Optimum bendy

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So I set out to start bending the lute ribs and affix them to each other on the lute mold.

I had made the pearwood ribs the same thickness as I had the big leaf maple I’d used to build the Gerle reproduction last year.  Only it was too thick to bend well using dry heat!  It flummoxed me, and I set work aside for the hour, scratching my head.

Then I tried to bend the ribs slightly in my hands.  Lots of resistance.  I tried it with the extra rib I’d made for the Gerle lute last year, and there was much less resistance, but still some. 

Then I realized what the problem was: I just had to reduce the thickness of the pearwood ribs until I got to the same level of resistance as on the (thicker) ribs of maple.  Turned out that ‘optimum bendiness’ for the maple hit at around 1.6mm, and the optimum bendy for the pearwood was about .9mm.

Thinner than Optimum Bendy bends easily, of course, but does not offer enough resistance; if there is no resistance to the bend, the ribs of the finished lute will not press outwards sufficiently, and what happened on my unrestored Hachez lute – that is, ribs so marvellously thin that they can actually dent inwards along the glue line between two ribs so that the glue joint is broken. 

I haven’t tested this yet, but I’d be willing to bet that woods as dense as the Dalbergiae (rosewood family)  and the Diospyrae (ebonies) would reach optimum bendy as thinly as .7mm.  Given the oily nature of both these wood families, though, combined with such thinness would make for a potentially disastrous glue joint.  Looks like some tests are in order!

Carving wood, or the benefits of leaving something alone for a while.

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I had to redo the neck block of the Frei 1530 lute.  I had glued up some lindenwood with grain direction running laterally to the axis of the lute.  I screwed it onto the lute mold, and then spent three unhappy hours ‘carving’, if I could call it that, the ‘nose cone’ of the lute.  By dint of using files, eventually, I was able to get around the horribly rough carving I’d done; then lots of sandpaper, and great difficulty faceting the neckblock due to the contrary grain direction.  I had an uneasy feeling about this for some reason…gut feeling was that something was wrong.  I needed to check the grain direction of my first lute as a reference, but I didn’t want to open up my first lute to check the grain direction on the neck block in there.  I was pretty sure, however, that for my first lute Mel had had me make a neck block with the grain orientation running parallel to the axis of the lute.

I consulted the late, lamented Robert Lundberg’s venerable tome, Historical Lute Construction, leafing through the pages until I got to a photograph depicting a neck block with the grain orientation clearly running laterally, and perpendicular to the axis of the lute.  Still, it was a photograph of a Renaissance lute with eight courses, and so in that case I could see the case of a lateral grain direction.  However, thinking of the stability of the neck of a six-course Renaissance lute, which is quite a bit narrower in width and with a more parabolic and compressed curve on the back, I thought that the lateral grain direction would eventually result in a loose neck down the line. 

Then I remembered that I still had the off-cut from my first  six-course lute when I cut the tip of the neck block off to make a place to join the neck to.  I looked at it, and the grain was running parallel to the lute’s axis.

So I decided to redo the ‘nose cone’, and to make a new one with the grain running parallel to the axis of the lute.  I think that a one-piece neck block would be accoustically better than a glued-up one, but I’m not certain of that, and in any case my first lute’s neck block is a glue-up.  I used three pieces, orienting the grain to the same direction.  I clamped it up and came back the next day. 

I cut two flat sides on the glued-up block, square to each other, and fastened it to the mold with two long wood screws. 

Then I began to carve the nose cone shape, using my Swiss drawknife.  This is the point at which the magic started to happen…with the grain oriented the other way, the carving went very swiftly.  I hadn’t really carved in about a month, with the exception of the laterally-grained neck block I had rejected, which was less about carving per se, and more about just brutalizing the wood into shape with files and sandpaper.  However, the last several times I had carved, back when I was making the mold itself, each time I’d put the drawknife down for more than a few minutes, I had this feeling inside as though my nervous system was still continuing to carve, or going through the motions of it.  It felt as though it was solidifying in my brain. 

There have been times in my life when I have been faced with a particularly difficult passage in a harpsichord piece I was learning; no matter how hard I practiced, I could not play it correctly…after which I usually gave up in disgust…and then, curiously, picking up the piece again after a month or so of not playing it, I was suddenly able to play through the difficult section with zero effort, just the way I had wanted to.  I had practiced the heck out of it, but it seemed as though part of the formula for success was to then stop practicing it for a few weeks, and let it simmer on the back burner in the brain; however somewhat later, after leaving the piece to ‘simmer’, when I tried to play the difficult passage again, I was inexplicably able to play it perfectly with no difficulties.  It seems to me that there’s a kind of very clever brain process that takes some time to gel, and after a ‘simmer’ period, it’s as if the brain has completed generating the various synaptic pathways so that the brain can eventually replay the sequence in the desired way.  The necessary ingredient, besides real practice, seems to be the necessity of a waiting period.

