# Bender and Dies for seatstays



## febikes (Jan 28, 2011)

What are you guys using for bending seat stays on 29ers?

I am planning to get a proper bender and am thinking about the JMR tube bender, JD2 tube bender, or the Anvil.

So far I have been bending using a 45# plate and while it works for a very basic bend on a medium sized bike it is hard to be accurate or repeatable. It gets the job done but I am not able to produce the results that I would like to have. Provided I do a fairly relaxed bend I have had reasonable success although the results are not always pretty and I often scrap tubing.

The JMR bender and dies are rated for 5/8" tubing with .035 wall and seems like it would be useful because it would allow building small 29er with large tires. The bender can also be used with 3/4" or 7/8" dies and .058 wall so it could be used for chainstays. My hope would be that I could use thinner wall but the mfg spec on the unit currently lists .058 as the limit on 7/8" tubing. There is also a lot of information about the JD2, JMR, and ProTools benders on 4x4 and auto/motorcycle forums.

The Anvil bender lists *"Available in 5/8", 3/4", or 7/8" @ 9.375" & 11.375" Radii"* but beyond those few words and a bunch of photos I don't know anything about the Anvil in terms of spec.

The next bike I am building will be a 29er with 16" seat tube running 2.35" tires. The radius to provide tire clearance is my main concern because I want to clear 2.8" from inner tube edge to inner tube edge for the tire clearance area. I am concerned that the Anvil might not be able to handle the tight radii needed to clear the tire and connect to the seat tube. Based on the way I read the specs on the JMR and it's dies it sounds like it might be the best choice.


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## Walt (Jan 23, 2004)

*Time to search*

Seriously, this has been covered a lot lately.

http://forums.mtbr.com/frame-building/homemade-seat-stay-bender-716608.html
http://forums.mtbr.com/frame-building/acceptable-tube-bender-659557.html
http://forums.mtbr.com/frame-building/whats-cheapest-way-bending-tubes-791364.html

etc, etc.

I am a "hardwood form+press" (Waltworks Bicycles: More bender stuff) kind of guy for seatstay work, but you can get good results with other types of benders too. Tube selection (Nova 16 and 19mm stays FTW!) is almost as important in my experience.

-Walt


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## TrailMaker (Sep 16, 2007)

Hey;

As I've related elsewhere, I am using a Pro Tools 105 bending .750 x .035 on a 3.5 CLR with perfect results to beyond 180. It's easy.

I would like to try both .028 on the current setup, and also .035 on a 3" CLR, but all that takes is money I don't have. Dies aint quite what I call cheap.


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## edoz (Jan 16, 2004)

TrailMaker said:


> Hey;
> 
> As I've related elsewhere, I am using a Pro Tools 105 bending .750 x .035 on a 3.5 CLR with perfect results to beyond 180. It's easy.
> 
> I would like to try both .028 on the current setup, and also .035 on a 3" CLR, but all that takes is money I don't have. Dies aint quite what I call cheap.


Are you using the stock dies for that?


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## RCP FAB (Jun 15, 2011)

Tight radius bender that I built (a lot of dead image links, they are updated later in the thread)

http://forums.mtbr.com/frame-building/shop-outfitters-bending-die-review-790123.html


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## TrailMaker (Sep 16, 2007)

edoz said:


> Are you using the stock dies for that?


Yes;

With my own positive locking tube holder instead of the saddle supplied.


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## edoz (Jan 16, 2004)

TrailMaker said:


> Yes;
> 
> With my own positive locking tube holder instead of the saddle supplied.


Yeah, I think I remember a thread where you said most of the problems come from tube slippage, or am I making that up?


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## TrailMaker (Sep 16, 2007)

Hey;

Tube slippage is an issue. If draw tension is not maintained on the tube, instead of stretching tight to the die and then be compressed into the inside of the bend, the metal will bunch up and kink. I was not impressed with the saddle they supplied for the job, so I made my own.

However, the real key for the thin wall is the anti spring back feature they incorporate in the smaller dies. When using the manual ratchet system, it maintains very high draw pressure even when you release the ratchet handle to go to the next tooth. This effectively freezes the draw pressure between cranks. Without that, it would be a complete fail on thin tubing. The larger dies do not use a spring back lock, as the thicker tubing does not need it.


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## febikes (Jan 28, 2011)

TrailMaker said:


> Hey;
> 
> Tube slippage is an issue. If draw tension is not maintained on the tube, instead of stretching tight to the die and then be compressed into the inside of the bend, the metal will bunch up and kink. I was not impressed with the saddle they supplied for the job, so I made my own.


Can you share some photos of the saddle you made?


