Prusa I3 MK2 Bed Plate Dimension

Can someone tell me the distance from center to center of heated bed mounting holes for the Prusa I3 MK2 Bed Plate?

I am trying to draft out a template by hand to use for cutting it out of a sheet of ply because I can't get my printer to just print one to scale for the life of me. The thing is that I am also getting mixed dimensions from the models I am finding online. What I am finding is one set to 197.2mm squared, one at 209mm squared, and a third at 208.8mm squared. I am hoping to find out which one model is correct for the original Prusa I3 MK2.

It would be nice if I could find a exact Draft Quality Layout already done. One that has exact dimension for the official Prusa I3 frame & bed. But my luck so far in doing so just sucks. I have searched everywhere and can't find one.

Right now I am using Sketchup to get the dimensions. I would love to just import Josef Prusa original files but he used AutoCAD dxf and Sketchup only support that in Pro which I can not afford to buy. If anyone has a way I could import or convert dxf to skp that would help as well. Without having to purchase software that is. Or even if there is a different open source software someone can suggest that may help.

Any help would be appreciated. Thanks

FreeCAD, OpenCAD, tinkerCAD etc are free options. There's a handful of free cad software but whether they allow importing dxf I would not know.

Your other option would be to try to reinstall the pro trial of sketchup but I found that sketchup actually breaks more things when importing/exporting dxf.

As for dimensions I would think the bed frame for the p3steel frames should suit you well. Granted you still have to work with dxf files but you would be able to get the measurements from it.

I use an android application called dwg fastview. Free and I can view and edit (to a certain extent) dxf files.

There are 6 mounting holes, 2 additional in the centre that theY-belt holder screws threw the plate into. So heated bed is held on plate in 6 points

Measured, with a ruler the 4 outer mounts seem to be 208.8mm apart. Centre of each mount is difficult to judge, its a hole...

From the board schematics in eagle measure 209mm so I would go with that.

Edited 1 time(s). Last edit at 04/23/2017 04:14AM by Dust.

Thanks Jaded & Dust for the help. It was much appreciated and very helpful.

I just wanted to show you all what my template looks like so far. Now I just need to clean up a few guide lines and such then cut and drill.



Edited 1 time(s). Last edit at 04/23/2017 08:59PM by VectorRoll.

NB The central holes are not centered, its offset slightly on the Y axis. (or the cutout is not equal)

eg When you upgrade from a mk1 to a mk2 they give you a tool to identify which side is which
see [manual.prusa3d.com] step 7-9

Also 4 bearing is over constrained and makes things worse over 3 bearings

Edited 3 time(s). Last edit at 04/24/2017 12:04AM by Dust.

I have had good luck with 4 bearings, others may not have. YMMV. I once found a dxf file on thingiverse (can't remember the user) where the user adjusted the p3steel bed to hold with scs8uu bearings or the lm8uu bearings. Again you could use that (if you found it) for the dimensions.

Are you hand milling the bed frame? What material are you using for the frame?

Quote
Dust
NB The central holes are not centered, its offset slightly on the Y axis. (or the cutout is not equal)

eg When you upgrade from a mk1 to a mk2 they give you a tool to identify which side is which
see [manual.prusa3d.com] step 7-9

Also 4 bearing is over constrained and makes things worse over 3 bearings

Hmm Didn't realize they were supposed to be offset for the MK2. Everyone bed I've seen so far was either 2 centered or the 5 holes. The printed parts I'm printing out required just the 2 centered so I went for that setup.

Thanks for the info on it. I'll look into that when I get to mounting the that part to it.

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jaded
I have had good luck with 4 bearings, others may not have. YMMV. I once found a dxf file on thingiverse (can't remember the user) where the user adjusted the p3steel bed to hold with scs8uu bearings or the lm8uu bearings. Again you could use that (if you found it) for the dimensions.

Are you hand milling the bed frame? What material are you using for the frame?

I am going for the single plate design. The frame is also drawn on the board there around the bed. It's a little harder to see as that right line drawn on there is going with the grain.
It is a a sheet of 1/2" birch plywood. I am using my table saw for to cut the square of my frame, then my scroll saw for the rest. I have drill press the holes.



About the Bearings. I thought 4 would be more stable but if I find it to be a bit binding I can always cut out another bed that uses just 3. I have extra plywood and it won't be a problem. When I get lumber I try to get extra.
Speaking of binding, when watching Thomas Sanladerer on youtube doing that clone of the Prusa I3 Mk2 he suggested to taper the slots for the bearings suggesting that it would help in aligning the bearing & that you could come back and file them if need be. I plan to do try that when I cut it out. It will be a bit of trial and error I suspect.

Perhaps this will help.

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slippyr4
Perhaps this will help.

Thanks... That is very helpful.