Neck and fingerboard build questions

[Br1ck]

I just glued the neck on my Arches build and have a few questions. The reinforcing piece that goes under the neck over the top, don't remember what it's called, but does it get glued in first before the fretboard? At the same time? After? Glued to the fretboard first?

And how on earth do you finish the top under the Florida or stain and finish that reinforcement block? Can you stain it first? That would require some color decisions.

Anyway, I'm taking a break to practice my binding and fretting skills on an old cheapo Harmony archtop that has painted binding now. My confidence factor is much better the second time around. Like I told my daughter after putting crown molding in her bedroom, I'll do it much better the next time LOL.

[Tom Haywood]

"Under the neck over the top"? A picture might help.

[jim simpson]

I believe you are referring to the fingerboard extension support. Roger Siminoff shows it in his book as being glued in prior to adding the fretboard. He drills and inserts a wood screw at an angle to hold it while it sets. I believe he mentions that he doesn't bother to remove the screw afterwards.

*arrow pointing at uncarved extension in my photo

[buckhorn]

I always install the extension after the finish has been applied.. I stain it black then drill for a screw at an angle sloping to the heel.. When the screw is tightened it will draw into the neck crossover piece.. the drill hole must be countersunk so that the head of the screw is below the surface of the extension and not contact the fretboard...

[Tom Haywood]

I'm sure there are different ways to do it that all work fine. I glue the extension support on after gluing the neck riser and neck. Seems to me it has to be done that way in order to level the "ramp" that the finger board sits on. I mark a "no finish" line on the top so that the glue join is bare wood to wood. I don't use a screw because there is a glue join to the top, the cross piece and the fingerboard when it is added later, and if any creep takes place it can be sanded to match the fingerboard when that is installed. I use Titebond, clamp and wait 24 hours. Spraying the finish, it's not a problem to do after the piece is installed. If rubbing, sometimes I put a little dark stain outside the "no stain" line before gluing the piece on. That does require making some basic color decisions. Sometimes I add stain later with a Qtip, but it's hard to control that way. Sometimes, I stain the whole top first except for the glue area.

[Chris Baird]

Hi Brick, You should glue the fingerboard extension on first, then level it and the riser block flush with the neck prior to gluing the fingerboard on. To level them down I use a long flat piece of thick glass. Stick sand paper on one end, and build the other end up with tape to match the thickness of the sand paper. This will ensure that the extension and riser block are leveled flush with the neck.

Be sure that you finish sand the top area under the extension before gluing it on as it is hard to finish sand it afterward.

Staining underneath the extension is tricky, you have to use q-tips or other small implements. But, a sunburst makes it somewhat easier as all the "nooks and crannies" are dark in color.

[Br1ck]

Thanks Chris, I'm going to have to make some finishing decisions soon I see. I was thinking a dark Amber with just a subtle darker burst around the rim. Time to order some dyes and experiment on some maple boards I have.

I can't say enough about your quality kit, and would council anyone who is going to spend the time and effort to go with quality from the start.

[V70416]

Timing is everything.

[HoGo]

I would just add that if I had to choose just one joint on mandolin to be glued with HHG, this is the one. All the strain from string tension is pretty much centered on the top of extension. The neck heel in dovetail (if well fitted) has little chance to move but the upper part, that is under all the pressure, may slip towards bridge if subjected to right conditions (or over long time) when titebond or simlar white glue (that allows creep) is used. We se this happening in this thread:
https://www.mandolincafe.com/forum/s...uss-adjustment
HHG will not creep and provide solid fulcrum for the neck acting as lever.
I suppose your kit has tightly machined neck joint that butts against neck block and riser so there is very little chance of this happening but on simple doweled tenons like "Siminoff joint" I see this regularly especially if the neck is not butted tightly against the neck block and riser block inside the joint.

[fscotte]

Reference that other thread, wouldn't that be an example of a poorly fitted riser block - perhaps not perfectly flat against the headblock when glued. Glue shrinkage would then compromise the joint, neck pushes riser block towards bridge.

[HoGo]

Reference that other thread, wouldn't that be an example of a poorly fitted riser block - perhaps not perfectly flat against the headblock when glued. Glue shrinkage would then compromise the joint, neck pushes riser block towards bridge.

