Machining Steel Tubing Flat

[toastydeath]

Originally Posted by Apples they could rough machine, heat treat, then grind Tht is what I would do. As in mill it then heat treat(stress releive and also flame harden at same time? is this possible?) Thin finish gring to tolerance.

Hardening and annealing are exact opposites in terms of what they do to the material.

If you want to harden something, you are going to re-introduce stress into the material, and crappy steel doesn't enjoy it. A better grade of steel, hardened, then drawn back in hardness will be the best bet for that operation. I'd look for a wear resistant, air hardening tool steel. Air hardening distorts the least, and the wear resistance is what you want in a machine way.

The only problem is that those kinds of steels are difficult to machine and grind once hardened, so you need to take advantage of the low-warp characteristics and leave as little material for finish grinding as possible. I would look at steels like D2 and D3, but I have access to the machines required to work it. If someone was really interested in this, I would buy a test bar and see if my equipment was capable of machining it before I went in and bought the full amount.

[harryn]

One more idea for the discussion of leveling out the tube wall before attaching a flat to it - self leveling epoxy. Precision Epoxy has an epoxy formulation specifically to make things flat. The most common use is for race car setup platforms, but it is also used for various machinery applications.

http://www.precisionepoxy.com/index.html

I spoke with them about using it to level items approx 3 in x 10 ft - They believed it would work very well. Several people, esp. Igalla has been a big promoter of the idea. It comes as a 2 part epoxy mix, usually mixed 2:1 IIRC and sells for about US $ 50 / gallon.

I was glad to find this thread which also included some comments on rust prevention on rails - that is a big concern of mine for my DIY router. I have even toyed with the idea of using extruded 7075 T 6 aluminum instead of cold rolled / ground steel just for the rust issue.