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PostPosted: Sun Mar 24, 2013 7:07 am 
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First name: Dennis
Last Name: Kincheloe
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Well, I was hoping to have this thing boxed up by now, but I've been lazy. Got the sides thinned down, and had one warm day perfect for bending... and failed miserably. Broken headstock bindings, and only one side sort of bent, but wrong.

So, I slacked off for a few days, never getting up the energy to go out and bend in the cold. Then I decided I've done enough bending that my iron is pretty much confirmed fire safe, so I just screwed it to the short wall in my room and got to wrk. Lots more going back and forth on that side and I finally got it straightened out. The rest went extremely easily. Maybe I'm finally starting to develop some skill at it... or maybe it was just dumb luck. In any case, working indoors is really nice.
Attachment:
SidesBent.jpg

However, I still couldn't get the pieces for the headstock crown to work, even going much thinner than acceptable, and even doing so with walnut instead of the rosewood I wanted. So, I decided to just cut them out like inlay pieces. Take an impression of the headstock by holding a paper over it and bending it over the edges, cut out paper templates from that, use those to draw the pieces on a scrap of reasonably closely matching wood to the binding, cut out, file smooth, and you can have as tight of curves as you want :)

Then stick them down to the headstock and scribe around, then freehand knife for the pointy part in the middle, and gramil for the pieces along the sides. This osage headplate is insanely hard, so I was too lazy to do this entirely by hand like usual. Took the dremel router to it and carefully routed to the scribe lines. Even that had a tough time cutting this wood, and was tricky because the dark and light grain lines are different hardness so the router is all jumpy the whole time.

Then cut all the miters, and everything's ready.
Attachment:
HeadstockBindingChannel.jpg

Glue on the crown pieces first... just hold them in place for a bit and they stick well enough. After letting those dry, add the side pieces. They're pretty accurately bent, but tape still helps to squeeze out any tiny gaps.
Attachment:
HeadstockBindingGlue.jpg

I haven't leveled them out yet, but that shouldn't take too long.

Then I decided the neck was too thick, so I re-carved it. Removed quite a lot of wood, actually. Feels much better now, and fortunately didn't cut through to the CF bars beehive

Oh, and I never posted a shot of the finished back of the headstock, which is all concave and cool looking. One of the advantages of pegs as opposed to standard tuners. So here's a shot with that, and a bit of the final carved neck.
Attachment:
HeadstockBack.jpg

That's it for now. Next up, thinning the top to final thickness, cutting the ledge for the neck to glue to it, and finally I can determine the bridge location and lay out the bracing pattern around it. After that, I'll have to make a crap ton of dentellones, and at last begin assembly.


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PostPosted: Sun Mar 24, 2013 11:32 am 
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Love how you bound the head stock.


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PostPosted: Sun Mar 24, 2013 2:12 pm 
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Dude, I love watching your builds! Your creations are so incredibly beautiful and interesting! I'm still afraid to try binding a headstock (and mine is softly curvy, not all angles) and here you are cutting the bits out like it's an inlay and matching them perfectly.....that is crazy good! Thanks for documenting. Can't wait to see it finished.


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PostPosted: Sat Mar 30, 2013 1:17 pm 
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Glad y'all are enjoying the build :)

Lots of progress this week. Here's the finished headstock binding.
Attachment:
HeadstockBindingDone.jpg

Then onto getting the neck attached to the soundboard. First, thin down the soundboard some more. I ended up around .100", which sounds thin for redwood with ~300lbs pulling on it, but it still feels really stiff. Then route the ledge in the headblock portion of the neck, excluding the reinforcement area in the middle. Then carefully cut a slot in the soundboard for that part to fit into.
Attachment:
NeckLedge.jpg

Perfect fit bliss
Attachment:
NeckGlued.jpg

Then I decided I'd better make the actual bridge to use as a drilling template, rather than assuming I'll be able to create it precisely according to the paper template later.

Thin down the blank, drill pilot holes for the pins, drill holes to define the ends of the saddle slot, and then route it out. Being the doofus that I am, I still haven't built a saddle routing jig yet, so I just whipped up something on the spot.
Attachment:
BridgeSlotSetup.jpg

The bridge is held by two cam clamps, the router just sits on the bridge surface, and the rosewood board acts as a fence. One of those clamps is just acting as a shim :lol:

I used a 1/16" bit, making 3 passes to cover the width of the slot. I just looked around for things of appropriate thickness to act as shims on the fence. Ended up using a flexible steel ruler and a binding strip. One thing when routing with a dremel... always go counterclockwise. The bearing is a bit weak so it pulls a little to the side when cutting a lot of material, and you want it to pull toward the inside of the slot, not the outside :)
Attachment:
BridgeSlotRouting.jpg

Then cut out the shape using my trusty featherweight fret saw from Lee Valley.
Attachment:
BridgeCutOut.jpg

Refine the shape with rasp, needle files, and scraper.
Attachment:
BridgeRasp.jpg

And drill out the pin holes. This is as far as I went on it, since I don't need it to be fully finished at the moment and I'm in a hurry to get the box closed up before spring sets in permanently. As you can see, my line of holes isn't perfectly straight... this is why I usually put them in a slight curve so it's less noticeable. Oh well.
Attachment:
BridgeDrilled.jpg

I've got all the soundboard braces glued except for the X, but the humidity is up to 40% today which is a bit high for a flat top, so I think I'll pause that until Monday when it's supposed to be cold out again. I'll post the photos then. In the meantime, I can make dentellones, join and thin the back, and finish the bridge. Or go out and plant some stuff in the garden.


