Trouble with me Tube Bender!

[robyamaha450]

Help!!

I’ve just tried to bend up a roll cage in the newly hydro converted JD2 bender this W/E. I’m using 1.5” x 0.13” wall cold drawn seamless steel tube (Un-annealed Dom) and the bloody thing pulls the tube in a tighter radius than the die causing it to kink/flat in the middle of the bend. It seems to lever the tube through the follower instead of pulling it around the die. It does work as I have made some good bends but it’s not repeatable. I am also struggling to find the start of the bend… it’s about the most frustrating thing I’ve tried to do in a while!

Its looks as though the hydro conversion pulls the tube too quickly? But I think I’m missing something simple with the set up? Any ideas on the problem would be much appreciated.

[K-fab]

Did it work correctly before you converted it to hydro power?
What is the die radius?
Are you lubing the sliding shoe?

I have no real idea why it would do it, so I'm throwing out random ideas that might be an issue.

[robyamaha450]

Hi Kfab

I didn’t really use it much when it was hand operated, I pulled a couple of bends just to try it then I haven’t had the time to use it until now. It seemed ok.

The die clr is 3 x d = 4.5” so it should be ok

I just got a reply from Van Sant who supplied the bender. They think it’s because the tube is slipping through the U strap, I have made sure the bolt was tight but I didn’t go too far in case it damaged the tube. I’m going to wang it down really tight, mark the tube at the strap, and then try again. The power of the hydro conversion shouldn’t matter but I don’t think it helps; it takes no prisoners when it’s pulling the tube. I’m also going to try a better lube like EP80 oil or grease on the follower instead of WD40.

[bdkw1]

The die radius is the center line of the tube, 3". This is really tight for 1.5" tubing. 4.5" CLR is what is most common. Polish the shoe die and use grease, the bolt on the shackle end shouldn't matter.

[dunerocket]

Crank that bolt tight. Place a piece of scrap between the bolt and the tube (I use a 1/16 piece of sheet that is crudely bent to look like the OD). Mine would slip a bit and the bend start would be off, but it would still make a good bend. Now it doesn't move a bit.

[bajatex]

If you are trying to find where the start of bend is on the bending die you can put the tube in and take out all of the slack with the lever arm then slide a feeler gauge between the tube and die where the opening is. Take note on how far in the feeler gauge goes in relation to the flat on the die and transfer this distance to the top and scribe a line. If the die has been used a lot you can usually see where the bend starts but not on a new one. I hope this makes sense, I can't really think of any other way to describe it.

bajatex

[Bugpac]

what wall thickness is the tubing? .13?

[masterfabr]

Did it work correctly before you converted it to hydro power?

Hydro power? I've never seen a water powered bender. My turn to pick on YOU!

[K-fab]

I’ve just tried to bend up a roll cage in the newly hydro converted JD2 bender this W/E.

I was just repeating exactly what he said! (I did wonder about it too...)

[robyamaha450]

Gents

Thanks for the info.

I’m hoping the problem is just a simple school boy error because I don’t want to do a load of fault finding to get to the bottom of it. I’m going to try again tonight on test bend no.4 and a super tight bolt.

I like bajatex’s tip on finding the start of the bend and I’m annoyed I didn’t think of that one my self. Does it matter if you don’t use the actual start of the bend providing you use the same reference point on the die to figure out the bend points?

Just to clear a few points the die CLR is 4.5” I chose this because it is 3 x the tube diameter.

The wall thickness is 0.13” = 3.302 mm in the UK tube size is spec’d in imperial and metric equivalents. I am using this for the main hoop and the beam; it will be 2.0mm for the rest of it. Its all CDS2 or 3FSBK spec seamless tubing.

There is a Hydro Electric Generation plant just down the road in Bala North Wales, does that count in a round about way for hydro power?? I guess we use different terms across the pond sometimes but I would have ribbed me for that one as well!
Cheers
Rob