Friday, May 30, 2008

Dry clamping Top

I've struggled figuring out the best way to glue on the top. Initially I thought I would use my workboard and a cork shim as Cumpiano suggests. The workboard seems to have worked well for carving the braces, but isn't correct for clamping. The workboard is flat, but the top of the sides are shaped to the 30' radius; and the top braces are glued onto the top in the 30' sanding dish. So trying to glue the top onto the sides on a flat surface will not work. Even shimming the neck/heel block up 1/8" doesn't work right because while the waist sits on the workboard right, the space between the neck/heel block and the waist is unsupported and thus can not be clamped.
One alternative I've seen is to glue the top onto the sides in the go-bar deck, applying pressure directly to the top... but this doesn't allow me to align the neck as I want. To do this, the top has to be down and the sides on top of that. Also, but having the top face down, the seam can be inspected from the inside during the glue-up to ensure a good joint.
So, I came up with the idea of using a workboard that is only 5" (or less) wide. This allows clamping directly to the top around the sides where the profile changes due to the 30' radius.
You can see that the top is shimmed at the head/heel by 0.125" and is gently bolted down. There is also a cork cushion under the whole thing (minus the sound hole to see center line) to protect the top surface from being scratched. The workboard has a center line along the whole thing for me to align the top to. The clamp pulls the center of the top down and constrains it to the 30' radius shape. Next, I start clamping the sides (with the neck attached) to the top.
The wooden clamps have cork cushions, but the black clamps only had rubber feet so I added a cork cushion to the rubber feet. This method allows me to properly clamp the top to the sides at all locations around the rim AND I can ensure that the neck is straight with respect to the top.

Sunday, May 25, 2008

More Top Brace Carving

A friend of mine (who is a luthier) inspected my top and said it was still way too stiff, not flexible enough. He suggested I remove a lot more material.
Compare this with before and you'll notice that the tone bars only have one peak now instead of two, and that the X has been tapered back further toward the center. I don't have a feel for this yet, but I was able to feel the difference from what I had last month compared to now.

Saturday, May 24, 2008

Fit top to neck...

This morning, I had some time and decided to fit the neck, sides and top all together. My concern is to make sure that the neck is straight with respect to the top, it would be real bad if I glued the top to the sides... and then found out that the neck was somehow crooked with respect to the top. I first had to notch out a space on the top for the neck tenon, and trim back the excess in that area too. Then I fit it all together.
Hey, it kinda looks like a guitar!!! You can see that the top is proud of the neck by a bit... my measurements suggest 10-15 mils.
It's hard to see from this picture, but I put a pencil mark on the top in the center seam where the bridge saddle will be. The straight edge is lined up perfectly with this line and the center line at the neck tenon... and the straight edge then runs true with the neck.
Now I just have to make sure that the top gets glued on correctly. A friend of mine suggested that I glue the top on with the neck attached to the side for this exact reason. As long as I can ensure that I don't glue the neck on with it, that sounds like a good idea.

Neck fit

Last night I decided to test fit the neck. The neck block came with the mortis already routed in. But when I glued on the sides, I covered this up. So the first step was to remove the side material that was covering the mortis. This didn't take too long with a chisel. Once this was done, I had to sand away a little bit of the neck tenon, until it fit nice and snug.
I measured the gap between the neck tenon and the neck block: 0.105-0.110". The top is about 0.125". This means that I need to either sand down the neck block and kerfing in this area some more... or take off some top thickness once it's glued on. Either way, the top and the neck must be flush for the fingerboard to eventually fit on.

Wednesday, May 21, 2008

Back almost ready

Last night I found some time (& energy) to work on the back. I began to chisel the edges of the braces down to nothing at the edge where they will meet the rim. I also removed a little bit of the center strip as it contacted the head and tail blocks.
I know that most people notch the back braces into the rim... but I don't like this. It weakens the sides and the glue joint in those locations and I don't see any advantages of doing it this way.
I still need to remove a tad more in a few spots where the rim meets the back, and I also want to remove some more of the braces as a whole to allow the back to vibrate in sympathy along with the top. After that I will sand the braces down.
I have left it in the go-bar deck overnight, it seems to curl up if left out... I'll be glad when it's glued on for good.

Monday, May 19, 2008

Top ready to glue

I found an hour to work yesterday while Jen and Anika were out shopping... Jonathan was sleeping and Andrew and Sarah were playing in the basement. Huh, that sounds familiar. Anyway, I finished the chisel work on the top and got the edge sanded and ready for gluing. I also sanded all the braces some... probably should do it a bit more, but it is essentially ready to glue to the sides.
But, before I do that I need to get the back notched in and ready since it will be more difficult to do that after the top is on. I also need to figure out my glue/clamping scheme...

Monday, May 12, 2008

Branded

I got an hour to work in the shop this weekend. Jen and Anika went out shopping, Jonathan was sleeping while Andrew and Sarah were playing in the finished side of the basement.
I bought a $50 branding iron from Rockler a while back, it says: Hand Crafted by Ryan Schultz. I was too cheap to pay the extra $30 to make it electrically heated. I thought I could heat it up with one of my little torches... didn't work. So I drilled a 1/4" hole in each side and stuck two 100 Watt plug heaters in. That did the trick, heated up in about 2 minutes.
Once I practiced a few times on scrap, I branded the neck block.
Turns out I got it a bit too hot. It would have been better for me to do this before it was glued onto the sides, and before I put a coat of sealer on it. Next time.
Here you can see (although not in focus) the branding through the hole in the top as the top sits on the sides. The top is notched into the sides at the upper face brace, and everything else except the lower X braces are tapered down to nothing at the rim. All that remains before I glue on the top is to finish the lower X braces and sand everything down.