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PostPosted: Sat Mar 30, 2013 7:16 pm 
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Looks great Dennis

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PostPosted: Mon Apr 01, 2013 4:15 pm 
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Wow that inlay is awesome the bridge is very cool keep up the good work. [:Y:]


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PostPosted: Wed Apr 03, 2013 3:31 am 
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Ok, bracing/voicing is getting pretty close. I'll probably carve a little more before gluing the sides, and a lot more afterward when I can tap and hear it with the rim constrained, but here we go.

First get the fingerboard taped in place (so the position pins don't get in the way of the straight edge) and locate the bridge. Mark with bits of masking tape since I kept scooting it out of position when trying to transfer the hole locations...
Attachment:
BridgeInPlace.jpg

Hold it down and turn the drill bit by hand in each hole to mark the positions, and then drill them all the way through. Then lay out the bracing pattern, with the bridge template to make sure the X overlaps the wings properly, and holes to make sure the fan braces pass safely between strings. I did the pattern first in pencil, then added little ink marks at the end of each brace to make them more visible, and to soak into the wood just a bit so I can scrape off most of the graphite that would otherwise contaminate the joints.
Attachment:
BraceLayout.jpg

Then make and glue the bridge plate (Honduran rosewood, after some debate about wear resistance and damping and what species I had conveniently sized pieces of lying around... it's small, so only 7g despite being a dense wood), and start gluing braces. Fans are notched to go over it, and other braces are notched into eachother. You can see some on the harp arm that are waiting to be glued. I'm using a thin piece of masonite here as a backing board when clamping braces, to distribute pressure. The clamp on the neck is just there to hold it up at the same level... it's not clamped to the bench.
Attachment:
GluingBraces.jpg

Then the first round of carving. This should be fairly close to final for all these little braces, but I can't feel the stiffness that well without the X to support everything so there will likely be some additional shaving.
Attachment:
Bracing1.jpg

Then it's a notch-o-rama on the X braces. Here's one done, and the other marked.
Attachment:
BraceNotched.jpg

And the current state, with X carved, ends trimmed for the sides (surprisingly, it doesn't look like they'll be needing any bending touch-up), but haven't capped the X yet. It's about 5/8" at the intersection, and still really stiff... I haven't ever built for more than the usual ~160lbs of string tension, so it's kind of hard to judge. This fully notched bracing style is extra stiff though, and with the lower string-height-at-bridge, I should be able to take it down a fair bit further before getting into trouble.
Attachment:
Bracing4.jpg

And the harp arm. Also notice the rosette all wrapped up in that little triangle of bracing... should be plenty strong to make up for cutting holes in the top. The headblock portion of the neck is endgrain butt joint glued to the upper transverse brace... not the strongest joint, but a rather large glue area, so it probably won't ever come apart. I retopped a guitar where I did that one time and had a heck of a time separating it.
Attachment:
Bracing2.jpg

And an overhead shot for anyone who may want to copy this in the future (better wait and see if it sounds like crap and/or implodes first :mrgreen:). The center fan, X intersection, soundhole, and bass edge of the neck follow precisely along the center seam of the soundboard. Elegance or OCD? :lol:
Attachment:
BracingPattern.jpg


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PostPosted: Thu Apr 04, 2013 4:44 pm 
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Wow...your brace-pocketing skills are amazing :) I'm really enjoying watching it come together, Dennis.


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PostPosted: Mon Apr 08, 2013 5:44 am 
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Lots of progress over the past few days. I'll just be covering the assembly stage in this post, but I've actually got the rim tapered too... I'll write that up later.

This osage is remarkably stable. Even a week or two after bending them, and some pretty significant humidity fluctuation, the sides hadn't moved a bit. I did still have to pull out the pipe to tighten up the bends on the pieces that slot into the headblock, but that's because they weren't trimmed to length before so I couldn't see exactly how far they needed to be bent.

After that, I did the cutaway miter. Place the treble side on the soundboard, mark where it hits the tip on the pattern, use a square to mark a line all the way across, saw near the line, drag it on sandpaper to angle the miter. Do the same for the short piece that slots into the headblock, make sure the miter fits tightly all the way up, and continue sanding until the lengths are just right. Then make a corner block to fit between them. Glue the corner block to the short side, glue the short side to the soundboard/heel, and add dentellones. I left a space where I may add a side brace for good measure... or I may just fill it in with another dentellone later.
Attachment:
Assembly1.jpg

Another thing that needed to be done prior to gluing everything together, was to figure out the joint between the two long side pieces. It's not at the tail block like usual, because this set was not intended for use on a harp guitar, so there was no super long side piece. I decided to attempt an invisible scarf joint, and if that fails I'll add a bit of binding detail to cover it (perhaps bloodwood with some "stitches", fitting with the halloween theme...). Rather than making a block, I just used the offcut of one of them as the joining glue surface (already bent to the proper radius :) ).
Attachment:
SideJoin.jpg

