The Luthier Community

Edward,

Khaya is fine wood - I've used it for back and sides on a double necked Acoustic lapslide guitar and for back sides and top on a tenor guitar.

Runout will be your biggest structural worry for a top - too much and it can basically implode/explode under string tension. That's about the way the grain runs when viewed from the side along the plank's length. Flatsawn/riftsawn as opposed to quartersawn has more to do with stability under humidity changes and stiffness. Look at the grain direction at the ends of the planks when you have cleaned them up - straight up and down (perpendicular to the plane of the plank) is quatersawn, side to side is flatsawn and in between is rift.

It can only take about half a day to make and fit linings (don't know about ouds but the lute I made recently had them) and their wight is miniscule. I just don't see the benefits of not using them.

yes, strangely ouds never use kerfing, but this perhaps has something to do with that it is nylon string and has less pull than steel.

Ok, yes I hear you about flat-rift sawn... yes, of course I will use near-perfectly quartered wood for the top. In the foto it looks flat sawn but that is actually the saw cut - because I cut it by hand.

Have a look at the new -runout- thread I started and the diagram I drew..... when I assess a possible cheap board of course the first thing is quartered on the end grain, and second thing is straight grain on the FACE..... but i wonder about runout along the SIDE GRAIN.

THANKS!

Hi Edward,

I'm with Dave, and forgot to mention it in my post above, but a guitar without linings - kerfed linings or solid (laminated) linings - has very little gluing surface for the top to the sides. Considering typical .080" thick sides/rims (very little gluing surface), adding linings triples or possibly quadruples the gluing surface. Another option is tentalones/dentalones - basically little individual rectangular or triangular "teeth" that some classical builders use. If you buy linings (such as reverse-kerfed linings), you'll pay about $16 for four sticks (enough for a guitar top plus guitar back.) You could make them from scrap for next to nothing but labor. I don't think this is something you want to skip, even on a prototype, as I believe you are taking a huge risk with structural integrity, and at best would have a very fragile instrument.

Dennis

yes you guys are right.... I already had the soundboard collapse on RAGMAKAMTAR #1 because of tine kerfings. You are right it won't be difficult to put them in.

...this is definitely and very literally a backyard build ....great weather for it too!

I have some severe limitations in tools.... so I rigged up my circular hand saw into a make-shift small table-saw, and sawed up the ribs which will be the rounded back..... worked perfectly !

ok - got the very basic rough 'rib blocks' done today.

weather is amazing

piece by peace, something is starting to take shape.

Ok.... making some progress. One thing is my lack of tools here - getting majorly slowed down on occation simply for not having some very very basic stuff--- but that never stopped me before, so I keep pushing onward.

After getting the blocks made and temp.-mounted -- I sat and looked at it and it just felt to me like the body is too small. The point is that this thing has GOT to eventually sound something like in the ball park of an oud - otherwise I am going to find myself building ANOTHER one very soon. Clearly if it is going to sound like an oud (on the oud side) then there is no getting around it, the soundboard has GOT to somehow simply quite resemble an actually oud's soundboard (and back etc).

So I took the fotos of the design and fed them into photoshop and then superimposed pictures of an oud and an oud's soundboard - - just to really get a feeling for the comparision. I went thru a number of "sound is round" type analysis of the situation, and to my surprise quite majorly increased my understanding of how the design of an oud creates it's sound. Sound is Round is really a fantastic theory - and I am using this to design this new soundboard..... finally when this instrument is finished we will really hear how effective were the results.

So I decided to widen the lower edge of the oud-side quite a bit... this will also make the oud easier to play as it will 'sit' higher. One possible drawback to this new shape is that the sarod side, which already sits a bit high, will now sit even higher....

Another change in design I decided on is to more the sarod bridge back even further, right up next to the edge.... this I realised will help the ergonomics because sarod right hand stroking likes to have ONLY the wrist hanging over the edge. This is how an actual sarod is played. An actual sarod has a tiny soundboard surface area - but a sarod produces almost no bass. The sarod sound is the very very least of my worries for this instrument. I think just tucking the whole sarod part as far off in the corner as possible is the best idea, both for the sound of the 'sarod', and also to get it out of the oud's way. The oud needs MEGA space with nothing blocking.

Both bridges will be floating, and I now am putting the sympathetic strings way way off in the top corner.They will sound fine up there, and they will be so far from the oud, and so close to the edge that this way they will add almost nothing to the structural strain on the instrument.

So the new design is set, and I began putting on the ribs. So far so good - got 2 of them on - and now the fun part starts...... trying to tweek and adjust by eye all these ribs. It is going to be a major exercise in compensation, and hopefully it will not get so far off and to finally not work. Luckily I now know what to look for and can spot when it is starting to go OFF. Already with this second rib on, I can see exactly how I am going to have to compensate this third rib in order to get it to fit and also provide a reasonably straight glueing surface for the next on.......

Edward,

Holy cow. That looks really cool. The holding frame looks almost pre-historic. Great shots.

Lefty