A guitar for my nephew

Thanks for staying with me. Here's a little more.

The back and front are now ready to glue to the sides but, before I do that I have to make the access panel. The access panel isn’t really essential, but it means I can get my hand inside the guitar to adjust the yaw or pitch, or whatever they are called, of the neck without taking the strings off. If I knew what I was doing, it would also enable me to get inside to fine tune the brace carving with the guitar strung up; but I don’t, so it won’t. I should also mention that this, again, isn’t my design; I borrowed it, with his permission, from Kent Chasson, another generous pro.

This is the end graft. The different tiles and strips of veneer were assembled on a piece of 1mm ply and this has now been glued to a piece of maple to make the whole thing 5mm thick.

This, together with the birch ply disc we saw earlier and a piece of very old dark mahogany (because that’s what I had), also thicknessed to 5mm, will form the access panel.

I trimmed the maple flush with the tiles and glued a piece of white veneer on either side.

A 5mm hole was drilled through the end graft to locate it, and the mahogany cut into two pieces and the cut edges trimmed.

The mahogany pieces were band-sawn to an oversize circular shape and glued to the plywood disk. The tapered end graft isn’t glued in place yet. It’s positioned with a dowel pin through the hole and into the plywood disc.

Now the wedge is removed and the mahogany trimmed to the required diameter.

A piece of white veneer is glued to the outside of each mahogany segment.

Thanks Vinny.

Now to make a corresponding hole in the sides. To do this, I made another disc from MDF with a 5mm hole in the centre, and which fitted snugly into the hole in the tail block. With this disc in place, I drilled through the 5mm hole and the sides where they are joined.This disc was then fixed to a square MDF base that I can hold in the vice. The tail block was placed onto the disc and fixed to the base with double sided tape and a dowel pin installed. That was a long-winded way of saying it now looks like this.

The hole was then cut using the circle cutter and a ledge carefully cut to fit the circular mahogany panel.

The wedge was then fitted into the circular panel and the panel positioned in the hole. A line was scribed on either side of the wedge and a recess cut to accept the ends of the wedge.

The wedge is now finally glued into the panel and the panel fitted into the sides. The panel is almost flush with the sides in the centre but, as it is flat, it protrudes more at the outer edges. To trim this down flush with the sides, it will need to be held firmly in place.

So now I need to make the bits that hold the panel in, starting with these two little maple blocks.

And this aluminium channel. You can see how it works from the drawing. You slide one end of the channel in, pivot the other end into place and slide it back to centralise it. The little blocks then stop it falling inside the body when you install the panel.

The blocks being glued in place.

One end of the channel inserted.

The other end swings in and the channel is centralised

A small block of wood is glued in the channel to take a wood screw.

The panel is now held firmly in place by that big wood screw and can be planed down flush with the sides. The wood screw is temporary; it will be replaced by an end pin after finishing.

Spent my life in engineering so I suppose I tend to go about things in a certain way.

Been a bit busy these last few days, but I can now add a bit more to this saga.

Now I can glue the back on. I glue the back on with the back in the radius dish and the sides on top.

Here's another long-winded tale.

What happened next was that I glued the front on, routed for bindings and glued in bindings and purflings and during all that I completely forgot about taking photos.

I also have to confess that I chickened out on the arm-rest bevel, so I just installed faux tortoise binding without side purflings.

It didn’t look very nice.

My little 1/8” down-cut router cutter is knackered so there was rather a lot of chipping out in the binding rebate that I only noticed when I’d finished cutting it. But I was hoping that glue and sanding dust would disguise it. This curly Claro does seem to be rather brittle and chips easily.

The cold weather had set in (this was in January) so I‘d bought a humidifier which kept the workshop at about 40 to 45% RH. It worked fine for about a month, and then it gave up the ghost. I took it back to the shop where they said they’d have to send it away to be repaired and then we left for ten days to go to Venice for the Carnival. Of course, I should have turned the heating off in the workshop, but I forgot and when we got back I found the humidity down to about 20% and the top had a 5” crack in it. Oh, and a message from the shop to say that my humidifier was ready for collection.

I didn’t mention this before, but I’d already had a couple of problems with the rosette. One was that there was some slight tear-out of the spruce in the purfling channel. The other was that in spite of sealing with shellac, it would appear that some of the CA leached into the end grain of the spruce and discoloured it slightly. I think the problem was that the shellac I used is old and didn’t dry hard, but I decided it would have to do.

I now had a distinct feeling that something or someone was trying to tell me something. Like I shouldn’t have ‘made do’ with tear out in the rosette channel, CA staining the spruce, using plastic binding and avoiding the side purflings and chickening out on the arm-rest bevel and was now being told to try ‘making do’ with a cracked top! So with more than a little help and advice from Colin and others, I routed the top off and started again; which is why some of the previous photos are of the first top and rosette and some are of the second.

Having decided that this time I should try to make a proper job of it, I made a new top and thought I really ought to have a go at the arm rest. By now, I’d gleaned some more information about how different people go about it and one thing I’d noticed is that some cut the armrest profile into the top and the side before assembling them. I couldn’t do that with the side as the lining was already glued to it, but I could do it to the new top, so after a bit of fiddling about drawing the profile in CAD, I cut the shape into the top and this is what it looked like.

The last photo gives a false impression of what the armrest will look like as the shape includes the surplus which will be trimmed off after the top is glued on, as shown here. My intention is to try to achieve a smooth blend of the armrest bevel into the body shape.

I then re-routed the binding rebate, slightly deeper than the first time. At this point the transition from armrest to body profile still isn’t smooth, but the purfling rebate has still to be cut.

I decided, this time around, to make wooden bindings using the off-cuts from the sides. The front bindings can be straight, but the back has such a wavy profile that I used the templates I made for the linings to make profiled back bindings. It wasn’t wasteful as the side off-cut already had that profile. It just needed smoothing out.

This time, I glued a single white side purfling veneer to the bindings before bending them. I took Colin’s advice and used waterproof (exterior) wood glue and it worked fine. The two bindings back-to-back (nearest the camera) are the straight ones for the top. The other two are the wavy back bindings which couldn’t be bent back to back but the purflings didn’t come unstuck even so. There was a little spring back, although there doesn’t seem to be in the photo. That’s because the bindings were stuck to the kraft paper and the paper stuck to the slat.

Can you see the little green clips (made from garden wire)? That’s another idea I picked up from Colin. There are 8 in all and they keep the inner slat in place while dismantling the rest, so the slat can’t straighten out and break the bindings.

At this point I needed to cut the armrest profile into the side. I drew the curve I wanted and stuck it onto the side and very slowly and carefully cut it using a craft knife and chisels.

I then cut the rebate for the top purfling and finally got a fairly smooth transition into the armrest. Not perfect, but not bad for a first attempt.

I stuck this off-cut from the top back where it came from while routing the purfling rebate, so that the ‘donut’ which rides on the top didn’t fall into the armrest area and ruin everything.

The top purfling was now glued in place. (Why don’t they make it long enough to go all the way round?)

Postimage is now telling me that the service is temporarily unavailable, so I'll have to post a bit more later on.