Official Luthiers Forum!

Well the next commission is under way so here are a couple early pics

WOW WOW WOW Michael, this is gonna be another fine lookin'!

yep

By the way boys and girls this is the change I made to the OLF SJ back bracing from X to Star-brace, that I spoke about a month or so ago on the OLF SJ. The Star gives the big round lower bout better ach support. The Star braces are .3125" wide x .625 tall. The X portion is nothched jointed and the laderal fingers taper to nothing just short of the X

Drooooooolll!!!!!!!!!!!!!!!!!

Nice guitar, Michael. I love that star bracing system!

Pete

Looks awesome Michael.

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Beautiful and unusual tone woods at a reasonable price.
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The Zootman
1109 Military Rd.
Kenmore, NY 14217
(716) 874-1498

Man you are an artist. Gorgeous.

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Eagles may soar, but weasels don't get sucked into jet engines.

Love the snakewood, it's my favorite, smells like cinammon when I cut and sand it :)

Good looking stuff Michael..

-Paul-

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-Paul-

Patriot Guitars

Right on Bill.

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Beautiful and unusual tone woods at a reasonable price.
http://www.rctonewoods.com/RCT_Store
The Zootman
1109 Military Rd.
Kenmore, NY 14217
(716) 874-1498

VERY NICE!

Stunning as always Michael!

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http://www.presnallguitars.com

That is some awesome wood, Very nice back bracing too!

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Anderson Guitars
Clearwater,Fl. 33755

[QUOTE=MichaelP] By the way boys and girls this is the change I made to the OLF SJ back bracing from X to Star-brace, that I spoke about a month or so ago on the OLF SJ. The Star gives the big round lower bout better ach support. The Star braces are .3125" wide x .625 tall. The X portion is nothched jointed and the laderal fingers taper to nothing just short of the X[/QUOTE]

Michael, I have a couple of questions. First, where did you get the narra? that sure is pretty wood.

Second, did you change the angle of the X at all in this version?

I'm just starting my first SJ build. I can only hope it turns out as nice as yours.

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http://driftwoodguitars.blogspot.com/

This is the second guitar I have built with Curly Narra, and I love working with this wood. However on both of them I had issues with the sides having multiple cupping divots in the middle of the planks. Mostly at both bouts and very small ones in the apex of the waist. The first time I thought I may have use too much moisture to sprits the wood prior to bending but this one was worse than the first and I use very, very little moisture at all. They seem to be located between the tube supports on my bending molds. I am using the spring steel slats that I got from John Hall and they are a good bit thicker than the ones I have been using so I can't picture support being the issue, but thatis sure how it appears.

To repair, I placed my spring steel slats between the assembly mold and the sides, steamed the divots from the inside and clamped them to the assembly mold using the spring steel slats as a backup between the assembly mold and the side and a firm, straight hardwood strip as a clamping caul. It got rid of 90% and sanded level the rest.

For those of you that have used this wood before, is this common with Narra?MichaelP38895.451712963

I agree Todd, but the SJ is just a bit larger than an OM. 15.5" lower bout and 19.94" long body so it is an in-betweener. Comparing ladder to x bracing is hard to do but I fell it allows the back to resonate free but still provides structural stability using lighter bracing. Most ladder bracing I have seen has been 3/8-1/2 x 5/8-3/4 tall My star and x bracing is 5/16 x 5/8.
Original x brace for the SJ worked good but the dome seemed to flatten near the apex of the lower bouts on the SJ due the large radius of the lower bouts. I added the lateral fingers to help maintain the dome shape of the back better, but I did not want to reduce the movement of the back much so I did not tie the lateral fingers into the X and tappered to nothing short of the X
MichaelP38895.4836921296

[QUOTE=WayneC] [QUOTE=MichaelP] By the way boys and girls this is the change I made to the OLF SJ back bracing from X to Star-brace, that I spoke about a month or so ago on the OLF SJ. The Star gives the big round lower bout better ach support. The Star braces are .3125" wide x .625 tall. The X portion is nothched jointed and the laderal fingers taper to nothing just short of the X[/QUOTE]

Michael, I have a couple of questions. First, where did you get the narra? that sure is pretty wood.

Second, did you change the angle of the X at all in this version?

I'm just starting my first SJ build. I can only hope it turns out as nice as yours.[/QUOTE]

I got the Nara from Zootman and yes the X in this version is a 90Deg X. If you change to a 90deg I would most certinly add the laderal fingers to support the dome in the apex of the lower bout

I thought I would share with you that are building or going to build off of the OLF SJ using the X back bracing, why I changed by X brace to a star. In the pic the pink is the area that seemed to flatten out or loose its dome shape. Now I am talking very slight flat not major flat the yellow is the approx location of the x per the OLF SJ plans at 70Deg across the bout. The change to 90Deg makde the spread wider but to eliminate the flattening I added the laderal fingers to maintain the dome.

MichaelP38895.5946412037

Good work and good thinking, Michael. When you said you changed the X to a star I thought you meant X the other way--with the acute angles on top and bottom. My X braced backs have the tops of the X going up a bit higher than on your star pattern, so that the top and bottom angles are slightly acute. But 90? makes sense if you are thinking of the lower bout as a passive woofer. I begin my taper to the sides further in, to get more compliance around the perimeter; in that area (with a few inches of the rim), I see the bracing as there not to provide stiffness, but just crack resistance.

Re the cupping: are you using steel rods or tubes to separate the sides of your bending pattern (I assume this is a Fox style bender)? Fox/LMI make them with solid steel. I have found that to be unnecessary (and cheaper) when you use a blanket. I use dowels. I think the idea behind steel was that with lightbulbs, you would scorch dowels, and maybe that you needed the steel as a heat sink under the slat. What I'm thinking is that if you are using steel, you are getting a higher temperature where they rods cross the sides. So the issue may not be greater support but greater heat at those points. I'd suggest replacing the steel with wood dowels. Another thought is that with some woods, stainless slats such as LMI supplies may be better than spring steel. Stainless is a less efficient transmitter of heat. At first that seems contrary to what you want, but I'm thinking that it may help to even out temperature by not transferring the heat as well where you have a hotter spot (like over the rods).

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

I recently built a new side bender and changed the way the bouts are pull into shape and have not had a problem with wood cupping or deforming since. My bending form as shown in the picture does not rely on dowels to support the wood so I get a nice smooth curve. Also I am spring loading the end of the steel slats to keep them pulled tightly against the form.

Very nice guitar Michael



John How38895.5675347222

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Thanks Howard! So your saying to start the taper closer to the center and allow the perimiter more freedom. Next one I will do just that.

On the cupping, I too was thinking that both the lack of support and the steel tubes may be the issue on the bender. My old forms had many more cross supports per inch made from wood slats on one form and aluminum flat bar on the others and I did not have this issue with the cupping, but since I bought my new forms, and on just some woods, with the Narra being the worst of all that I have had this issue with. The first thing I think I will do is to nake two intermediate profiles to go in between the outer profiles to give more support in this area. I am using a blanket.