-
7 Attachment(s)
Re: Neapolitan Mandolin Build in Naples - November 2022
And the soundboard is on!
The first step was to glue in the lable. Then the process of fitting the soundboard. It starts with trimming the soundboard at the line of the 10th fret. Then trimming neck block to accept the soundboard. This means removing 2mm from the top of the block first by cutting a line and then chisel to the correct height. A top reinforcement and braces either side of the position of the soundhole are added to the soundboard for strength.
Then a bit of practical brilliance. The centre joint at the top of the soundboard is cut about 15mm. A nail is then driven into a corresponding point on the neck block. The outcome is that there is no question about the position of the soundboard on the neck block as the process of precise fitting commences. It is just pushed into the same position each time.
The position of the soundboard is precisely determined by lining up the edges of the cant with the corresponding points on the bowl. The inlets for the braces are marked out and cut. Everything has a few mm left for trimming and fitting. Then the process of fitting the soundboard precisely. The position is continually checked for level in all directions. The level at the cant is measured against the fillet line on the wide ribs. When everything is right the soundboard is trimmed to shape. It isready to be glued on. Paper is added to the inside of the bowl to catch any glue drips as the soundboard is glued on.
The only comment I will make about the gluing is that it uses a lot of masking tape. It was glued with titebond and a good 3 metres of masking tape. It is tight!
Attachment 204261
Attachment 204264
Attachment 204265
Attachment 204268
Attachment 204269
Attachment 204266
Attachment 204267
-
Re: Neapolitan Mandolin Build in Naples - November 2022
Quote:
Originally Posted by
sebastiaan56
Im sure you are aware of the acoustics arguments that go on over lining bowls.
Umm, no, please do enlighten?
-
6 Attachment(s)
Re: Neapolitan Mandolin Build in Naples - November 2022
Quote:
Originally Posted by
Tavy
Umm, no, please do enlighten?
I know it goes on in Bouzouki circles (ref The Bouzouki Building Bible) and I believe Lundberg makes some comments in his book as well. Generally lining the bowl is considered to warm the instrument. That is it is considered to increase internal damping and to reduce upper harmonics. It does certainly reduce the boing of an empty shell. FWIW Woll suggests tap tones for the bowl. The lined bowl has a pleasing thud :-)
And we have a soundhole!
Serious measurement time today. First the soundboard is trimmed to the edges of the bowl. Then the neck is flattened to the top of the soundboard. The whole assembly is then ruled up with the placement of the fingerboard and the soundhole. This is done with great care as the intonation of the instrument must be correct. Note the use of templates. Simple, repeatable and standardised for production environments. The sides of the neck are then trimmed to the fretboard profile and the neck given an initial shaping. Several types of rasps are used here. The rear clasp has a binding channel routed. Finally the soundhole is cut. Both the binding channel and the soundhole are cut in the same sitting. An angled chisel is employed, ie a very sharp chisel is held at an angle and the forefinger of the opposing hand controls the cut. Highly skilled work!
Attachment 204276
Attachment 204277
Attachment 204278
Attachment 204279
Attachment 204280
Attachment 204281
-
Re: Neapolitan Mandolin Build in Naples - November 2022
Quote:
Originally Posted by
sebastiaan56
I know it goes on in Bouzouki circles (ref The Bouzouki Building Bible) and I believe Lundberg makes some comments in his book as well. Generally lining the bowl is considered to warm the instrument. That is it is considered to increase internal damping and to reduce upper harmonics. It does certainly reduce the boing of an empty shell. FWIW Woll suggests tap tones for the bowl. The lined bowl has a pleasing thud :-)
Interesting, I wonder how that relates to Embergher instruments with wood lining to the bowls? Or indeed many US makers which had no lining?
-
Re: Neapolitan Mandolin Build in Naples - November 2022
I agree, there is interesting work to do here. My fear is that we open the “Strad” violin question but some proper testing is called for.
