MIMF

I am interested in using a top mount rather than a hinged tailpiece that attaches to the end on a set of guitars that I am building. Some examples of the idea are Sakashta's Version-R, many of Murray Kuun's guitars such as the Spitfire, or Letain guitars Eraser as a few examples. The question I have about this idea is whether or not it is important to allow the tailpiece to float to the angle at which the strings pull or if it's ok to have the tailpeice firmly attached to the top assuming the resulting angle is close. These are going to be primarily electric guitars so any acoustic considerations are secondary. Thanks for your ideas.

Trying for a rigid mount is just going to put a lot of stress on the attachment point. Why not simply let it float?

I am also inclined to think that it should float. In some examples of this sort of attachment it looks like it's just held on by a bolt or screw and I'm trying to figure out how it could be as simple looking as that but with the ability to float. I'm probably over-thinking the whole situation, but want to come up with a design that makes sense.

This is probably not very pertinent here in the achtop section, but here is a crude floating tailpiece I made years ago. Basically a screw into the tail block with a hole and a slot in the tailpiece that fits over it.

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Peter, that's a great instrument! That #8 or so wood screw was strong enough in shear to support the shear load from the strings? I'm definitely over-thinking this. I was thinking that if it was to float on a pin or screw or whatever there should probably be a groove of some sort to let the tailpiece pivot on. Maybe that's a bit much.

Check Ken Parker's website for some ideas.

On my 'Winter' archtop I tried a number of different things. One was a tailpiece based loosely on the way they do them on viols da gamba. In those they use a post, about 1/2" square, that's dovetailed into the tail block and sticks up above the top. It has notches in it along the back edge. The tailpiece has a square hole to fit over the post, with the back edge of the hole shaped to fit the notch. It's easy to adjust it up and down in steps to find the setting that gives the best sound.

I wanted to try making it so that I could have continuous height adjustment. I ended up drilling a 1/2" hole into the top and the tail block. I lined it with a piece of stainless tube, and set a nut in the bottom. I made an ebony post with brass tube on the outside to fit the tube in the tail block, and a screw set in the bottom. The top of the post was turned spherical. The tail piece has a cup in the top to fit that, with a hole that the post goes through. I'm sure its all overkill on several levels, but it looks OK, and seems to work well. I'm sure that round post with a notch or a crosswise pin that could be screwed into the top would work as well, and be easier to make.

I've made top-mounted floating tailpieces, for various reasons abandoned and replaced with traditional. Most down to poor planning and execution on my part. What I found was that I couldn't get the axis of the tail piece (the point the string load goes directly through, and that determines the break angle over the saddle top of the bridge) high enough without creating too much bending moment in the bolt I was using as my pivot point. The bolt shifted in the wood, tilted, dented the top, etc. Many ways to do it right, I did it one of the wrong ways...

I believe that they can work great, you need to craft a pivot so the tail piece is floating and not constrained, and that you need to pay attention to the break angle over the bridge. Kuun and Parker both have great examples of what works. The reason my try failed is down to not paying attention to break angle, at the end of the day. I went to a sacconi cable bridge with a tall fulcrum to get my angle right.