It ended up looking like this in the end... I haven't sanded it smooth, but I think it's a little too visible so I'll probably add the bloodwood.
Attachment:
SideJoinGlued.jpg

Another bit of prep work was to cut ledges in the harp headstock for the sides to glue to. The inner side is just a straight ledge, but I decided to do a bit of binding detail on the outer side. Cut out a little curvy line of rosewood, figured where on the side would glue to the headstock, traced the binding piece onto the side, cut with jeweler's saw, used the side to mark the line on the headstock, scored with knife, chiseled it out, forgot to take picture. But here's one after everything was glued up.
Attachment:
Assembly5.jpg

Then sanded down the harp headtock's headplate thickness until it matched the soundboard precisely, glued it to the soundboard, and finally I could get on with the assembly, gluing the sides to the harp headstock.
Attachment:
Assembly2.jpg

When testing that clamping setup, I got the upper clamp up a little too high and cracked the outer side oops_sign I think the crack will be replaced with binding in the end anyway, so a bit of CA to stick it back together.

Then gluing the cutaway tip. It fit so nicely, and I was so lazy, I didn't bother with any fancy clamping setup. The bottom was springing outward a little bit, so I just stuck a cam clamp on it with really light pressure to hold it in place (notice it's clamped against the side of a brace... can't put much pressure there!). Basically an unclamped joint. Seems to work pretty well with hide glue, since that's how all the dentellones are done as well.
Attachment:
Assembly3.jpg

Here it is with the edge rounded over just a bit. You can see a hint of glue line in places, but given that such things stick out like a sore thumb on light colored woods, I'm quite happy with how tight it is. No binding necessary :D
Attachment:
CutawayTip.jpg

Oh, and here's an interesting bit... I decided to see if I can induce just a tiny bit of neck angle to compensate for pull-up... a sort of bend at the upper transverse brace. The harp arm should still be level with the neck, so notice a couple shots ago the headstock was hanging off the end of the bench, so the headplate nut lip wouldn't prop the neck up. I glued all the harp arm dentellones in that setup. Then, add a ruler under the harp arm and neck, to prop them up by about 1mm, and a plane sitting at the soundhole to weight it down, and some boards to hold the sides down while gluing dentellones.
Attachment:
Assembly4.jpg

Unfortunately, it worked a little too well somehow and now my neck angle is about normal for a 1/2" string-height-at-bridge (3/32" or so gap at the bridge location, with straightedge held against the neck). But my bracing may be on the light side for that, and my bridge on the thin side, so I think I'll try flexing it when gluing the back on to get it where I want it, rather than changing design mid-build. Heck, maybe it's a good thing to build a little tension into the box, if it's in the opposite direction of the strings pulling the neck up.

Technically, this thing doesn't even need a tail block. But I left a space where I'll glue in a small one, incase I ever sell it and someone wants to add an endpin for playing with a strap.


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PostPosted: Tue Apr 09, 2013 5:18 am 
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Ok, so here's the tapering process. Start by marking the final height at the tail, and at the heel. Then half way between them, mark half way between those heights. Repeat the halving process until you have 8 marks along each side. Then mark more marks 1/8" above those, and draw a line connecting them. The initial goal is to get the rim level at this height.
Attachment:
SideTaperMark.jpg

There's also the harp arm, which just needs to be low enough that it doesn't get in the way for now. In the end it will sweep down in a sort of gentle S curve from the neck heel to the harp heel. I marked some approximate lines for it, and sawed 1/4" above them or so to be safe.
Attachment:
SideTaperSaw.jpg

Most of the rim, I just chiseled since sawing like this is difficult, and you can split long strips off with a chisel pretty easily. Then finger plane to make a nice smooth surface. The sides are quite thin, about 1/16". Surprisingly stiff, though. I was thinking about using tons of side braces incase they were too flexible, but I think it will be fine with the usual spacing, so I'll be filling in half of the spaces I left between dentellones for them with small dentellones.
Attachment:
SideThickness.jpg

As you approach the line, place it down on the bench (with a large plane as a weight) and shine a light through the soundhole to see where the high spots are, and mark them. Then plane around the marks, and repeat until level. You can also see some scruffing on the soundboard beside the rosette in this shot. That happened during the sawing before. Must have been rubbing back and forth on a wood chip, or just a rough spot on the bench (doesn't take much to do that sort of thing to redwood). It's really shallow so it'll steam out no problem, but I'm still sad that I'm not perfect :lol:
Attachment:
SideTaperLight.jpg

After getting level at 1/8" above the head-tail block height, mark a new line around 1/8" down from the edge and see how accurate your original estimated marks were :) Plane down to that, but leave the waist a little high to support the dome of the back. Also need to taper the neck and harp headstock heels (finger plane followed by sanding block), and finalize the harp arm profile (mostly freehand planing until it looks right).
Attachment:
SideTaperDone.jpg

