I acquired a Diacro #3 without dies and a friend machined two sets out of AL using a rotab on his Bridgeport, so just like what you’re thinking. I don’t think it’s hard to do once you have the pin locations dialed in. I can ask if he’d share his process and any heads-ups if you’re interested?
The one thing about a Diacro is they are great for flat bars and bends in one plane, but they don’t have a lot of vertical clearance for riser bars because of the big base.
That would be sweet, thanks! I’m mostly interested in doing wide swept back bars which I think will fit on the table!
I have a #3 DiAcro sitting around with no dies. I’ve been planning on making some, if I ever do, I could possibly make more. I did try to buy dies from DiAcro, they committed to making them, but never did. Look at Ebay, they do show up occasionally.
As mentioned, the pin hole locations are key to getting started. If anyone has mapped them out, or knows the pattern, please post. If not, I can do the plot and post.
Bottom line: Does anyone want this info? Does anyone want PMW manufactured dies? Probably from aluminum for low expense/low production, but they could be steel for high production, which is few of the buiders out there. Seems like 7/8" is the winner for a first try.
I really don’t know how much demand there is for this but i imagine there are several builders with a Diacro that have had to figure out how to make dies or find a machine shop that will.
Aluminum is just fine for material but could be a Pandora’s box in choosing which CLR for each diameter and how many to offer.
I currently have 3/4 and 7/8 in 3.5” CLR for the tighter bend chain and seatstays that the Cobra and Anvil won’t do, as well as bending up to 90 degrees. I would like to have a 2.5” CLR for wishbones, and maybe a 1/2” x 2.5.
Page 10 in the Art of Bending. All the important measurements of the tube dies are listed by Diacro.
Thanks!
I don’t know much about the Diacro but seems to be the Holy Grail of benders from what I see. Reading Art of Bending I see that it’s extremely versatile for all types of pieces of metal, does it have any interesting features for framebuilding specifically?
The Diarco bender is a great tool but can be an expensive proposition. The benders themselves are easily found cheap but the tooling needed to put it to work can very expensive. The tube dies, follow blocks and tube holders are easily made but you need a rigid/heavy mill to produce them. Aluminum dies will hold up fine but if you plan on using it in a production/volume setting, cold rolled 1018 steel would be a better choice.
The Diarco tooling is not the same across all the models. A model 2 tube die will not fit on a model 3 and so on. The different models have different capacities. The largest tube die Diarco makes for my model 2 is only .75”. That doesn’t mean you cannot bend larger diameters with a model 2. I’ve made my own larger dies, the largest 1.25”. The model 2 and up are very heavy and cannot be lifted without some kind of mechanical help.
The biggest problem with bending .035” 4130 is stopping it from slipping out of the holder. If it slips even slightly, the inside of bend will wrinkle. The wrinkling gets worse as your CLR gets smaller. I can make beautiful bends all day long with crew tube, 4130 is a mofo. As you all know .035 4130 is expensive, I wasted a lot of $$ on 4130 tubing trying to figure it all out.
Then there is the Diarco quick clamp. It’s expensive and not easily found. The quick clamp I bought was well used and would not hold .035” 4130. I had to modify it by getting rid of the quick locking mechanism and use a big chuck of cold rolled steel.
My Diarco model 2 is a great bender, useful for many things but not a total bending solution for making bike frames.
If you make a 7/8” die that will fit my model 2, I’ll take one. It will save me from spending the day setting everything up and making a mess. Aluminum will work for me.
Re: Diacro Benders
From the research I have done and the people I have talked to, the Diacro is a great general-purpose bender, but not necessarily the best bender for framebuilding. It can achieve nice bends beyond 180deg, but dies are hard to come by, expensive, and it can’t bend tubes in tandem.
I don’t have a Diacro, but I can look into modeling the dies for future reference.
IMO I think these are the needs the framebuilding world does not have good solutions yet:
If you can get me the pin pattern, I’ll see what it will take to make one. As mention, the pin patterns are different for the various sizes.
We had a Diarco 4 with a good set of dies for a while. I was never really happy with the results with the wall thickness of bicycle tubing.
I probably could have made it work just never had the time.
Definitely agree! I really appreciate how Smith (aka RatKing) has put his Di-Acro to use making the RIP Rack. He has a pretty slick setup for measuring bend distances and using different stops to get consistent angles every time. Those bender shine when used in a production setting where tooling can be custom-made once and then parts churned through.
I’m pretty surprised that there’s not a better dimpling solution. It’s one of those things that I’ve personally settled for “good enough” on but would love to step up my game.
Some hot rod tips for the Chinese bender:
I replaced the stamped tube retainer with a larger sleeve to spread the pressure on the tube to prevent dents
Anyone bending/modifying oval stays?
Would a bending die+ follow block (similar to Toob Bender) work ?
I’ll get a shot at it if I ever come accross a big enough aluminium chunk to make the die but maybe someone here as already some insights
I’ve done this with fork blade benders in the past. But only really to “nudge” the stays a few degrees, never putting major bends in them. You can’t really use a follow block unless the profile is consistent through the whole clamp/bend area which isn’t the case on most tapered/ovalized stays.
Excellent! I’ll try the follow bar and see how it goes. I 3D-printed a sleeve which worked fairly well but I’ve been thinking of copying the Cobra bender’s approach to the tube clamp to see if that’s viable.
Cobra can make an oval die and follower. I believe Prova cycles has one for 22.2 ovalized stays, so I know it is possible.
When I get a chance I am going to try bending (with the cobra bender) a 19mm stay with a 3/4 die that is squishing the tube. It’s a dumb test to see if it’s possible to oval and bends in the same step.
@Seriousbicycles That is a great mod!
This is great, I’ve done almost exactly the same modifications to this bender and it works really well for stays. I used a row of bearings where the wheel shaped die would go. For those without a mill the follow bars/dies can be 3d printed. Add a steel backer and it should last a while
