DaveFJ
|
| posted on 29/5/07 at 12:22 PM |
|
|
Tube bender 1.75"
OK - thought I had this sussed but a bit of searching on here and I am confused 
I have some 1.75" CDS tube 3mm thick wall, that I want to bend up for my roll bar. I thought i would be OK hiring a bender from speedyhire or
somewhere for a week and it would bend this easily BUT...
After reading previous posts what 'pressure' do i need ? will a 10 ton hydraulic type do the job? and will it bend the pipe properly or
will it kink?
it it helps the maximum bend will be about 75 degrees
Also - the adds all say 'a selection of formers' do they usually have 1.75" or have I shot myself in the foot there?
I know i can pack the pipe with sand and heat it to get a good bend but would need proper gas kit for that and would rather not bother...
was thinking of this one:
linky
Yes I know i can ring them - but I can't do that right now.......
Cheers
[Edited on 29/5/07 by DaveFJ]
Dave
"In Support of Help the Heroes" - Always
|
|
|
|
|
Minicooper
|
| posted on 29/5/07 at 12:59 PM |
|
|
Hello,
That pipe bender will just kink the cds tube you have, the formers won't fit the tube properly unless your lucky, a pipe is measured internally
and a tube externally. But even if the former is a good fit the tube needs to be supported all the way round unless the wall thickness is very
heavy
I bought one of these which does perfect bends but I only have 1 inch, 30mm and 1.5 inch formers, otherwise I would have offered to bend it for you if
you aren't too far away
http://www.pro-tools.com/105.htm
Cheers
David
[Edited on 29/5/07 by Minicooper]
|
|
|
Hammerhead
|
| posted on 29/5/07 at 01:38 PM |
|
|
you need a mandrel pipe bender
|
|
|
timf
|
| posted on 29/5/07 at 02:53 PM |
|
|
Dave
would you like to borrow my proper tube bender to do the job properly.
Tim
A prisoner of war is a man who tries to kill you and fails, and then asks you not to kill him."
- Sir Winston S. Churchill, 1952
|
|
|
DaveFJ
|
| posted on 29/5/07 at 02:59 PM |
|
|
Now there's a thought..... 
Dave
"In Support of Help the Heroes" - Always
|
|
|
rav
|
| posted on 29/5/07 at 05:24 PM |
|
|
Have you got enough to try a sample first?
If it were me I think I'd take it along to a friendly local engineering workshop - somewhere on the more agricultural side perhaps (somwhere
that might have some time for you and not tell you it can't be done without a mandrel bender etc etc) and see if they can bend a sample ok.
If they cock it up they'll probably not charge you, saves hiring a bender and finding out the hard way!
|
|
|
DaveFJ
|
| posted on 29/5/07 at 05:26 PM |
|
|
I have a 6.6m length of the stuff so I do have a small amount spare - not sure how much yet though because I want to put in rear braces and a
crossmember......
Dave
"In Support of Help the Heroes" - Always
|
|
|
timf
|
| posted on 29/5/07 at 08:52 PM |
|
|
you mean like
 
tiger1
full service design, lenght calculated, cutter wrappers
see http://www.locostbuilders.co.uk/photos.php?action=showphoto&photo=tiger3.JPG
and
http://www.locostbuilders.co.uk/photos.php?action=showphoto&photo=tiger2.JPG
A prisoner of war is a man who tries to kill you and fails, and then asks you not to kill him."
- Sir Winston S. Churchill, 1952
|
|
|
DaveFJ
|
| posted on 30/5/07 at 07:56 AM |
|
|
Actually more like this....
 
Description
excuse the crappy drawing.
The main hoop is as you designed Tim when you came round that time. The rear braces will have to be made, I think, after the main hoop is in place so
that i can g accurate measurements. the Horizontal tube is for the seatbelt mounts.
And before eveyone piles in - yes i know that the design isn't 'optimal' for strength etc - but i like it 
Dave
"In Support of Help the Heroes" - Always
|
|
|
timf
|
| posted on 30/5/07 at 08:10 AM |
|
|
quote:
Originally posted by DaveFJ
The main hoop is as you designed Tim when you came round that time. The rear braces will have to be made, I think, after the main hoop is in place so
that i can g accurate measurements. the Horizontal tube is for the seatbelt mounts.
Got new software since then will allow me to design every thing and they come out accurate to 5mm or so perhaps we should meet up and take some
measurements that way you wont waste any tube.
Tim
A prisoner of war is a man who tries to kill you and fails, and then asks you not to kill him."
- Sir Winston S. Churchill, 1952
|
|
|
DaveFJ
|
| posted on 30/5/07 at 08:24 AM |
|
|
Sounds good
Dave
"In Support of Help the Heroes" - Always
|
|
|
NS Dev
|
| posted on 30/5/07 at 11:23 AM |
|
|
quote:
Originally posted by Minicooper
Hello,
That pipe bender will just kink the cds tube you have, the formers won't fit the tube properly unless your lucky, a pipe is measured internally
and a tube externally. But even if the former is a good fit the tube needs to be supported all the way round unless the wall thickness is very
heavy
I bought one of these which does perfect bends but I only have 1 inch, 30mm and 1.5 inch formers, otherwise I would have offered to bend it for you if
you aren't too far away
http://www.pro-tools.com/105.htm
Cheers
David
[Edited on 29/5/07 by Minicooper]
Hmmm, interesting!
Strange as I used this:
 
tube bender
together with 45mm x 3mm CDS tubing to make this:
 
main hoop 2
 
main hoop
Not a kink in sight.
You need to anneal the tube locally first though, as the bending work hardens it.
That is a simple case of this:
[img][/img]
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
|
|
|
NS Dev
|
| posted on 30/5/07 at 11:28 AM |
|
|
PS I did no calculations and no CAD drawings, made it all to fit, and its within a couple of mm of being right in all the right places.
Trickiest bit, no matter what you use to bend it, is the get the hoop in an exactly flat plane.
On a 7 its not too bad as the upright lengths are pretty short, but on a full size cage they can end up quite a bit out at the bottom.
You need to allow a good amount of extra length on each leg, then cut it back to suit, bit by bit. You waste less doing it this way than you do
calculating it accurately and getting one of the 4 bits too short.
[Edited on 30/5/07 by NS Dev]
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
|
|
|
