rolling a bead on tube ends

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

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 snipped-for-privacy@verizon.net