Primo Corner Design

Mostly Printed CNC - MPCNC Advice
1

Hey there,

I’m about to redesign my cnc from burly to primo and currently i have a lot of issues with conduits sliding out of the corners and i see the new primo design is similar. And i’m wondering if there is any way to edit the corner pieces to have blind ends and the end to prevent conduits from sliding further out of the corners?

Like having the yellow marked space filled with material to make the conduit stop at the end. Let me know what you think. I would gladly take my time to redesign it if i get the original files or its even better if you guys do it with your skills.

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I am surprised that your conduit is coming out. Maybe they should be just a tad tighter. Maybe add a spot of CA glue to act like locktite for the tube.

The reason they are open is in case your tubes are too long.

I haven’t seen anyone try to mod them this way

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3

Well i get the quick fix but the stresses on belts and tensions can move the conduits. So if the material was added there with belt tensioning you would also make the conduits fix in place. Glue gets tricky if you want to replace the part. And tighting it even more would damage the plastic. Just my opinion … it would be nice to have that choice.

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4

What about roughing up the last couple of inches of the conduit so it “gripped” in the clamping pieces?

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I dont know i dont have the primo parts yet but in the burly nothing works for me i guess the plastic deformed so muc

6

Wrap the end of the conduit in a layer of electrical tape.

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As long as there is a gap between the upper and lower corner parts, the screws should allow gripping very, very tightly. If the parts cracked or somehow the gap were to close (e.g. if the tubes were too small) then it wouldn’t be able to clamp very hard.

Or if it were stored in a hot place, the plastic could soften and loosen. So don’t do that.

If the gap were to close for whatever reason, you could add shims (or electrical tape) on the tubes to open the gap and it can hold tightly again.

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8

I can say in 6 years or more of this machine I don’t think tubes moving has ever been an issue other than people forgetting to tighten them. The early models had much smaller contact areas as well.

The trucks don’t actually put any resistance on the tubes, so the only thing is holding against the 7lb belt tension. The current corners should easily handle 5x that load if not a lot more. They are left open for ease of adjustment. A lot of us have some extra sticking out for various reasons, some people even cut long tubes and run the machine smaller at first then expand it later.

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