Workplace holding

Well I just learnt a huge lesson! Workplace holding just got me! I was trying to do a sign! I just found using screws to hold it bowed my pine! Made z off on one side 2mm! Sucks, i just ruined my sign, but learnt a lesson! Ohhhh, but i am running 2000 minimum (lr4) on everything and my bits are NOT heating up! I am going to enjoy this, if i can quit making mistakes :wink:

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If you were able to bow the pine that much then your spoil board must be off that much as well. Might think about surfacing your table so that cant happen in the future.

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Clamps fixed it. But i have ran into clamps before. I think i need to just spend a ton of time with it. I already feel more confident then i did with the mpcnc. The pine was gapped the screws bowed it is all. Dumb mistake.

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Ok I guess I am not following how the screws caused it to bow. Glad you got it figured out!

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Drove them in side ways on 45 degree angle on the sides! Hard pinch

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Maybe consider double sided tape.
It usually works fine, but sometimes it can be tricky to remove.

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Depending on your setup, I took the time and did up a spoil board with inserts that I can tighten a fence on two sides then made some clamps that turn into the piece and tighten, hasn’t failed me yet. Then if the clamps don’t reach cause of the spacing can always use something to wedge against the clamp and piece, like an extension.

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Yeah, i am good. I really should start thinking about what I post. I used to use blue tape and ca glue, need to go back to that.

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I think its good that you posted it! Someone new might learn a lot from it!

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I don’t know what your hold-down system is, but my solution was to design some low-profile clamps that don’t extend above the surface of the stock. Since my solutions are made of plastic, I found the clamps needed to bite just a bit into the side of the wood to avoid the stock pulling out during contour cutting. The CAM clamp has a “knife” edge, and three of them use machine screws driven just a tiny bit into the edge of the stock. All worked. None are perfect. The left two on the bottom row are my go-to clamps.

While I have an array of inserts for these clamps, they would work just fine using screws with a flat surface like sheet metal screws.

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@robertbu ,

Are you willing to share the 3d files for your clamps? They look great and I could also use them on my laser machine.

Mike

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Here are the models for four of them. The fifth uses fiberglass rod to assemble and doesn’t work any better than the other models, so I did not include it. Needed screws will be ANSI sizes, 1/4-20, #8-32, #6-32 (or maybe #4-40). The major slot was designed around 1/4-20 cap head machine screws.

I’ve reprinted my clamps like the one on the bottom row left end in in PETG. When I used the lip over the top of stock as a tie down (and therefore the clamp was bridging and unsupported), PLA snapped. The others all work fine in PLA.

CNC Clamps.zip (929.7 KB)

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Thank you!

Mike

These are what i just went back to, but they are so big if you even get close to them, you hit them.

I just downloaded yours, they look pretty interesting!

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Yeah, got them, too. Not great. :sweat_smile: