The Cabinet Scraper

Today I’ll be going in a slightly different direction and talking a little about a common tool overlooked by many guitar builders… the cabinet scraper.

They come in quite a few thicknesses and can be used in place of sandpaper.  With woods such as cocobolo and cedar they can be irreplaceable.  These and many other woods can cause severe sensitivity. In some cases, like cocobolo, you can become so sensitized that you can never work with it again!

They range in thickness from .04″ to .1″ and are available in different shapes.  The edge must first be honed or filed even and true with a 90 degree angle.  The tool in the picture is used to first draw out a burr.  This is accomplished by laying the scraper flat and using the rod sticking out of the tool and drawing it along the surface, always keeping the rod parallel to the scraper.  The metal is softer than the rod and causes a burr or hook to form.  Always use machine oil to keep the wear on the rod to a minimum.  One pass should suffice as more passes will heat harden the metal and cause the scraper to become brittle and make the hook break off.  A screwdriver shaft can be used in a pinch but the tool is not that expensive when compared to all of the sandpaper you’ll save.

Now we have to draw the hook.  Now we hold the scraper in a vice and use the tool to draw against the top edge of the scraper to form a hook.

You should only take one or two passes.  The amount of pressure used is a matter of trial and error but usually it takes less than you think.

Now you have a micro plane that is capable of removing a lot of material, save you money on sandpaper and hankies as well.

Building a Solid Body Neck pt. 2

On to the next phase of neck making.

As the picture shows, the truss rod slot is now cut, tuning machine holes drilled and the step down on the peg head is cut.  I do this using a Wagner Safety Plane.  This inexpensive tool is chucked in a drill press and easily planes the wood safely as the name would imply.

After this step is done we now have to drill a 3/8″ hole long enough to accept the truss rod nut.  The rod nut is usually a little smaller in diameter to allow the nut to turn.  Then use a bell hangers 1/4″ bit (these bits are 12″ or longer) to connect the 3/8″ hole to the 1/4″ truss rod channel.

I then make the truss rod out of 3/16″ steel rod that I thread on both ends with a 10-32 die (Fender has used both 10-32 and 8-32).  On the heel end I drill a 1/2″ hole to accept an aluminum rod drilled and tapped to accept one end of the threaded rod.  Thread the truss rod into the aluminum so that the truss rod protrudes about a 1/6″ the other side.  Now put the setup in a vice and peen the end over.  This will prevent the rod from turning when in the guitar.  Thread the rod through the peg head first and then set the heel.  Now a fillet strip is cut to fit the channel so that it forces the rod into the arc mentioned in the previous post.

After this has been glued in and the glue dry you can trim the fillet flush with the fret board and glue the fret board on.

Now is the time to put the radius in the peg head to blend the fret board into it.  You must be careful with this so that you don’t sand too deep.

Once this is done you can shape the back of the neck with any combination of spokeshaves, rasps, gouges, chisels, etc.  A cut belt from a sander can be used to “shoe shine” the neck to make a round backed neck.

You can now put the radius on the fret board and fret it.  I do not, however, dress the frets until the neck is bolted onto the body.  The tension of the screws in the neck change the geometry and I’ve found it best to level them after the neck is installed.

I sometimes use threaded inserts in the neck so that bolts are used to connect the neck to the body instead of wood screws.  This is an extra step but will keep the screw holes from stripping if you are a tinkerer and like to pull the neck off a lot.

Cheers from a member of the dirty trades.

Bolt on Neck pt. 1

Now that we have the body, we need the neck to go with it!  For a Fender style neck we’ll need a piece of maple about 1″ thick surfaced.  You’ll also need a fret board.  It’s much easier to do the neck with a separate fret board than the single piece neck on vintage Fenders.  The familiar skunk stripe down the center of the back is for installation of the truss rod from the back of the neck.  Except on vintage 60’s repros, all Fender necks have the rod installed from the back.  While this looks pretty cool it takes more complicated jigs and if its a single piece neck the ability to cut the slots in the neck itself.

The easiest and simplest way to do the fret board is to buy it with the radius and slots done by the supplier.  They use CNC templates for the slots and the cost is slight compared to the appropriate set up for cutting them in your shop.  You can cut the slot by hand with a miter box and back saw of the correct dimensions.  For example, if you want a scale of 25 1/2″ you can use what is called the rule of eighteen, or more accurately 17.817.  If you take the scale length (in this case 25 1/2″)  and divide it by 17.817 you will get the distance from the nut to the first fret.  The remaining distance is now divided again by 17.817 and that is the distance from the first to the second.  This is done until you have the desired amount of frets.  Now you’ll need a good set of calipers to transfer those figures to the board.  This is not as easy as it sounds because you must be consistent in your use of the calipers so that you don’t grow or shorten the scale length.  Most suppliers will charge less than  $10.00 for this service!  I use a table saw with a hollow ground blade to .023″ with a jig and templates that are made of polycarbonate, the positions of which are cut with a CNC.  I can cut the slots in about 10 minutes but this requires the cash outlay and if you’re only doing a couple of boards a year it doesn’t make sense monetarily.

