Building banjo #44, part 3

On the 21st I got to the shop about 6 PM and worked for about three hours.  My first task was to remove the clamps from the peghead and sand it flat on the disk sander.  Then I traced the template onto it, ready to cut out.  The template and the fret position sheet shown later in this post both came from the former Bluestemstrings.com and have been very helpful to me.  I believe they are still available online but I don’t know the current address.

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Next while the neck was still squarish I put it on the Shopsmith and drilled a 5/8″ hole with a Forstner bit.  I set the table of the Shopsmith to a 3 degree tilt toward the headstock.  This should make the dowel stick come out very close to parallel to the head since the neck heel is cut to 3 degrees.

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Then I took the neck back to the bandsaw and cut the corners off to save time sanding the neck profile.  I don’t tilt the table for this job, I just carefully hold the neck at an angle. It’s pretty rough, but there’s no need for precision as long as I don’t cut too deeply into the neck.

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Then I took the neck back to the disk sander and used it to round it into a comfortable shape.  I aim for a continuous curve but I don’t use profile templates so each neck is a bit different.  I used a 1″ belt sander to shape the bass side of the neck along the first 5 frets.  Then I went back to the spindle sander and used the 2″ drum to shape the heel and peghead transitions.

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The next step was to put a dowel in the vise to hold the neck up vertically and sand it further with the random orbit sander.  I use the lamp to show any defects in the surface, and with the heel end of the neck held in place by the dowel in the mortise I can hold the peghead in my left hand and the sander in my right and rotate the neck as I sand.  I’m not trying to get the final surface here, just to remove the scratches from the sanding disk and any irregularities that remain.

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While all this was going on I was also waiting for the hot glue gun to get up to temperature.  I like to leave it plugged in for at least 20 minutes to assure that the glue is good and hot.  I ran a bead of hot glue around the edge of the particle board faceplate and stuck it to the back of the rim blank.  I’m thinking about making an aluminum faceplate instead since the particle board flakes away a bit when I pop the rim off after turning, so I have to keep replacing the faceplate after every 20 rims or so.

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Once the rim is mounted I start turning the outside down to size, and then I turn the top down till it’s flat all the way around.  Then I can check with a framing square to see if the rim walls are perpendicular and what the diameter is.  I turned it down to 12″ and then held a strip or 120 grit sandpaper against the rim while it was still spinning.

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Then I returned to the top of the rim and made a tone ring profile, and turned the inside of the rim, aiming for 5/8″ thick walls.  P1210040.JPG

Then I popped the rim off the faceplate with a chisel and took it to the spindle sander to clean up the interior.  I don’t do well at sanding the inside while it’s still on the lathe and the spindle sander makes the inside of the rim stay parallel to the outside while it’s being sanded.

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The next step was to get started on the fretboard.  I had a piece of jatoba in my box of fretboard wood that was already cut and planed to size, so I didn’t have to do that step.  I often cut and plane them in batches to save time.  I put the truss rod into the neck at this point too, just so I wouldn’t forget to put it in before gluing the fretboard on (I did that once).

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I used the helpful fret position template to lay out the fret locations on the board for a 25.5″ scale length with 17 frets.

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Then I clamped the fretboard down to the workbench and used a speed square and a fret slot saw to cut the frets.  I had cut the first 5 or so when I took the picture.  I am working on a cheap power saw setup for slotting but it is not ready for the big time yet.  I hold the speed square in my left hand and the saw in my right to cut each slot, and the square keeps the fret slots all parallel if I do it right.

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Once all the slots were cut I used my ever-faithful tomato paste can to draw the scoop.  I use it a lot when laying out necks and such too.

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Then I got out my ‘good’ router which is variable speed, and routed the scoop with a tray bit on a fairly low speed.  I have found that it burns less when I am moving the router slowly if the RPM is low.  I can’t move the router fast or I miss the line, but maybe someday I’ll get better at it.

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Then I laid the neck on the back of the fretboard and got it lined up carefully and drew around it, then I cut it out on the bandsaw.  I used a ruler to lay out the position of the 5 dots, making an x from corner to corner for the centered ones and measuring to accurately place the double dots at the 12th fret position.  I used a 1/4″ Forstner bit in the drill press to make the holes.

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I make my dots from cut off pieces of 1/4″ brass rod which are scraps from when I buy a 4′ piece and only need 39 inches or so to make a tone hoop.  I cut 50 or so at a time and keep them in a little bag, and then I can compare each hole to the assortment of dots and find ones that will be proud of the fretboard surface by a little bit but not too much.  I use #30 Stew-Mac super glue in each hole and tap the dots in with a hammer.  Then I roughly sand them down close to the surface on the disk sander with its usual 80 grit, then with the random orbit sander and a 120 grit disk, and then with a sanding block and 180 grit, working back and forth.  I give the fretboard surface a final going-over with 400 grit sandpaper to remove the scratches from the 180 and it’s ready to fret.

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I use EVO Gold fret wire on banjos with brass hardware because it sort of matches the color and also it’s supposed to wear a little better than regular nickel-silver like I use on everything else.  It comes in a coil and I find that I don’t get as good results with the arbor press with it as when I’m using straight wire, so I hammer the frets in and that way they seem to be more uniform.  I cut them off as close as I can with end cutters, always cutting in from the sides.  I find that if I cut them from top to bottom the tang gets mashed out of shape so I don’t do that.  With regular fret wire I use a pair of cutters from Stew-Mac that cut closer to the surface but they can be damaged by the EVO from what I have read.

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The next task was to dress the fret ends flush.  First I lay the board flat on the sander table and sand off the ends, and then I roll the ends against the disk to dress the fret ends to an angle so they won’t feel sharp or rough.  I try to take off just a tiny corner of the fretboard when I do this and then cut the fret tops back at about 45 degrees, and that seems to me to be the most comfortable to my hand.  P1210052.JPG

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My last activity for the night was to put masking tape over the truss rod cavity so that it runs out to about 1/16″ on either side and then glue the fretboard to the neck.  I have an ash caul that I always use for fretboards because it is hard and quite straight, and I use any pine scraps for the back of the neck cauls.  This is to keep the clamps from digging into the wood and so that if any wood gets crushed by the pressure and mis-matched shapes it will be the softer pine and not the cherry at the back of the neck.  I use the knife to hold the nut end of the fretboard down by wedging it between the top of the fretboard and the bottom of the caul.P1210054.JPG

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