A neck-reset is a common repair for most shops. In order to do the job properly, a thorough knowledge of the materials and processes involved is required. Because the subject is too large and difficult to comprehend in one sitting, it will be split into multiple parts. Click here to revisit the article, “Resetting a Neck, Part 1” or Resetting a Neck, Part 2“. This article, Part 3, will review whether a neck reset is necessary and outline all the steps involved. Steps 13 through 16 will be covered in more detail, including setting the neck, shaping the neck heel, and all related touch-up.
MATERIALS AND TOOLS
-Chisels (1 Inch and 1/2 inch)
-Large clamp for gluing in the neck
-“Knife edge”straight edge
-Cam clamps for gluing on the fingerboard
-Caul for gluing on the fingerboard
-Counter block for the button
Reasons to reset a neck
-The appui, also referred to as the overstand, is too short. Measured at the foot of the neck, it is the distance from the top plate edge to the fingerboard. A higher appui adds a sense of ‘stickiness’ of the bow to the strings, and can also help with the clearance for the left hand moving into upper positions. Click here for a photo example.
-The projection is too low (The projection is the angle the fingerboard and neck is set in relation to the instrument). Click here for a photo example.
-The poirette needs to be corrected. The poirette is the twist in the neck set that favors the bass or treble side. Click here for a photo example.
-The neck is not centered.
-The neck has broken out (It’s not enough to simply glue it back in).
-The neck length needs to be corrected.
Order of Operations
- Release the neck if it is not broken out already.
- Remove the fingerboard.
- Select, fit, and glue maple and spruce wood pieces into the mortise as needed. This can be done while the glue is drying on other steps.
- Select, fit, and glue a piece of matching wood on the bottom (endgrain) of the neck-foot.
- Select, fit, and glue a piece of matching wood on the back (button) of the neck-foot.
- Fit a new soundpost, if needed. Measure the fingerboard projection by itself and establish the angle at the bottom of the neck-foot. Cut the angle and plane flat.
- Spot glue the fingerboard on the neck.
- Find the corrected position of the bridge by assessing the twist in the instrument body.
- Do a mock neck setting and determine if and where a neck-foot side piece will be needed.
- Select, fit, and glue a side piece on the neck-foot if needed.
- Remove the fingerboard. Plane the sidepiece to match the already established angle of the bottom of the neck-foot.
- Glue-size the bottom of the neck-foot, add pins in bottom and back pieces of the neck-foot, and spot glue the fingerboard back on.
- Set the neck.
- Remove the fingerboard once again, color the exposed bottom of the neck-foot, and permanently glue on the fingerboard.
- Establish the neck heel compass, shape the heel, and blend into the existing neck.
- Color and touch-up.
In this article I will only be covering steps 13 through 16 of these operations in detail. Steps 1 through 3 are covered in “Resetting a Neck, Part 1” and steps 4 through 12 are covered in “Resetting a Neck, Part 2”.
13. Set the neck.
Setting the neck requires a lot of different aspects to come together all at the same time. One of the biggest mistakes that people make the first few times they set a neck is to focus on one measurement or angle rather than taking everything into account all at once. It is easy to make one aspect fit the parameters only to realize that you have gone too far in other parameters. Good spatial skills will serve you well while setting a neck. I find it helpful to imagine the neck in 3D space and think about which surface on the neck heel or in the mortise needs to be addressed, in order to move the neck in the desired direction.
In the last article, the neck heel ended in this condition, roughly shaped with plenty of wood left.
The added pieces to the neck heel had just been pinned and the bottom of the heel was glue-sized. After this the fingerboard was spot glued back on the neck with three small dots of hide glue.
If there is still too much wood in the mortise, it is time to roughly open things up a little. I will take the bottom of the mortise down to about 5.5 mm deep (including the rib thickness), keeping in mind that my final target depth is 6 mm. I will pare the sides down as well, but this can be done once the actual neck setting begins.
At this point, a poirette gauge is used.
A line is drawn onto the bottom of the mortise from the center line of the instrument to the back of the mortise at the center of the button. The poirette gauge is pinned at this line and then adjusted to match the poirette line on the mock bridge.
The gauge is then transferred to the bottom of the neck heel so that a line can be drawn that will match the mortise.
