Pipe bending - avoiding small dints from rollers

[CT]

I had a crack at my first pipe bending and I'm quite happy with the actual bend. Used a dawn bender and die, 40nb pipe with 3.2 (?)mm wall for 48mm OD.

My only query is what is the best way to avoid the small dints that the rollers left? I quite possibly dinted it at the very end as my 90 deg bend ended up a little bit more than 90.

I've read somewhere about using other bits of material to spread the load at the point of contact with the roller. Whats the best way to do this?

Or heat the bend area with the oxy first so that less pressure is needed?

Or is there other, better ways?

Cheers
Craig

[barbz]

one trick is to use a short section of tube one size up and cut it in half so it can protect the piece to be bent as it moves on the rollers.

I just welded up the dents and used the grinder to clean it up or bog would work.

Paul

[PJ.zook]

As Barbz says, get a short length of pipe/tube that slides over the pipe/tube you are bending, then slice it lengthways down the middle, then use these half pipes between the roller and pipe/tube you are bending. They help spread the load.

[CT]

Thanks lads, I'll have a crack at that for a fix.

Cheers
Craig

[Guy]

Move the support pins to the next hole along. (Ie a bigger space between them)
Get the rollers made from delrin

[just cruizin']

Make up some sleeve that go over the pins and then weld some angle to the sleeves that cradles the tube. Same idea as the larger tube but will work for different diameters. Don't weld directly to the pins as you won't be able to get them inplace.

[ausyota]

I use a couple of short bits of angle iron between the pipe and the rollers.
The trick was shown to me by a metal fabricator.

[CT]

Move the support pins to the next hole along. (Ie a bigger space between them)
Get the rollers made from delrin

Unfortunately the support pins are out at their max for the size pipe I'm using.

The delrin rollers sound like a good idea but our lathe is stuffed so I can't machine any up myself. Are they available of the shelf anywhere?

[CT]

I made up the "half pipes" today so I'll see how they go.

I like the angle iron ideas too. Avoids having the pressure point on the upper most radius and should split the load. I'll give that a go next if what I've made so far doesn't work.

Cheers
Craig