The Ultimate Bluegrass Mandolin Construction Manual Virtual content
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NOTE: Books published after November 15, 2005 (indicated by "2nd Edition" on first page, above ISBN numbers), include numerous editorial corrections. However, those items below highlighed with a red dot (•) have yet to be made.
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Soundboard thickness, f-hole area, Drawing #12: Soundboard thickness measurements do not include the gauze around the f-holes. These measurements are for wood thickness only and should be taken before the gauze is added.
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Soundboard and backboard thickness, Drawings #12 and #13: The thicknesses provided on these Drawings are the MAXIMUM starting thickness that the wood should be carved prior to tuning. The final dimensions will depend on how much wood has to be removed to arrive at the correct tuning. Dense maple backboards and close-grained soundboards could result in post-tuning thicknesses that are .015" to .025" thinner than measurements shown.
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• Dovetail joints, p 70: The photo caption for Fig. 8.20 says to attach the headblock cap "before" cutting the headblock and cap's shape. The cap should be attached "after" the headblock is cut to shape. Therefore, first sentence of the caption should read:
"When making a dovetail joint, the maple top piece is glued to the headblock wood after the headblock is cut to shape."
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Dovetail joints, p 71: We discovered some copy and a photo missing, and an incorrect photo caption on page 71 just before the book went to press. Click here to view and print the corrected page,. Then press "BACK" on your browser to return to this page. Or, click here to download a PDF copy (120K) of this page. Tape the corrected page over page 71 in your book. If you would like a complimentary printed version of the corrected page, please send a stamped, self-addressed #10 envelope (business size) to Roger Siminoff, Editorial Correction p71, PO Box 1388, Arroyo Grande, CA 93421, USA. (Books shipped directly from us contain a correction page.) (Books that say "2nd Edition" directly above the ISBN numbers on page one already have this correction made.)
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Router depth gauge, Fig. 10.27. To help clarify what is in the photo: the wood depth gauge has a small cut-out and fits over the router bit. When in use, the router base sits on the piece to be routed and the edge or "finger" of the depth gauge maintains depth of cut.
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Making kerfed lining flush with rib, Fig. 8.1, p 65: The book shows how to make the kerfed lining flush with the rib (rim) by using a table sander. If you choose to use a dovetail joint, the headblock cap (which you should install before cutting the dovetail through the headblock so that you cut the cap and headblock at the same time) will be in the way for this type of machine sanding. An excellent and easy way to accomplish this task is to prepare a sanding block like the one in the photo below (lower left). This block is made of a piece of 3/4" x 4" x 16" maple with a solid wood handle attached to one side and a piece of 80-grit sandpaper (from a 4" x 36" sanding belt) attached with contact cement. Then, you simply lay the sanding block on the rim and sand until the rib and kerfed lining is flush. Be sure to keep the block moving all around the rim so you don't sand in one place and cause a low spot.
Installing a scroll strengthener (peghead), Page 34: Here's an extra tip when preparing the scroll strengthener plug: Drill a 1/16" hole at an angle, all the way through the plug, going into - not across - the grain. The hole will act as a weep hole to allow excess glue to ooze out when clamping the plug in place. This is especially important if the plug you prepare fits very tightly into the plug hole. (My plug hole drill, and plug tool were machined to create a very tight fit of the plug into the hole.) If the glue can't ooze out, there is a possibility that you could crack the peghead when you try to force the plug in. And, you want as much glue to come out as possible so that you have wood-to-wood contact. One reason that I drill into the grain is so that I can easily see how to orient the plug's grain direction when I'm gluing in the plug. And, I orient the plug so that the glue hole is out on the peghead's scroll and not near the cutout where it could weaken it.
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Shading the peghead, Drawing #19: The lower two arrows in Drawing 19 were in the wrong place and not corrected during our editing. The correct locations for shading the dark areas of the side of the peghead should be as shown in this drawing. The peghead is shaded at the lower points, the equivalent of the upper points, and at the tip of the end of the peghead. (Corrected in "2nd Printing")
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Neck heel angle, slotted-and-pinned neck joint (pg. 67): As shown in Fig. 8.8 and Fig. 8.9 for preparing "V" joints, , the opening in the headblock is cut with the body held at a 6° pitch. If you are preparing this type of joint, the neck heel should be perpendicular to the fretboard plane (rather than at the 6° pitch shown in Drawing #1). The rationale for cutting the opening in the headblock at an angle is to allow deeper insertion of the neck heel into the headblock for an opitimum secure connection. However, if you have already cut the neck's heel at a 6° angle (since the straight heel is not shown in Drawing #1), you can cut the opening in the headblock so that its back wall (not the sides) are perpendicular to the rim (i.e. straight up and down). While this does not allow the neck to go as deep into the headblock, it still provides for a secure joint, especially once the dowels are set in place.
If you do the dovetail joint (pg. 70), it's the opposite; the headblock is cut perpendicular to the axis of the body, and the neck heel is angled at 6° as in Drawing #1. In both cases, the corner where the end of the neck meets the fretboard plane, should be 7-7/8" from the inside edge of the nut.
