bending 5/16 parts store steel line

[Dale Davies]

good COMPREHENSIVE info, I will get after it! thanks guys. RR

OK, so you use 5/16" tube. What is the wall thickness? For our instrument low pressure lines we used 0.035" wall. So 5/16" is 0.3125". Now minus 2 × 0.035" is 0.2425" ID. That is less than 1/4", not very big for cooler lines. And your mild steel may be a thicker wall tubing.
If you step up to 3/8" tube, the OD is 0.375" minus 2 × 0.035" is 0.305" ID. That is an increase in diameter of 25+%.
Now if you calculate inside area, the 5/16" is 0.046"square. The 3/8" tube is 0.073"square. That boils down to a 58.8% increase in flow area. That is substantial, and will aid keeping the trans oil cool.
Tubing is always measured by OD while hose is by ID.
Eventually for 1/2" and larger tubing the minimum wall thickness was 0.045". The pressure capability drops off rapidly as the diameter increases, which requires a heavier wall tubing. A couple of units required 1/2" tubing capable of 3,000PSI. This required the wall thickness to be 0.093".

 

[jas0162]

A good flare tool is very nice. Those cheap clamp together things with the little buttons are hit and miss. I bought one that you clamp in the vice... it has different dies you put in and pull a lever to do the flare. It makes a nice centered flare 100 percent of the time. Im at work, dont remember the brand name. One of the best tools ive ever bought

 

[mopardude318]

A good flare tool is very nice. Those cheap clamp together things with the little buttons are hit and miss. I bought one that you clamp in the vice... it has different dies you put in and pull a lever to do the flare. It makes a nice centered flare 100 percent of the time. Im at work, dont remember the brand name. One of the best tools ive ever bought

yea. Eastwood, summit, Amazon. All have the same one. Cheapest I’ve found was on Amazon.

 

[PROSTOCKTOM]

I've bent 1/2" x .065" wall 4130 Chromemoly tubing with my Swagelok and it was all I could do by myself, so something in the .090" range in mild steel would be no problem.

Anymore wall thickness you need a hydraulic bender.

Tom

 

[Mojoe9955]

OK, so you use 5/16" tube. What is the wall thickness? For our instrument low pressure lines we used 0.035" wall. So 5/16" is 0.3125". Now minus 2 × 0.035" is 0.2425" ID. That is less than 1/4", not very big for cooler lines. And your mild steel may be a thicker wall tubing.
If you step up to 3/8" tube, the OD is 0.375" minus 2 × 0.035" is 0.305" ID. That is an increase in diameter of 25+%.
Now if you calculate inside area, the 5/16" is 0.046"square. The 3/8" tube is 0.073"square. That boils down to a 58.8% increase in flow area. That is substantial, and will aid keeping the trans oil cool.
Tubing is always measured by OD while hose is by ID.
Eventually for 1/2" and larger tubing the minimum wall thickness was 0.045". The pressure capability drops off rapidly as the diameter increases, which requires a heavier wall tubing. A couple of units required 1/2" tubing capable of 3,000PSI. This required the wall thickness to be 0.093".

Huh?

 

[Rapid Robert]

this is a 5 ft length of generic parts house 5/16" steel tubing. I measured the OD at .313" (5/16) & the tightest drill bit that I could find that would go in (with a bit of slop) was .241" so I'm getting .036" for the tubing wall thickness if I am doing this right. RR

 

[Dale Davies]

I've bent .065" wall 4130 Chromemoly tubing with my Swagelok and it was all I could do by myself, so something in the .090" range in mild steel would be no problem.

Anymore wall thickness you need a hydraulic bender.

Tom

We were bending 316 SS with the .093 wall. That took some effort. We had some 3/4" and 1" that required a geared bender. Functioned like the Swageloc, but had a gear that engaged a sector. When you got into the heavier wall tubing, even that required some strength.
And yes there are hydraulic benders. The company rented one for a couple of packages that spec'd 2" 316 SS drain tubing.
Then if you get into nuclear construction there is a friction welder to weld lengths of tube togeter so there is no union joints that could leak. Compression fittings only at the source point and the end.
On top of that the Swageloc fitters book lists tube material, size and pressure ratings for running and burst. Also about 8 tubing chemistries for different applications. A lot of stuff to be aware of in the instrumentaion field.