And this is what seemed to have happened with the carving.  By dint of all the practicing I had done while carving the mold, and then the mellowing period during which I didn’t carve, after I returned to the same motor activity, it was as if my brain had sorted out the difficulties so that I was able to carve with much, much greater facility and control than before.  And it was streamlined: what had taken me 3-4 hours before now took me about 20-30 minutes.  Fun!

Busy, industrious day…

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Yesterday I threw caution to the winds and (gulp!) cut into the Great Slab of Tree.

I cut the right third off the top of the slab, and then ripped off the natural edge and set that aside.  Then I planed it flat to have a flat surfact to slide against the fence of the bandsaw, and began to cut the ribs.

Previously, I had thought to just cut each slice and surface them later.  However, I had shattered a good deal of the expensive, beautiful curly maple, so not wanting to do that again, I would plane the surface of the rib before cutting it off the main piece of wood, then scribe a mark with the purfling cutter, then cut along that line; I’d set aside the rib, and then plane the surface again for the next rib.  That way, the ribs all had one surface planed nicely and ready.  After I’d cut fourteen ribs that way, I lined them up and then used the low-angle block plane to even the thickness and smooth the back, and then I used an oscillating sander to finish-smooth them.  They all came out quite well, much more consistent in thickness than I’d done before. 

There is a figure in the pearwood; it’s subtle and doesn’t trip up the plane too much.  I suspect it will show better under the French polished shellac.

After that I cut an experimental rib off the holly; it came out well, so I proceeded to cut the spacers from that.   And I cut, and thinned (and thinned and thinned) the holly veneer for the back of the neck, which has to be thin enough to go smoothly onto the catenary curve of the back of the 6-course neck, unlike the peghead veneers which must be quite thick (as veneer goes).  This also succeeded and I am chuffed with it!  Veneering the back of the neck with holly will make the color scheme of the lute make sense.  The neck will be Spanish cedar, the peghead pearwood, both veneered with holly.  I will French polish the back of the neck where the holly veneer is but will use drying oil on the fingerboard.

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The Great Slab of Tree

 

The slab of Swiss pearwood (Pyrus communis)

The slab of Swiss pearwood (Pyrus communis)

Two days ago a huge slab of pearwood (Pyrus communis) I ordered was delivered.  For the sake of ease of shipping (and at greatly reduced cost!) I had the vendor bisect the long slab, which was as tall as I am (6’3″), 18″ in width, and more than three inches thick.  This pearwood was cut a long time ago and has been seasoning in Pennsylvania for generations.  It was beautifully-stored and maintained.  The top has some slight cracks but overall there is basically no warping or cracking – pearwood is fabulously stable!

I stood the two halves of the slab up in the shop, just to look at it, this huge slice of tree.  Although I am eager to cut it into lute ribs et al, I decided to put off cutting into it for a week since I just want to kind of bask in the amazingness of that slab of tree.  Part of wanting to take my time really stems from the understanding that what I can cut into pieces in an hour took centuries to grow.

The color of the wood, showing where the slab was cut in half last week, is a fine pinkish-tan, very characteristic of Swiss pearwood.  The grain is so fine and subtle that it is almost too difficult to see except in very strong light.  There does seem to be a place on the lower right part of the slab where there seems to be figure, but that will be evident only after that area is planed of the saw marks from the huge saw that flitched out this noble pear tree.

Before the arrival of this pearwood, I was thinking that if the pearwood was particularly light in color, I would use ebony spacers; but although it is still rather light in color, placing the freshly-planed surface next to one of holly, I see that there is a curious color harmony between the ivory-esque white of the holly wood, and this pearwood.  I think I will use the holly instead, and echo the lines with a half-binding of holly as well, and holly edging to the pearwood fingerboard as well.  I think I’ll make the neck and pegbox of either pearwood, mahogany, or Spanish cedar.

Work on the 1530 Frei lute copy…

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For the past couple of months I’ve been working on the next lute, which is to be based on the 1530 Hans Frei in the Kunsthistoriches Museum, Vienna.

So far, the two things which have taken up the lion’s share of time in the shop are two things that I didn’t do during my apprenticeship with Mel: that is, carving a lute mold myself  (rather than just having discussed how to do it), and cutting my own staves for the back of the lute; I had used a lute mold for the Gerle that had been made by Mel, and it was Mel who had cut out the lute ribs.

Since getting the better bandsaw, and a really good blade, resawing the lute ribs has been quick and easy.  However, since after resawing both faces of each rib needed to be trimmed of the bandsaw blade marks, I have had some challenges.

