Neck Reset on Kay K22 Acoustic Guitar

I've been busy in The Dungeon the past few days.  Let me get you caught up.  Lots of pictures.  Possibly a record for me for one post.

The main event is the neck reset on the Kay guitar.  You may recall the original factory set was quite sloppy and the dovetail was ugly.  Jake Wildwood, who I bought the guitar from, had replaced an old bolt at the bottom of the heel which someone had put in many years back.  Kays are notorious for bad neck sets. 

My goal is not only to get the set correct, but to tighten up the dovetail.  This isn't anything out of the ordinary on a reset actually.  It's just that this dovetail probably has never been correct - even when it was first built.

First I need to remove a small amount of material from the bottom of the heel.  This will pitch the neck back.  In this case, the amount I calculated was just .018 of an inch.

I've written about how to determine the neck set and how to calculate the amount to remove elsewhere on the blog, so I won't go into it here.  You can also find out how elsewhere on the interwebs.

I put some masking tape on as close to that measurement as I could - it's just a bit more than 1/64 of an inch.  A third of a millimeter?  I don't know, but it's a small amount by any measurement.

After stupidly trying to use chisels for this work, I have seen the light.  I made up a sanding stick to take the material off.  Much easier to control than a chisel!

This is 120 grit paper glued to a paint sanding stick with spray contact cement.

After sanding close to the tape, I need to shave off the little 'island' right at the heel that doesn't get sanded.  This I can do with a chisel.

I take a little material off, then check the set on the guitar.  It took about three passes to get the set right.

Don't try to take the full amount off at once!  It's very easy to take too much off and then you have a mess on your hands.

Now we can fit the dovetail to the guitar. 

I first put some card stock (index paper) shims in the joint to tighten it up.

Then I sanded a piece of mahogany down close to the thickness of the card stock shims.  They measured about .018 of an inch - here you see I got the mahogany down to .025.  Close enough - we'll make adjustments to make the male part of the dovetail fit exactly.

Or darn close.

Here's a test fit of the shims.  When I put the neck in place, I could only get it down part way.  I had about an eight of an inch - maybe 4mm - of clearance between the fingerboard extension and the top of the guitar.

This is good.  Now I can work with the dovetail to tighten it up.

I glued the shims in place with Titebond.  Hide glue would be too mach trouble here - the Titebond is fast and easy.

I've gotten in the habit of putting waxed (aka paraffin) paper over these kinds of joints.  We don't want the cauls to get glued in place!

I have an assortment of wedge-shaped cauls for just this application.

Now it's the tedious, but critical, process of shaving the male part of the dovetail bit by bit until the fit is exact.

I use carbon paper in the joint.  As the paper gets used up - usually about 3 or 4 applications - just replace it.

I also have sign painter's tape on the body - you'll see why in a moment.

Here's what we do.

Put the neck into the joint as far as it will go.  I give it a whap with my fist to get it seated.

You can see the carbon paper in the joint.

Then clamp up the joint as you would if you were gluing it together.  This means a caul on the fingerboard, and one underneath.  Crank the clamp down some.  You'll probably hear the joint creaking.  This is good.

However, don't overdo it!  The neck block and dovetail are made of hardwoods, so they'll only go so far in any event.  You'll still have some clearance between the fingerboard extension and the top of the guitar - see the red arrow.

This will take a number of passes to get the joint fit exact.  That's the tedious part I mentioned.  I think I had 8 assemble-and-reassemble passes on this one.  Be patient.

Your dovetail fit should be quite tight after squeezing it down with the clamp.  Whoo hoo!

To get it apart, give it a sharp rap (as opposed to a whap) with a rubber mallet.

The finished dovetail should be so tight that you can pick up the guitar by the neck and not have the joint slip or shift.  In fact, Bryan Galloup, of Galloup Guitars, usually strings them up to check the neck set without glue before the final gluing.

Stew-Mac has a fantastic neck set video that features Bryan along with Dan Erlewine doing neck sets.  Highly, highly recommented.  A must-have if you're going to do any neck set work.

This is what we have after removing the neck.  The carbon paper has marked any points where there's interference between the male and female parts of the dovetail.

Scrape off the marks.  I'm using a scraper here, but a sharp knife like an X-Acto works well too.  You don't want to take much material off - just skim the marks off.

Then it's back to the carbon paper, put the neck on, clamp it down, etc.

There are three elements we're watching during this process.  One is the set of the neck itself.  The second is the fit of the dovetail.  And the third is the alignment of the neck.

I measured the centerline of the neck and the bridge.  Use a straightedge to check the alignment.  You may need to adjust one side or the other of the dovetail to align the neck.

It MUST be centered so that the strings will fall correctly on the fingerboard and the bridge.

When your neck is getting close to fitting well, take some 120 to 150 grit sandpaper and pull it between the heel and the body of the guitar.  The sign painters tape will protect the body of the guitar.

This will ensure you have a nice fit on the neck heel.

My dovetail is seated.  Here I check the neck set.  The straightedge is about 1/32 of an inch above the bridge - pretty much perfect.  The pull of the strings will bring it down a hair, so this should be a good set.

Now I'm ready to glue it on.

I scraped the old glue - and a fair amount of finish - off the area where the fingerboard extension will be glued down.

Check out my new Carruth ultimate scraper.  You can never have enough tools.

Heat up the hide glue, and apply it to the fingerboard extension, the area on the guitar we scraped, and just the sides of the dovetail.  Since our dovetail is so tight, the glue is just an extra bit of insurance. 

Here it is clamped up.  One clamp for the joint, and one for the fingerboard extension.  Cauls on the board and under the guitar.  The one under the body has a cork facing so it doesn't scratch the finish.

While I had the glue heated up, I decided to stick a dowel into the old bolt hole in the heel to fill it.  Since the dovetail now fits well, I won't be using a bolt to help hold it together.

I'll put a strap button here later and the dowel will give me something to drill into.