tube benders

[Saab2000]

This is not really the question, but my Anvil had some really elegant S-Bend chainstays and seatstays.. I wish I knew how DWF made them. Well, not really. But they were very, very nice. They just looked cool. Unfortunately, I don't really have any good pics. It has been sold a few years back.

But it had the nicest seatstays ever.

These are the only pics I have that show the bend at all, and even in these it's not very good.

[SeanEasley]

from portland

[swoop]

a note from the desk of swoop.

hey saab and sean.. and any other non builders.. lets support the conversation by posting bike pictures in the galleries and lets just listen in while the builders talk it out. that's the point here.

for the non builders, lets keep this section of the forum close to what its intended for and only post pertinent questions that forward the conversation. we have a whole forum to post our bikes on (and those are lovely pics), so, lets use it. i'd even suggest that you two start a 'stay pictures' in the gallery section with those two lovely examples so we can delete the comments here and let the conversation continue in the right spirit.

help us keep it pointed in the right direction.

[twowheels]

question to the builders--do you believe that curved stays perform any differently than straight stays? i.e., are curved stays simply an aesthetic touch?

[steve garro]

On my godforsaken and apparently un-race worthy frames (insert awkward chuckles), I always use s bends, and find custom mitering canti bosses to achieve the 75-80mm offset a hell of a lot easier than custom bending seat stays, especially s-bends. I have found my Nova fork raking tool works fine for adding a bit or less bend to said stays when necessary. Keeping the bends in phase from one stay to the other is trickery and trial and error, as with all bending techniques.

I have created the bends from scratch on occasion, thanks to the very limited production of benders made by the holy mr. d.ferris maybe 7 years ago. I can't remember the radius diameter on my bender, but it was designed for seatstay bending primarily, and the mechanics of this fine tool, including the roller mechanism, sound similar to the type Drew refers to.

caveat: I am not a machinist, nor do I aspire to be.

hi, Margo! do you find it difficult to find S-bends stock to fit small frames? that's what made me start bending my own......on smaller frames the "tire bend" has to angle in allot more abruptly, and i just never found what i liked stock {29ers with almost 3" of BB drop and short ST's come out with some really short stays too, esp. with the loooong paragon dropouts - in the 340-390mm range} also, them dang disc brakes like to bust stays, and i can adjust thicknesses to suit.....steve.

[steve garro]

from portland

damn, those canti posts look close together........steve.

[zank]

question to the builders--do you believe that curved stays perform any differently than straight stays? i.e., are curved stays simply an aesthetic touch?

I think there are functional reasons, such as canti boss position like we are discussing here and tire clearance. I did a mountain bike for myself with straight seat stays that were side tacked and I can not tell any difference between that bike and my current mtb with s-bend seat stays in terms of shock absorption. But you also have a 2.25" tire to take up a lot of the shock.

[Saab2000]

a note from the desk of swoop.

hey saab and sean.. and any other non builders.. lets support the conversation by posting bike pictures in the galleries and lets just listen in while the builders talk it out. that's the point here.

for the non builders, lets keep this section of the forum close to what its intended for and only post pertinent questions that forward the conversation. we have a whole forum to post our bikes on (and those are lovely pics), so, lets use it. i'd even suggest that you two start a 'stay pictures' in the gallery section with those two lovely examples so we can delete the comments here and let the conversation continue in the right spirit.

help us keep it pointed in the right direction.

That's cool. No sweat.

[SeanEasley]

damn, those canti posts look close together........steve.

ITs a road frame...you might be seeing the L and R marks on the stays? I guess its just like surgery--smart to mark the limbs left and right so as to avoid cutting the wrong side!

Swoop; no prob will avoid pics on this board for future ref.

[mjbabcock]

regarding the Dr. Ferris tubing bender, John Caletti has the following over on his site,

"I made a cool tool to bend stays for single or double bends...The bender is made from delrin, machined on the mill using a rotary table, the roller is made of several parts that were turned on the lathe, the base is welded and machined steel with a 2 piece brass bushing pivot made on the lathe. There are numbered holes for a dowel pin stop so bends can be measured and repeated. Many thanks to Don Ferris at Anvil Bikeworks for his input on designing this tool!"

I went to make one for myself out of delrin but found the costs insane. Went with Oak in stead and everything seems to work well.

[zank]

very cool pictures. Thanks!

Just an FYI...Dupont Delrin (h0mopolymer acetal) isn't the only acetal in the game. There are plenty of companies making copolymer acetal for much less and a lot of the extruders making stock shapes offer lower cost alternatives to Delrin. Just do a google search on POM, acetal copolymer or Celcon (a Ticona product) and a few stock shapes providers will pop up. The h0mopolymer has advantages, but mostly in dimensional staibility in molding. That wouldn't be of much concern to us.

But wood is still a great way to go!

Edit: LOL. The prefix h0mo- actually has many appropriate uses in the English language. Seems silly that the forum software edits it out in all cases.

[hansolo758]

On my godforsaken and apparently un-race worthy frames (insert awkward chuckles), I always use s bends, and find custom mitering canti bosses to achieve the 75-80mm offset a hell of a lot easier than custom bending seat stays, especially s-bends. I have found my Nova fork raking tool works fine for adding a bit or less bend to said stays when necessary. Keeping the bends in phase from one stay to the other is trickery and trial and error, as with all bending techniques.

I have created the bends from scratch on occasion, thanks to the very limited production of benders made by the holy mr. d.ferris maybe 7 years ago. I can't remember the radius diameter on my bender, but it was designed for seatstay bending primarily, and the mechanics of this fine tool, including the roller mechanism, sound similar to the type Drew refers to.

caveat: I am not a machinist, nor do I aspire to be.

Margo: Although I'm far from being a framebuilder, I'm very glad to see you're posting. Happy New Year.

[Dazza]

we need more of Margo
:thumbs_up:

Cheers Dazza