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I am going to build a Fox style bender this weekend. I have a 12 inch press screw that I got from McMaster Carr. I have to say their shipping is super fast. I have built a solid bending form and dedicated waist caul for the 000 I’m going to build. I wanted to get some opinions on some design aspects. I have the 12 inch screw.

Considering the removal of the side after the bend, how much space do I need to leave between the waist of he solid form and the fully open press?

When you are looking at the side of the bender, how wide are the sides? I’m working with a 000 now, but can see myself doing some smaller body guitars in the future. I was thinking about 12 inches.

Also, is there anything else I should be thinking of that I am missing? I was just imagining my self getting the side nice and bent and then having to disassemble the bender to get it out.

Thanks,

John

John there are plans available for the bender,I might have a set I neevr used I would be willing to sell, if I can find them... every thing ended up in boxes after the fire.. Jody

mine now uses a 9 inch screw (took the 12 inch out and used that on a students build, wanted mine smaller as I never needed all that thread length anyway) .. and removable, one per mold, solid wood waist cauls. What I do is make the cauls with a slot that allows the centre bar from the original Fox caul sit in. Its about 3/4 to an inch deep, that way, once you raise the screw, the caul comes out and you can than get the wood and slats out of the bender.

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Yea I know. I was going to order the plans from LMI, but once you add the shipping on there...

I think I can pretty much pull this together as a project for this weekend. I just was wondering about some of the standards people follow.

Thanks for the offer Jody

Thanks Tony. I think we were posting at the same time.

That sounds like a good idea. I was planning on making the caul removable. I went with the larger screw because I figured, while I was ordering it and since I have never used one like this, I should just plan for the worst. I didn't want to wish down the road that I had the next size up.

On my first build I used a Doolin style bender. It didn't go as smooth as I would have liked, but that was more of my own method and not understanding of the process than the bender style.

John

I think I got mine for free by asking on the forum here if anyone had a set they were finished with - its one of those things that when your done building one the plans arent really good for much except decoration...... Id give you the set I had but I believe I already passed them on,,,,
mabye someone here has an old set they could loan you, sell cheap... or what have you.
Cheers
Charlie

Thanks Todd. That is exactly what I needed.

Actually after reading your numbers I realized I was calculating my size wrong (or using the wrong measurement for determining the size). I probably would have caught it, but this really helps.

John

I'd stay away from the solid form as it leads to spring back problems with the blanket on the bottom. If you can wait I'll send you my plans. Although they are marked with my changes for a removable waist press for storage concerns.

When I first used my bender I had lots of spring back and we came to the conclusion that the solid form was acting as a heat sink with the blanket on the bottom and I didn't get any good results until I moved the blanket to the top. I now use two blankets one on top and one on the bottom. The next form won't be solid either. And the next waist caul will be a custom fit as I agree with you on that adjustable caul. I wish I had known that before I made the adjustable one. It will certainly put creases and marks in the waist if the leaves move. One person said he used a section of a rolling pin to get a smooth bend. I was going to get some scrap pieces of different sizes of EMT off the job for the cauls.

I have had to move to solid forms, at least in the upper bout, as I have added a spring loaded arm to the upper bout which tensions the top slat of spring steel
(see John How's bender for the mod). If you dont, there is enough tension provided in the arm/slat to force the wood to facet (or in some cases break - DAMHIK) over the steel bars in a open form. I use the blanket on top of the wood .. and spring back is dependant (at least I find) on the wood species - the rosewoods are the least to springback, others vary.

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Tony are talking an arm like on the Doolin bender?
http://www.doolinguitars.com/articles/bender/

Thanks for the tips guys. I was planning on using the solid form because it would eliminate the structural issue I had when I bend my uke sides in the bender I made for that. Let’s just say I didn't support it quite enough and had to add some emergency structure in the middle of the bend. That will teach me to build something from pictures I found on the internet instead of investing in a proper set of plans. Plus I have already built it. I'm going to put the blanket on top of the stack.

Chris I'm going to give it a go this weekend. If I end up needing plans, I'll send you a PM. I can get them back to you at the next Florida meeting I can make it too (which if it isn't this one, hopefully will be the next).

I do have one question about the form and the support bar for the caul. How thick is the bar usually, and what is the best technique to use for cutting the slot in the solid form if you don't have a band saw?

Todd, I don't know about that but I tried to bend the mohogany 3 or 4 times and it was terrible spring back and the sides were getting scorched. I had Hesh and John Hall and others giving me tips and I was using your video and times and temp and it just wasn't going no where until someone came up with the heat sink threoy and then I gave bending it with the blanket on top a try and got the first workable side. I think it was my first topic post here at OLF. I was bending flat sawn practice mohogany and you even offered to send me some quarter sawn pieces to try but I got it to work so I didn't need them. It seems all the heat gets drawned into the slat and the form and not into the side.

I've seen alot of great looking benders, probably some of them made from various plans. I didn't want to spend much time or money on mine. It's not a masterpiece but it bends sides. The form is interchangable. I didn't see the need for a press screw, that much pressure just isn't necessary. I've even seen a picture of a nice looking bender with a hydraulic jack. Anyway, here's my eyesore of a bender.

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That looks a lot like the first one I built Woody. I used screws instead of springs but basically the same thing.

So far I have made a template similar to the one in Todd's pictures. I have been able to reproduce the template to make up the two sides. It actually came out pretty good. I realized when I started working on the other parts that I needed to square up the fence on my table saw. So once the table saw is back in line, I should be closer to getting this together.

For the legs I'm planning on using 6 1/8" x 6" pieces. I'm going to give the with of the bender an 1/8th of an inch wiggle room so I don't have to wedge an oversized form in there. Just in case. I'm wondering about stability though. I'm thinking that it might be a good idea to put a brace between the lower legs of the bender. I suppose I can evaluate this after it is together.

I think that I'm going to have to make an adjustment to my caul once things are together. I'm pretty sure it isn't going to be square with the bender. I'll probably be able to shim it, but may try and come up with a more permanent\less shimmed solution.

When it comes down to it, I probably should have gone ahead and just built my form into a Doolin style bender. It defiantly would have taken up less room and would have been simpler to construct. But I bought the screw and this is one of those things, after my last build, that I said I would do before I started the next. So once this is done, I'm finally off to actual guitar building. ... or guitar like object construction.

John

Are you sure you don't want those plans. And you missed a good meeting today.

I had the same issues with springback, took days to get one set to match the mold sort of... I did not use spring steel, it was a nightmare...

This time I wrapped in the wet brown paper, and foil like Toddstock, only used one open end, and I did thin the wood to about .80 (baroque style guitar) I bent and removed it in one hour. Got it up to "300" on the outside top spring steel bottom of wood said about 220 for 25 minutes let it cook at 250 top, 200 bottom wood. From top to bottom Steel, blanket, steel, wood sandwich.

I am also redesigning the 'top and bottom' endclamps, like a spring clamp without the spring. It rotates 90 degrees, then you push/wingnut the straight cauls on. Soon I will have a screw setup so I can use a cordless and just drill the top and bottom cauls to fit the wood to the mold, but I think the 'fox' style waist thing is overdone.

I would say look at your side thickness, flex the wood, and, I wet the wood in the foil wrap and let is sit for 10 minutes before I get started. I actually have to redo my outside molds for no springback, the sides 'stuck to it'. Off in one hour, NO springback. It IS doable!

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