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X-Brace Question
http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10102&t=14512		 Page 1 of 1
Author:  davidO [ Tue Nov 13, 2007 5:21 pm ]
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So, I am radiusing my X-braces and it occurs to me:
the upper section of the x-brace is shorter than the bottom section.
So should the lap joint be at the deepest part of the radius or does it matter?

DavidO
Author:  paul harrell [ Tue Nov 13, 2007 11:00 pm ]
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It doesn't matter, you will be changing the heighth of the braces anyway as you taper and/or scallop them.

                      Paul
Author:  Michael Dale Payne [ Wed Nov 14, 2007 1:16 am ]
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It would be hard to have the intersection not being fairly near the deepest section of the braces unless you make your braces 24-30 inches long and hag a bunch extra over the lower bout.

But like others said it only matters if the height of the brace at the intersection is important to you. And IMO it should matter by the way because height is the major axis in determining strength of the brace ( here we go back to the cube rule )

Anyway I recommend that one form the intersection at the mid point, the deepest section of the brace. This should still leave plenty of brace length for the lower bout. The reason I say this is this allows your brace to be as tall as possible, which in return allows you to keep the brace thinner with out loss of strength.
Author:  Hesh [ Wed Nov 14, 2007 1:41 am ]
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What the others said.

I glued one up last night and ended up with the same brace height on all sides of the joint.  But something occurred to me last night and I wanted to ask the forum about this.

When I make my X-brace I radius the two individual braces in the dish after roughing them out from a template and then on the belt sander.  The joint itself is a piece of cake for me now that I figured out to cut my notch inside the lines making the joint to tight initially and then hit the binding sides once or twice with a plane and it presses nicely together.

What I was thinking though, and I know this is where it gets dangerous, thinking.... was why do we glue the X-brace joint together off the guitar top?  I mean since the two individual pieces are already the correct radius, then you make a joint that fits perfectly and everything sits flush on all four legs underneath.

Once the X-brace is assembled and you take it to the top in the go-bar deck you have 5 points of alignment that you have to get spot on while using HHG and this means working very fast.......

So, sorry to be long winded I just try very hard to communicate clearly as a habit, why not do this:  Make the X-brace so it all fits and aligns perfectly but do not glue the joint.

Instead take the lower half to the go-bar deck and glue it on with HHG.  Now you only have 3 points of alignment to worry about.  When this brace is dry repeat with the other brace only this time butter up the notch of the joint with HHG, snap it in, align both leg ends, clamp with go-bars, and Bobs your uncle?

It just seems way easier to me so long as your dry fit and angles are perfect prior to gluing.

Thoughts please?

Oh, here are some pics of what I did last evening:





The X- is just sitting on the top, not glued yet
Author:  Michael Dale Payne [ Wed Nov 14, 2007 3:24 am ]
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Hesh I have done it both ways but now days I fit and verify that the joint is tight and fits the dome. Then I glue the down notched brace to the top first followed by the up notched brace. this makes squeeze out clean up a tad more detailed but nothing difficult.
Author:  Daniel M [ Wed Nov 14, 2007 5:35 am ]
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I must disagree with the thought that gluing the X together first is a bad idea. I appreciate there are many ways to skin the cat... All the methods mentioned have merit & obviously work well for the folks who use them.
I glue my X first, then sand the glued together unit in the dish with 220 paper. This assures the notches are seated firmly together without having to fuss with getting the the depth perfect on both pieces. Any small overhang is sanded off in the dish, immediately prior to gluing the X in place.
Just one more cat skinner with a different idea.
Author:  Dave Rector [ Wed Nov 14, 2007 6:35 am ]
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I just wish I could afford those fancy clamps like Hesh uses.

Oh, and I do glue the brace together before gluing to the top. But that could change soon, now that Hesh made me think about it.
Author:  Hesh [ Wed Nov 14, 2007 8:10 am ]
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Thanks guys.  Grump if you see this care to comment please?

It just seems way easier to deal with gluing one brace at a time so long as you have a perfect dry fit AND after the first brace is in place you clean up beside it well where the second brace will sit.

Michael I didn't think about clean up but that is another good reason to consider this method.  It's a bit harder getting in a corner than just cleaning up beside a straight brace.

Daniel when I make my notch I cut inside the lines and use a file to seat the two pieces together in the notch.  But there is no reason why you could not still sand the X as an assembly in the dish without it glued so as to level out the bottom of the intersection.  Then take it apart and glue it as two separate glue ups.
Author:  davidO [ Wed Nov 14, 2007 6:09 pm ]
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Thanks for your replies guys, it helped.
BTW I glued the joint first
Author:  BTucker [ Thu Nov 15, 2007 10:38 am ]
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I glue down the up notched brace first, then the down notched brace.  I fit the bridge plate last....makes it easier for me personally. 
Author:  Blain [ Thu Nov 15, 2007 3:58 pm ]
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I've been gluing the X first and then sanding everything flush in the dish as Daniel said.

I do like Hesh's idea though and might give that a try the next time around.
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