Look for a coupling so you can screw on an extra leverage extension pipe when needed.

The handle on the bender is made from a flattened piece of 2” pipe. 

The handle extension slips inside, as shown in this video from Hossfeld (skip to the 7:50 mark):

According to the Grauman drawing for the handle extension (officially the 28B5 Hand Lever), it’s made from 1-1/2” pipe flattened down to about 3/4”. 

28B5 Hand Lever.pdf

Do you want it to be exactly right, like the original, or make it work?

Fabricate a goesinta for the flattened 2 inch pipe, and then weld to the goesinta on what ever you like or need for leverage.

For starters, I’m going to go with something that’s as close to the original as possible. I do have a fair amount of the 2” pipe, so I can make a longer version if necessary. 

Only the end or goesinta needs to be flattened to fit.  The rest can be left as round pipe.

It could. On the other hand, flattened pipe is going to be stronger in the direction of pull than the round pipe would be. 

Handle update: The 2” pipe was too big, and the next largest pipe I had (1-1/4”) was a bit too small. I did flatten one end of a 24” piece of the latter and use it as a mini-extension, which works well. Still keeping my eye out for some proper 1-1/2” pipe.

The fellow who gave me the 2” pipe also gave me a piece of 3/4” round bar, from which I made a replacement 19B4 “U-pin with Lug“. This will help with bending eye-bolts, especially in smaller sizes. 

There was an existing bend in the bar that I tightened up, which is why it came out a bit taller than the other pin (see bottom photo). The oxypropane torch came in very handy for spot-heating the bend.

A bit of cleanup, and we’re good to go.

Made a yoke (part #23B) from some 1/2” square bar and a 3/4” x 10NC x 8” grade 5 bolt (I already had the nut, as the previous owner had doubled up the nuts on the eye-bending dog for some reason):

And a circle gauge (part #27B) from a chunk of 2” square bar and a shopmade thumbscrew:

I don’t think this is a feature of the original, but I’ve decided to angle one side of the block, thus:

In theory, this will make more solid contact with the swing arm and decrease the chances of it getting knocked out of place. 

So, I angled the side of the circle guide block:

And realizing that the thumbscrew would get in the way of the swing arm, I angled the other side as well, so that I could flip the block over:

 Which also provided clearance for the workpiece:

I then tried using the circle guide, the square bending blocks, and one of my fly press circle jigs to curve a pair of pieces of 3/8” x 1-1/2” flat bar for a railing project. 

The results were surprising. For some as-yet-undiscovered reason, the same setting produced different curves in the two workpieces. The good news is that I could flip the piece over and use the same setup (albeit with a repositioned circle guide) to open the curve up a bit. In the end, I did get two pieces that matched both each other and also the curve in the drawing:

Still on the steep side of the learning curve, but I’m feeling good about this. 

Looks good ..

Another detail about the circle guide: I realized fairly quickly that with a flat bottom to the notch, the guide block did not sit firmly against the circle assembly, only touching in the center of the notch. The gap on either side of the center (the shaded area at the arrow in the sketch below) allows the guild to wobble, which throw off the setup. I therefore relieved the center of the notch with a die grinder, so that the guide only touches the circle at the outside corners of the notch, as in the bottom half of the sketch. This makes the block much more secure.

I have no idea if the original part 27B is shaped like this, but the great thing about making your own tooling is that you can modify it without feeling guilty about "ruining" an original piece.

  Do you think the play/fit around the center pin in your bending die could have something to do with inconsistencies in your results?

That's possible. I'm planning to make some flat face radius blocks (part #20B2) that would fit the center pin better; we'll see if that improves things.

  I made a roller to replace part 11B square block on the "swing arm" out of pipe and pressed in bearings with the same bore as the pin.  It made bending smooth as butter, but wonder if it would hold up to heavey stuff you want to bend.

Interesting. I suppose one could stack bearings through the entire height of the pipe, if one were so inclined.

