tube flattening

[graffian]

I have to make some mudguard stays and need to flatten the ends of the
tube, I use 1/2" 16swg CDS. I want it offset flattened, I flatten it normally in an old machine vice. I will be flattening it in a hydraulic press. One of the flattened bit's is 5" long!

Anyone have a pic of the sort of tooling used?

 

[chunkolini]

I had this problem the other day, modifying a pannier rack on my Africa Twin.
it looked as though the end of the tube had had a bar pressed along the length of it, making the material on that side bulge and flatten the other side.
Possibly a piece of round bar welding onto a strip clamped onto one side of the vice jaws? Ah! reading Op again, maybe a strip with a bar on it in the press?

 

[Shox Dr]

Im sure I know what you are reffering to but a picture would help

 

[chunkolini]

no picture, the tube on the bike rack had been flattened so that one side was flush to the surface it was bolted to. The other side had been squished and left two ridges of tube with a flat in between them for the bolt head. I reckon you could make a die by welding a strip or bar onto a tool in a press or vice.
I shall have to have a go on Monday and see if it works.

 

[gordon stephenson]

The best man to ask about your problem is johnakay, One of our members that has made hundreds of top class motor cycle racks etc.and I.m quite sure has a jig he made for doing just what you want, He sells his stuff internationally and it looks much better than all the mass produced ones I have seen.Look him up and send a PM.

 

[outofthefire]

I'd but a piece of round bar with the end rounded off inside the tube up to the point you want to flatten then have a good bit of the length supported underneath then your press will squash it from the top down.

 

[hotrodder]

Probably already found this as it's the first hit from 'tube flattening dies' http://www.offroadfabnet.com/forums/showthread.php?t=9664 No offset example there but 'tube flattening tool' got this which is kinda how i pictured it although my first thought would have been a split/shaped block to support the OD (like the pressure/clamp die of rotary draw bender), maybe shaped at the transition to flat to guide/support the tube i.e. lengthen the transition rather than let the tube collapse how it wants to. A mandrel inside as mentioned would be less work but depends if you're squashing both ends or not?

 

[stuvy]

cheers for the link hotrodder, the second one doesnt work though?

 

[MattF]

the second one doesnt work though?

http://farmlog.blogspot.co.uk/2011/09/chicken-dome.html

 

[stuvy]

http://farmlog.blogspot.co.uk/2011/09/chicken-dome.html

yepp i can see it now

 

[graffian]

Cheers for the links, I had already seen them. I use an old machine vice for plain ones and offset ones I weld in a section of flat to the tube, then a fillet of braze and sand smooth. I have 8 to do and thought a pair of dies might be quicker to make, especially if I am not happy with one, or two and have to re-do them.

I made a pair of dies, one end is stepped to do the offset crimp and the other is a plain crimp. I need to put some dowels in them and squash some metal.
My "press" needs binning, I knocked up the press from the remains of a home built folder, it's stood outside for years, I used it to press some gears on a layshaft for someone the other day, it was scary getting the old ones off, it was creaking away and flakes of rust were popping off!

should this have been in metal shaping?

 

[MattF]

Just out of curiosity, what do you mean by an offset? I'm envisaging something with a portion of the tube retaining some semblance of its former shape. Is that correct?

 

[graffian]

Normal flattened, when the tube looks symetrical looking from the side.
Offset when one face of the flattened bit is in line with the surface of the tube.

I will put some pics up if my squashing thingie works, I have started on something else so I will finish that first, yes I know I span and attention of
gnat. Just nicked a pic..

 

[MattF]

Cheers for that clarification. I was thinking of something completely different. That looks like it'll be a devil to achieve with any ease?

 

[graffian]

Had a go at squashing a tube a few minutes ago. I was aware edges of the lumps of steel might need rounding and now I know what wants doing.

I was going to do the top piece in two bit's, one bit clamped on to hold the tube, it clearly needs it as the tube angles when pressed. Maybe I can push it down once it's squashed.
I am tempted to start again as I now have a better idea of whats needed, but hopefully a couple of mods and it's done.

I need to get another jack, a 5 ton jack needed a 3 foot lever on it, well a 12" 3/8 drive extension and a GSXR fork leg;-) That seems a lot to crush a bit of tube? Maybe rounded edges and some beeswax will make it easier.

Just realised that bit of 'scrap' tube was a bit cut for something, am I going to spend an hour looking for the cut bit before I cut another bit;-)

 

[hotrodder]

That's come out nice for the first trial. I normally use washing up liquid with a little water when pressing ally and the gauge on the press shows well over 2T when putting a 3 - 4" dia, 1/2" deep recess into annealed 2mm 1050 sheet ally

 

[MattF]

That does look tidy. Tooling seems a lot simpler than I'd have expected too. Nice work.

 

[johnakay]

The best man to ask about your problem is johnakay, One of our members that has made hundreds of top class motor cycle racks etc.and I.m quite sure has a jig he made for doing just what you want, He sells his stuff internationally and it looks much better than all the mass produced ones I have seen.Look him up and send a PM.

thanks for your kind comments Gordon

 

[graffian]

Few modifications, filing a radius on the edges of the die and some wax. It works great now and takes a fraction of the force to stomp the tube.

The "press" was much happier with a short handle on the jack, it was quite scary with the long tube on the jack. The press lives out side[since ~1986] and is really rusty. I knew it was under some tension when rust started popping off;-)