Building the Body Jig

Saturday, February 14, 2009.

Checking on the glue job after letting it dry over night, it feels like a really tight hold. Looks like my glue to water ratio is ok.

I had intended to split the piece of maple I bought for my back today only to discover that my bandsaw is way to small for the job. The block is 6” wide in the direction I need to cut and the bandsaw is only capable of accepting material up to about 3-1/2” tall. Since my wife thinks its probably not the best use of money at this time to buy yet another bandsaw to make just one cut (go figure), I guess I will have to find someone who can cut this for me elsewhere. So, instead, I focused on making a body jig and some cello clamps.

The body jig is used to help shape the sides, once they are bent, and to support them later when gluing the kerf lining and then the top and back wood. I am making it from a piece of 24” x 24” x 23/32 plywood.

Here you can see where I traced the outline of my plastic template onto the plywood and then cut it out while leaving enough extra for finishing. To finish it, I then used a drum sanding attachment on the drill press and a piece of sandpaper glued with rubber cement to a scrap of thin acrylic for support.

Here is a picture of my drum sanding setup.

Here is a shot of the body jig after I finished sanding it to shape. I spent extra effort on this since, as Mr. Siminoff points out, this jig will ultimately define the finished shape of my mandolin.

Once I finished with this, I started making about 20 cello clamps. These are small spool shaped clamps that will be used to clamp the top and bottom wood onto the sides for gluing. I started with a 1-1/4” x 36” long oak dowel rod that I bought at Lowes. Using the band saw I cut it into 48 disks, each 3/4” thick. Once cut, I took them to the drill press and, using a jig that I made from a scrap piece of maple, I drilled a 1/4” diameter hole in the center (roughly) of each.

My drilling jig. I had to use another piece of scrap wood under the drill press table to account for the ribs on the bottom of the table.

And here are all 48 of the disks with holes in them.

To finish making the cello clamps, I will start by taking each of the disks and gluing a piece of scrap leather onto one face. Then I will cut 24 lengths of #10-24NC all-thread rod into 6” lengths and to each of those, screw on one nut, two washers, two disks, and a wing nut.

I haven’t attached the leather in this picture, but it will be on each face interior face where it contacts the mandolin.