Built a 20B2 flat face radius block with a 7-3/4” radius on one side and an 8-3/4” radius on the other. The sides are made from 3/8” x 2” flat bar bent hot and welded up with a 3/4” schedule 40 pipe nipple for the center and a couple of bits of 1/4” flat bar as internal supports.  

Worked great for bending the S-curves into some 3/8” x 1-1/2” flat.

Also made an extension for the handle for extra leverage, although I couldn’t get my hands on a sufficiently long piece of 1-1/2” schedule 40 pipe to match the standard 28B5 Hand Lever. Instead, I’m planning to make an additional extension from the piece of 1-1/4” that I’d previously used. Not yet sure if I’ll use as removable pin (like the 28B7 hand lever pin) to make it knock-down or weld it on permanently. 

The fly press was great for flattening the pipe. 

  I am getting a lot of ideas for my shop built Hossfeld.  Do you plan on pipe or tubing bending dies in the future.

Not at present, and I think if I did need one for a project, it might be more worthwhile to buy one from Hossfeld or American Bender. I gather that the insides of those dies are designed to compress the tubing and keep it from collapsing. 

That said, I might throw a piece of 1” square tube on the larger radius block just to see how it behaves. 

Filling it with sand works pretty well on a Hossfeld type bender.

Frosty The Lucky.

Since the 1-1/2” pipe I’d gotten to make a 28B5 hand lever was too short, I made an extension for the extension. Total length is about 53”, which is about 6-7” longer than the standard. More length = more leverage. More leverage good.

The pin that holds the tenon-and-socket joint together is the same as the 28B7 hand lever pin. 

I think I might make a couple extra pins, just to be on the safe side. 

nah, it's not like you're gong to lose one is it? 

Frosty The Lucky.

On 3/22/2023 at 2:29 PM, Scott NC said:

I made a roller to replace part 11B square block on the "swing arm" out of pipe and pressed in bearings with the same bore as the pin. 

I remembered that I have a bunch of industrial rollers, and a little investigation revealed that their bearings fit nicely over the 19B4 pin I’d made previously.

So, I took the pipe from one of them and cut it down to 4-1/2”. Then I took that roller’s bearings plus two more from another roller and trimmed their rims so that they would press-fit inside the pipe.

Their inner races were a little long, so I had to grind them  down a bit to fit all four bearings into the 4-1/2” length. 

I haven’t had a chance to try it yet, but it seems sufficiently beefy.

  I hope it works as good for you as mine does.   I've never stacked bearings like that before. 

  I have some ideas for angle apparatus when I retrieve my bender from storage.

A thought about using the stop block for repeatability: an unexpected problem, and an unexpected solution. 

The stair railing project that I’ve been working on includes a number of pieces of flat bar with long sweeping curves. The Hossfeld works great for bending those pieces, but it takes a certain amount of trial and error to figure out the proper stop block settings. This means that test pieces sometimes end up with different curves than their final shape. 

Here’s where things get interesting. Because of the different amounts of force necessary to overcome the elastic limit combined with the inevitable springback, a piece that’s been bent to one curve and then bent more to another does not come out the same as a piece bent from flat directly to the final curve. Strange, but there we are. 

However, I discovered a way around this problem. Rather than trying to bend a curve *more*, if I flip it over and bend it back the other way, it comes out the same as a piece bent from flat.

 So, the procedure goes like this: (1) set the stop block for the first test bend, (2) bend the workpiece, (3) check against the drawing, (4) adjust the stop block, (5) flip the piece front-to-back, and (7) bend it again. Repeat 3-7 until the workpiece is at the desired curve. Then bend any additional pieces to match. 

Ayup, opening a curve is much easier than tightening it up. I haven't used a Hossfeld since high school and remember vividly how hard it was to get scrolls even and matched. It's a skill set of it's own.

You're getting there nicely John.

Frosty The Lucky.