The sides of the neck heel can be planed down using the line that was just drawn as a center. Measure the width of the button and make the back of the neck-foot that width, plus an extra 1-2 mm on each side for later corrections.
Five measurements of the neck set need to be taken throughout the process and all of them need to be spot on before gluing in the neck. I’ve included some photos of how the measurements are taken, although this particular instrument being photographed already has a neck in place.
1. Neck projection: This is measured using a straight edge on the fingerboard and a ruler at the bridge location and center line of the top. The final measurement here should be 27.5 mm.
2. Appui (Overstand): This is measured from the top plate edge to the bottom of the fingerboard. Only measure from the bass side. The final measurement here should be 6.5 mm.
3. Centering of the fingerboard: This is measured from the left and right sides of the fingerboard edge to the inside of the purfling at the widest parts of the upper bouts. The numbers should be the same when the neck is set.
4. Centering of the neck to the bridge and poirette: This is measured by sighting down the fingerboard to the mock bridge. The edges of the fingerboard should eventually be centered to the mock bridge and the poirette should match the line drawn on the mock bridge to represent the poirette. This line is 1 mm higher on the g side.
5. Neck Length: This is measured from the treble side top edge to the point where the fingerboard playing surface meets the nut. The final measurement here should be 130 mm.
It is also helpful to draw a neck length line that is parallel with the bottom of the neck foot. This line allows you to check the neck length at any time during the neck setting process. When the neck length is correct the line will run right at the point where the top edge meets the neck foot.
If possible, start putting the neck into the mortise. The sides might need to be pared away to get the neck inserted. Once the neck has started to go in, measurements should be taken.
As stated before, the tricky part of setting a neck is being able to hit all the numbers at once. Because of this, it is easier if you have someplace to start. Getting the projection on track is the best place to begin. This next part may be confusing, but bear with me. In order to see if the projection is on track, the appui (overstand) measurement and the neck projection measurement are needed. The final projection measurement should be 27.5 mm and the appui should be 6.5 mm, but you will not be at those numbers until the neck is ready to be glued in. In order to find out if your neck projection is on track you must subtract the excess appui from the neck projection measurement.
For example, if the neck projection measurement was at 37.5 mm and the appui was at 14.5 mm, your projection would be 2 mm too high:
14.5 mm (measured appui) – 6.5 mm (desired appuis when finished) = 8 mm (excess appuis)
37.5 mm (measured projection) – 8 mm (excess appuis) = 29.5 mm (a projection 2 mm higher than the desired 27.5 mm)
This math will work just fine and doing this little calculation each time will get the desired result, but in order to speed things up an extra step can be taken out.
Subtract 6.5 mm (final appuis) from 27.5 mm (final projection) and you get 21 mm. Each time you measure the appuis and the projection, you can just subtract the measured appuis from the measured projection and see how it compares to 21 mm. Using our example from before:
37.5 mm (measured projection) – 14.5 mm (measured appuis) = 23 mm (2 mm higher than 21, so your projection is 2 mm high).
If the projection is not on track to be 27.5 mm, make the necessary correction in the mortise. In the example of the projection being 2 mm high, a little wood should be taken out of the bottom of the mortise towards the top plate. A chisel is a good tool for this job, or a custom sanding stick would work as well. I often use the very fine No 7 cut Pechar Rasps. The finish left by these rasps is better than traditional rasps and allows exacting work.
*When making a correction to the mortise for the projection, it is necessary to take the other measurements into account. If the neck is not centered for example, one side of the bottom of the mortise can be cut more than the other while making the correction for the projection.
Start getting your measurements to line up. Do this with a combination of cutting the sides of the mortise, cutting the bottom of the mortise, and/or planing the sides of the neck foot.
If the projection is on track, the neck is centered, and the poirette looks good it’s time to start setting the neck further into the mortise. Do this by cutting the sides of the mortise and planing more off the sides of the neck-foot. Put chalk on the sides of the neck-foot to see where it is touching the sides of the mortise. Then use a chisel to pare off the chalk marks. Then repeat this process over again. Here is a video showing the sides of the mortise being cut. Notice the thumb being used as an anchor to produce controlled cuts.
Avoid the pitfall of undercutting the sides of the mortise. Make sure there is contact with the neck-foot throughout the surface. Especially watch the sides of the mortise toward the button as there is a common tendency to undercut at those spots.
