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Hi, guys,
I have up until now used the tent method to join tops and backs. But I would like to build a jig similar to the LMI jig.
Does anyone know of a free plan available, or does anyone have the dimensions? It looks fairly simple to make, but making it too small or too big would be aggravating, lol.
Thanks,

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Mike

The only thing nescessary for evil to thrive is for good men to do nothing.

I've got one. I can measure it later when I get down to the shop.

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Steve Smith
"Music is what feelings sound like"

Thanks, Steve. Much appreciated

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Mike

The only thing nescessary for evil to thrive is for good men to do nothing.

Mike, I took a bunch of photos, hope they help. Plywood is quality birch about 9/16” thick. Plastic looks to be 1/2” UHMW or similar.







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_________________
Steve Smith
"Music is what feelings sound like"

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_________________
Steve Smith
"Music is what feelings sound like"

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_________________
Steve Smith
"Music is what feelings sound like"

This style of jig with wedges and ropes has been around for hundreds of years and is called a Spanish tourniquet. They work very well but they are no substitute for not learning to properly join a top and hand plane technique including sharpening technique.

This is not directed at you Mike it's simply on my mind. In the past some search for a better method to join plates because they had poor results in the past. No matter what joining methods one uses it will never correct poor joining technique in the preparation of the joint.

With that said... I built a Spanish tourniquet and used it on the first maybe ten guitars. Then I learned the tape method and that I did not have to store the jig any more and I never looked back. With good joining technique the tape method was all I needed for the next and production guitars I built.

I used the tape method to join head plates, heel caps and rosette blanks and it worked great. No jig required just some tape, wax paper and something to weight things down.

Adding on to what Hesh said. I think it was at a ASIA symposium a one of the pro builders hand planned a spruce top and joined it with nothing more than hand pressure and Hide glue.

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Say what you do, Do what you say.

I used the tape method for years, I like this jig better. I agree, whatever method you use the plates must be properly jointed. Doesn't matter how you do it as long as the result is correct.

_________________
Steve Smith
"Music is what feelings sound like"

Just curious, but how long does it take to match up the halves, wrap the rope, and insert the wedges, after the glue has been spread on the edges?

Less than 60 seconds.

I use this jig because I can join a top or back, wrap it up then go stand it in a corner or somewhere out of the way. My shop is small so bench-top space is at a premium. If I had more room I might still be doing the tape method, I get the same results from both.

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Steve Smith
"Music is what feelings sound like"

There are going to be alternative methods for just about everything, but I also prefer this jig over taping. I'd previously used tape and HHG but ran into some issues aligning thin panels. The LMI jig keeps the panels dead flat. Of course, you could accomplish the same thing with tape if you have some long supports running the length of the joint to keep everything flat.

Mike I have an LMI plate joining jig I'll sell you for $100.

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Steve, @SteveSmith this is incredibly awesome!
I very much appreciate it.
Thank you!

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Mike

The only thing nescessary for evil to thrive is for good men to do nothing.

No problem Mike, you’re welcome.


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_________________
Steve Smith
"Music is what feelings sound like"

Steve - That series of photos documenting the jig design and dimensions is awesome!

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

Hesh, your tute on the tape method got me started in top joining. It does work great. There's just something about that tourney that calls me, so I'm going to build that sucker, lol.

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Mike

The only thing nescessary for evil to thrive is for good men to do nothing.

Tape method is good with HHG but break tests have failed on me with TB…

I've used the tape method for about 15 years. No failures to date. As stated, perfect joinery is required.

There are several good ways of doing this job. Since I use hot hide glue, I want to get my plates stuck together and under clamping pressure as fast as possible. This jig helps me do it:



It's a 24" square piece of plywood with a 3/4" wide, 1/4" deep trough up the middle. That's where I position the center seam. There are pegs in the edges on either side of the trough, and I stretch silicone rubber bands between them so that there is a rubber band on either side of the center seam. The wooden circles have holes that are slightly off center, and there are screws through the holes, so that the circles act as cams. You can also just screw down some blocks and stick wedges between the blocks and the plate edges. These days, I tend to use construction shims between the circles and the plates. They apply the right amount of pressure really fast.

I start off with the plates under the rubber bands, but with the center seam about 1/4" open, and over the trough. Then I spread glue on the edges to be glued, stick them together (staying over the trough), and apply either the cam pressure or wedge pressure. The rubber bands keep the plates from popping up from the clamping pressure. The time from spreading the glue to applying the clamping pressure is just a few seconds. Then I pick up the board and set it aside until I am ready to unclamp.

Cheap, easy, fast, convenient, and effective.

Outstanding idea! I use tape and HHG but that jig is so neat I want to make one even though I don’t need it.

Glad you like it, Bob! I’ve been pretty happy with it. I haven’t done plates any other way for a few years.

EDIT: It’s a good idea to put strips of packing tape on both sides of the trough, in case some stray glue gets under the plates in that area. A single strip on each side is plenty wide enough to prevent a “workpiece to jig” gluing mishap. Also, this jig is great at dealing with odd-shaped plates (like the coffin shaped ones). You just unscrew the circles and put them where they are needed.

I've tried a few different methods and all seem to work well. One thing to watch for is how the grain looks. i have a bunch of tops with very fine grain that made it almost impossible to find the center once joined. I have to offset the two panels by a few millimeters to save me some frustration.

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Rather have a bottle in front of me than a frontal lobotomy

Same here. I always put a small notch at each end so it will be easy to find the center line.


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_________________
Steve Smith
"Music is what feelings sound like"