And profile view:
Attachment:
SideTaperProfile.jpg

Thinning down the cutaway tip is a pain, chiseling spruce endgrain. But after cutting some away, I got a nice view of the glue line between the cutaway block and the treble side, to see how my lack of clamping there worked out. Looks great right near the tip, but a little gap on the inside... which means the block wasn't shaped quite perfectly so clamping would have had to bend the side out of shape to force it together, thus not a clamping issue, so I think I can continue to use this method in the future. Certainly better to have the gap on the inside than at the tip :) Looks like there's plenty of contact to hold it together, and the fact that it survived the force of endgrain carving proves it.
Attachment:
CutawayBlockGlueLine.jpg

Oh, and here's a shot of the current bracing, which I think I carved down some since last time I showed it. Pretty sure I'll be carving it down some more. It still sounds a little tight.
Attachment:
Bracing5.jpg

Next up, joining and thinning the back, preparing braces for it as well as the sides (to be glued when the humidity goes down), and final carving of the bridge (also to be glued when the humidity goes down... before closing the box, because I can verify that the braces don't get chewed up while drilling/reaming the holes, and get more accurate tap tones out of it while I'm still able to carve the braces, and because there probably won't be any more low humidity days by the time I've got the binding done and fingerboard glued on).


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PostPosted: Thu Apr 11, 2013 4:15 am 
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Small update today, but mainly a question for any of you who care to help me through a tight spot...

The humidity has been above 50% for a couple days now thanks to some crazy thunderstorms, but down to 40% right now, and should get into the 35% range on Friday, which is where I'd like to glue my back braces. That's probably the last chance I'll get to work in stable low humidity for the year. Unfortunately, my wooden jointer plane has gone out of flat and a bit dull, and despite my attempt at re-flattening and re-sharpening it, I can't get the back jointed absolutely perfectly... doesn't help that the halves aren't 100% flat thanks to the humidity.

My original plan was to use a Brazilian rosewood back wedge with no backstrips, which would blend in with the binding:
Attachment:
BackBrazilian.jpg

Attachment:
BackBrazilianCloseup.jpg

However, that requires absolutely flawless jointing, which I can't do at the moment. So, option 1 is to switch to this light colored Honduran rosewood center, with strips that match the binding inlaid to serve as the primary back joints, along with the cross grain reinforcement inside.
Attachment:
BackHonduran.jpg

Attachment:
BackHonduranCloseup.jpg

Still makes a nice framing effect with the binding, and doesn't use up the Brazilian stash, but the color is a bit more boring, and it doesn't smell as good. Also I feel like a wuss every time I cover for my lack of jointing prowess that way.

Option 2, I buy an expensive plane (probably this one http://www.leevalley.com/en/Wood/page.aspx?p=47298&cat=1,41182, so guitars are super accurate, and I can do acoustic bass guitars and cellos and things too), but have to wait for it to arrive, and thus attempt to dry the back in the oven for brace gluing even though it doesn't fit in there with the door closed (I've successfully used that method before on things that did fit).

I'll probably have to do the oven routine when closing the box either way, but humidity for braces is more important so I'd really prefer to do them on Friday. Which way do I go? :?

And for the actual update, I've got the bridge most of the way done. Arched across the width, tapered down toward the back, and some relief carving on the leaves. I need to carve a little deeper so the outlines are more obvious, and I think I'll add some veins too. 28 grams... not too bad for a 13 string bridge.
Attachment:
BridgeCarving.jpg

And made a tail block. Take an offcut of the neck, saw it diagonally...
Attachment:
TailBlockSaw.jpg

Then glue the two halves together, some plane and sandpaper work, and it's ready to glue as soon as the humidity goes down.
Attachment:
TailBlock.jpg


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PostPosted: Fri Apr 12, 2013 5:19 pm 
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You all are no help at all pfft But everything's good. I decided neither of those options would do, so I made another attempt at flattening the plane, and got it this time. So back is joined up as it was meant to be, and hopefully will stay that way for the remainder of its existence :)
Attachment:
BackJoin.jpg

Attachment:
BackJoinTape.jpg

Attachment:
BackJoined.jpg

Then a bit more carving on the bridge... still need to do the leaf veins, if I can get it in my mind exactly what they will/should look like.
Attachment:
BridgeCarving2.jpg

And glued the tail block, using my fingerboard radius block and a piece of cork as a caul.
Attachment:
TailBlockGlue.jpg

Unfortunately, the clamps seem to have pulled it upward so there's a small gap between it and the soundboard... technically it's possible to undo hide glue joints like this, but it takes forever and risks warping/cracking things, so I just made a little shim to go under it.
Attachment:
TailBlockShim.jpg

Poke it under there with some hide glue and it should be good to go.
Attachment:
TailBlockShimGlued.jpg


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PostPosted: Sat Apr 13, 2013 9:36 am 
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Does a harp guitar require heaver bracing than a regular acoustic.


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PostPosted: Thu Apr 18, 2013 4:32 am 
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Kent Wilkinson wrote:
Does a harp guitar require heaver bracing than a regular acoustic.