-
Re: Neapolitan Mandolin Build in Naples - November 2022
Quote:
Originally Posted by
sebastiaan56
I agree, there is interesting work to do here. My fear is that we open the “Strad” violin question but some proper testing is called for.
Right after I posted I thought that too: unless someone makes two identical instruments, one with paper lining and one with wood, we will probably never know.
-
10 Attachment(s)
Re: Neapolitan Mandolin Build in Naples - November 2022
A big day yesterday.
We started with refining the shape of the neck Templates are used to describe the ideal and it is a simple matter of refining the neck to the template shape. Then the first oops of the build. While filing the neck the mando slipped from my grasp and hit the floor. The result was a soundboard crack. :crying: “No problem” was the universal reply and I got an unintended crash course in closing and fixing a crack. Essentially the plate sides are aligned perfectly and slightly runny hide glue squeezed into the crack. An application of paper and the hot iron and we were ready to go.
The next step was to start creating the binding ledges on the sides and around the soundhole. Firstly the purfling assembly is created. Alternating layers of black and white purfling are arranged and tacked with a spot of glue. The width is measured and the measuring gauge set. The gauge is elegant simplicity, photo attached. Once the lines are scribed the channel is cut using the chisel method. Fast and effective. The channel is cleaned up with files and the purfling is ready to be set into the channel. Lots of titebond and masking tape later the purflings are done. The same process is repeated for the soundhole.
Finally adding the headstock to the neck.The end of the neck is trimmed to the desired angle and finished square and flat. The headstock is glued on and held with cauls and clamps. Now for a few days of drying.
Apologies for the order of photos, I hope you get the idea.
Attachment 204317
Attachment 204325
Attachment 204324
Attachment 204323
Attachment 204322
Attachment 204321
Attachment 204320
Attachment 204319
Attachment 204318
Attachment 204326
-
Re: Neapolitan Mandolin Build in Naples - November 2022
Great stuff, Sebastiaan.
A couple procedural questions...
What was the point of the extra material left on the neck blank for so long....?
I'm assuming to provide something heft for clamping the mandolin under multiple phases of development. Then it is cut away when neck profiling begins. Is this correct?
Can you provide a bit of clarification on "Once the lines are scribed the channel is cut using the chisel method"? In the days of a Stewart MacDonald dremel jig for everything, I'm impressed.
Lastly, can you provide a bit of detail on the headstock to neck joint and glue up? This is another area where Italian bowlbacks differ from US made ones, which typically have a one piece neck with headstock.
I know I'm jumping ahead, but will you be covering your neck in veneer in the Italian fashion?
Thanks!
Mick
-
Re: Neapolitan Mandolin Build in Naples - November 2022
Can we see a closeup of the fixed crack?
-
8 Attachment(s)
Re: Neapolitan Mandolin Build in Naples - November 2022
Quote:
Originally Posted by
poul hansen
Can we see a closeup of the fixed crack?
When the instrument has been cleaned up. The practise is to leave all of these bits of paper on until the final clean up. Makes sense, only do any job once. Im sure it will be fine. The same process on other glue ups has led to very tight joints. FWIW the crack was my mistake.
“I'm assuming to provide something heft for clamping the mandolin under multiple phases of development. Then it is cut away when neck profiling begins. Is this correct?”
This is correct. It makes a useful handle to clamp the instrument in the vice for other work.
“Can you provide a bit of clarification on "Once the lines are scribed the channel is cut using the chisel method"? In the days of a Stewart MacDonald dremel jig for everything, I'm impressed.”.
It is so simple when you see it done and much quicker than setting up a router. Firstly the line for the channel is scribed. You then get a very sharp chisel, you hold it in your dominant hand with the flat back facing inwards towards your body. You angle the chisel to 30 odd degrees to the horizontal and 5 degrees to the vertical. This creates a slight undercut which aids fitting and gluing. You push 2mm of the angled blade into the spruce and using your non dominant thumb steer the chisel in the direction of your cut a few mm at a time. Your non dominant arm is cradling the mandolin so that it doesnt move. Because the chisel is held so firmly and pushed slowly you get a great degree of control. Grain becomes irrelevant. I’ll attach a photo.
