Building Acoustic and Classical Heel Blocks and Ukulele Heel Blocks properly is key to keeping your instrument in tip top shape and resistant for the need of a neck reset, by using materials and methods discussed in this posting.
Tools and Materials:
Neck Assembly Jig
Bessey or Large C Clamps
Chop Saw or Table Saw
Stationary Belt Sander or Drum Sander
The Heel Blocks:
The Guitar and Ukulele Heel consists of several stacked blocks of neck blank wood, glued up with specific grain orientation and neck joint considerations. We also discuss the use of a Neck Assembly Jig, which is available at Georgia Luthier Supply in both plan and fully built jig configurations.
Choosing The Proper Wood:
Typically, the heel is constructed from the same piece of wood as the neck blank. This is not always true though and you certainly do not have to follow this traditional procedure. One of my favorite guitars had a walnut neck and I built the Heel from Burled Walnut and it turned out incredibly beautiful and trouble free.
Classical Guitars almost always use the same wood as the neck blank and you get a dramatic change in the appearance of the heel because all you see is end grain, which is darker in appearance than face grain wood.
Whatever Your Decision is, here are a few steps that should be addressed for this procedure.
Preparing the Blocks:
It is best to sand the wood blank before it is cut up into separate blocks. This is most easily done with a Stationary Belt Sander, a Joiner or a Planer. If you don’t have access to these power tools, hand sand the wood dead level along its entire length.
When the neck heel block stock is all squared up cut the Heel Blocks to length being sure to account for the extra material required for a neck tenon or the classical guitar foot.
Make sure that the grain for the heel is mirrored for each stacked pair. We want all of these blocks of wood to resist warping or separation and if you just randomly stack the wood blocks on top of each other, you are missing a very important concept. That concept is to have the wood grain work against one another in order to resist warping.
As you cut your blocks just take every other one and flip it over. That is all it takes. To clarify this refer to the Heel Grain Diagram here.
Double Check Sizes and Locations:
Be sure to take into consideration the dimension for your neck joint – this portion that will extend into the Guitar Head Block. You should by now, have decided on which kind of joint you would like to use on your Acoustic Guitar Neck.
There are 2 major types of joints, with variations on each of these types. Here is a run-down of the selections. We will dive into the desirable qualities of each joint in upcoming articles.
Standard Dovetail Joint:
This is basically a wedge-type joint that depends solely on the joint for its strength. This is the joint of choice for most factory produced guitars, and a lot of handmade guitar as well. It is believed that C.F. Martin developed this joint for their steel string acoustic guitars and they still use the same joint today. This is the joint of choice for many factory produced guitars.
Mortise and Tendon Joint:
This is a much simpler joint to make and it is just like a tongue and a groove. Usually you will need a supplemental attachment apparatus such as:
- Dowels Running Perpendicular to the Fingerboard
- Metal cross dowels run through the Head Block and through the tongue of the neck
- Bolts from the face of the Head Block into the end of the tongue with threaded brass inserts
Gluing the Heel Blocks:
The gluing of the heel blocks can be somewhat of a trick because the glued blocks tend to slide around quite a bit once clamping pressure in placed on them.
The best way to do this is to set up a jig – I use the Georgia Luthier Supply Neck Assembly Jig, as shown in the included photos on this post. I have one each for classical necks, and acoustic necks. The jig securely holds the heel block stack in place while being clamped for consistent results. You will no longer have to knock a neck apart because the heel blocks slipped around during gluing.
Just lay waxed paper in the jig, arrange the neck and heel blocks and apply clamping pressure with the Bessey Clamps or 8″ C clamps and you are done.