Yep. This one has more than twice the normal number of strings, and the sub basses need as much or more tension than the neck strings. I like low tension strings though, so I'll be starting with my "extra light" set, which ranges 11.5 to 47 gauge on the neck strings, right about 20lbs each. Then 52 to 70 gauge on the sub basses, ranging 22 to close to 25lbs each, totaling 286lbs... so about 1.75x a normal set of lights. Then with the string-height-at-bridge being about 3/8" as opposed to the normal 1/2", the total torque on the bridge should be about 1/3 more than normal. But the heaviest set I want to support ranges 12 to 52 gauge on the neck, and 56 to 80 gauge on the harp strings, totaling 330lbs. So that's about double normal tension, which with the low string height is 1.5x normal stiffness required.

On to the update, got the back cut out (of course using the actual instrument as a template, rather than the plan) and thinned down. Quite a pain, as it kept tearing deeply every time I tried to plane it, so I had to remove quite a lot of wood by scraper. Thankfully, I bought a Carruth scraper from StewMac a while back. Much faster and easier on the hands than the regular type. Ended up about 0.75" in the lower area, and 0.65" on the harp arm to flex onto the curve of the rim. 328 grams. Then give the show face a light scraping to clean it, add a couple coats of shellac, and it's quite beautiful bliss
Attachment:
BackShellacked.jpg

Add braces and seam reinforcements...
Attachment:
BackBracing.jpg

I thought about tapering down the big one like the others to see if I could get the harp arm and lower portion of the back sort of vibrating together, but decided against it. This brace doesn't need to be as strong as the top's upper transverse brace, but still seems like a good idea to beef it up since the headblock is linked to it fairly directly, plus I'm not entirely sure a larger active region on the back is even a good thing tonally.

The center reinforcements are redwood, chiseled down nice and thin. One fun thing is that the top offcuts I was using (from a different guitar) had some dark blue-ish staining at the end, so I decided to use those strips in the most visible area where the label painting will be. Nice gradient between the light colored osage and dark rosewood center wedge :)

Then fit and glue many side braces... this is boring and tedious work, so I may change my methods in the future, even though I like the end result of this style.
Attachment:
GluingSideBraces.jpg

Then some more carving on the bridge...
Attachment:
BridgeCarving3.jpg

Sand from 220 to 1500 grit and add shellac.
Attachment:
BridgeCarving4.jpg

Then fit the bridge to the soundboard. Tape a sheet of 120 grit sandpaper to it and rub the bridge around until there are scratch marks everywhere. Repeat with 220 grit, and finalize with light scraping... or moderate scraping in this case. The soundboard is actually just a touch concave in the bridge area, so the bridge ended up with a slightly convex bottom. Slightly more than perfectly fitting, as I could slip a sheet of paper under the front edge of it. So I carefully scraped it flat. At least all around the edge gets good contact. There may be a slight hollow underneath, but hopefully the water from the glue will swell it and eliminate that if so.

Then get the bridge in position, and stick a bunch of masking tape bits around it to mark. I leave just a little bit of space so I have room to rub it back and forth a bit.
Attachment:
BridgeMarking.jpg

Then heat the top and bridge up nice and hot, coat the bridge in copious amounts of hide glue, and rub it in place until you feel friction with the top. Suctioned right in place, very difficult to move even with the glue still liquid.
Attachment:
BridgeRubJoint.jpg

Cleaning up the squeeze-out was actually quite difficult, certainly not helped by the many nooks and crannies of the bridge shape. But it also just didn't want to peel up in nice lumps. so I kept having to use a moist paper towel on it, but I couldn't use too much water because redwood stains if you get it wet, plus I didn't want to swell the wood too much. But eventually I got it pretty much clean, and can get the last specks later.
Attachment:
BridgeGlued.jpg

And that's where I am right now. Next up, painting the label on the back, adding back linings, and final voicing. Then it's box closing time, although I'm not sure I'll get another low humidity day for it... but setting the back on the oven while baking something should be enough to dry it out, plus the braces force it to dome up when moisturized now anyway, so box closing humidity isn't too critical. Glad I got that bridge glued when I did :)


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PostPosted: Thu Apr 18, 2013 7:46 pm 
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Dennis....this is really amazing! Some of the processes go right over my head, having no knowledge of harp guitars. But the aesthetic is incredible (as your work always is) and your approach extremely thoughtful. I also really admire that you work only with hand tools, though I sure do appreciate my power tools ;)
Looking forward to seeing the end of the process, and hearing it played (I have also never HEARD a harp guitar that I know of).
Thanks for documenting.


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PostPosted: Thu Apr 18, 2013 9:18 pm 
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Cool build. Thanks for the pics!

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PostPosted: Thu Apr 18, 2013 11:51 pm 
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Beth Mayer wrote:
Some of the processes go right over my head, having no knowledge of harp guitars.

It's actually interesting how little difference there is in this, compared to building normal guitars :) My building style works pretty much the same on anything from ukuleles to these things... which is to say, the slowest possible way to produce any of them :lol: Is there anything in particular that needs clarifying? I'd like this thread to be as much a tutorial as a show... hopefully get a few more folks building harp guitars, cause they're just so darn cool :)

Quote:
Looking forward to seeing the end of the process, and hearing it played (I have also never HEARD a harp guitar that I know of).

The end is in sight. After box closing, binding is the only really difficult thing left. That does involve some tricky work that doesn't come up on regular guitars, around the harp headstock, and the tight spot where the harp arm meets the neck. Then the headstock inlay, fingerboard/fret work (I'm getting pretty fast at this part now), and strings go on.

