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Fitting the neck

To successfully fit a neck the following set of criteria must be met:

a) 2:3 ratio between neck stop length and body stop length.
b) Overstand of 6 mm. See a in Fig. 1.
c) The center of the neck must coincide with the center of the violin body.
d) The elevation of the fingerboard projected to the bridge position must be 27 mm.

Marking the neck root

First we need to transfer the real widths and thicknesses on the back of the root. See Fig. 1.
  1. Mark out the "a" overstand of 6 mm.
  2. Measure the thickness of the top plate at the overhang, where it will meet the neck root. In our case its 4 mm. Mark this on the neck root "b".
  3. 2 mm downwards from the top plate is the place to measure the first width for the mortice "c".
  4. Measure the height of the ribs, 30 mm in our case, and make the mark "d" /29 mm in our case/.
  5. Measure the thickness of the bottom plate, and make the mark "e".
  6. Finally, 2 mm from the "e" mark is the place to measure the second width, "f" /18 mm in our case/.

Transferring the widths

With the widths "c" and "f" measured, you can proceed to the violin body to make the neck mortice.
  1. Set your compass to half of the width "c". Using the compass, mark this width at the top of the plate, from the plate centerline. See the red vertical dashed lines in Fig. 2.
  2. With your sharp knife make two incisions on these marks, cutting through the thickness of the top plate, through the purfling, to the depth of about 4.5-5 mm. The knife should be a little tilted, copying the directions of the neck root walls, see the two red dashed lines in Fig. 3. to get an idea.
  3. Connect these two cuts with a straightedge and again use your sharp knife to cut through the top plate down to the neck block. See the red horizontal dashed line in Fig. 2.
  4. Remove the vaste material between these three cuts. Making a series of incisions along the grain helps.
  5. Using your compass again, transfer the width "f" to the top side of the button, close to the ribs. See Fig. 3.

Cutting the mortice
  1. Put your straightedge inside the cut-out in the top plate and make two incisions, through the ribs, see the two red dashed lines in Fig. 3.
  2. Make sure the incisions are deep enough to remove the rib material between them safely.
  3. Using a suitable chisel, remove the rib material between the lines down to the button.

Fitting

Bear in mind that small changes in the mortice may cause great changes in the position of the neck. Always make sure that when removing material, the walls of the mortice are perfectly straight for a good fit.
  1. Make a small mark at the top of the top plate at the centerline right where the mortice starts so that you can check the centering of the neck root to the centerline of the plate.
  2. Offer the neck root in place. If the bottom of the root touches the button, cut it a little shorter so that a gap, lets say, half a millimeter is present.
  3. Measure the basics: Neck stop {130 mm} Fig. 4, elevation {27 mm} Fig. 5, overstand /neck step/ {6 mm} Fig. 6 and the centering Fig. 7, so that you have some idea from whence to start. The numbers in the curly brackets are your goal towards which you should carefully proceed.

    The elevation is connected to the arching. Thicker tops can have slightly {tens of a mm} more elevation, which causes the sound to be more powerful.

    The overstand is connected to elevation. It should be around 6 mm. On less arched tops it can be slightly less. Always make sure the fingerboard gets a clearing of at least 2.5 mm from where the top's arch is nearest to it.

    As for centering, it is good to make the mark mentioned above, at the top of the mortice. Make yet another at the end of the fingerboard so that you can compare it to the centerline running beneath it in the top plate. These should be perfectly aligned. This is by no means a substitution for bridge checks, which are the final check of centering.
  4. Bridge check for correct centering: With the help of two rubber bands, put the bridge in place and sight along the fingerboard. See Fig. 7. The fingerboard should be in alignment with the bridge.
  5. Work carefully and slowly towards the aforementioned numbers at the same time making sure the neck root is in good contact with the mortice walls. When being a mm away from the designed numbers, chalk fit the neck so that when at the final numbers everything sits perfectly. Bear in mind that the pull of all the four strings tuned to standard pitches is about 22 kg so a good joint is required.
  6. When everything is all right, put on the neck, take a spare bridge, put it on the top plate right at the end of the fingerboard and scribe on its face the fingerboard radius. This helps you compare the elevation now with the one after you have glued to neck on. It should be identical which means that nothing went wrong during the clamping and gluing.
  7. Clamp the neck down to the violin body and check whether the measurements change. The elevation should be checked with the spare bridge. If the elevation changes it means that the fit is not perfect and that it changes under pressure so it needs some more work.

Gluing the neck
  1. Prepare medium hide glue.
  2. In the meanwhile, try to dry fit and clamp the neck, as in Fig 8. so that you are comfortable with the procedure and can carry it out as fast as possible.
  3. When dry clamped, check the elevation, centering, overstand. If anything changes, you need to go over the mortice and make corrections.
  4. With everything perfect, apply to both the mortice, the button and the neck root itself ample amounts of hot hide glue.
  5. Insert the neck root swiftly in place, squeezing out all surplus glue.
  6. Clamp down as in Fig 8. again and let dry overnight.

Marking and shaping the button

See Fig. 9. The actual dimensions will depend on the violin you are copying. With the Messiah, the "a" is 17 mm and "b" is 15 mm.
  1. Make a mark at the top of measurement "b", see the upper "x" mark.
  2. Set your compass to half of "a", put the needle on the centerline (see the lower "x"), the compass marker on the previously marked point (the upper "x") and draw a half-circle. Check for correctness with your model violin.
  3. Start removing material with your knife, checking the curvature of the heel with the neck template.
  4. Using a round file, finish the shape.

Shaping the neck
  1. Put the neck template in the middle of the neck underside and move it towards the heel and chin again to see whether the neck is in good shape. Remove any irregularities.
  2. The final thickness of the neck is 20.5 mm towards the neck root and 18.5 mm towards the heel so make sure it is close to these numbers. These are general numbers which may need to be changed based on the size of the player's hand.
  3. When the side profile of the neck is perfect, turn the violin around its axis to see the other surfaces of the oval underside and remove anything odd with a flat file.
  4. Finish the whole neck with abrasive paper to remove file marks.

Category: Assembly