“Lastly, can you provide a bit of detail on the headstock to neck joint and glue up? This is another area where Italian bowlbacks differ from US made ones, which typically have a one piece neck with headstock.”
I hope this becomes clear in todays post. Let me know.
More progress. Things are happening quickly now. The headstock joint is cleaned up and the transition to the neck is provisionally completed. Then the neck profile finalised. Great attention is needed here as it affects the playability of the instrument. Sorry no photo as I was busy with a rasp and a chisel getting it just right. A strip of veneer is shaped and then glued to the neck. It is securely tied and then set to rest. I have a vid of this process. Two binding strips of rosewood are added to the binding channel on the back of the bowl. Finally two strips of mahogany are added to the inside of the soundhole. CA glue is used for these strips. Workshop pragmatism! The whole assembly is set aside to dry overnight.
Attachment 204351
Attachment 204352
Attachment 204353
Attachment 204354
Attachment 204355
Attachment 204356
Attachment 204357
Attachment 204358
-
8 Attachment(s)
Re: Neapolitan Mandolin Build in Naples - November 2022
Another big day in the workshop.
The first task today was to liberate the bindings, top and sides from the paper/hide glue matrix. This work proceeds with a rasp to start and a sharp scraper to clean up. The whole soundboard was then lightly sanded in preparation for the scratchplate insertion. The next step was to shape the transition from the neck to the headstock. This is done in several stages each time getting closer to the perfect theoretical line. Great care is need to not touch the veneer on the neck.
Finally the scratchplate is prepared and the soundboard cut to accept the plate. Again I watch in awe at the quality of the hand work to cut the inset shape with a chisel. The inset on the soundboard was levelled with the same chisel. Some minor adjustments to the shape of the insert and the whole lot was glued with hide glue. It was then clamped and set to dry. One important detail, the workshop has a clamping caul for each individual scratchplate design. A whole shopping bag full. Very impressive!
Attachment 204383
Attachment 204384
Attachment 204385
Attachment 204386
Attachment 204387
Attachment 204388
Attachment 204389
Attachment 204390
-
Re: Neapolitan Mandolin Build in Naples - November 2022
Very exiting as it's very difficult to fathom the beauty of the rough instrument under a lot of glue and paper. We are waiting ;-)
-
4 Attachment(s)
Re: Neapolitan Mandolin Build in Naples - November 2022
An interesting day,
Spent quite some time perfecting the headstock transition. Sorry no photo, imagine files on the back of the headstock. Then started scraping the bowl to reveal the pattern of the ribs and the rosewood. Finally shaped the fretboard, levelled the neck and glued the fretboard. More specialised clamping cauls!
Attachment 204410
Attachment 204411
Attachment 204413
Attachment 204412
-
Re: Neapolitan Mandolin Build in Naples - November 2022
question. I see the pick guard/scratch plate is glued in a slot cut into the top. The top is made thinner there (amazing chisel work!). Does this cause a structural problem with this type of mandolin?
I am asking because we have a 1969-vintage japanese made flat/cant top mandolin (very nice sounding!) with a structural problem. it wants to fold across the sound hole, but only on the treble side, where top is made thinner to accommodate the pick guard/scratch plate. on the bass side, the top has full thickness and does not fold there. (fix is extra light strings, and a pencil stub/post between the top and a back brace, prevents top from caving/folding in. proper solution is to add length-wise braces around the sound hole, as suggested in the other thread).
So I was looking a the photo of OP chiseling away at the top to make it thinner and thinking to myself, did he just add a weak spot where his mandolin will fold 50 years later? is this a designed-in structural weakness?