I do need to remember to install some fingerboard side markers before I glue it on, though. I still haven't made up my mind between abalone dots, gold MOP dots, or something more creative than dots :? Any ideas?

I've never played or heard a harp guitar in person, but I usually figure out new instruments pretty quick so I'll probably have some videos up within a couple days of stringing. But in the meantime, there are some great videos on youtube. Here are a couple of my favorites.
http://www.youtube.com/watch?v=AdLCn450VQE
http://www.youtube.com/watch?v=Q1RXgN-2b-c
http://www.youtube.com/watch?v=eSypqOGqH38


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PostPosted: Fri Apr 19, 2013 7:23 pm 
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Thanks for the links and reply. I will study the thread some more and pm you with any additional questions.
I vote for gold MOP given the theme.


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PostPosted: Mon Apr 22, 2013 5:46 am 
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Lots of fiddly work the past couple days. Got the back linings done. I decided to go with reverse kerf style, but make them myself because the ones luthier suppliers sell look a bit chunky to my eye, and I'm not doing purfling on the back so they don't need to be big at all.

Start with some sample spruce scraps that were in the box with some stuff I bought from Alaska Specialty Woods (thanks Brent!). Scrape 'em smooth, slice 'em up, plane the edges straight.
Attachment:
BackLinings1.jpg

Then some finger plane work to round over one corner, saw a bunch of kerfs, see which space the strip fits best and sand the ends to precision fit. Glue with little spring clamps from home depot.
Attachment:
BackLinings2.jpg

I don't think I'll be doing reverse kerf style this way again... I kept either accidentally sawing through, or just breaking them, and ended up wasting a few strips that were too short to use. With the kerfs-in style, you can just glue broken strips next to eachother and it looks fine.

Then drilled through and reamed the bridge pin holes. The fan braces lost a bit of width.
Attachment:
BridgeHoles.jpg

The bass side fan is pretty much perfectly positioned, just a tight squeeze between holes. But the other two I apparently got a bit sideways from where they were supposed to be. I do know the center one is curved just a bit, so that made it a bit more tricky to position. I may have also figured the bridge position slightly differently when gluing it than I did when I drilled the holes to lay out the bracing. Perhaps I should have drilled two of those through the bridge plate and used them as position pins when gluing the bridge. Oh well, should be fine as it is.

Then slot the bridge. I decided to go with unslotted pin style, although nobody sells unslotted 3 degree boxwood pins, and I don't have a lathe to make them, and it's easier to buy cheap ones and fill the slot than to pay someone to custom make them for me... so that's what I did. Take an offcut from the back (thickness was about equal to the slot width), plane the edge into a half circle, and saw off a thin strip. Then sand the end rounded to fit the top of the slot, cut to length, glue it in, and carve it flush with a knife. I know I could just turn the pins around, but using a slotted pin on a bridge made for unslotted pins would wear quite quickly I think, so better safe than sorry incase I ever sell it and someone flips them around unknowingly.

And for slotting the bridge, I use a zona saw from LMI with the keyhole blade, and a knife style needle file. It takes a while carefully cutting such large slots for up to 70 gauge strings.
Attachment:
BridgeSlotting.jpg

I also carved on the X brace ends just a touch more. I think this is final top bracing, but I still need to spool clamp the back on and tap on it to get an idea what the closed box will sound like, so I could possibly shave a bit more. It already sounds good and feels reasonably plush though, so I probably won't.
Attachment:
Bracing6.jpg

Oh, and notice the pin holes there... I'm going to wait until I have the strings on to slot for the neck strings (and plug their pin slots), because sometimes I need to nudge their positions left or right a bit by angling the slots. Especially with the heavily angled fan fret saddle, it may tend to push them a bit to the left. It's nice being able to see and work on the slots from both sides while the box is open, but perfect playability is more important.

And lastly, I painted the label. I was panicking a bit in the middle because it was looking pretty lousy (doesn't help that I was painting on Brazilian rosewood!), but it turned out ok in the end. Not my best work, but it'll do.
Attachment:
LabelPainting.jpg

And a surprise for anyone who peeks inside the harp arm soundhole :mrgreen:
Attachment:
HarpSoundholePainting.jpg

Next up, leveling the back linings and closing the box. But I may work on the headstock inlay today instead, since tomorrow will be much colder and thus better humidity for box closing, and it's gotta get done sooner or later.


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PostPosted: Mon Apr 22, 2013 10:15 pm 
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This has been absolutely one of my favorite builds to follow. Although I'm only working on my first for the OLF challenge, my goal has long been to build and play a harp guitar like yours.

jim


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PostPosted: Tue Apr 23, 2013 7:38 am 
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Dennis How did you learn to build? Are you self taught or did you study under some one?


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PostPosted: Tue Apr 23, 2013 9:41 am 
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Kent Wilkinson wrote:
Dennis How did you learn to build? Are you self taught or did you study under some one?

