Official Luthiers Forum!

I'm just about to order a new batch of kerfing for the next 6 or so guitars. Before I do I thought I would just call upon the collective mind to see what you're all using.

I like to use reverse mahogany to join the back and sides, I like to get this joint as stiff as possible and as my main B&S woods are mahoganies. For the top I use triangular Spanish Cedar, I like the neatness of the triangular, oh, and the smell! I don't want to stiffen the joint too much just provide a gluing surface.

So, you opinions please, I didn't do a poll as I find raw data to be of no real use, but argued reasoning I like.

How many of you pre-bend the kerfing on the form or on a pipe? Something I've been playing with.

Good sources too please.

Colin

Colin S38713.2372337963

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

Colin,

Currently I am using mahogany reverse kerfed linings because I like the way they look and that glue cleanup is a lot easier for me as there is only the top slits to deal with that clead up nicely with the tip of a Stanley knife blade. Also I find it easier to notch these to accept my side braces and the flying buttress braces:



I haven't tried pre-bending them - they are quite fragile and are tricky to keep in one piece round tight bout bends. I have learned to glue the waist parts in first so that if the snap, any break lines are in the far ends of the bouts where they can't be seen through the soundhole. The Taylor Factory Friday's videos showed a neat trick of using a sharp knife to widen the kerf slots for tight bends around the waist.

I get mine from Stew Mac and LMI and think they are expensive so I must check out the great suppliers of this Forum.

I'm not really convinced about the stiffness arguments.

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Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

Hi Colin and Dave,

My opinion might shock you but i did mine on my first guitar with pine that i cut on my TS and had sawn the angle on my bandsaw, it was time consuming enough but since it was my first one, i wanted to work on every single part i could. I guess that if i were do this for a living and have deadlines to meet, i would probably look for a good supplier as well.

I don't use any kerfing, since, well, saw cuts do absolutely nothing to stiffen or widen anything. Kerfed LINING, on the other hand... *

I like the look of reversed kerfed linings, and what they seem to do to the stability of the sides, so I'm sticking to those. I am making them myself, african mahogany so far, will add some spanish cedar in the near future, and I've got some spruce I want to process for joining the top to the sides, and I've got a big chunk of Willow that's going to be processed into solid liners (first, anyway, see how a few test pieces bend). I'm also a bit doubtful of claims re: hugely increased stiffness between the top and side connection caused by using one or another type of liner. I'm be more tempted to simply use thinner liners if I thought that area was 'too stiff', and I will be experimenting with using lighter woods (spruce, in this case) in that location, as I do think mass could matter. But I'm not willing to sacrifice stiffness for it. In my 'mental model', I want the sides as stiff as possible, not damping vibrations, and reverse kerfed lining seems like a good way to achieve that, on both top and back.

* Apologies to Howard for stealing his (most rightheaded) spiel..

Hi Colin

I can't make up my mind

At the moment I have Reverse and Triangular in Cedar and Spruce, I quite like the spruce as it is less fragile than Cedar.

Steve at Colonial is a good source, all of his linings are top quality, and he gives a discount if you buy them in quantity.

Russ

I use Reverse Mahogany, Cedar and some times Basswood. I use to use triangular but switched about 2 years ago. I do pre bend on soft cutaways with mixed results. It seams I snap about half as many pre bending cutaways as I snap not pre bending. I hate to add too much moister to the linings as they tend to swell. then you have to wait for them to srink fully before gluing. I have a clothing steamer I use on them some times but I am still working on the technique to avoid interducing mostiure to the sides. I have used this with just half an assembly mold as the form, taping them down as I go, so that I keep the moisture off the sides. Then gule them up after a day of dry out.

I've always used tentellones (individual pieces) on my tops. It takes a little longer, but they are inherently more flexible to use, I think. For the backs, I used mahogany reverse kerfing, until about four guitars ago, and then I started using basswood linings. I cut the basswood linings into ~0.100" thick strips, bend them on my mold, then laminate two strips together. Basswood likes to wrinkle when bent, and I've found that bending thinner strips eliminates this problem. Also, after being laminated together, they are much more rigid and hold their shape better than solid strips.

Best,

Michael

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I have tried all kinds and seem to prefer the reverse kerf in Spruce. I have had a little trouble getting them but I have some on the way right now. I have also tried prebending and I like that. On the last couple of guitars I have put the side braces in first and then installed the kerfing between them to get the side brace running across the whole of the side. That was kind of a pita so I'm thinking of doing it the way I just saw Dave White doing it. Notching the reverse kerf for a nice clean look. I have also laminated linings for a nice no gap very stiff side. I liked that but it is also a messy pita. I like the spruce because it is as light and strong as mahogany and gives a very nice look against a darker back and side wood.

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Tickle your guitar daily, and it'll tickle you back.

In the last guitar I made I used reversed kerfed lining. I doubt I will use
them again. If it breaks anywhere, or you need to start a new piece, you
can see the joint between the separate pieces. The seam between pieces
of conventionally kerfed lining don't show, as it is against the side. I also
think reversed kerf lining adds a lot of unnecessary mass. I use
continuous linings on the back seam of classicals, but steel string guitars
need slightly wider linings that don't bend well, so kerfed linings are all I
use there. I have a simple indexing jig for my band saw to make the kerfs.
I glue in the linings having a rectangular cross-section. That makes it
easy to get uniform clamping pressure. Once glued, I use a knife to cut
the taper, leaving a slight curve rather than flat.

I use solid linings made from spanish cedar on all my instruments. Cutting cutting the pockets for the braces is one of the things that drove me that way after using standard kerfed linings for years.
I've never tried the reverse linings, but seems like a good idea also.

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Jim Watts
http://jameswattsguitars.com

Colin,

I actually am starting to do it just the opposite of your description.
But it has more to do with my building sequence. To wit:
I am starting to glue the backs on first, and then the tops. I like to really clamp the sides to the mold to get a true shape, and thus am not depending so much on the linings helping to maintain the shape. So, a triangular lining will be glued on there at the sides/back joint. When done, the clamps come off, and I'm depending on "spreaders" at that point to keep the sides true when the top is glued on. And that reverse kerfing really makes a stiffer area that keeps its shape much better. Of course, I could use the reverse kerfing on the back/sides joint, but I like the more traditional look of triangular kerfing at that place.
So, for me it's a matter of 1)practicality, and 2)aesthetics. Oh yes, I love the smell of Spanish cedar, so that's what I use as much as possible, except for maple quitars which use basswood (Lime). I'm too cheap to buy it, so I cut my own.

Sorry for the windy response,

Steve

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