No the riser block may be fitted perfectly but once the neck wants to move the f'b support and riser block is the only thing that can hold it in place. I repaired F-9 with failed neck joint and the bottom of the joint was still glued to the back but the large fingerboard surface pushes the riser block and support towards bridge and the relatively small glued surface between support and top creeps and riser slightly rotates (causing finish cracks between the riser and ribs) even if it is butted hard against top edge and may even open fingerboard joint under 13-15th fret.... If the support was glued with HHG it would likely hold the neck in place (were there no other problems like filler in the neck joint)

[fscotte]

I've read that opposite grain orientation between the two surfaces can contribute to glue creep as well. I wonder how would we know if the creep was a result of the glue itself or poorly matched surfaces, where excess glue would have to fill the spaces.

[HoGo]

I've read that opposite grain orientation between the two surfaces can contribute to glue creep as well. I wonder how would we know if the creep was a result of the glue itself or poorly matched surfaces, where excess glue would have to fill the spaces.

Opposite (or better said perpendicular) grain orientation can cause creep if there are large humidity changes i.e. differential shrinkage will make the joint creep or separte if extreme.
Titebond is good glue if everything is good - good fit good clamping and good conditions during life but anything is not ideal it's performance goes rapid downhill. it is rubbery and will not work in poorly fitted joints, if you don't clamp well it will not be as strong and if heat or especially temperature swings, the joints under tension will move. HHG is much better in all three. ALthough surprisingly slightly poor joints held better with HHG than with modern glues, clamping is often not needed if you use the "rubbed joint" (though that works only if the joint is perfectly dry-fitted) but best of all it will hold even in rough conditions. It won't fail in heat and larger joints will hold surprisingly well in high humidity too (I once had to disassemble double bass top plate joint few minutes after clamping when I found out the glue gelled too fast - took me few hours with knife and hot water/steam).

[Cush]

I like to attach the extender to the neck with the addition of a dovetail to the extension piece. This makes a very solid connection between the two pieces with little contact between the top and the extension piece. I always did my archtop guitars this way, so I thought why not use it on my mandolins.

[Chris Baird]

For my kits the riser block is glued on first and then the the neck joint cut into the riser block and the rim. The joint just barely has enough room for glue, so there wouldn't likely be any creep, regardless of the glue used. But I do trust HHG more than any other glue.

[jim simpson]

I realize this is an older thread but I have a question about what material is typically used (as is illustrated in Chris Baird's post) and glued to the riser block? Chris Baird's looks like a piece of bone but not sure. I am using ivoroid/celluloid binding on my build and not sure where to source a piece tall enough for the riser. I don't think my binding terminating to another material would look that good. I don't want to glue and stack side binding to get the height needed. Thoughts?

[Walt]

Jim, here’s a link to some ivoroid sheet stock. NFI.
http://www.axinc.net/mobile/Product.aspx?id=37895

With the hazard fee everyone is charging to ship ivoroid, you just about have to buy it bulk for it to make sense.

Alternatively, I wonder if it would be possible to stack two pieces of binding without a visible seam?

[HoGo]

Alternatively, I wonder if it would be possible to stack two pieces of binding without a visible seam?

Sure it is but it requires some experience.

Old Gibsons typically didn't have that large piece of celluloid but two strips of binding at an angle following the outside surfaces, thus creating triangular or trapezoidal empty area underneath. Historically on F-4's, the riser block was in direct contact with top wood (no support piece was used) and on treble side a saw cut was made at the joint for the small angled piece on one side only. On bass side the top binding followed body outline and the spruce-maplle butt joint was left alone.
On some Loars they did the body binding before the crosspiece and just added one long lower piece over the end of the top plate across whole area (butted it to the riser block above the top binding and the support piece butted to that)

[jim simpson]

Walt, thanks for that link. That material would do it but the surcharge, whew! I do like that one could make point protectors in addition to the cross piece. I stacked 2 pieces on my last build and used acetone to glue/blend. It was okay.

Adrian, I hadn't thought of the trapezoid angle. I think that may be what I'll try. Thank you.

[HoGo]

Walt, thanks for that link. That material would do it but the surcharge, whew! I do like that one could make point protectors in addition to the cross piece. I stacked 2 pieces on my last build and used acetone to glue/blend. It was okay.

Adrian, I hadn't thought of the trapezoid angle. I think that may be what I'll try. Thank you.

Here are some pics that show it. Some old Gibbys, one of mine (white) and CT of Loar with the piece laid over the top of binding....