I wouldn't exactly call myself self-taught considering the wealth of information available these days, but no hands-on teaching. Internet, Cumpiano book, Somogyi book, logical reasoning, and couple failures to learn the limits :P

Some things like sharpening planes and scrapers, installing frets, and French polishing would have been much easier with someone to watch and explain what I'm doing wrong. But in general I'm happier working on my own where I can do whatever I want and not worry about following someone else's style. I've really been enjoying building since I gave into my love for integral necks. May come back to bite me in 30 years or so... but then again maybe not. Of all the guitars cited as proof that resets are inevitable, most/all have obviously insufficient upper bout structures. This one may actually benefit from some carbon fiber rod buttresses due to the cutaway weakening it on one side, and the harp arm pulling forward on the other... but hopefully the headblock extension and A-frame style braces will keep the neck locked in place relative to the X/bridge. And even if a few guitars do need heel slip resets in the future, I think it's worth it for the fun building style, more heel shape possibilities, and lower weight compared to bolt-on.


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PostPosted: Tue Apr 23, 2013 10:04 am 
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DennisK wrote:
Kent Wilkinson wrote:
Dennis How did you learn to build? Are you self taught or did you study under some one?

I wouldn't exactly call myself self-taught considering the wealth of information available these days, but no hands-on teaching. Internet, Cumpiano book, Somogyi book, logical reasoning, and couple failures to learn the limits :P

Some things like sharpening planes and scrapers, installing frets, and French polishing would have been much easier with someone to watch and explain what I'm doing wrong. But in general I'm happier working on my own where I can do whatever I want and not worry about following someone else's style. I've really been enjoying building since I gave into my love for integral necks. May come back to bite me in 30 years or so... but then again maybe not. Of all the guitars cited as proof that resets are inevitable, most/all have obviously insufficient upper bout structures. This one may actually benefit from some carbon fiber rod buttresses due to the cutaway weakening it on one side, and the harp arm pulling forward on the other... but hopefully the headblock extension and A-frame style braces will keep the neck locked in place relative to the X/bridge. And even if a few guitars do need heel slip resets in the future, I think it's worth it for the fun building style, more heel shape possibilities, and lower weight compared to bolt-on.


I would love to find someone like you to study under. I don't thank there are any builder in my area.


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PostPosted: Mon May 06, 2013 1:27 am 
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Whew. What a pain these last couple weeks have been.

I got the linings all leveled and back brace ends fitted to pockets and back overhang trimmed close to the line, and went to spool clamp it up for testing... but discovered that the area of the lowest two back braces was pretty much flat at 35% humidity. Not good, because it needs to survive down to 20% in the winter here. I think I didn't let it sit by the oven long enough when I glued the braces the first time, and it hadn't fully dried until the third brace. So, chisel 'em off and try again. Then spool clamp the box up:
Attachment:
BoxCloseTest.jpg

Tapped, and sounded a little wimpy. Not much echo. I recorded some taps and checked the frequency plot in Audacity and I think the peaks were 150Hz and 210Hz or so... which I assumed meant the back was high, although I now know it was the other way around (although I'm not sure how meaningful tap frequencies at this stage really are).

I did a few rounds of carving on the back braces and clamping back up, and nothing seemed to really change except that it felt more and more floppy... the frequency peaks didn't seem to move significantly. But at this point, I realized that I'd gone way too far, and in fact had started already way too far.
Attachment:
BackBracing2.jpg

So I had to redo it... again. Including the second brace this time, which is right next to the label painting so it's extra difficult. And it was summer for a week or so. 85 degrees, 50% humidity, no amount of heat could get it below 45%, so I had to wait.

A couple days ago it turned back to winter (went from 85 to 30 degrees and snowing in less than 24 hours :lol:) so I finally got to glue the new braces... and screwed up the second brace gaah I had it all positioned properly, but somehow it managed to slip while I was sticking clamps on, and I forgot to double check it until the glue was too dry to pull off. So I had to chisel it off again, damaging the tree painting a bit since the brace was covering the base of it. No big deal, it's just black so it's easy to touch up.

Made yet another brace and glued it on, finally with some success. Did some rough carving, leaving them pretty huge this time. A bit of fiddly fitting to the notches in the linings, and spool clamped it up again... and it's still lower than the top. But only by about 2 semitones, and it has a decent echo, so I think I'll keep it. Might be a good thing, since I need to support low frequencies as much as possible. I wish I could get the top lower, but I'm afraid of going too far. I've never built for anywhere near this amount of string tension, so it's kind of hard to judge. Perhaps I could get away with shaving down the brace ends a little further, but then it might just pull up and re-stiffen itself by means of curvature instead.

So after a bit of cleanup, the back braces look like this:
Attachment:
BackBracing3.jpg

They still look bulky to me, but then this spruce I used for the lower 3 braces is pretty low density/stiffness. Perhaps I should have left the back a bit thicker, or used a brace pattern that includes longitudinal stiffening. It's about .075", and feels good to me, but I don't exactly have that much experience to go on.

And here are a couple other things I did while the humidity was high. Cut the fingerboard end to match the soundhole:
Attachment:
FingerboardEnd.jpg

And started the headstock inlay. I decided to use some Brazilian rosewood veneer that I found in the basement a few years ago when I first started guitar building (it had been there since before my family moved into this house 25 years ago!). Trace the design on paper, cut out the piece templates, glue them onto the veneer, cut them out by a combination of dremel router and jeweler's saw (router first because the veneer was too long to easily saw from, and I could conserve material better than if I just rough sawed a section off). The glued-on templates turned out to be quite handy to hold the pieces together since several of them cracked. Easier to glue back together this way.

