Monday, June 06, 2005
The Profiler
So now that both the neck block and tail block are both glued in, it's time to start profiling the sides in order to prepare for fitting the back on. Right now the sides are the same depth, about 4" deep, all the way around. The tail end of the guitar will be about 3/8" to 1/2" deeper than the end where the neck attaches. So on the back side there will be a taper from end to end. Also, the back will be slightly spherical, with a 15 foot radius. So I need to mark the sides so that I can cut them to the right shape, spherical and tapered end to end. Remember the radius dish I made a couple months ago? Here's where I start to use that.
It may help you to visualize this as if the guitar were complete, it would be face down with the soundhole towards the table.
So I start off with my sides in the form. I've made two small blocks that are the same thickness and set them on the neck and tail blocks. Ignore the pencil line around the sides, I went a little out of order on the pics.
Then I set my radius dish on top of the blocks. If you look at the picture above, you'll notice the neck block is not as tall as the tail block. This is how I'm accounting for the taper from the neck end up to the tail end.
Here's what I'm going to use to mark the sides. It's a Berol brand silver pencil, which leaves marks that are easy to see on dark wood. I put it in a cheapo compass, and use a nut and bolt to lock it in place.
So now I'm transferring the spherical shape from the dish to the sides. It doesn't seem like a precision operation, and it's not. It doesn't need to be, it just needs to get close. So I mark all the way around the guitar. I can't make a continuous line all the way around because the blocks from the form are in the way, which is fine.
Here it is with the profile marked, and I begin to remove everything above the line with a small block plane.
It's almost done, I just bring it to the line and then stop. It doesn't have to be perfect, just close.
Here's a view from the front, if you stare at it long enough you can see the spherical shape, how it's a little higher at the narrow waist. It doesn't have to be perfect right now because I'll finish up by lining the radius dish with sandpaper, and then sand the final profile into the sides and then it'll be perfectly spherical.
And a view from the side.
It may help you to visualize this as if the guitar were complete, it would be face down with the soundhole towards the table.
So I start off with my sides in the form. I've made two small blocks that are the same thickness and set them on the neck and tail blocks. Ignore the pencil line around the sides, I went a little out of order on the pics.
Then I set my radius dish on top of the blocks. If you look at the picture above, you'll notice the neck block is not as tall as the tail block. This is how I'm accounting for the taper from the neck end up to the tail end.
Here's what I'm going to use to mark the sides. It's a Berol brand silver pencil, which leaves marks that are easy to see on dark wood. I put it in a cheapo compass, and use a nut and bolt to lock it in place.
So now I'm transferring the spherical shape from the dish to the sides. It doesn't seem like a precision operation, and it's not. It doesn't need to be, it just needs to get close. So I mark all the way around the guitar. I can't make a continuous line all the way around because the blocks from the form are in the way, which is fine.
Here it is with the profile marked, and I begin to remove everything above the line with a small block plane.
It's almost done, I just bring it to the line and then stop. It doesn't have to be perfect, just close.
Here's a view from the front, if you stare at it long enough you can see the spherical shape, how it's a little higher at the narrow waist. It doesn't have to be perfect right now because I'll finish up by lining the radius dish with sandpaper, and then sand the final profile into the sides and then it'll be perfectly spherical.
And a view from the side.
