We do a lot of stainless steel tubing fabrication and have found that milling
and abrasives both work well for coping. Using a small diameter mandrel on a
stationary belt sander does a good job if the mandrel diameter is close to that
of the tubing. Jancy makes a machine for this purpose but it's quite
expensive and is sized primarily for pipe as opposed to tubing. Has anyone
built such a machine?
I make a lot of Stainless steel handrails for houses and boats.
I use a 10" atlas lathe.
The tube is mounted in a vise mounted to the toolpost rest.
A holesaw is mounted in the lathe chuck and the tube end is fed across
It works really well and can be used for very accurate angle coping.
The vise is very easy to build and basically consists of 2 u-bolts that
hold the tube against 2 V-blocks.
The V-blocks are mounted in the T-slot of the toolpost rest of the
The degree markings for the toolpost rest can then be used for the
You can either use a holesaw and feed it in from the end, or use a
roughing mill and feed it in from the side.
You just want to make sure that the center of your V-blocks matches the
center of your lathe chuck.
It is much easier to use than the smaller tube cutting jigs, and cost
almost nothing if you already have a lathe.
I can send you a picture of mine if you like.
I used to do this in a Bridgeport when building bow and
stern rails for sailboats. Tip the head to change the
angle. With the end mill, you feed into the side of the
cutter rather than plunging as you would with a holesaw.
This made it very easy to shave a very small amount off the
the cope, or make a small adjustment to the angle. This was
very important on something as irregular as a boat rail
where odd compound angles on both ends of a piece were the
A two piece split block sized to the tubing clamped to the
table, or in the vise (or to the cross slide on a lathe),
makes clamping quick and avoids marring the finish on the
tubing. Most of what I did was 1" ornamental tube for which
a 6 flute endmill worked very well.
I had a large hollow shaft worm reducer set aside to make a
dedicated machine to avoid tying up the mill, but never got
around to it.
Following up on Ernies suggestion of using a lathe for tubing coping, I gave it
a try and it works really well. For holding the tubing, my Aloris boring bar
holder worked really well with the added benefit of being able to quickly
adjust the tubing position above or below the centerline of the mill for weird
off center copes. The Aloris tool holder I have is sized 1" with a bushing to
allow clamping 3/4" . I see in the J&L catolog that Aloris also has a holder
that would do 1.25" and 1". These 2 holders will cover most of the tube sizes
we deal with. I set the lock screws firmly but not rock hard and did not mar
the tube. It was necessary to debur the edge after coping to get the tube out
of fixture- it's a snug fit.
All in all I'm very pleased and again thanks for the tip.
This works really well on stubborn tubing, like 4140. For oddball sizes, just
a big block of Al. onto the toolpost mount, bore it thru with an end mill in the
lathe chuck, slit one side of the hole & drill/tap for a pinch bolt to grip the
tube in the hole. perfectly on center!
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