Official Luthiers Forum!

Here's some pictures of my bender based on John Howes and Doolins bender. Works great for me, I'll have to add a piece so I can do cut aways.

Chuck

_________________
_________________

Hey Chuck, that's pretty much the same idea I had about it. Pretty much like combining the two Taylor benders. Did you use the door closer springs that have something like 150 lbs. of pull that are at Lowes?
I also was thinking that if you made or replaced the back springs with turnbuckles that you could put a locating pin in the end of the mold that a hole in the slat would register on. You could then bend the lower bout first and have the side locate in the proper place each time like on the Taylor benders. The turnbuckles would allow you to adjust the slats for setup and the springs would be in the front. Bend the lower bout then waist and upper and then cutaway maybe? Locating the back would also be more inline with the Doolin bender. What do think, would it be worth it?

Chris, the springs I used are around 40 to 50lbs each,, just tested one. They are about 3/4" dia. at the coil and length of coil is 3 3/4". I bought them at the local Ace hardware, but I am sure they would be available at Lowes. They have plenty enough tension to pull the upper and lower bout and keep them tight to the form.

I think you're idea of registering the slat and side on the lower bout and replacing the springs with turnbuckles is pretty slick. You may need heavier springs since you'll only have two. I may look at modifying and trying that when I set up for cutaways. What I do now is mark the sides at the waist and bend the waist first, keeping the mark in position which is visible through the slot where the ram slides. I am able to match the grain at the butt wedge with no problem.

Thanks, Chuck

_________________
_________________

Want an all aluminum monstrosity? Here is one the machine guys at McPherson made while I was there.

Personally....I hated it. I pretty much refused to use it as well until the very end when they took them away and made me use the metal one. The wood one bent with much better results and was much easier to use. They also attempted to make a bender almost just like the one Taylor showed in their videos. It never worked right.

sometimes simple is the most effective.

_________________
John Mayes
http://www.mayesluthier.com

It's nice to see that the idea works in your prototype of adapting the form. That's the first step forsure. When I was thinking about it I was going to put two arms off the bender frame and have the bending arms pivot off them so the form could just be changed and then the TBs adjusted for a different body size. It could be an easy modification to alot of benders if you know what I mean? And a new frame could be made easy enough from plywood so everyone could use their existing forms. Thanks for showing yours. I like the simplfication of jigs where possible. I also have some ideas that might make unloading it a little easier.
What do you do to unload it? Just release the springs and unload as usual?

Chris, removal of the bent side is just as you said, pull the pins, release the pressure from the springs, remove the pins that hold the arms and also unhook the springs, then unwind the ram...I used left over railroad tie spikes for the pins from a wall I built when that type of wall was popular.

Oh yeah, the bender is set up, if you look close (I know the pics aren't so great) so that I can interchange body size forms. I am using my old forms. Just had to drill a couple of holes for the arms.

Chuck

_________________
_________________

Here is a picture of mine. It does non cutaways great but has no real advantage over other fox style benders in the cutaway dept. I use a similar cawl and screw just like everyone else for cutaways.
Personally I am interested in seeing if Brad comes up with something for the masses!!

_________________
Tickle your guitar daily, and it'll tickle you back.

John, do you also locate the side from a waist mark? That's how I've been locating my sides on my bender to date. Bender looks pretty clean. Any thoughts on what you like or dislike about it or any changes you might want to make on it?

Good question. At the time of the first post Nelson showed the bender that I prototyped for him to help with the problems he experienced bending highly figured maples. I had built a bender several years ago that had some good ideas but never addressed cut aways. This bender was my second prototype and improved many aspects of my original design. After the thread started cooking it was clear that many were interested in learning more. Some liked the ideas of plas, some wanted to buy a bender, and some just wanted to learn more. Ironically the only prototype ended up staying in Nelson,s shop in Kansas. After he had time to give the bender some time he wqas very pleased with the initial results. I am hoping that he can chime in now that he has had some more time to get used to the tool. As for the future of the bender? This is a tough one. In the spring I was kicking around 3 options for the bender. Option 1) Sell plans. Option 2) Sell a production model. 3) Set up a build thread and share my experience and see how others can expand my ideas into new and creative directions. All three have are good choices for various reasons. The toughest part for me is balancing a very challanging engineering profession, my guitar repair business, my hobby building guitars, as well the rest of life. This summer I have taken some time off from the bender but am hoping to build another one in the fall for myself and then will decide how much more time I want to spend working on future improvements. Irregardless of my plans I hope this thread inspires others to create and build new and better ways to solve bending problems. I have learned a ton from my designs but their is always room lots of improvements.

So lets keep the treading going and let's see what others come up with.

Thanks!

_________________
Brad
Avon, OH

Well its almost Fall, and I like the build thread idea. This way you could mention materials, dimensions, etc as you go along. Those of us with interest can build along with you.

Mike

BTW, while I like exotics like 80/20, perhaps the challenge should be able to build with locally supplied materials (Lowes, HD, Ace, etc)!

My vote would be for plans. I don't work in the winter so that would be a perfect time for me and I could do it at my own pace. But that is just me..

