Easyscriber engrave attachment for Hypertherm torch's

Cutting RHS and alignment

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Cutting RHS and alignment

Post by kylieliveshere » Sun Oct 14, 2018 11:43 pm

Hi, we are receiving our first table in the next month or so and are newbies but have been following this forum for awhile.

Just wondering how to go about and if any tips for cutting square tube and how to get it to line up exactly right. Specifically we use 35x35x2mm and 40x40x3mm by 1600mm lengths, cutting just the topside.

We've seen it cut on a bloke's table and it seemed to go ok, but the biggest issue to sort out is how to line it up to cut exactly the same everything. We plan to rise the water level to midway of the rhs to assist with cooling to reduce bend.

I would imagine we would line all the 1600mm long lengths to fill the table and tell the machine it's 1600 x 1500 (eg 43 pieces of 35mm side by side). So I guess we would make the cad file the same, 43 rows of what we want to cut.


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Re: Cutting RHS and alignment

Post by plasmanewbie » Wed Oct 17, 2018 9:42 am

Set up a physical hard stop to set your tubing up against so the tube is in the exact same spot every time and start from the same 0,0 point each time and you should be good.

A great tip for cutting tubing is to shear off a strip of thin steel or aluminum to slide inside the tube before you cut the top face. This will eliminate the molten slag from sticking to the inside of the tubing and save you lots of ugliness and clean up!!! Once the cuts done pull out the strip and you will have a much cleaner tube.

Best of luck and keep us posted!

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Re: Cutting RHS and alignment

Post by SeanP » Wed Oct 17, 2018 11:53 am

I usually just do one at once working from stops, guess you can line them up side by side but will add chance of error would imagine.
I tend to mark centre of box and zero from there, somehow I find it confusing zeroing from a edge when making adjustments.
It's doesn't warp as much as you would think, I added loads of cutouts on one side and it was fine.
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Re: Cutting RHS and alignment

Post by Ironken » Wed Oct 17, 2018 2:17 pm

I built a removable fixture in the water tray with stops that I trammed in in relation to the torch's X axis. I remove the slats and drop in the fixture.

Probably 1/2 of my cutting is tube profiles. I seldom drill tube anymore.

For accuracy, I only cut one part at the time. If you were to load the table with a bunch of tubes, you will probably get some tolerance issues between the first piece and last. Even a bit of shit or burr between the tubes will add up and cause headaches. In CAD, I basically draw the tube with the profiles to be cut into it. I use Sheetcam as my CAM program. I put the actual tube profile on its own layer and turn that layer off. I put the cut profiles on a layer and add an operation for those profiles and run it. I even cut the holes in the angle iron pictured on the cnc clamping it to the fixture.

As SeanP mentioned, distortion has not been an issue but, My tubing sits in about 1/2" (12mm) of water while cutting. If you are taking a big hunk outta the tube for the majority of the length, plan on distirtion as there are internal stresses from it being formed and welded that are released when you remove all of that material. Kinda like slitting a piece of tube the full length will cause it to open up at the cut or close up.

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