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mike.m9
(@mike-m9)
Eminent Member
stripped back right bed screw

so... i fiddled with trying to level my bed for days. in the process i have now managed to strip the back right bed screw. i cannot get it out. i have tried:

jd weld (epoxy that is supposed to be stronger than superglue; 24 hr cure)
super glue b/c jd weld failed
rubber band
unanswered prayers
cursing

unfortunately, support has not been very helpful (thanks guys i realize im up the creek without a paddle i dont need you to tell me too). does anyone have any suggestions for something else to try?

im doing this because the variance in my bed is .6 and i cannot get a good first layer even with the micro-calibrations between left and right sides of the bed. my live-z is -1.1 with a left of -25 and the right a +10. ive tried everything in between.

thanks!
mike.

Posted : 11/06/2018 1:24 am
john.n13
(@john-n13)
Estimable Member
Re: stripped back right bed screw

strip the back right bed screw

I assume that you have "stripped" the Phillips screwdriver slots in the head? Depending on how badly it's mangled, my choices would be between making a straight slot with a cutting wheel on a dremel or drilling out the (countersunk) screw head with an appropriately profiled sharp drill bit. The first could be done on the printer, the second I would remove the bed and its support frame and put it on my drill press. In that case, once I had "drilled away" the head I'd take out the other screws, remove the heated bed plate and unscrew the remains of the damaged screw with pliers or similar.

Posted : 11/06/2018 4:15 am
gaston.d3
(@gaston-d3)
Reputable Member
Re: stripped back right bed screw

I do not remember the name of this type of screw but this image shows the kind of head that you can try and see if it helps: http://e-catalog.rusbiz.com/product/Bit_socket_Hex_bit_socket_Torx_star_Bit_socket_Spline_bit_socket_72346.html

They have so many sides so they are good for these situations.

Posted : 11/06/2018 4:35 am
gaston.d3
(@gaston-d3)
Reputable Member
Re: stripped back right bed screw

I think they are called "torx heads". Let us know if this helped.

Posted : 11/06/2018 4:37 am
Erik
 Erik
(@erik-3)
Estimable Member
Re: stripped back right bed screw

It sounds like you need some screw extractors. They will drill into the top of the bolt using the opposite direction (spin it counter-clockwise to bite, and also unscrew the bolt). You can get them at most hardware stores. I've only used them once on my wife's car when a bolt head sheared off. They're tough to use, but work exactly as described.

I'm not sure if you're in the US, but if so you can run to Lowe's and get a set like this one. https://www.lowes.com/pd/SpeedOut-Damaged-Screw-Extractor/1000170531

Just be careful that when you're drilling you don't hop out of the screw and onto the bed. It requires a lot of down-force, and if you hit the bed you'll likely be buying a new one... And if that's the case, you can just break the bed apart and then use some pliers on the bolt. 😆

Posted : 11/06/2018 2:37 pm
john.n13
(@john-n13)
Estimable Member
Re: stripped back right bed screw

It sounds like you need some screw extractors.

Hmmmm. I have a ;lot of experience with these - didn't recommend them in my post above because, in my view, the screw in question is likely too small (not enough "meat") to drill and use an extractor (if you can even find one small enough to consider using).

Posted : 11/06/2018 2:51 pm
themzlab
(@themzlab)
Estimable Member
Re: stripped back right bed screw

The screws on the bed in my printer are simple Hex drive, not Phillips nor Torx. Torx would have been the best type of drive to use here all other things being equal.

if it is the drive socket that has stripped maybe you will need to grind the head away so that you can remove the bed. Is this what has happened or are the threads of the screw cross-threaded in the base plate?

Posted : 11/06/2018 5:23 pm
mike.m9
(@mike-m9)
Eminent Member
Topic starter answered:
Re: stripped back right bed screw

sorry i didnt write back sooner. this week at work has been hell. i had to resort to drilling out the screw. i tried the m3 extractor but that wouldnt work. i had to move up a drill bit size and it basically broke the head off onto the bit which then allowed me to unscrew it. what a PITA.

now to figure out how to level this bed. it's so horribly off doing the octoprint prusa mesh leveling plugin. i think it's .67 variance between the sides. this is AFTER putting in some washers to bring the left side more in line with the right. needless to say, it hasnt worked. i think the bed is severly warped at this point. customer support has been less than helpful since i bought the MK2S upgrade kit off ebay. they are giving me the run around.

thanks for all the suggestions! at least that piece is out of the way and i know it can be done without destroying the bed.

ciao,
mike.

Posted : 16/06/2018 10:54 pm
ejberg
(@ejberg)
Estimable Member
Re: stripped back right bed screw

A large left-right mismatch is easy to fix. I reduced a 0.71 variance down to 0.13 by doing this:

First plot the bed level map (you have obviously done this already).
Then turn off the stepper motor power, if they haven't done this by themselves.
Now grap onto both z axis screws. Prevent movement on one of them, while turning the other a few stepper clicks.
Replot the bed level map, and repeat the above steps until you have minimized the left-right error.

Posted : 17/06/2018 10:03 am
themzlab
(@themzlab)
Estimable Member
Re: stripped back right bed screw

have you looked looked closely at how the Z axis 'homes' at the top? Maybe there is an obstruction or oddity that is causing one of the sides to zero incorrectly. This directly influences the bed level readings.

On my machine ( and I assume others ) it is the head of the M3 screws that sets the z axis top. The body of the bearing housing plastic just catches this.

To check it perform a Z axis calibration from the menu or better yet drive the axis upward manually.

Posted : 18/06/2018 1:15 am
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