Gary

The inspiration an the okay for any of us to use your ideas is enough for me. Thanks for the time and sharing what you have so far.

Yes Chris, the sides are laid out and marked at each end and the waist and inserted into the bender referencing the mark at the waist thru the slot in the cawl slide. I pull the waist all the way down first. Since the ends are spring loaded there is no worry about not getting a tight bend the springs are fairly heavy and the pull increases as you make the bend.

As for changes, I'd like to come up with a better method of doing the cutaways. I have a couple of ideas but haven't tried to put them into practice yet.

Thanks John,
I also find it interesting how you and Chuck came up with the same idea that I also was thinking about. Did you all see that design somewhere else or did the idea come to all by seeing the Taylor benders and Doolin bender as that's what made the light bulb go off in my mind along with this discussion.

I don't know where Chuck got his idea but my inspiration was the Taylor videos. I just wanted to simplify it a bit. They have automation and fancy air cylinders while mine has spring tension and manual operation. Other than the way the tension is applied to the bouts, it is purely a Fox bender.
Now there (CFox) is the guy that showed us that there is more than one way to bend guitar sides, as well as a ton of other incredible operations, and he gave them all away as well.

_________________
Tickle your guitar daily, and it'll tickle you back.

John, I really like your take on it. I'm rethinking my bending process. The necessity of slat tension didn't make sense to me until I realized it would fix the problems I'm having later on in the binding process. How do you connect the slats and the springs?

I have modded most of my forms to use the spring loaded arm on the upper bout (the lower seems fine the way it is).

To connect the springs to the slats, I rivetted on a piece of aluminum bar, about 1x6, then drilled holes into which S clips go. I closed the one side of the S so that they dont fall out. Then just hook them onto the springs.

I also used this idea to make my florentine cutaway piece ... one of my students and OLFer Rick Cowan coined the name the Hulk ....

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

Guys, I got my idea mainly from John How, but in conjunction with the Taylor vids and Doolin. I liked how John How put it all in one unit, and that I could use my own previously built forms. Thanks John! These type of benders work great because once you have tightened the waist down, there is constant pressure on the side as you bend the upper and lower bout, yeilding very consitent results.

Chuck

_________________
_________________

It's quite Hulky, Tony. Do you have two slats? I can't make out a bottom slat.

No, just one slat .. you dont need a bottom one IMO ... the mold is solid, and the bend is done in about 3 minutes, including heat up time ....

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

I've noticed, in bending a dozen or so sets of hi-flame curly maple, that the tensioned slat method seems to follow the convex shapes of the mold so well that I've had to further refine the contour of the upper bout and cutaway on my mold. Any slight irregularity in the mold will show up in the bent side(s).
I think that the bending machines shown in the recent update of this thread are on the right track in that they all use the tensioned band method.
One drawback of the spring tensioning method, at least in this old man's mind, is that the spring tension at the start of the bend is going to be much less at the start of the bend than at the end of the bend. One method of overcoming this would be to put a crank type adjustment screw in the end of the swingarm to which the spring(s) would attach. The screw could be initially retracted enough to put good initial tension on the slats and then gradually extended during the bend to maintain that slat tension. I think the spring tensioned slat method is good even without the crank feature, however, in that it does maintain "tension on the slats"
The advantage of the air cylinders in Brad's BetterWay Bender is that they maintain the same tension on the slats throughout the bend. This is assuming that the air line is left connected to the air reservoir during the bending process so that excess pressure buildup can vent back to the reservoir.
Nelson

For those of you using tensioned slats in a Fox or Doolin style bender, what is your order of operations? Lower bout, upper, waist? I'm wondering if doing lower, upper, waist without tensioned slats is enough to have a similar effect as pre-loading the tension with springs?

Well, who would be interested in starting a build thread? I really want to build one.

James, I noticed in reading back over the recent posts that ChuckB describes what you're asking ie tightening the waist first to pre-tension the springs and then doing the bouts. Sounds like this method works well in spite of the increasing load from the springs as the bend is made. I'm guessing that you don't really need so much tension that the build up becomes a "show-stopper" during the bend.
I do think that a distinction needs to be made between the benders used for non-cutaway shapes verses the cutaways. With all due respect, I would say that bending non-cutaway sides is consistently doable in the Fox type bender especially with the spring loading. A cutaway of, say, 1" radius or less, in highly figured wood is a "whole different animal". This is where the highly tensioned slats, both inner and outer, come into play. Brad's BetterWay Bender is built on this premise and it seems to work very well.
Nelson

Great thread.

What are the latest developments out there in small-shop made (from mostly wood) benders with the Doolin-Taylor tensioned slat(s) approach?

Also, who like Taylor, Brad, etc. have stopped using water and bend everything dry successfully with even tight radius cutaways with highly figured wood?

It "appears" that Taylor bends at one temperature for all woods (~300F?). Anyone doing this? What temp are you using for 1) bending 2) setting and how much time for setting? Appears that Taylor only allows a couple of minutes for "setting" where many indivituals use 10 minutes or more. (Like Brad stated, how do we weed out the "black magic" variables in bending?)

Got any new photos and experiences to share?

Ed