Status of Slip Roller & Tubing Bender

I’m preparing to assemble a large project after prototyping some fabrication methods at a smaller scale. Before I can continue with securing designs, I need access to a few specialty tools. These include a bender / ring roller for square tubing, a roller for sheet metal, & a foot shear (or any effective substitutes). When I last came into the makerspace, I remember seeing the custom tubing bender in the metal shop, and the foot shear in the main room tucked away out of service, but I don’t think I ever saw that slip roller listed on the wiki.

Most critical to this project is a square tubing bender. As far as I know, the Space’s tubing bender has interchangable rolling dies judging by the collection scattered below on the nearby shelf, but can anyone help me with the specification for these? Specifically, I was hoping to bend some 1" square tubing. If possible, I’ll even look into making a custom set of dies on the lathe. Of course, any cheap alternatives are welcome. This isn’t the most expensive part of my build.

Another, maybe more important piece of equipment is a sheet metal roller. I never saw one around, or if I did, I’ve forgotten by now. The one listed on the wiki is max 40", a great size but I wouldn’t want to buy an extra. Can someone help me find this one? I think I asked about it before but never got a straight answer. I’m hoping to put an equivalent curve of 3ft diameter in some 1/16" - 1/32" aluminum sheet.

And about the foot shear: last I saw it, it was sitting in the corner supposedly out of order. Are there any plans to fix this? I would be willing to lend a hand if it meant putting this machine into regular use again. The clean cuts would be nice to have, but I could always just use an angle grinder.

One last thing, there is a Baleigh pan & box brake listed on the wiki, but I’ve never seen it nor heard of it. Does the makerspace actually have one of these? It probably would come in handy for metal fabrication, and if the square tubing thing doesn’t work out, this might be my next best option.

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If I remember my history, it’s either a blade alignment issue or a blade sharpness issue. I think it’s waiting on a volunteer to re-align it, test it and determine which of tge two is the issue.

If it’s a blade issue we can order a replacement, but we need to know its that first.


IIRC correctly:

  • Baliegh stomp shear is 53" or 54" wide, thickness capacity varies by material. when the blade goes out of alignment is it out of service until realigned.
  • Magnetic brake is 48". The is also a smaller heavy duty brake in Machine - approximately 18" capacity.
  • Slip roller I’d guess is also 48" or close to it, much larger than 36" and has bead roller, don’t recall seeing interchangeable bead dies but I haven’t looked).
  • Machine Shop has a Tube Notcher with 2.5" diameter capacity. For square tubing that would be the max across corner width.

Not out of service, it’s just used back there since there are work tables for actually working on whatever boxes or pans are being made.

The alignment often gets thrown a bit due to members fiddling with it, but generally it is functional just tucked away to save space when not in use.

We have one in the metal shop (it’s in the corner, but on casters to move it around). The class slides on the Metal shop drive share have all the specs

You would need to get the Dies for the bender for that tubing, as we only have the dies for round tubing. The machine is on loan from @TBJK and was built to use the ProTools dies. For 1" square tubing your die choice depends on what Center Line Radius you need. These dies are appropriate for our bender should you decide to procure one:

Yes, and it is stored next to the shear in the main workshop.


Awesome, thanks for all the info!

If everything is well, it seems I might be able to continue with only the tools available. The most crucial part of this build will ultimately be dependent on a slip roller. If anyone has experience working/forming/bending 7075 aluminum – specifically 1/32" sheet – or any other aluminum at this relative thickness, I’m all ears.

Concerning the tubing bender:

I think what I’m looking for is more along the lines of a tubing roller for making shallow bends, like this relatively cheap Harbor Freight model:
There is an existing aftermarket of dies for this roller for anything from square to angle stock, but even if I were to learn the lathe and build my own set, the cost would be more than the materials being formed. Otherwise, in the future I might be making some investments and adding these tools to the Space’s inventory (if that’s ok with you).

I’m planning to work with pieces no larger than 24"x48" – easily disassembled, fit into the trunk of an ordinary car, and reassembled using only a drill and simple hand tools. This is more of a rugged design, so I’m counting on a larger margin for error. I’ll post results on the Discourse when I get the chance, and you can see what I’ve got so far in the Show and Tell thread.

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Technical question: what Temper is the 7075, 0, 4, 3511, or 6? How tight a radius are you forming? 7075 can formed fairly well if in an O condition but will work harden. Depending application not sure if it will need to be in something higher than 0.

If surface finish is important, buy the sheet stock with the protective plastic applied especially if it is Alclad (clad side scratches really easy). Non-Alclad is usually cheaper. Could save you a lot of work cleaning up.

Great tensile strength in 2000, 6000, and 7000 series alloys. Trade off is a little more prone to cracking.

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The tubing roller we have (did have last I knew) is that model; the on-hand dies for it is still pretty slim, and round only, if I recall correctly (which is highly suspect). As you said, though, there are a number of “parallel market” items that could be purchased if desired.

We have that very roller and the bender I built. We do not currently have any square dies for either machine.

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After looking further into this, 2024(T3) seems more suitable for rolling and easily forming. It’s used commonly in ultralight aircraft as the wing wrap material. The shortest radius of the bends I would intend to make is at least 18 inches center to arc, and I’ll probably go no thinner than 1/32" sheet to stay in a comfortable margin of safety.

This sheet is intended to bear the pressure of vacuum, but I get the feeling at this thickness and load, the differences in strength between available alloys won’t be so noticable.

Assuming you have a cylinder that is under vacuum, the high tensile strength of 7075 may be over kill. If it were a pressure vessel then 7075 may be more relevant. 6061 may be a better choice as it is probably has better formability in a non-annealed condition. (I’m assuming you want to avoid heat treatment so not considering T0 grades). It’s also weldable - a good quality to have to seal any leaks.

The reason T3 is used for skins is it is stress relieved by stretching by about 5%. It may be slighly more expensive than T4/T6. T3 is also non-annealable in that if annealed the benefits of the T3 stretching disappears as annealing relieves stress and the grain structure imparted by stretching disappears. The sheet stock you get SHOULD have an arrow on it indicating the direction of the stretch forming.

Probably all of these alloys will provide the strength you need, if the vessel is to experience a lot of cycles, then maybe 5052 should be considered, good workability and high resistance to fatigue cycling.

How you intend to fabricate the assembly may dictate more concern for weldability than formability as those are fairly large radii you are talking about, approximately 600T of the material.

Not trying to add to your confusion with all this. But I think how you intend to seal these rolled pieces - into a cylinder should be your major concern not tensile strength.

Good luck, working with aluminum is fun, but each alloy has it good and bad points.

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Thanks, after reading your post and reevaluating, I think 5052-H32 would be the best fit of the options readily sourced at a lower price. No welds intended, I don’t trust myself for that, and wouldn’t want to ruin the material. I’m trying to follow in the footsteps of the experts to make up for my complete lack of engineering knowledge, so submarine tech sounds great.

Bending square tubing will probably not be happening for a while, unless someone else decides to make a set of roller dies sooner. Instead, open-celled polyurethane foam placed to fill the gap between the rolled sheet and an outer ribcage of “sheet metal strips” might displace the load better and add even less weight. Just a shot in the dark here…

As said I’ll post results and my current not-so-scale model. I just wish I had the bigger magnet right now.

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Swag Off-road sells dies for the rollers for the Harbor Freight roller we have.

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I was looking at Swag specifically. They carry a set for 2" square that could probably be used on rectangle “the easy way”. I’d also like to bend angle “the hard way”, but that’s a custom job, I think.