At this time I might also put chalk on the bottom of the neck foot to fine tune the fit to the bottom of the mortise. You can use the end of the fingerboard as a lever to see how the bottom of the neck foot is sitting in the mortise. Here is a video illustrating this idea.
As the neck is moving back into the mortise, it is necessary to keep planing wood off the back of the neck foot.
As the neck is moving into place keep track of all the 5 measurements. Do not ignore any of them. It is easy to get focused on one aspect only to find that you have gotten off track elsewhere.
Eventually, if you have done the job correctly, all the numbers will line up and the neck will be ready to glue in. At this point you should be able to push the neck all the way into the mortise with hand pressure only. It should feel snug. There should be no looseness.
Dry clamp the neck into the mortise to check how everything looks. Use a counter block against the button that is angled to be parallel to the fingerboard, but be careful not to put any pressure on the button alone. Use some orange juice carton squares (or something equally suitable) against the fingerboard to keep the clamp from marring the surface. As it is clamped up, make sure the 5 measurements are still correct and then take a measurement from the top plate to the bottom of the fingerboard on the bass side. Before gluing it’s a good idea to put a chamfer on the bottom corner of the neck heel to allow for some glue squeeze out.
Use strong hide glue for the neck set. Hide glue is at its strongest if it has been freshly made the night before and allowed to sit in the refrigerator over night before being reheated.
For gluing have everything needed at hand and ready. Brush glue into the mortise and then up the button. Then brush glue onto the neck foot on the sides, bottom, and back. Then insert the neck by pushing it firm against the bottom of the mortise and slide it back into position against the button. Glue might squirt out at this time and that’s okay. It means there is a good fit. Put the button counter block in place and put the clamp on. Check the measurement from the top plate to the bottom of the fingerboard on the bass side. It should match the measurement taken while dry clamping. Now use water and paper towel to wipe down the whole instrument. Glue can splatter anywhere on the instrument and it’s important to do a full wipe down for this reason. If glue is left anywhere on the varnish it could be damaging once it dries.
Let the neck set dry overnight.
14. Remove the fingerboard once again, color the exposed bottom of the neck-foot, and permanently glue on the fingerboard.
Remove the fingerboard as before.
For coloring the exposed part of the neck-foot a number of things can be used, but the criteria is the same: the exposed part of the neck-foot should blend in and not be seen. I use water colors for this process. I mix a color that is close to the surrounding varnish on the top plate and brush it on. Earth tone pigments mixed with alcohol on a brush can be used for this step as well. After the color is dry, seal it with a little shellac.
Now permanently glue the fingerboard back on. Double check the neck length measurement. If needed, any slight modifications to the neck length can be made while gluing the fingerboard on. Use cam clamps for gluing the fingerboard on and a gluing caul for the fingerboard. Alternate the clamps and use the button counter block to support the button.
15. Establish the neck heel compass, shape the heel, and blend into the existing neck.
Before carving the heel down, I will establish the edge of the fingerboard with a rasp (finest cut). I will draw a line about one third of the way up the side of the fingerboard and rasp at the angle shown in the photo. From doing many necks I already know when the rasp is at the correct angle, but if needed, a template can be used. If the sides of the neck are already pretty thin I will use a file for this step and proceed carefully. This photo is from a new viola neck, but the concept is the same.
Check the center of the neck and the thickness measurements at the scroll end and the neck heel ends. The ideal final measurements here would be 20.5 mm at the neck heel and 18.5 mm at the scroll end of the neck, but leave an extra .5 mm for sanding and fingerboard finishing if possible. Also, ideally there would be a slight bulge in the line from the two points to mimic the scoop of the fingerboard. Of course, when doing a neck reset compromises may need to be made, but if there is room to make adjustments do so. Once any adjustments to the center of the neck are made, draw a line along the center and do not touch this until sanding. Here is a photo of a new instrument neck being finished, but the same idea applies.
Now it’s time to connect the dots. I use a couple of knives for shaping.
Here is a photo of a new instrument neck being shaped. The process is similar for a neck reset. The difference is based on what the existing neck looks like. It may not be possible to do any shaping on the neck if it is already too thin. In that case all the focus will be on the heel.
