Archtop Mandolin #5: Purfling, Binding

So, the purflings and bindings slowly go on, layer by layer……..

Until!

Archtop Mandolin #5: Body together

The top and back have been glued on to the rim to create a magic box!

When making flat-top instruments, you can locate the top and back relative to the rim by housing the ends of the braces in the linings, however, as there are no braces on a carved instrument, I use wooden pins to stop the top and back sliding around and to ensure that they are correctly aligned.

Before I glue the back on, I always like to drill the jack socket hole right through the tail block, so that the inner surface of the block doesn’t splinter when the 12mm drill breaks through. So, there is a bit of tricky lining-up to do with the tail-piece and incomplete body.

The holes for the two retaining screws are easy to drill, but I never like trying to locate the centre point of the jack socket hole. This time I had a eureka moment- I put a 4mm washer into the tail-piece’s 12mm hole, which gave me an accurate centre to drill a pilot hole! It’s bizarre how these little tricks make life so much easier and give such great satisfaction when discovered!

With the holes drilled for the tailpiece, the back can be glued on and then the overhanging edges trimmed-off. Behind the mandolin’s body, you can see my “True Channel” router jig which I’m not 100% happy with; more on that later!

And here is my current and preferred method of routing the binding channel on an archtop instrument. This works well because the top and back edges are flat and parallel to the work bench and there’s plenty of clearance between the router and the highest points of the arches.

Ready for purfling and bindings.

Archtop tone bars

The two tone bars have just fitted to the Archtop’s top plate. This is one of those tasks that takes time, has to absolutely spot-on and yet will never be seen! Here’s the video of how I do it.

Archtop’s sound holes

I’ve just been working on the Archtop’s sound holes (can’t really call them F holes, can I?). The top plate is fixed to a template which has the holes cut-out, full-size and in the exact position.

My Dremel is then set-up as a pin-router- all the clamps are to ensure rigidity in an attempt to eliminate any chatter from the cutter. In the photo below, you can just see how the pin, which the template is held against, is aligned with the cutter.

And then we route! I do a number of passes, incrementing the depth of cut 1mm at a time.

Once cut out, the next stage is to bind the holes (something that I feel strongly about) with black veneer. On the first few Archtops that I made, I used a soldering iron as a small diameter bending iron, in order to form the veneer to shape, but after some experimentation, I now soak the veneer, then put it in a zip lock plastic bag, pop it the microwave for 30 seconds and it bends with ease around these simple formers.

The veneer is glued in place and after a good clean-up and ready for the next stage: tone bars.

Archtop #5 update.

Here’s the latest video, in this one, I look at carving the top and back plates.