-
Re: Neapolitan Mandolin Build in Naples - November 2022
My experience is very limited in this area. Im sure others will add an opinion.
What I have seen is that the area of the scratchplate isn’t where these mandolins tend to fail. It seems to be in the area between the top of the soundhole and the neck. My limited understanding is that suitable reinforcement in this area is critical. I have just watched a repair where extra braces were added either side of the soundhole on a 1898 Washburn. The soundhole area is quite warped. Also if the bowl is poorly made this can be a cause of failure as well and a lot more difficult to fix..
I assume the scratchplate you are mentioning is made of turtle shell? It is nowhere near as rigid as rosewood.
-
Re: Neapolitan Mandolin Build in Naples - November 2022
oh, the scratch plate is rose wood. I missed that detail. so it is laminated wood on wood and there is no loss of thickness. so that's the difference between a Napoli-made Neapolitan mandolin and a cheap knock-off. (joke!). the one that folded (and others I see) all have some kind of non-structural plastic.
btw, big thanks for all the photos and descriptions. i have a bowl-back mandolin that self-disassembled. i am looking for ideas on how to reassemble it (i am not setup for proper woodworking) and it is extremely helpful to see how these things were originally put together.
-
Re: Neapolitan Mandolin Build in Naples - November 2022
Largely +1 on sebastiaan's comments.
Generally the weakest area is either side of the sound hole: you can straighten that out and add finger-braces along the length of the grain either side of the sound hole. This does not generally effect the sound of the instrument (and the top should be stiff in this direction anyway), and some of us add these braces to new instruments anyway as a bit of extra insurance.
After that the next weakest area is under the fretboard extension, most of the better makers will reinforce this area as well, cheaper brands (including most of the Japanese imports) do not, which can result in the neck rotating forwards.
After that you see bowls splitting apart, and/or the top under the bridge bellying upwards, lots of tension in those strings, so there's always something that will get you on a hundred plus year old instrument.
-
5 Attachment(s)
Re: Neapolitan Mandolin Build in Naples - November 2022
More scraping, Then levelling the fretboard and slotting.
Forget your perfectly machined piece of stainless from your average lutherie supply house. The levelling beam is a foot long piece of 1”x2” mild steel. The one in the photo is smaller, I chose to use the larger one. Solid, flat and well up to the task at hand. I was a bit taken aback by the 40 grit initial paper but we finished with 100 grit. The fretboard extension is then finalised with rasps and a file.
Slotting the board is another exercise in practical thinking. The saw is made in the workshop from and old re-sawing bandsaw blade. The teeth are cut by hand with a triangular file. The template is a series of slots cut into a maple board, 1” x 3” x 18”. The pictures describe the process pretty nicely. There are 27 frets but the last two frets are a full tone apart rather then a semitone. Simple, repeatable, fast.
Attachment 204434
Attachment 204435
Attachment 204438
Attachment 204436
Attachment 204437
-
Re: Neapolitan Mandolin Build in Naples - November 2022
I know "this is the way it's always been done", but given that they're now using a more modern thickness for the fretboard, why not cut the slots on the work bench before fitting? It's just so much easier! Or are they cutting right through in the traditional style?
BTW I assume there is something other than luck and judgement to protect the top while slotting the board down there? I have a couple of offcuts of aluminium sheet I tape to the top either side of the fretboard whenever I'm working down there, just cuts down on the worrying/nightmares a bit :grin:
-
Re: Neapolitan Mandolin Build in Naples - November 2022
Yes, there are a couple of plates of steel taped to the top of the soundboard to protect it. I prefer to prepare the fingerboard first as well. I think the reason it is done this way is to make sure that the placement of the bridge is correct.
-
9 Attachment(s)
Re: Neapolitan Mandolin Build in Naples - November 2022
The tailpiece mounts are on and we have frets!
