just a little too wide (around .5mm). I guess I could trim the bit of plastic that protrudes the pulley around its shaft (sorry, I can't come up with a better way to describe it) but I would rather avoid that because it'd seem that it should help the bearings to work properly by avoiding contact with the pulley itself... so failing that I think the only option would be to get some thinner bearings, something like 3x8x2.5? It'd still be a tight fit but at least it should go in.

edit: finally bought and used successfully some 2.5mm wide bearings. No need to trim anything Smile
For whoever is interested, I just published my own take on the X axis tensioner with MR63ZZ ball bearings:
I just wanted to add my solutions to this post. I put most of the details on the thingiverse page, (thing:1105146) but I basically made a printable pulley and used 623zz bearings (3x10x4mm) because that's what I already have. You could also use 693zz (3x8x4mm) or MR63 (3x6x2.5) bearings and make your own custom pulley.

I also found a source on ebay for a smooth idler pulley (from HK). It's "16 tooth" (sized) and uses the MR63 bearings. It has a 13mm OD and is 8.6mm wide, so it should fit perfect with some washers. I'm buying those now, but the printed ones work well for now.

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