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New Doolin side bender
http://www.luthiersforum.com/forum/viewtopic.php?f=10102&t=9260		 Page 1 of 2
Author:  Rod True [ Sat Nov 11, 2006 7:15 am ]
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Well, i've never been very pleased with my side bender, it's a fox type but not as good as the real macoy or John Halls. And after breaking two sets of sides I knew it was time for a change......

I decided to make a Doolin style side bender as it looks fool proof to me (and I'm the perfect fool so I figured it would work great for me).

Now, I know that it's probably more complicated than is really needed for bending sides, but hey, there's always an other way of doing things right.

Mine is much closer to Mike's than Brad Way's was (post a couple of months ago) but both are based on the same spring princile. Thanks Mike for the cool design and Brad for posting yours, they both helped me build mine.

Anyway, since most everyone here want's to see pictures, I'll get on with it............

One of the additions which is very key in side bending IMHO is a way of telling how hot this all gets, so I got myself a good little digital thermometer with a long prob. It sure helped with the first bend.

These are pictures of the first bend with it. A practice piece of curly maple. I figure this is a good test as it has lots of flame to worry about with the bend.





Here I am opening up the top slat, the wood didn't even move, it held it's shape perfectly.



Out of the bender unwrapped



And no scorching



I compensated the inside form for spring back, but there was none so now I think I don't need to double cook it as I would like a little spring back or at least to figure out the correct shape.

Thanks for looking.Rod True39032.6363194444
Author:  LanceK [ Sat Nov 11, 2006 7:18 am ]
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Nice job Rod! Man that makes me what one of those bad like!
Author:  JJ Donohue [ Sat Nov 11, 2006 8:37 am ]
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Very nice Rod...nice clean design and workmanship...thanks for the pics.

What elements of this design do you think contribute to better, more controllable, reliable bends over the Fox bender? What about your old bender do you now think was causing the breakage? It looks like those springs keep it quite taut and was wondering what your thoughts might be.

One thing I notice about the sequencing of your sandwich...you keep the wrapped wood next to the blanket. I was doing the same until I noticed that the waist area had indentations where the blanket's coils "telegraphed" into the wood. It's possible that my blanket has more prominent coils. Nevertheless, I changed the sequencing so that now the wood is between the metal slats and the blanket is the top layer. Probably slows down heat transfer but it eliminated the indentations.
Author:  old man [ Sat Nov 11, 2006 8:43 am ]
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Very good, almost like mine. Nice job on that maple for sure.

Ron
Author:  Rod True [ Sat Nov 11, 2006 11:14 am ]
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Well JJ, I'm certainly no expert let alone barely a rookie even when it comes to side bending.

My first 4 guitars are all EIR which IMO was very easy to bend. The first was done on the pipe, the next 3 on the bender I made with light bulbs.

These next two I tried my original bender with the blanket, now, my guess is that I had several things wrong with MY design, not necessarily the Fox or Blues Creek design.

I did not have a support under the waist other than the spring steel which wasn't held by anything to keep it tight. Next my bout clamps were very very wimpy and when I tried bending the bouts, there wasn't enough support. Third, I didn't really know what the temperature was at. I just used the "spray the top slat and see if it sizzles" method, which may be fine, but something was wrong. And forth, I don't think I had enough water on the sides which broke. I think they were to dry and they just cracked because of this and too much heat maybe.

I'm really can't say if this is better than the Fox or Blues Creek design (don't even know the difference between the two), all I know so far is that this side came out perfect

Now, this Doolin bender is clamped at the tail end of the form and the side is registered from there. Than the lower slat is pulled tight across the form, but not bent at the waist (see 3rd picture down). Next the side is clamped in at the tail end and pulled over the lower bout and upper bout with the top slat onto the blanket (which is hot of course) This takes about 2 minutes to do. Now the side is bent at the lower bout and the upper bout is pulled tight around the front curve but not clamped down hard. Next the waist clamp is screwed down (about 2 minutes also) which is supported by the tight lower slat. These are the bending instructions off Mike's web page and this side came out perfect.
Author:  Rod True [ Sat Nov 11, 2006 11:23 am ]
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Oh and the other part of your question regarding the location of the blanket. This is also Mike's suggestion and I have to admit, that I like it on the inside, just in case there is any chance of burning the wood, it's on the inside and much less noticeable. The other part of this is that when lowering the bouts, your essentially clamping the side to a hot form, remember the Taylor factory Friday video, they take the side which is cold and wet (wrapped) and bend the waist over a hot form. Same sort of idea I think.
Author:  Brad Way [ Sat Nov 11, 2006 1:47 pm ]
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Nice job Rod! I built a Doolin bender a few months ago and really liked the way it works (based on my limited experience). One thing I noticed when I was testing it was that the power cord for the blanket seems to be in the way. After my first bend I modified the bender so the power cord now comes out the tail end. Since the tail end is fixed it seems to simplify things during the bending process. Time will tell if it was a good modification.

