Jigs, Templates and Fixtures

I’ve discussed this briefly in past posts but I think it’s a subject that could use some further investigation.

First we must define each of these terms:  A jig is a device that attaches to the work and guides a tool.  Some examples would include this jig for routing truss rod channels. 

Or this for making a saddle slot in the bridge.

For my purposes, these are mostly used for router applications.  In this case I use an 1/8″ down cut spiral bit with a fence attached to a plunge router.

Templates are usually attached to the object.  This humbucker template is a good example

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This is used with a plunge router as well but with a pattern makers bit.  This has a bearing of the same size as the cutter and it’s on the top of the cutter or where the shaft meets the cutter.  I always use the largest cutter because the smaller bearings are very fragile.  In the case of the humbucker I use the bigger bit to “hog” out the majority and use the smaller bit just to clean up the corners.

This template is used to cut the heel on a neck.

I use a massive 3/4″ pattern bit for this.

As an aside, I always use the best bits I can.  My choice lately has been Amana.  The better the bit the less chance of blowing out chunks of precious wood.  This goes for the router as well.  The more horsepower, the less likely to bog down.

Lastly, the Fixture:  A fixture differs from a jig in that it is usually the work that is attached to the fixture.  An example would be this shooting board

In this case the “board” is attached to my bench and the back or top is clamped to the fixture to joint them for gluing.  Notice one of my favorite tools, my Lie-Nielson 24″ joiner plane!

A couple more, my homemade side bender and vacuum table

As you can see, most of these jigs, templates and fixtures are pretty simple to make and use.  Some of the other things I use these for are profiling necks, fingerboards, profiling solid bodies, forms for sides etc, cutting fret slots… the lists goes on.  While you can buy some of them, body and pickup templates, I encourage you to make your own especially if you’re on a budget.  A little 1/4″ MDF goes a long way and it’s cheap.

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Les Paul take Three

Now we come to the final stage…  Finishing!

I’ve probably said this before but finishing can take up to a third of the time in a build.  This is the first thing one notices after the initial shape.  You’ve spent all this time with the wood. Don’t short change yourself with the finish.

I start with 100 grit and work my way to 220.  There is no need to go any further as the scratches from the 220 will not show under a finish.  As I’ve said before finish follows but does not fill.  So now is the time for all the holes and flaws to be dealt with.

I don’t drill holes for mounting rings etc. as they will allow water to get into the hole when you’re wet sanding and pucker the finish.

Next, I use marine grade epoxy with a fast cure to fill the pores of the mahogany.  The stuff I use is available from http://www.tapplastics.com/product/fiberglass/epoxy_resins/tap_marine_grade_epoxy_system/27 . Most any epoxy will work but I find this one with the fast hardener allows me more than one coat a day.

I cut the first coat of epoxy 25% with denatured alcohol to allow it to get into the pores and make sure my finish sticks to the body.  Two more coats full strength, poured on, then squeegeed off with a piece of plastic against the grain.  Don’t worry about the lines of epoxy build up. They’ll be scraped even when dry.  One more coat and the mahogany is usually filled.  If I’ve scraped through to the wood I go back to padding the area with epoxy cut 25%. I do not sand the epoxy because the white dust created can get into the open pores and it’s very hard to extract.

This is when I color coat.  I almost never color the wood itself.  I use toner coats in the finish.  I do this for two reasons.  First, if the color goes horribly wrong, I can sand back without the worry of discoloration on the wood.  The second reason is that wood has summer and winter growth patterns.  The summer wood being softer will take the stain deeper than the winter.  Now if that is the effect you want, go for it.  In fact PRS has a finish that they call “Cat’s Eye” where they stain black the figured maple cap and when dry, sand it off.  The harder parts of the figure will look like the maple had never been colored while the softer parts will still be black.  Now they spray a color, say amber, and you’ve got figure that really pops.

On this guitar however, I’ll be doing a classic tobacco sunburst.  I start by spraying the entire top amber followed by a teardrop shaped burst adding reddish brown to the mix.  The final color is a dark brown and used very sparingly close to the edge of the body.  I still want to see the figure of the maple grain in even the darkest parts.

Sometimes I get little flecks of darker color in the lighter field.  When this happens let the finish dry and using a steady hand, flick the intruder off with a sharp xacto knife.

When this is done I color the back in the same way, only with a cherry stain.  Of course while this is going on the top is masked off to avoid ruining the sunburst.  This means taping any control cavities so that finish doesn’t run through.

When I’m satisfied with everything, I mask the fret board and shoot the finish.  Make sure you use enough coats so that you don’t go through to the stain.  Unless it’s the darkest color it will be almost impossible to fix. 

All in all this was great fun and I think the ultimate challenge for this is all the thought that went into creating the jigs and fixtures.

Cheers,

Mark

Les Paul part deux

Now we can concentrate on the neck and what a set neck entails.

