MK2S carriage screw blocked by frame  

Re: MK2S carriage screw blocked by frame

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Has anyone else experienced this?
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no, not really.
there should be enough clearance for the screws (and their heads) when the threaded 10mm rods sit deep down into the notch of the z-frame.

did you use the genuine corner parts ?
can you post a picture of how you assembled the 8mm rods at the corners (where they should "snap in" into the upper part and then get fixed by the zip ties) ?

ok, I got only the genuine MK2, not the s-version with the bolts, but this shouldn't be an issue.

Re: MK2S carriage screw blocked by frame

Yep, geniune corner parts, they may appear more yellow due to the flash. Only part I've replaced is the y-motor printed part after it snapped on the endstop extrusion.
I've taken off the carriage today to be sure it was definitely flat and check that the linear bearings weren't warped. Smooth linear rod appears straight as well though I haven't checked them thoroughly yet. I've also unscrewed the PSU from being attached to the Y-axis to see if that changed anything when I reattach the carriage.

Corner Top View

Corner Side View

Y axis Sides

Re: MK2S carriage screw blocked by frame

hmmm.... nothing wrong with it.
so either your 10mm threaded rods are no longer straight (maybe due to some force used to push them down into the notches of the z-frame) or the depth of the notch inside the z-frame is to deep.
or the dimensions of the z-frame are incorrect at the location where the y-carriage should pass the frame (there I measured 48mm frame height).

if the rods are still straight, I would use the chat of the shop to get into contact with the prusa team and would ask for a replacement of the z-frame, which is obviously out of tolerance then.
you can point them to this thread to support your request.

another option is to use a moulding cutter and alter the z-frame yourself (only recommended if you know what you're doing, required skills assumed).

another solution would be to print 4 new (altered) corner parts, which would lift the rods +3mm. but obviously this is only an option if you've got another possiblity to alter and print them.

by the way: does anybody know if prusa altered the dimensions of the printed parts and the z-frame with MK3 ?
maybe they've accidentially mixed up some of the parts in your delivery ?

Re: MK2S carriage screw blocked by frame

I tried rotating both the threaded and smooth rods since if they weren't straight then I should get varying results if the bend is on a different orientation, however nothing has changed. Depth of the notch and height of the z-axis match on both sides.

I got my kit back in July so very unlikely to be MK3 parts 😀

However I'm fairly certain now it is either the carriage or the linear bearing, using calipers I found the distance between the threaded rod and the smooth rod to be pretty much equal on both sides (from the the front of the y-axis to the z-axis location on the y-axis), however the distance between the carriage and the smooth rod varied by around 1mm on the side with the issue (lower distance nearest to the z-axis placement).

I'll contact support and reference this thread see what they suggest. Thanks JeffJordan.

I've uploaded some better pics of the screw head issue.

Re: MK2S carriage screw blocked by frame

So after talking with support and trying several things, the issue turned out to be that the back right corner was raised 0.1mm. Hidden by the padded feet and my anti vibration mat. It must have happened when I replaced the y-motor printer part, and got worse when I corrected the x/y axis skew recently.