I would check this first.
I stand corrected. What is the tube to tube distance for your Beam, I can double check against mine.
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Directly across my screws I have 139.3mm. If anything, I am thinking your core is the issue.
My core is 178.6 the height it prints.
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Do you have all 8 bearings in? I think we have seen a core with only 6 of the 8 required bearings.
I think I am going to reprint it as well. Hate to waste all that filament but oh well. Ive replaced almost all the braces and the core is still rubbing. I’ve measured the braces at multiple points and it matches the .3mf.
Brand new brace and the grey is new rubbing. (worse in person and I played with the core tension for like an hour.)
Yeah, I do have all 8 in.
So have you done any tests on your printer cal cube or anything? I would hate for you to reprint another core and have it not work.
No hate, just helping get info further down the thread as I’m sure others will have similar questions
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Calibrations are running right now!
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Well good news! I printed a new core and almost all new braces. (2 on the ends I left for now) and it runs smooth! No binding or rubbing. Not sure if it was mainly the core or mainly the braces but whatever. It works! It was also much much easier to get the wiggle out of the core. I didn’t have to tighten near as much. So thats a plus as well.
I don’t really know what happened as far as dimensional accuracy. I had test prints that were accurate but oh well. I’ve since sold those printers so I guess it doesn’t matter.
Next step is to recut the YZ plates. I cut them on the laser out of 1/2 birch plywood. And it worked ok but they look ugly and some of the smaller holes blew out. Also going to cut @DougJoseph torsion table.
The other cool thing is next week I leave for a month long work trip. We travel in a tour bus and so I’m literally throwing the gantry underneath and a couple smaller pieces of plywood for a base and I’ll be able to play around with my machine when we are parked! I don’t know if @vicious1 planned for it to be “portable” but I’m going to make it so!
Thanks for all the help! I’ll get some more pics up soon.
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Congrats on the progress!!
Gotta see that in action!
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Make sure to get some video!! There are a few that made mpcnc s portable not sure i have seen a portable lr yet!
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Wait… So you’re saying you’re throwing your CNC under the bus? 
That’s EXACTLY what I’m saying hahaha. I hope it works out! I need something to do in my downtime.
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SUCCESS! I got some cuts done. Nothing special or fancy. Just wanted to see if my core and braces issues were settled and they seem to be! No grinding/rubbing/binding. Smooooooth!
The one thing is the dimensions are wrong. They are off by about 1mil in some measurements. All undersized. The cuts are also not square on the diagonal which makes sense because I have not squared the machine with M666. Its just “close” with careful measuring when setting up my temporary table. I assume that not square could account for undersized measurements?
I did measure my bit. 2 flute up cut bit. 1/4in and measured about 6.2mm. Using estlcam with just a part cut. No finishing pass. This was in 1/2 osb. Running 20mm/sec feedrate and 3mm DOC. Im not terrible worried about it at the moment as I haven’t done extensive squaring yet. More so curious if that could be the case or if I need to look elsewhere as well.
Thanks!
It looks to me like the holding tabs have broken in a couple of places, and the cut out pieces have shifted.
OSB isn’t terribly strong when thin, so you might have better success with plywood, MDF, solid wood, or thicker tabs.
I second trying again with bigger tabs to make sure it isn’t a movement issue.
Also make sure you do a full depth finishing pass if you are taking measurements under 1mm.
Sorry I should have clarified. I broke the tabs after. In the picture they are free but they all held while cutting. I suppose it still could have deflected?
So if the part was supposed to be 120mm square. But I’m reading 119 ± .5. The finishing pass addition would mean it cuts it to 121mm and then the 1mm finishing makes it 120mm?