Much of what I’ve said about a bolt on neck applies here as well.  The obvious difference being that once the neck is attached to the body the angle is set for the life of the guitar.  Other than that its truss rod, fret board, etc. are the same.  The fretting is slightly different because of the binding.  The way Gibson did it on their guitars was to fret the board before the binding and add a piece of binding taller than the board and routing the binding to follow the board and the frets.  Stew-Mac has a great description of this on their site.  http://www.stewmac.com/tsarchive/ts0131.html

I’m not a fan of this type of fretting because you lose about an 1/8″ of fretting surface.  I notch the fret wire to go over the fret board.  This is also a bit quicker. 

Here you can see the finished board.  I did two guitars at once. This one is Madagascar rosewood, the other Brazilian.  They are almost impossible to tell apart by looks alone.  Gibson and Martin both fret their boards at this stage but I like to get it on the neck first.  I have less issues with leveling later on.

The next issue is cutting the tenon on the neck.

Here’s a picture of the finished tenon with the truss rod installed.  This is a crucial part so getting it right is imperative!  The angle has to perfectly match the angle on the body.

I made both sides of the template at the same time so as to give them perfect symmetry.  I then made sure they were lined up during construction.  I used a pattern makers bit in a router making sure I double checked the depth.  The finished tenon should be a tight fit.  If you’ve gone a little to far in your depth don’t throw it out you can shim it with veneer.

When I’m satisfied with the fit I start carving the neck and cutting the binding channel.

A lot of people I know spend a lot of time making all sorts of torture devices to carve necks by machine.  I don’t have any problem with this except to say I get a lot of enjoyment carving the neck by hand and after doing it for so long can get the job done in about the time it takes to set a machine up.

After that it’s binding and gluing the neck in place.  Since this is a ’59 the binding is the same width all the way around.  You can see the maple cap in the cutaway.   Also notice the tight fit on the neck joint.  This has more to do with my skill at making templates and jigs than chisels and saws.  This is also when I do the fret work.

Another picture showing both guitars at different stages.

Now we’re ready to finish.  The trapezoid markers are real pearl and not MOTS and the headstock veneer is real ebony, not dyed holly.

See you next time in part three… finish.

Building a Les Paul style guitar

This will be the first of several posts on building a Les Paul style guitar.  While I’ll be keeping pretty faithful to a Gibson ’59 Standard, this will not be a “fake”.  I don’t condone “replicas”, plus if I put all that hard work into it I want my name on it.

First of all if you go on any of the Les Paul forums you can find all sorts of minutia about the guitar.  People have come to turn the details into a fetish!  The mother of toilet seat has to be the kind produced in that time period with almost silvery color and minute black spider webbing etc. The shape must be period correct.  The mounting rings for the pickups have to glow under black light. The Stew-Mac blue print isn’t the correct shape, blah, blah, blah.  Yasuhiko Iwanade’s book “The Beauty of the Burst” is a perfect example of what I’m talking about. What I ultimately take away from this is that they were all hand made and probably were all different from each other.

In this build I’ll be using both the Stew-Mac print and templates by guitarbuildingtempates.com.  A friend had the templates so I gladly used them but in all honesty you don’t need them.  A good print will work just as well.

The first thing you must do is source the wood.  I used genuine Honduran mahogany for the neck and body. You’ll need 8/4 (two inch rough) for the body and 6/4 for the neck.  One piece bodies were used in the original but two and more piece bodies are fine, if not more economical.  The neck was made in three pieces, the main shaft was at two inches with the “ears” for the head stock glued on.

The top on the originals was eastern hard rock maple and very rarely bookmatched.  Sometimes this was very figured and sometimes not at all.  Most of the modern repros (including Gibson) use western big leaf maple which is softer and doesn’t sound quite the same.

I cut the mahogany body first and make the routes for the control cavity and wiring channel.

Now I join the maple cap which is used non-bookmatched eastern hard rock maple (this is purely an aesthetic) and cut this out to the same pattern.  Don’t worry if they don’t match perfectly. You will have to cut the top for binding later. The holes in the mahogany are for weight reduction because this was a particularly dense piece of mahogany.

Once the cap is glued I drill the holes for the hardware and use a panel bit to bring the top to 1/4″ thick where it joins the body.  This also gives the start of the arch.  Also in the picture is the jig I use to get the proper neck angle .  The angle should be as close to 4.4 degrees as possible.  Any more or less and the bridge will be too high or low.  I use a protractor to determine the angle and make a simple jig to hold the guitar at that angle. Then I use a Wagner Safety Plane (yes the same plane I’ve mentioned countless times before) to give me the proper angle.

Here’s what it will look like with the angle planed and the panel bit cutting the start of the arch.

The next step is to cut the long tenon so revered by Les Paul junkies.  I use a pattern makers router bit and the template for the neck pocket.

After this I cut the pickup routes while the top is flat.  This makes the templates easier to adhere. I also drill for the stop tailpiece and the bridge at this point.

Now comes the elbow grease!!!  Using an Ibex arch top plane with a toothed iron I plane the arch.  When I’m close I use a pneumatic sander with a 40 grit patch to finish the curve.

Almost done

Next week the neck and fitting.

Cheers,