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## TrailMaker (Sep 16, 2007)




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## cable_actuated (Jun 7, 2012)

*Bend like the pros*

Sorry to dig up an old thread, but I saw this photo of Todd from Black Sheep in an article from our local paper on the fat bike craze. Clearly, the key to getting a pro bend in your seatstay is strategic placement of traction mats on the floor.


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## afwalker (Apr 26, 2012)

The anvil bender is the bee's knees. Both radii work well on seat and chain stays, I haven't had any wrinkling. The ProTools was what I first tried, but it wasn't working on seat tubes so I sent it back. Probably my not realizing heat treated tubes make a big difference. I tried a Baleigh bender from Aircraft Spruce but it seems to wrinkle even filled with sand non-heat treated tubes. Also the Anvil is great because it keeps bends in phase if you do complex bends.
A HF tube roller with Swag Offroad dies works well for seat/toptubes for me.
cheers
andy walker


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## Live Wire (Aug 27, 2007)

afwalker said:


> I tried a Baleigh bender from Aircraft Spruce but it seems to wrinkle even filled with sand non-heat treated tubes.
> cheers
> andy walker


Did you ever try to bend 5/8" tubing with that?


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## TrailMaker (Sep 16, 2007)

Hey;

I think it is important to point out the distinctions between the type of bend needed, and the bend processes required. As the resident pros who drop in on this forum occasionally point out (Mr. Walter speaking to this often), there is no one perfect bender for everything. You need different tools for different types of bending.

It mostly depends on the radius you are working with. Large swooping radii like for a curved TT/DT are best achieved with a roller. We're talking radii of a few feet or more. I too have the HF roller with SWAG dies. Spiff. If we are talking about what I would call medium radii bends such as is desirable on a ST or some stay work, the simple 1:1 leverage Anvil type manual die rollers are the ticket. If you want to do large radii bending and can make your own wooden dies, as has been chronicled here in this forum, these manual roll benders can do large radii work. At this point, you are not looking at any serious deformation of the material, and so these benders will do the job. If you want to get down to radii in the single inches, a draw through die bender that tightly controls the movement of the material is going to be necessary.

I kind of laugh at that pic. No... not because of his outfit, or even the sand strips on the floor. If I were looking for a tight radius bend, I could bend his tubing without the handle, using one hand, on the Pro Tools bender. Yes, I realize it is a completely different type of tool, and it may even be hardened tubing (which I have no experience with), but I don't have to get that serious until I hit a stick of 1.75 x .120 DOM!!

Then, you might better be wearing a helmet, just in case something lets go!


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## febikes (Jan 28, 2011)

I have been using the pro tools bender with good results. "S" bends are not too hard to make. The key is to use a flat surface as a reference plane to keep the bends in phase. I am not saying it is the perfect tool but it seems to work fairly well for what I need from it.

I did these with NOVA tapered seat stays using 5/8" die with 7" CLR.









I will post some more about my "S" bend seat / chainstays when I get the next frame completed.


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## afwalker (Apr 26, 2012)

The 5/8' worked on the Baileigh, it's a small clr radius, the 3/4' wrinkled pretty easily. This was a versus tube, non-heat treated. The Anvil is a much larger CLR so less likely to wrinkle, plus it helps with phase alignment, but it costs 4x more. I'm sure the jd or protools would do a nice job. I'll probably sell the Baileigh since I have the Anvil now.
cheers
andy walker


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## Live Wire (Aug 27, 2007)

afwalker said:


> I'll probably sell the Baileigh since I have the Anvil now.
> cheers
> andy walker


Sent you a pm....just in case


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## afwalker (Apr 26, 2012)

I agree with TM, Mr. Trailmaker Several benders are needed for different type bends.
The HF tube roller works well with additional dies from Swag Offroad. Those dies are nice but you'll pay $165 +sh. for each. That will get you nice large bends for top/seat/down tubes. For a small radius bend, wooden dies, the Paterick pattern fork bender from Northwest Casting in St. Paul for $150, the Baileigh bender, or Jd or Protools, and the cream of the crop is the Anvil. Prices go up accordingly.
cheers
andy walker


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## afwalker (Apr 26, 2012)

Thinking about the OP choice of JMR, JD or anvil, The JMR is better for long bends, the JD can do shorter radius bends but wont work well for seat tubes/top tubes. The Anvil is awesome on seat and chain stays since it can do complex bends and account for the phase of the tube, but it's for shorter bends not seat tubes/top tubes. The JD is not that much less after the cost of dies to the Anvil. Best case Anvil + HF+Swag dies.
cheers
andy walker


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## febikes (Jan 28, 2011)

As an update, I went with the PRO Tools bender we discussed in this thread. It worked out great.


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## todwil (Feb 1, 2007)

What radius is the die? And is it 3/4" or 7/8"?


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## febikes (Jan 28, 2011)

The die for seat stays is 5/8" and 7" CLR. The photos and the bike are using Nova 16mm stays.


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