Most of the remarks on building the body apply to the neck as well.  Use a bandsaw to cut the neck to shape and templates to route the final shape with a pattern makers bit.  I use a 1/4″ round bottom bit to cut the channel for the truss rod.  I make a simple jig that consists of a base longer than the slot will be plus the diameter of the router base times two and another piece glued to the base to act as a fence.

I then do a run with the router just to cut through the base (1/2″ baltic birch plywood works well).

Then I mark my maple neck for the truss rod and using double stick carpet tape, attach the jig to the neck using the slot you just cut in the jig as reference.  Make sure to measure the rod’s thickness.  If it’s a double action truss rod (recommended) just measure the depth of the rod and route to that.  If it’s single action, you will need to go to about an 1/8″ from the bottom of the neck.  The deeper the rod is in the neck the better it will work (single action only, of course).  Fender rods are curved deeper in the center than at the ends, so the easiest way to do this is to cut the slot at a consistent depth and make maple filet pieces that are cut to the curve and installed so that the fatter pieces are at each end.

As a note:  When I’m routing the slot I don’t take the full cut but do it in increments of about 1/8″ at a time.  Maple is hard and it’s possible you could break the bit or at the very least, have a rough trough.

Next week: part 2.

Building a solid body, body part 2

Today we’ll get into the build.  First, you will need several tools for the job:  A decent band saw (a 14″ saw with a 1 hp motor will do).  Stay away from the bench top models as they don’t have the necessary grunt to power through 1 3/4″ of hard wood.  An oscillating sander also comes in handy for the making of body templates and sanding of the body.  A plunge router for cutting the cavities.  The more horse power your router has the cleaner and quicker the cut.  I use a 3 hp Makita for this.  A router can be used if that’s all you have but the plunge feature makes it a lot easier.  You will also need at least two pattern makers bits, a 1/2″ and 3/8″.  These are bits with a bearing on the shank that is the same diameter as the cutter.  If you want to round the edge off you will need the appropriate radius bit.  For an arm and belly relief you will need a rasp or a Surform.   Finally you will need the appropriate templates for cutting the pickup, neck and control recesses.

Start by tracing the template or plan onto the wood.  Using the band saw cut to about 1/32″ to 1/16″ from your line.  If you’re new to the band saw keep your fingers away from the blade and go slow.  If you do start to wander stop and try to correct.  Do not keep going as you will probably cross your line.  I usually use a 1/4″ blade for this and make sure it’s SHARP.  In fact it’s a good idea to use a new blade as at about $10, it’s much cheaper than buying a new piece of wood at about $80 to $150.

If you’ve made a template you can use a router table and a straight bearing bit to do the final shaping but on a first attempt I would use the oscillating sander to sand to the line.  While this is a slower method, I would recommend it for your first time because operating a table mounted router or shaper can be very dangerous without proper training. Also be aware that just because the manufacturer of the template says they’re laser cut from the original holy grail they may have flaws.  I’ve seen patterns with edges that weren’t true.

Once it’s sanded you can route the radius on the edges, or if you’re binding cut the binding channels.  Now you can route for the neck pocket, pickups and control cavities.  Carefully mark their locations on your body using a very sharp pencil (I actually prefer leadholders to pencils because the lead can be sharpened to a very fine point).  Templates for just about every pickup can be had from various suppliers, but you can if you’re patient make your own out of 1/4″ Masonite or plexiglass.  Use double stick carpet tape to affix the template to the body.  This is very aggressive tape and works very well.  Use the largest pattern makers bit you can depending on the tightest radius (1/2″ works for most templates and if you need a tighter radius still use the 1/2″ first then switch to the 3/8″.  The bearings on a 3/8″ bit are very fragile, due to the fact that the shaft of the bit is only 1/4″ and that leaves the bearing at a mere 1/16″ thick).

Start by adjusting the plunge on your router to the depth you need keeping in mind that it will have to be as deep on your first cut as you need for the bearing to contact the template.  Start at the center of your template and initiate the first plunge.  If you have a shop vac you may want to keep it near to clean out the cavities.  I clean out all around the template without going to the edge so that when I do it has the least resistance and makes a clean edge.  This is the process for doing all the cavities and can seem daunting at first but with some practice on scraps you can become proficient in a very little time.  Remember, keep the bit sharp and the more horse power the router has the less likely you are to get tear out.

A word of caution with routers… a 3 hp router will not stop because your hand is in the way.   Always unplug when changing bits and familiarize yourself with your particular tool before you proceed.

Now is when I drill for bridges and jacks etc.  As with most woodworking, always use a brad point bit and measure twice, drill once.  One thing I don’t do is drill screw holes for pickguards, mounting rings etc.  I find it makes finishing easier when I don’t have to seal them when I’m compounding.

I also use 12″ brad point bits to drill from pickup recess to control cavity etc.  Also, don’t forget to drill a hole from the bridge mount to the control for the grounding wire.

Next week:  Necks