I need to put a bead on the ends of short lengths of 1.5 x 16swg
aluminium tube.
it's for joining car radiator hoses.

I knocked up a beadroller, it's nice'n'stiff, and everything
seems to work nicely[untill you put a tube in it], far better than the
large one I made for use on sheet..
I made the internal roller with a 60thou 'hump' approx 60deg one side
and 30 the other, the top was radiused with a file; the roller has a
step
about 8 mm from the hump to positivly guide the tube. the top roller
was just groved .125" wider than the widest part of the hump, when the
whole thing was smoothed off and polished..the bottom
roller is in ballraces and the top is in a wide broze bush and it's
all shimmed to keep them aligned.

the problem with the first internal roller was cracking on the crest
of the bead formed, it made a nice shaped bead that had a steeper
angle one side, just how i intended.
I altered the roller so it is symetrical and enlarged the
radius on the crest, it's still cracking on the crest of the bead. The
tube is almost imposible to direct, I have done abpout twenty beads
and only one or
two would be acceptable. On one I have driven the tube up onto the
step behind the die and opened the end up, it looks pretty good but it
wasn't meant to be like that;-)

The tube is an extrusion and I cut some bit from it and folded them to
see if it wqas maleable enough and it seems OK, I will annneal a bit
tomorrow and see if that's the problem.

I wonder whether a simple guide a few inches in front of the rollers
with vertical slot, in line with the rolers, the width of the tube to
be rolled would be enough to keep the tube straight?

Does any one do this and how do they do it?
what alternatives to the roller are there?

--
richard

Does any one do this and how do they do it?
what alternatives to the roller are there?

I've done this on bot ends of one piece of 2.5" 16 ga. 304 stainless
steel and on a few pieces of 3" 0.065" wall aluminum tubing. I got the
Harbor Freight bead roller that lists for $189 and used to go on sale
often for $89 but now seems to be on sale for $99. It comes with three
bead dies, 1/4, 5/16, and 3/8", and I use the 1/4" die. I think it's
rated at 18 or 20 ga so for mild steel so the SS was past it's rating.
Both male and female dies seem to be semicircular in cross-section, and
the OD of the male die is about 2.2" or so (sorry, it's been awhile
since I measured it but I posted it here so google could find it), so
2.25" OD tubing is about the smallest it could handle. The roller has a
14" throat and the arms are about 1/2" x 4" steel plate. I haven't seen
the arms flex upwards/downwards but they will deflect sideways if I try
to go too deep on thick stuff. I added a tie bar next to the dies that
cuts the throat to about 2" but stopped the deflection. On the SS I
spread the dies to insert the tubing, then forced the dies together
while rocking the tubing a little forwards and backwards until the
groove was about 1/3 of the die depth. Made a circle around the tube,
tightened the dies another 1/3 or so, made a circle, tightened the dies
until they touched the tube beside the groove, and made one or two more
circles. So far no tubing has cracked. I did the aluminum the same
way, in at least two passes. I didn't rig a guide fence but just drew a
line on the tubing with a marker and hand fed it while cranking the
roller. Maybe your die is not wide enough for the width and you are
trying to go too far in one pass? The bead width doesn't really matter
for hose retention since the bead is to keep the hose clamp from being
able to slide off, so maybe try a wider bead?

--
Regards,
Carl Ijames