Sharp corner square steel tube?

[Ststephen7]

Hey all,

I'm not sure where to post this, so if this is not the right place please let me know what is the correct place.

I have learned so much from this site, thank you all for participating and sharing your knowledge and experience. This is my first post.

I am in no way a machinist. I have a little 'metal shop' in my garage, consisting of a drill press, small plasma cutter, Miller 135 welder, and oxy/acetylene torch, an old Rockwell 6x48 belt sander, 4x6 bandsaw, and a Miller Econotig. I am a self taught welder, which, I think actually means I don't 'really' know how to weld.

I have made a bunch of things to put in an Etsy shop, and sell at Craft fairs, however... my pride and joy are the Mjolnir I've made. I hope I will be able to post some pictures.

Anyway, I have accepted an actual job, creating a replacement base for a 10' long (and very expensive) Florence Knoll Credenza. The man who owns it lives a few blocks away and met me at a local craft fair.

So far, taking my time, I have been able to reproduce all of the part of the base, except... the rails (I'm calling them rails) are 1" square tube (.062 wall) with SHARP CORNERS (no radius on the corners). I am not able to find this stock anywhere, and I was hoping someone here could help me out, so I can finish up my first commission and actually get paid. I need close to 30' of it, or 'only 30' for those of you who actually buy a lot of steel.

Thank you in advance for any help you can provide.

Steve

 

[engineer2]

The only things that come to mind are cold rolled solid bar and aluminum. You might find some stainless with sort of sharp corners if you look around.
I had to look up Mjolnir and Florence Knoll Credenza.

 

[readhead]

Solid bar or aluminum square profile. No steel tube with square corners.

 

[Thumper68]

Solid bar or aluminum square profile. No steel tube with square corners.

This ^^^

I have been buying metals for close to 40 years I have never seen steel tube with square corners.

You could fake it buy getting 2 pieces of 1" angle and welding it into a tube and grinding or milling the welds square.

 

[matt_i]

I would look at Telespar (telescopic tubing). Square tube with no holes is in the catalog.

Its not a sharp edge as a piece of flat bar but its pretty close.

Also the ERW tube from the "steelyard" in thin wall sizes (around the .062" = 16ga) seems to be pretty sharp on the outside.

You might have to metal-finish, meaning fly-cut the outer surface of existing tube to get what you want. I've not studied it but I'm guessing a .010" deep cut on all 4 faces is going to be close...not sure if the milled finish is acceptable at the end...it could be a problem if it opens up other cans of worms.

 

[readhead]

16ga has a radius. Whenever square corners are called out we quote solid bar but I usually note how much weight will be involved. I can usually talk the architect into tube under the guise of value engineering.

 

[readhead]

I would bet money it doesn't have square corners. I've been buying tubing for forty years and have not seen steel tube with square corners. Google how steel tube is made and you will see why square corners won't work. Anything square in steel components will cause stress risers. That is why when we fab structural steel we don't cut any square corners. Every notch and cope has radiused corners to avoid stress points. Look at an angle or channel. They have rounded corners inside just like tubing.

 

[matt_i]

Just thinking out loud. Could it be extruded aluminum tube and painted to look like steel??

I feel certain there is sharp corner 6061 tube in a 1" square OD.

Imo the radius in the square tube due to the ERW electric resistance weld process. Its basically bent/folded together while hot from a flat bar in a continuous process and then seam welded. The hot rolled structural shapes are continuously cast. But your point about stress risers from corners and notches is a good one.

 

[readhead]

Aluminum shapes are available as square extrusions or structural and bar shape extrusions. You are correct about how square steel tubes are made. It is basically squared pipe with welded seam.

 

[Whiskeymike]

Aluminum is going to be the easiest thing but you’ll probably need someone help you weld it.

This looks exceptionally square - https://www.my365hardware.com/86911...wze1At41BMNcpxibA6ZUPz1X21ZFrtcsaArQeEALw_wcB

Not sure if picture is accurate.

You might also check out the c channel at your local metal supplier. I’ve gotten some stuff that is very square on external corners. But it would be a lot of labor to weld them up.

Solid bar that has been machined with a fly cutter is the sharpest you’ll get it. But it’ll be heavy.

 

[rockettgpw]

Could you use your tig to build up the round corners of regular rhs and grind/linish it to a sharper edge. I'm assuming being a base there will be only one or two corners visible. 30' is a lot of welding and grinding I know. The really thin wall square tube is the only stuff I've seen with sharpish corners.

 

[dave89iroc]

thick wall, and mill the sides

 

[Chaz]

True square tube does exist, It just isn't available at your local supplier. I've seen it on furniture often (usually chromed) I'd check and see if there are any manufacturers near you that use it. They may sell you a length or two.

 

[Justind97]

Hollow Structural Section (H.S.S) 1x1x.065 is available at my local metal supplier.

Ask yours, they should have it.

 

[StingRay]

The term for the full square is architectural tubing. Round corner is structural tubing. Probably only available in thinner wall cross sections.

 

[APEowner]

Link to one source

 

[6768rogues]

I would bet money it doesn't have square corners. I've been buying tubing for forty years and have not seen steel tube with square corners. Google how steel tube is made and you will see why square corners won't work. Anything square in steel components will cause stress risers. That is why when we fab structural steel we don't cut any square corners. Every notch and cope has radiused corners to avoid stress points. Look at an angle or channel. They have rounded corners inside just like tubing.

He knows what he is talking about.

 

[RPH]

Stingray nailed it!
https://shop.wagnercompanies.com/pipe-tubing-bars-angles-channels-and-zees

 

[strutaeng]

Does it have to be hollow?

Just use 1" solid stock. That should have a nice sharp corner.

All of the HSS or TS sections that I have seen have some sort of radius, some more than others, especially the narrow sections.

http://www.cim.mcgill.ca/~paul/HollowStruct.pdf

Otherwise use some alloy square tube and TIG weld it to the steel.

 

[StingRay]

And yes even architectural square will not have truly sharp corners. There is a much smaller radius. It is quite or almost square in appearance. I spent quite a few years purchasing and a lot of it was steel and aluminum.