Then score the headplate. The big ones I can just hold in place with my fingers while I run the scribe around them. Little ones have to be temporarily glued in place. I start at the base and work my way up to the branches.
Attachment:
HeadstockInlay1.jpg

Normally I'd use my layering method here. Route, glue, and level the smallest ones, then do the next larger, and next larger until reaching the base. But I was feeling lazy, and this wood is dark, so I just routed them all at once and filed the ends of the pieces to fit against eachother pretty well. Turned out fine. A couple gaps, but more due to bad routing than bad fitting of pieces to eachother. Osage is really tough to route because of the alternating hard and ultra-hard grain lines.
Attachment:
HeadstockInlay2.jpg

Still need to add the abalone D, but I'm procrastinating on that because cutting abalone is a pain.

Oh, and for fun and science, I tried putting a couple strings on it while it was spool clamped up :) Wouldn't be a good idea to put all of them on, but the spool clamps hold it together pretty well so it can handle a bit of tension. Made an African blackwood saddle (don't have any bone blanks long enough), and it sounds a little weak on the low E, but quite nice on the A. About what I expected to get out of a box this size.
http://deku.rydia.net/guitar/haunt/StringTest.mp3
I want to try 18" lower bout and 5 or even 5.5" depth at the tail next time. And perhaps a smaller soundhole. I think the 4" plus 1.5" harp arm soundhole on this one might be a bit too much.

So I think I'm finally ready for box closing, after which I can do top binding and then glue the fingerboard and install frets. I'll probably put off doing the back binding until after that, because I'd like to get it in playable shape for the St. Louis gathering, and back binding is not strictly necessary. Don't want to rush like I did last year, which resulted in not going.


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PostPosted: Mon May 13, 2013 2:48 am 
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After much more procrastination, I finally got some more done on this thing. I'm kind of glad building season is over, because I'm a bit burned out for the moment. Or maybe it's just that I wanted to have this thing done with time to spare for the St. Louis gathering, and now it's looking like it might not even be in playable shape. I really should quit trying to socialize :lol: Hate anything resembling a deadline, thus when one approaches I don't want to work, but then force myself to do it when the time's almost up.

Anyway, I kept almost closing the box, but then being unsatisfied with the spool clamped tap tone, and eventually decided to do one last bit of brace shaving, on the X legs between the intersection and the bridge. Livened it up surprisingly much. My thinking was that the center fan connecting the bridge directly to the X intersection should allow the X legs to be just a bit more flexible. Plus some people scallop the X legs ridiculously low around there and somehow survive, so even with the extra string tension I'm probably not too close to the edge.
Attachment:
Bracing8.jpg

Then glue 'er up.
Attachment:
GluingBack.jpg

A little too much squeeze-out...
Attachment:
CaulGlued.jpg

Fortunately the back is shellacked, so it peeled off pretty easily.

A couple flaws that I'm not sure whether I care enough to fix... first, I got the heel taper angle a bit wrong so there's a divot where the back is glued to it. Should have checked more closely before gluing. I could see that there was a gap when test fitting the back without clamps, but it's a bit deeper than I was anticipating. Proper fix would be to separate the heel from the back and add a shim, but that would most likely separate the back seams, plus shims are kind of ugly inside the box, and judging by past experience with Murphy's Law, I'd probably screw up the neck angle when regluing it. I have it right where I want it currently, so I think I'll just live with the divot.

Second flaw is that the waist brace's bass side pocket wasn't quite deep enough, resulting in the linings not making full contact with the back in that area. I doubt it will ever come apart, but you can see it through the soundhole. Really not much I can do about it other than completely remove the back and cut the pocket a hair deeper. I suppose I could fix the divot as well if I remove the back, but I really don't want to. I think I'll just leave it, and see if I can squeeze more of the gap closed when doing the back bindings. I hate it when things don't go perfectly :P

Got the back overhang trimmed. Next up is scraping the sides and cutting the top binding ledge.
Attachment:
BackLedgeTrimmed.jpg


Oh, and interesting regarding the resonance modes... basically no change in the main air and main top frequencies between spool clamps and final closed box, but the back's peak seems to have vanished... I'll have to fiddle around with it some more later.

I'm also still puzzled by how high the frequencies are. 107Hz for the main air and 209Hz for the main top. That's pretty much the same as Coral Snake, which is tiny, with box dimensions 11.3x17x3.75", whereas this is 16x20x4.6", plus a huge harp arm. You'd think at least the main air would be lower... the main air on my rosewood topped experimental guitar with similar dimensions is all the way down at 75Hz, and it has the same size soundhole, and no harp arm (although the harp arm soundhole may cancel out the added air volume's frequency effect). Does the top stiffness affect the air resonance that much? Or maybe it's the weight, since this one is a lot lighter all around.

Oh well, I tried putting the E and A harp strings on it again, and it sounds surprisingly nice and loud. Perhaps my plan worked, keeping the soundboard as light as possible so even if it can't resonate with the low strings, they can still yank on it directly.


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