We are getting to the end of the build now. Firstly the end clasp is shaped to its final design. Simply done by either the chisel method or with a rotary cutter.. The tailpiece mounts were then cut from Rosewood and shaped. They are glued on and then further shaped with rasps and files for the final shape. A notch is cut either side of the tail so that the tailpiece can be precisely located for gluing.
Now adding the frets. First the fretboard is re levelled. The ebony does move after the fret slots are cut so a re levelling makes good sense. It is flooded with titebond, then wiped clean with a wet sponge. The frets are then hammered in and cut to length. Tidying up will happen after everything is dry.
The work remaining is to trim the fret ends and level and crown the frets. After that the instrument will be strung and checked for all parameters. It will then be on to finish sanding and scraping and then french polishing. Finishing will happen when I get home as our time budget is nearly done.
Attachment 204461
Attachment 204462
Attachment 204463
Attachment 204464
Attachment 204465
Attachment 204466
Attachment 204467
Attachment 204468
Attachment 204469
-
Re: Neapolitan Mandolin Build in Naples - November 2022
Quote:
Originally Posted by
sebastiaan56
... I prefer to prepare the fingerboard first as well. I think the reason it is done this way is to make sure that the placement of the bridge is correct.
Thanks, Sebastiaan...it is very interesting to see the fret slot cutting jig.
A clever jig.
My fear is that the saw blade would eventuall enlarge the slot that it is riding in.
Or are the jigs resistant to that (hardwood, greased or something...)
Can you clarify your answer quoted above?
How would cutting the fretboard slots in situ effect the bridge location...which is going to be placed where it is going to best placed?
Am I missing something?
Mick
-
Re: Neapolitan Mandolin Build in Naples - November 2022
The jig is hardwood (maple) and there are cork feet on the bottom about 3mm high. I think this is to keep the teeth of the blade away from the edges of the jig. It also has marks to indicate the placement of the nut, 10th fret, dot positions etc. There is another rule that has these and the bridge position precisely scribed. The correct setup of the jig starts with making sure the bridge location is correct and working back from there. The fingerboard is trimmed at the nut end after the second levelling. So the set up works backwards from the bridge. I have seen a bunch of mandolins made by this system and the position of the 10th fret can vary by about 4mm. I have also seen the same system in use in other Luteria we have visited. The bridge location is regarded as critical to sound quality. A bit like a violin.
Ive been pondering this method and it seems to me to be an excellent way to ensure semi skilled labour can produce repeatable results. The Calace factory here is the dominant player in the industry and from what I can tell most workshop staff in Naples have come through Calace. I suspect a lot of these working methods have there origins there and in earlier makers. Bear in mind that the original Vinnacia factory was in the Rue Catalina which is about 1 kilometre from where the Luteria resides. I dont know how many times the terms Simple, Effective and Repeatable have gone through my head.
-
Re: Neapolitan Mandolin Build in Naples - November 2022
Thanks, Sebastiaan...this is very interesting.
I've had a bunch of MOR Neapolitan mandolins from the Lanfranco, DeMureda, Stridente, Ferrari crew that I bought to tinker around with.
The fretting on these varied widely from one another and the intonation was wonky at best.
I've replaced some fretboards on some of the MOR bowls to help compensate for out of place necks and those play wonderfully now.
The intonation on my Vinaccia, DeMeglio and Ceccherini bowls is really pretty good. Night and day difference.
I've comped the fret spacing with some well made US bowls and find them nearly exactly the same.
So I'm fascinated with these jigs and the hole fretting process that you are discovering and working through.
Thanks for sharing and for answering my questions!
Mick
-
6 Attachment(s)
Re: Neapolitan Mandolin Build in Naples - November 2022
Today was the last “build” day.
It was simple enough, add side dots, dress the fretboard and an all over scrape. The finishing will happen when I get back home. Im planning to French Polish before final assembly.
Finally, a pilgrimage photo. Rua Catalana 34
Attachment 204518
Attachment 204519
Attachment 204520
Attachment 204521
Attachment 204522
Attachment 204523