Things With Strings

I saw a piece of scrap offset in my bin that got me wondering about whether to try cutting some thin slices of wood and laminating curved sections. I tried to bend the piece of scrap around an 11" diameter MDF circle I'd made previously and I was quite surprised just how flexible the piece of scrap was. The scrap was varying in thickness, but one outer edge was about 0.15 inches. The photos show how easily it bent, and this was just dry, no steam or water involved. I might try laminating a few layers out of curiosity. scrap and 11"MDF disk test bend

After having all three layers done, I decided to try to get the middle layer (shallowest) to size using a router and template, then I would glue all three layers together and machine the outer two layers using the middle layer as a router follower bit against the middle layer. In short this turned out badly, as I broke the middle layer whilst trying to route the inside surface. Fortunately I was able to patch it up, and in the end the patch should be invisible, but I decided at that point that it was probably best to get the three layers glued together before I made an unrecoverable mess of things. glued and clamped I'm not 100% sure how I will shape it yet. Probably router plus jig for the outside and sanding drum for the inside. Part 2 is here

I'm still experimenting with things really, and decided to try a different approach for the next segment layer. This time I thought I'd make a octagon using 45 degree scarf joints. There are a number of reasons why. I'd had difficulty with the mitred angles on the previous layer, and using scarf joints means half the number of angles to using equal angles each side of the block. Half the angles means the cumulative error is going to be less if anything is off (in theory). The wood I have is a not really as deep as I would like, and doing it this way means initially I only need to get one side and one face squared. The other face can be fixed after gluing the segments. I don't have to worry about the length or width of each segment providing they are above the minimum requirement. On the downside, the glue-up is tricker as I found out later. So here is how it works out in sketchup 11 inch segmented rim using 45 degree scarf joints First off, I trued up t...

Things are moving a little quicker now due to being able to square-up the stock faster due primarily to a jig I made for that purpose, hence I managed to get two layers done for the banjolele this weekend. I'd planned to work on the banjo rim, but avoiding nail holes, knots etc. left me with insufficient pieces for an 11" rim, but plenty for an 8" rim. Each layer is quite different in density and cloud, but I'm hoping it will hold together and look decent. The layers were 1" deep, as opposed to the 3/4" of the first one I made. The first one was quite yellow in colour, and I think I'll use that as the middle layer. It will probably end up looking like a cheese sandwich. Two layers glued and clamped I'm now quite looking forward to the next steps which will involve ensuring each layer is flat and then gluing them together. I'm not sure yet whether I'll sand the layers flat or try to use the router, I'll have to sleep on it. Part 3 ...

Despite taking an unprecedented amount of care squaring the stock material and getting the angle on the mitre saw correct, the joints turned out pretty poor although it's difficult to see from the picture. banjo rim layer 1 However when driving home tonight I had a eureka moment and have gotten myself a solution. When it's dry, I will take a slice through a joint and insert a saw-blades thickness shim. Then I will let that dry and repeat the process for every joint. I may even use a darker colour to make it something of a feature. Sorted!

After a few practice attempts (aka false starts) at making rim segments last year, this weekend I had my first proper crack at it. The problems I'd run into previously were mainly due to starting off with non-squared stock material. This time I picked a ropey log from the pile of pallet wood I have (allegedly Mango, but could be anything) and squared it up. This particular piece was not the best, mainly consisting of knots, nail holes and worm holes and a little bit of wood holding everything together. I don't want to screw up on something that was too nice, but what started off as a fairly substantial piece only yielded enough wood to make one 12-segment layer for the banjolele. Anyway, once I'd squared up the stock, I needed to cut the segments at 15 degrees on the mitre saw. The calculation to get the correct angle to set the mitre saw for segmented is (360 / #segments) / 2 which is where the 15 degrees comes from in this case. First problem! My mitre saw had fix...