Monthly Archives: March 2015

Guitar #30/3

Assembling the box

After days spent reorganizing the shop, which had become next to impossible to move in, I am back at it. Yesterday I bent the sides ( also called ribs) and assembled them to the end blocks. The end blocks had been made some time ago. These determine the rib depths and the correct angles at the four intersections where the ribs join the top and back (neck and tail). The first step was to trim the blanks to just a bit wider than the maximum finished width (depth of the body). I trimmed these to 104mm – the maximum depth being 100mm. That left me room to trim after assembling the ribs and blocks before attaching the plates. The next step was to mark each rib with yellow pencil at 25mm intervals. This is a great aid in checking progress against the pattern, which is also marked at 25mm along the outline. While I did this I had the bending iron heating up.

one rib trimmed and marked, and soaked down for bending

one rib trimmed and marked, and soaked down for bending

body half pattern with 25mm markings

body half pattern with 25mm markings

bending iron hot and ready to go

bending iron hot and ready to go

Bending walnut is not very difficult. You keep it wet and hold in one place for a few seconds, pressing gently, then move a centimeter and press some more. The hot metal pipe dries the wood in seconds and it sizzles when it contacts wet wood. No sizzle means the wood is dry and has to be wet again. I start at the waist, then do the upper bout, then the lower. It takes constant small adjustments but with patience it can be made to follow the pattern shape quite closely. Once it is close enough it gets clamped into the mold, where it then dries and takes the shape in which it is clamped.

rib clamped to mold

rib clamped to mold

Once both ribs were bent and dried in their final shape I trimmed the ends and assembled the pair of ribs into the mold, checking that the joints met tightly and along the centre line of the guitar. Then I glued in the end blocks. The easiest way to do this is without the mold, just one end at a time, clamping the ribs onto the block. Once both blocks are done then the assembly goes back into the mold and is clamped with spreaders.

ribs in mold with spreaders

ribs in mold with spreaders

The spreaders ensure that the ribs are in the right position for attaching the plates. Just a bit of pressure is enough to keep the ribs pressed to the sides and ends. I assembled the back plate first this time. I wanted to try a different method of gluing in the linings. First I glued the back to the blocks, neck and tail. Then I put the whole thing on its back and clamped the back plate here and there to the ribs, so it was tight. I then glued in the kerfed lining strips, rubbing them to increase the initial tack, and holding them pressed into place for a short time. In a few places I resorted to putting pressure with a re-purposed chopstick and a clamp. This saved me doing two steps, where the linings are first glued to the rib, after which the plate is then glued down onto the linings. This way I was also able to avoid having to cut pockets in the linings for the ends of the braces. Instead I simply glued several teeth from the kerfed strip at each brace. This will be sufficient to hold the brace end tight. Note here that I first trimmed and fitted the back plate to the ribs before this procedure.

gluing the linings to attach the back plate

gluing the linings to attach the back plate

After the back plate was done and the glue set, I then fit the top plate to the ribs. Then I glued the linings for the top in place. Since my main top x-braces are tapered to zero they require no pockets in the linings, except for two which hold the upper face brace. These will be cut before the top is glued on.

box ready for the top plate final fitting

box ready for the top plate final fitting

 

Advertisements

Leave a comment

Filed under Guitars, Uncategorized

Guitar #30/2

installing truss rod & carbon fiber rods

installing truss rod & carbon fiber rods

I decided to do some work on the neck blank today. The sun was shining into the carport this morning when I set up my workmate and clamped the neck blank in place. Fetching the router I found that it had the truss rod bit already in place and set to go. I attached the fence, made some adjustments to ensure I had the center lined up, and then routed the slot in a jiffy. I went to put the truss rod into the slot next. It didn’t fit! I looked a little closer and discovered that my supplier had changed their truss rod in a very small way, but now it was wider by about one millimeter. Problem: no 12mm router bit. I looked through my bits and found one that was 1/2″. Close enough, so I swapped it into the machine and set the depth, then ran it down the groove, shaving off the millimeter required. Only now the rod was a bit loose. No major deal here, I put electrical tape on the rod, which made it snug in the groove. But if they keep sending me 12mm wide truss rods I guess I’ll have to buy a 12mm bit. I have learned that it is sufficient for a truss rod to be installed without glue, and in fact I think it’s better. That way if it ever breaks it can be withdrawn and replaced. If it were glued, forget it – make a new neck.

neck with truss rod and carbon fiber rods

neck with truss rod and carbon fiber rods glued in

After the truss rod groove I switched to a new 1/8″ bit and routed slots for twin carbon fiber rods I recently bought. I cut one long piece in two, sufficient to do both sides of the neck. These were glued in place with epoxy. The slots had to be widened for these just a bit, which was done by adding tape to the sides of the neck blank and to the router fence for a second pass at the slots. After that the carbon rods dropped right into place perfectly.

neck with carbon fiber rods & truss rod

carbon fiber rods before gluing

the bit for the old truss rod

the bit for the old truss rod

the new wider truss rod

the new wider truss rod

Leave a comment

Filed under Guitars

Guitar# 30/1

Before I head off with this post about my next guitar, here are the real answers to the last blog.