In the photo the left hand is behind the right. The right thumb sits on top of the knife blade and the depth of cut can be controlled with the right wrist. Both hands slide up the neck and a succession of chamfers are made starting at the button. The legs are holding the instrument steady while the hands slide up the neck. Here is what the result looks like on the instrument from the previous photo.
Neck heel compass is a measurement from the spot where the edge of the top plate meets the neck-foot to the crook of the neck. When the neck heel compass is finished, the compass should meet the spot in the crook of the neck from both sides. Here is a photo that illustrates this idea. Although the instrument in the photo is a new viola, the concept is still the same for a neck reset on a violin. On a violin the compass should be set to 26 mm.
Now the larger chamfers can be broken up into smaller chamfers. If everything looks right and the neck heel compass is near to 26 mm, sanding can begin.
Sand out the chamfers with 220 grit paper. A scraper can also be used to speed up the process. When it’s close to smooth, check it over for any serious bumps and correct those before proceeding.
Lay out three piles of sandpaper. Three pieces of each grit: 220, 320, and 600.
Sand three times with each grit. Wet the wood between sanding and dry it with a hairdryer before sanding again. During the sanding, focus on long strokes with follow through from heel to neck. By setting out the sandpaper ahead of time, you don’t have to remember what sanding you are on. Just go through the grits. This process of consistently raising the grain and sanding smooth again, ends with a very stable and smooth neck. It also ends up with beautiful wood figure after the finishing treatment.
16. Color and touch-up.
Some will use potassium dichromate to start the coloring. I prefer to avoid it because of the toxicity, but if it is used it can produce a nice graying effect that will make the neck look older.
If the side piece is a very different color from the rest of the neck, sometimes it is helpful to put a UV lamp on it for a little while. I will isolate the side piece with tape pryer to putting it under a UV light. If potassium dichromate is used, the UV light will accelerate the reaction.
For a nice base color, chicory can be used. Brew a very thick batch of chicory. It can be stored in the refrigerator and used over. It will keep for a very long time. Put a little on a some paper towel and apply it to the neck.
Next, use some dry earth tone pigments. Choose a color that is close to the varnish on the instrument. Pigments can be mixed to achieve the right tone.
Put a couple of dots of mineral oil on some paper towel and put some of the earth tone pigments on top. Fold the paper towel over and rub it together so that the oil and pigments mix.
Apply it directly to the neck. Start at the neck first and work your way toward the heel. Rub fast and furiously. At first it may appear too dark, but it will blend as it’s worked in.
Avoid rubbing directly into the joint where the side piece is glued as a dark line can sometimes form and it makes it difficult to touch up later. At this spot it works better to rub away from the base of the neck to avoid rubbing directly into the joint.
It should look something like this when it is finished.
Next apply a little alcohol to a brush and use some of the left over earth tone pigments to work a little more color into the base of the neck heel. Focus on the spots where the hands do not wear away the varnish and dirt will accumulate and darken. Then wipe it with a dry paper towel to remove the excess. If there is too much pigment in the wood on any spot of the neck a clean paper towel with a drop of mineral oil can be used that will take some of the color out.
At this time the wood can be sealed. For this application I have an air brush that is used to spray shellac on the heel. Make sure to be accurate or put painter tape over the ribs to avoid overspray. if an airbrush is not a possibility, a little shellac on a cotton rag with some mineral oil can be polished into the heel.
Next, using touchup colors, put some more color into the crevasses. I use Ciba Geigy colors for this, but other transparent touchup colors will work. Start out darker in the crevasses and blend the color into the rest of the heel. If needed, abrade some of the color off, especially on top of the heel to mimic wear from the players hand. Seal in the color and repeat. Build in layers and then remove some spots. This mimics the natural wear. If more opacity is needed, earth tone pigments can be dusted on to the heel with a makeup brush and sealed in with shellac. Less is more with this as the dusted layer can sometimes be very effective even if it is almost imperceptible when applied.
When everything is finished put a couple layers of shellac over the heel. Once the shellac is dry, polish the whole neck with a cotton rag, some shellac, and mineral oil. Add some talc powder to the rag and use it in the polishing to keep the neck slippery.
Here are some before and after shots so the progression can be seen.
Here are some more shots of the finished neck with different lightning.