What would be the best way to cut a round bottom groove (need a few
diff. sizes-1" 11/4" and 11/2") in a piece of steel about 8-9" in dia.?
I want to make dies for a tubing bender. Would a radius attachment work
for something like this? Where could I find one?
Thanks,
Craig

"Craig" wrote in message
ups.com...
What would be the best way to cut a round bottom groove (need a few
diff. sizes-1" 11/4" and 11/2") in a piece of steel about 8-9" in dia.?
I want to make dies for a tubing bender. Would a radius attachment work
for something like this? Where could I find one?

Do you want to buy one, or make it? If you want to buy one, you may want to
talk to the lathe manufacturer. You might be able to buy after-market ones
as well.

If you want to make it, you can look for examples and perhaps plans on
google. Search for "radius cutting attachment lathe" or some such. Here's an
example I found: http://www.jerry-howell.com/Radius.html

You could also use some math and calculate some depths for a grooving tool
(say, 1/4" wide if you have a heavy lathe, smaller if necessary) to rough
out the groove. Then file finish. Sounds like a lot of work, but
building/buying a radius attachment for your lathe could cost serious
hours/dollars.

HTH.

Regards,

Robin

Craig wrote:

What would be the best way to cut a round bottom groove (need a few
diff. sizes-1" 11/4" and 11/2") in a piece of steel about 8-9" in dia.?
I want to make dies for a tubing bender. Would a radius attachment work
for something like this? Where could I find one?
Thanks,
Craig



Something like this?


http://cgi.ebay.com/ws/eBayISAPI.dll...6584 810&rd=1

"Craig" wrote in message
ups.com...
What would be the best way to cut a round bottom groove (need a few
diff. sizes-1" 11/4" and 11/2") in a piece of steel about 8-9" in dia.?
I want to make dies for a tubing bender. Would a radius attachment work
for something like this? Where could I find one?
Thanks,
Craig

A company called holdridge makes a unit for around a thousand that is manual
and works great. You would want their 4" model. MSC or any of the others
have them. There are three on Ebay right now.
Dixon

On Fri, 14 Jan 2005 17:13:54 -0500, "Dixon"
wrote:


"Craig" wrote in message
oups.com...
What would be the best way to cut a round bottom groove (need a few
diff. sizes-1" 11/4" and 11/2") in a piece of steel about 8-9" in dia.?
I want to make dies for a tubing bender. Would a radius attachment work
for something like this? Where could I find one?
Thanks,
Craig

A company called holdridge makes a unit for around a thousand that is manual
and works great. You would want their 4" model. MSC or any of the others
have them. There are three on Ebay right now.
Dixon

Did mine with a fly cutter and dividing head in the mill, slow, but it
worked.

Greybeard

"Robin S." wrote in message
...

"Craig" wrote in message
ups.com...
What would be the best way to cut a round bottom groove (need a few
diff. sizes-1" 11/4" and 11/2") in a piece of steel about 8-9" in dia.?
I want to make dies for a tubing bender. Would a radius attachment work
for something like this? Where could I find one?

Do you want to buy one, or make it? If you want to buy one, you may want
to talk to the lathe manufacturer. You might be able to buy after-market
ones as well.

If you want to make it, you can look for examples and perhaps plans on
google. Search for "radius cutting attachment lathe" or some such. Here's
an example I found: http://www.jerry-howell.com/Radius.html

You could also use some math and calculate some depths for a grooving tool
(say, 1/4" wide if you have a heavy lathe, smaller if necessary) to rough
out the groove. Then file finish. Sounds like a lot of work, but
building/buying a radius attachment for your lathe could cost serious
hours/dollars.

FWIW, I built the one referenced above from Jerry Howell's plans - a picture
of it is buried in one of Jerry's galleries. I modified it to fit a
Craftsman 12x36 lathe and it worked very well for the only job done with
it - the ball for the radius attachment handle! I never tried it with an
internal radius but expect it would well for that, too. I've since upgraded
lathes to a Clausing 5900-series and will eventually get around to modifying
the attachment base for the Clausing lathe.

The holdridge stuff is VERY nice but you need a fat wallet!

If you want to build something you might try:
http://www.metalwebnews.com/howto/baltool/balltool.html

This is basically the DIY version of the Holdridge design.

Made up one myself but changed the design a bit and added
bushings.

Works very well.

DOC

Buy my junk! http://www3.sympatico.ca/doc/robotone/for-sale.html

"Dixon" wrote in message
news

"Craig" wrote in message
ups.com...
What would be the best way to cut a round bottom groove (need a few
diff. sizes-1" 11/4" and 11/2") in a piece of steel about 8-9" in dia.?
I want to make dies for a tubing bender. Would a radius attachment work
for something like this? Where could I find one?
Thanks,
Craig

A company called holdridge makes a unit for around a thousand that is
manual
and works great. You would want their 4" model. MSC or any of the others
have them. There are three on Ebay right now.
Dixon

"Craig" wrote in message
ups.com...
What would be the best way to cut a round bottom groove (need a few
diff. sizes-1" 11/4" and 11/2") in a piece of steel about 8-9" in
dia.?
I want to make dies for a tubing bender. Would a radius attachment
work
for something like this? Where could I find one?
Thanks,
Craig

Assuming you have access to a rather large lathe I would use tool steal
of the dia. you specified above and make a form tool mounted on an arbor
to fit your lathes tool post.

Greybeard also has a great idea using a mill and dividing head.

Bernd

See my roller at:
http://www.metalworking.com/dropbox/...retired_files/
See roller.txt and the accociated jpgs.
An example of a home-made radius cutter is in the pics
JR
Dweller in the cellar

Craig wrote:
What would be the best way to cut a round bottom groove (need a few
diff. sizes-1" 11/4" and 11/2") in a piece of steel about 8-9" in dia.?
I want to make dies for a tubing bender. Would a radius attachment work
for something like this? Where could I find one?
Thanks,
Craig



--
--------------------------------------------------------------
Home Page: http://www.seanet.com/~jasonrnorth
If you're not the lead dog, the view never changes
Doubt yourself, and the real world will eat you alive
The world doesn't revolve around you, it revolves around me
No skeletons in the closet; just decomposing corpses
--------------------------------------------------------------
Dependence is Vulnerability:
--------------------------------------------------------------
"Open the Pod Bay Doors please, Hal"
"I'm sorry, Dave, I'm afraid I can't do that.."

"Robin S." wrote in message
...
You could also use some math and calculate some depths for a grooving tool
(say, 1/4" wide if you have a heavy lathe, smaller if necessary) to rough
out the groove. Then file finish. Sounds like a lot of work, but
building/buying a radius attachment for your lathe could cost serious
hours/dollars.

I think I would try something like this. Grind yourself a tool bit with a
round nose and have a radius gage. You now want to cut your radius profile
by eye and checking after each light cut with the radius gage. It would be
slow going but if all you need is one or two this might suit you.

It might also be easier to make your die in sections cutting a quarter
radius on a plates and then assembling the two plates together for use.
This way you could mount a pivot on the tool rest and clamp the tool bit to
swing your arc with a lever.

--

Roger Shoaf

About the time I had mastered getting the toothpaste back in the tube, then
they come up with this striped stuff.