1. Common Bulrush

2. Western Painted Turtle – Vancouver Island’s last remaining native turtle species, and unfortunately, already endangered.

3. Double-crested cormorant

4. Ring necked duck

5. Northern Flicker

Now for something completely guitar:

Here is the top of #30, ready for assembly. It’s the same as #29, that is an x-braced domed soundboard. This one is Sitka Spruce.

Guitar#30 top - bracing

Guitar#30 top – bracing

Here is the back plate. Unlike #29 I just went with regular ladder braces. Less work. Spacing was done by eye, more or less, but I placed the braces on more or less even centimeter marks, as can be seen if you zoom in on the tape. The arching was done with a template I had, giving a set rise over a given length. In this case 5mm in 400mm. I drafted the “fair” curve with a bent rod and pins.

back plate, braced

back plate, braced

back arch template

back arch template

The interior body blocks are a little different this time around. The tail is still 100mm deep inside, but the neck is deeper – 90mm. The Martin I used to get the sizes of an “O” guitar had a shorter neck block, (81) which I decided was too short. About 10mm difference is more to my liking, and that also makes for a slightly greater interior volume. It also aids in the fitting of the back to the ribs, as you will see from the next photo.

mock up of plates with blocks

mock up of plates with blocks

Here I have clamped the plates to the blocks so I can see how the angles on the blocks work out.

neck block with dimensions and angles in pencil

neck block with dimensions and angles in pencil

tail block as per neck block

tail block as per neck block

The angles are often best guesses as after assembly they seem to change mysteriously. The key angle is the one that sets the neck. For that I am using 1 1/2 degrees. The upper face brace arch dictates this, more or less. I’m aiming for a bridge height of 15mm, which this should give me.

dry run assembly with popsicle sticks showing the body depths

dry run assembly with popsicle sticks showing the body depths

The body depth is 100mm from the tail to around the waist. Then it tapers at the back side down to 90 at the neck block. The first 5mm of taper occurs between the waist and the upper bout at its widest. The plates are shown here in their natural curved state, clamped to the blocks. The soundboard face of the ribs will be flat, and the back face will be flat until the waist, then tapered.

fingerboard already fretted, ready for assembly to neck

fingerboard already fretted, ready for assembly to neck

This is a Bubinga fingerboard. It’s hard and tough, and a lovely pinkish colour. Also cheaper than Rosewood or Ebony. I did this all at once, starting with cutting the fret slots, putting in dots, tapering the sides, sanding to 16″ radius, then fretting. I double stick taped the wood to a bench to do the radius sanding and then put the frets in right there. After I nipped off the ends I pried it up and sanded the edges straight on the bench belt sander. There’s still an extra millimeter on each side. I always leave room for insurance.

Leave a comment

Filed under Guitars

The Junior Naturalist

No. 1

No. 1

We live beside a small pond called Swan Lake. We never see swans here, however. It’s a bird sanctuary, in a park that by some miracle was never destroyed by development. Thank you for that, whoever you were that was responsible. Daily, we walk around the lake, a distance of about a mile, which takes 45 minutes almost invariably. Sometimes I carry a camera, but we have a joke that whenever I do so, we see no wildlife worthy of a photo. Of course when I leave the camera home we run into owls and hawks face to face! But I still like to lug the camera sometimes. Yesterday I put on my 500mm mirror lens. It’s a Tamron, and in its day was very expensive. I got it at a thrift shop for $65, which isĀ  not much. I regularly see photographers on out walks, carrying gigantic telephoto lenses mounted on tripods worth more than my camera. All for taking pictures of ducks? I don’t know what they do in truth, but as amazing as those lenses must be, I will probably never buy one. I’m more of an opportunist – I hope for good shots to present themselves randomly. As long as I have the camera at hand, turned on, and set to the right settings of course, then sometimes I get a lucky shot. This long lens is hard to hold steady, however – it probably requires a tripod but I’m too lazy to bother. My Pentax K50 has built in shake reduction, and with my shutter set to 1/1000 I shoot and hope for the best. Of course I also have to focus manually, which is the trickiest part. But here are a few shots. I have numbered them. It’s a quiz! Guess what they are. My answers are below.

No. 2

No. 2

Write down your answers – no cheating!

No. 3

No. 3

Put down that book!

No. 4

No. 4

One more to go, then all will be revealed…

No. 5

No. 5

OK, here are the answers:

1. Fuzz on a stick

2. Donatello and Raphael

3. Black footed log roller

4. Orca-like duck

5. Giant hummingbird

 

OK, who guessed right?

2 Comments

Filed under Animal psychology, Cameras, Photography, Thrift shop finds

Aviation Primer

avian social life

the Hummingbird is a solitary creature - by and large

the Hummingbird is a solitary creature – by and large

the Starling cannot bear to be alone

the Starling cannot bear to be alone

the Crow has many guises - alone or in his murder

the Crow has many guises – alone or in his murder

Leave a comment

Filed under Uncategorized