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Clearance for soundboard's scroll, "V" joint fixture, Fig. 8.13: To enable clearance for the soundboard and headblock to come down to the neck properly, the base board of the fixture has to be carved away in the area of the soundboard's scroll. The notched-out area is barely visible in Fig. 8.13, to the left of the neck heel as you look at the photo. Remove as much wood as necessary so the scroll does not touch the fixture's base board.
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Surrogate bridge height, V-joint neck setting fixture, typographical error, page 69 and Drawing #20: The text in the paragraph entitled "Attaching the Neck:" on page 69 says that the fixture's cradle should be 3/8" high. It should read 1/2" high. The text in Drawing #20 also says 3/8" and it should read 1/2" high. The illustration on Drawing #20 is correct and shows the cradle 1/2" high.
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Assembling the rib and block set, Chapter 7, page 62: Here is some additional information to facilitate assembling the rib and block set. Click on this link for a photo essay of 15 steps for assembling the rib.
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Preparing the V-joint, Chapter 8, page 68: In the book, I suggest that the two fillets on either side of the neck joint can be added after the V-joint is cut. As an alternate, you can also add the headblock cap before you cut the V-joint, preparing it in much the same way as you would for the dovetail joint. (This mandolin features a Brazilian rosewood rib.)
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• Typographical error, page 83 - "soundboard's" should be "backboard's": In second paragraph, upper right corner, second paragraph, second sentence should read "It also helps to maintain the backboard's basic shape.
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• Typographical error, page 69 - "1/4" should be "5/16": In last paragraph, the reference to dowel size for the "V" joint should be 5/16" and not 1/4".
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• Peghead thickness (taper), page 33, Fig. 4.21: The peghead on original F5's was tapered so that it is thinner near the end. This is shown in our ProSeries F5 Drawings but not shown in the book's drawings. To cut this taper, tape a piece of .060" binding across the face of the peghead so that it is aligned with the hole in the small scroll. This shim will enable the cut on the back of the peghead to be on a bias to the peghead's face.
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Attaching the neck, Chapter 8, Initial Assembly: Some questions have arisen about down pressure problems that result from improperly set necks whose neck pitches are above 6°, or from improperly carved soundboards that result in string break angles over 18°. Click here for more about String-break-angle loads.
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Advanced method for dressing the edge of the soundboard and backboard flush to the rim, Chapters 8 and 10: Chapter 8 (Fig 8.7) and Chapter 10 (Fig. 10.10) show a simplified method for sanding the soundboard and backboard flush to the rim. This can also be done with a spindle sander or small drum sander. However, if you are planning more advanced production, you can use an overhead router with a flush-trim bit. For trimming the backboard, a fixture is required to hold the body squarely above the work surface.
For making the soundboard flush to the rib, a router fitted with a flush-trim bit is mounted on a sturdy extension arm and will make the job fast, clean, and easy. The router is mounted perpendicular to a large smooth work surface so that the rib and soundboard assembly can be moved easily against the bit, with the bit kept parallel to the rib.
For making the backboard flush to the rib, the instrument should be held in a fixture so that the entire outer edge of the soundboard's face is supported parallel to the work surface. In the scroll area, the fixture is larger than the body (difficult to see in this photo) to allow the raised edge of the scroll to sit into (not onto) the fixture.
The body, with the neck and backboard attached, is then placed in the fixture, held in place snugly by the outer guides, and the backboard is routed flush to the rim similar to the method used to make the soundboard flush.
Only the edge of the soundboard contacts the fixture, to allow room for the center or crown of the soundboard to fit into the fixture. The small white piece with two black knobs (center photo) is an adjustable support that moves back and forth to contact the neck and help to support the body squarely in place. As with all cutting tools, hold the work securely and watch your fingers!
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Advanced method for preparing the Siminoff V-joint, Chapters 8, page 67, "Slotted-and-pinned neck joint": For those who plan to use the V joint in extended production, here is a fixture to assist in easily and accurately cutting the V-shaped sides of the neck's heel.
The fixture provides for the neck to be clamped to one face of the fixture. The neck is first aligned to the centerlines drawn on the fixture, then the toggle clamps are closed to lock the neck in place. (The two wrenches are for the router's chuck.)
Here the fixture is clamped to the workbench. The top of the fixture has been fitted with a V-shaped plate that is identical to the shape of the "V" in the headblock (see the headblock cutting fixture in Chapter 8, Figs. 8.8 and 8.9). Then, a router with a top-bearing flush bit is simply moved against both sides of the V-shaped plate which results in the neck heel below it being cut to a V.
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Fitting the heel of the neck, Chapters 9, page 89, "Attaching the backboard": If the heel of the neck came out larger than intended, before attaching the backboard, draw a pencil outline of the backboard's neck nub onto the neck heel. Then you can remove the backboard and more easily shape the neck heel up to the pencil line without the backboard getting in the way.
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