Author:  L. Presnall [ Sat Nov 11, 2006 3:05 pm ]
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That Maple's the toughest test you could've put your bender thru...and it sure looks good!
Author:  Rod True [ Sat Nov 11, 2006 3:32 pm ]
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That's what I was thinking Larry. I'm a happy man
Author:  Joe Beaver [ Sun Nov 12, 2006 3:36 pm ]
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That's a beauty Rod.... Makes the one i just built look pretty sad Joe Beaver39033.983912037
Author:  Rod True [ Sun Nov 12, 2006 5:55 pm ]
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Thanks Joe, but you should have seen my first one . It'll keep me nice and warm this winter
Author:  sharp_custom [ Mon Nov 13, 2006 1:53 am ]
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Rod, I've been planning to make one of these myself. When permanently attaching the one end, did you include a spacer to accomodate for the heater and side? Or is that even necessary? Also, what size springs did you use (ie. length and diameter)? Finally, did you use the perforated steel like Mike Doolin used on his?

Your bender looks great.
Author:  sharp_custom [ Mon Nov 13, 2006 1:54 am ]
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.sharp_custom39034.413287037
Author:  Pwoolson [ Mon Nov 13, 2006 2:08 am ]
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Looks great Rod. I've been trying, in vain, to improve on my bender. It works but is a bit fussy.
Question for you: on the end where you have the slats "clamped" together with what look like rivots; you aren't going through the blanket are you? It seams like that would be bad. I've seen several people rivoting the slats into a permanent sandwich but it looks as though the blankets are also part of those sandwiches.
Thanks Paul
Author:  Serge Poirier [ Mon Nov 13, 2006 3:09 am ]
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Nice bender for sure Rod, i know the feeling when we are satisfied with it, it looks well made and i meant what i said!

Serge
Author:  Rod True [ Mon Nov 13, 2006 4:23 am ]
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Don and Paul,

I made the "held" end with two pieces of 1/8" aluminum bar that I had kicking around, the layup went like this, slat, alum bar, slat alum bar.

I did not rivit the heating blanket in, that would be bad.

I made that end removeable as I thought that I would like to be able to take it off at some point and also, I didn't have as long of slats as Mike seems to have.

I have spring steel for both slats and drilling them isn't hte easiest thing, make sure you have a good sharp bit for drilling steel, not just a wood bit.

Here are somemore pictures of the held end if this will help anyone out.

Thanks Serge buddy, I know ya do





Author:  sharp_custom [ Mon Nov 13, 2006 4:28 am ]
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Thanks Rod! That makes it a lot clearer. I couldn't see fixing the heater along with the slats. Looks good.

Author:  j.Brown [ Mon Nov 13, 2006 10:30 am ]
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Whats a good source for the springs and the steel slats?
-j.
Author:  Serge Poirier [ Mon Nov 13, 2006 10:41 am ]
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John Hall is the guy to talk with J.
Author:  Todd Rose [ Mon Nov 13, 2006 1:36 pm ]
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Thanks for posting this, Rod. I still haven't gotten around to building a bender like this, but when I do, I'll refer back to this and may bug you with some more questions.
Author:  Rod True [ Thu Nov 16, 2006 3:09 am ]
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J, sorry for the long delay in replying to your post.

I got the blanket and slats from John Hall as Serge mentions Blues Creek Guitar and an OLF sponsor.

Sharp...I got the spings from a local auto parts store, they are 9/16 dia x 4-1/2" long, you will have to make the base to accomodate the springs you get. I just tryed to pull the springs with my own power, if I could pull them than I thought they were not stiff enough, if I could just move them a bit that was good (real scientific testing there eh? )

If any of you want some more information, I'm glad to help.
Author:  Mike Doolin [ Tue Nov 21, 2006 6:04 am ]
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It's great see other people building these things and getting good use
from them. I have to say, all of yours look a good deal better built than
mine! I guess I put as little time and money into jigs as I can and still end
up with a functional jig. I loved Brad Way's mod where he lets the power
cord out the back, that's a great idea that I'll likely use myself.

A few details:
1) The perforated top slat is very important, to let the water out of the
wood. Otherwise you can pull a side out and find it still wet, which will
result in a potato chip, especially with Brazilian. I didn't have the patience
to drill holes in spring steel so I used stainless, which isn't ideal since it
does remember the bend. On the other hand, I don't wrap the sides, and
spring steel will definitely stain light colored woods while stainless won't.
Wrapping in paper is OK, but wrapping in foil can also trap in water.

2) It generally works best to heat the inside of the bend, so that's why I
put the blanket under the wood. True, that means you're heating the
outside of the bend at the waist, but by the time you get to clamping
down the waist shoe the wood is pretty hot so that doesn't seem to be a
problem.
Author:  Dave White [ Tue Nov 21, 2006 7:13 am ]
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Mike,

Nice to see you here at the OLF. I really admire your work and innovative approach to instrument making
Author:  Rod True [ Tue Nov 21, 2006 7:22 am ]
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Hey Mike. I guess you got my email.

Welcome to the OLF and thanks again for your input into the great guitar building community.

Please, don't be a stranger.
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