Just what does the profile look like for dies used to bend square
tube? I would like to either adapt some home made dies to the HF pipe
bender or the hosefield (sp) type of bender that HF sells if its
possible. I know I had a set of dies one time for bending up square
tube but darned if I can find them now or remember what they looked
like.

I have bend some pretty decent radius in square tube with a set of
home made dies made out of a pieceof steel pipe and the homebrew press
brake, but I prefer to have a more smooth radius on the tube. Would
like to go 180 if possible, and the tube size / gage would be 1/, 3/4
and 1" in no more than 14 ga more than likely mostly 16 ga.

Regards

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I created one using scrap I bought where I buy my metal. They have round
"cutouts" from different thicknesses of plate. They have a small notch and
hole at one point arond the edge where the torch was started but otherwise
they're clean.

I picked up one that was 3/4" thick by maybe 8" diameter. I also found a
couple that were 1/4" thick with a diameter about 1.5 or 2" larger than the
3/4" piece. I sandwiched them together, drilled a 5/8" hole through the
middle and and a couple of holes to put bolts through to hold the whole
thing together and that's my die for 3/4" square tubing.

Works great on the HF hossfeld style bender. The only problem I've had is
that the bolts that hold the 3 plates together get in the way if I want to
go over 90 degrees but I could fix that by countersinking the holes in the
top plate, threading the ones in the bottom and cutting screws to the
correct length.

I also tried it for 1" with another center piece but the tubing I had was
very thinwall and it didn't work so well.

Best Regards,
Keith Marshall


"I'm not grown up enough to be so old!"


"Roy" wrote in message
...
Just what does the profile look like for dies used to bend square
tube? I would like to either adapt some home made dies to the HF pipe
bender or the hosefield (sp) type of bender that HF sells if its
possible. I know I had a set of dies one time for bending up square
tube but darned if I can find them now or remember what they looked
like.

I have bend some pretty decent radius in square tube with a set of
home made dies made out of a pieceof steel pipe and the homebrew press
brake, but I prefer to have a more smooth radius on the tube. Would
like to go 180 if possible, and the tube size / gage would be 1/, 3/4
and 1" in no more than 14 ga more than likely mostly 16 ga.

Regards

Visit my website: http://www.frugalmachinist.com
Opinions expressed are those of my wifes,
I had no input whatsoever.
Remove "nospam" from email addy.

Square tube dies are typical 3 pieces: a core with the correct
diameter to match the inside radius, and 2 side plates to contain
the tube. Bolt them together and you are done.

The devil is in the details: the core needs to be about .005"
thicker than the tube, you can get there with shims or just clamp
it down tight. But if you don't give it some clearance, you get
some pretty hefty scuff marks on the sides. The side plates
usually need to be loosened to get the tube off. Use some grade 8
bolts or else you will have galled bolts by about the 5th bend.

Bends over 90 degrees (or less) are problematic on a hydraulic
bender. The additional stroke causes the end supports to need a
LOT of logitudinal travel under very high pressure. If they don't
roll or slide easily, you will crumple the tube in the bend area.

You have your choice of trying for a smooth inside or doing a
controlled 'crush' bend. Take a look at a lot of the cheap
stacking chairs, the inside of the bend has a heavy crease. This
allows the metal to flow somewhere, minimizes the cosmetic
ripples. You can do this by putting a rod around the center of
the bend die, start with a rod about 1/4 the size of the tube.

Bend RADIUS should be at least 4 to 6 times the tube size if you
are trying for a smooth inside of the bend. Crush bends can go
down to about 2 to 3 times and still look nice.

I have personally found that I can't do much better than a 45
degree bend on 1" x.083 wall square tube on my pipe bender before
I start crumpling the tube.

The commercial draw bender folks can do a tight radius with
uniform cross section all the way through the bend area. All it
takes is a draw bender with hydraulic release dies, mandrel,
wiper, pressure die assist, flash controlled tube, and a skilled
operator.

Roy wrote:

Just what does the profile look like for dies used to bend square
tube? I would like to either adapt some home made dies to the HF pipe
bender or the hosefield (sp) type of bender that HF sells if its
possible. I know I had a set of dies one time for bending up square
tube but darned if I can find them now or remember what they looked
like.

I have bend some pretty decent radius in square tube with a set of
home made dies made out of a pieceof steel pipe and the homebrew press
brake, but I prefer to have a more smooth radius on the tube. Would
like to go 180 if possible, and the tube size / gage would be 1/, 3/4
and 1" in no more than 14 ga more than likely mostly 16 ga.

Regards

Visit my website: http://www.frugalmachinist.com
Opinions expressed are those of my wifes,
I had no input whatsoever.
Remove "nospam" from email addy.