Although the hand-held belt sander does well to smooth the ribs,  it takes a while to sand down, and even a coarse grit takes a long while to thin the wood.  So I’ve been thinking that there are several approaches to this:

A. Buy a drum sander like Mel’s – this would probably do the job of both flatting the faces of the ribs, and also smoothing them.  Can’t afford a drum sander right now, and there is also the same difficulty that I have with the large planer – the electricity in our building does not support them.

B. Buy a hand-held electric planer – which is what I did yesterday.  It worked well with some significant limits: Planing must be done in the direction of the grain that a handplane would follow, or else the planer basically destroys the rib with tearout.  Also, it seemed that with some of the ribs, because of the pronounced figure and the energy flow it creates within the wood, coupled with the thinness of the wood, the force of the planer, whose speed cannot be regulated, simply shatters the wood.  Even on a couple of the ribs that came out nicely (and I mean, like glassy-surfaced, really showing the curl of the maple), when it came to bending the rib, it seemed like the rib had somehow been compromised so that it broke in several places right where the curl is, as if the planer had ‘pre-broken’ it even though it appeared intact.

C. Use the Lie-Nielsen smoothing plane with the York pitch frog to plane the ribs down by hand.  I’d been having difficulty with this simply because of space issues in my shop, but yesterday, and I don’t know why I hadn’t thought of this before, I bought a long thick poplar board to use as a planing run; I tried two-sided carpet tape first, which was messy and not effectual, and subsequently an F-clamp to hold the end of the rib in place.  This last solution really worked well.  Giving myself sufficient space and length of ‘swing’ with the plane allowed me to hand-plane well, and this last method yielded the best results, from the point of view of not only smoothness of the faces, but leaving the fragile wood intact for bending.  In a very real way using the smoothing plane was easier and faster than using the hand-held electic planer, with the added benefit of not needing to wear ear protection.  And it made my biceps feel strong!

What I’m thinking is that I solved the problem simply by the purchase of the poplar board and using it as a long plane run.

D. Planing one face of the curly maple with the hand-held electric planer, and then resawing a stave that already has one side flattened and smoothed; this will be numbered and set aside.  Then, before resawing the next stave, electric-planing the face again, and then resawing, which will come out more accurately anyway.  This adds a step using another device, but I think that this will result in better resawing in any case.  Then, once the staves are all cut, leaving a bunch of staves with one side already smoothed and flattened, I can use the plane run and the Lie-Nielsen handplane to do the other side of each stave.  In this way I can avoid using sandpaper on the staves until the lute is finished – that way, I can use edge tools such as scrapers on the bowl without having to worry about the residual sand grains dulling the edge tools.

Which brings me to the other realization from yesterday: yes, I can sharpen a scraper properly, and yes it made shavings and not dust.  Worked very well – though I think it’d be better if I could use a cabinet scraper that was somewhat thinner in guage than the one I’m using, which is a little too stiff from its thickness and which aggravates my thumbs in use.

On Alexander Hopkins’ website, I note that it looks like the tool he seems to use as a scraper is something like a truncated plane blade, thick metal with a beveled edge, rather than the flexible metal of a cabinet scraper. 

It chuffed me to succeed in sharpening the scraper and getting clean shavings.  I used it on the lute mold to add cleaner flatness to the facets where the staves will be seated.

I was somewhat horrified and a little depressed to ruin 3-4 ribs of the curly maple that was so expensive and beautiful, but I couldn’t possibly have learned what I learned about the maple and its interaction with the machine planer without trying it on that very wood.  If I had used clear timber it wouldn’t have torn out or shattered along the curl, so it was best that I faced that music as soon as I did, because it forced me to seek a solution.

This morning I also got a call from Troy in Pennsylvania regarding the pearwood he had set aside for me and on which I had paid a deposit.  Although it is unsteamed, Troy says that it is of a beautiful color.  It’s been seasoning in the barn for more than fifteen years since it was slabbed out from the original log, so it’s a good thing.  Hope it looks good!

I’m thinking that I’m going to cut ribs from that piece as well, for at least another lute, and if hopefully I can get enough surviving curly maple staves from that piece of wood I’ve been cutting them from, I will make one lute with the maple bowl and another with a pear bowl, both of them copies of the Frei and made on that same mold.

The Replacement Thickness Planer

About two months ago, I purchased a Ridgid Thickness Planer from Home Depot. Since this particular thickness planer got as good reviews as the DeWalt I was actually hoping to buy (but which was no longer carried by HD), I decided to buy one.

When I unpacked the new planer and went to use it, I was able to make one or two passes on a piece of maple I was hoping to plane. The planer choked on the third pass, and the machine stopped. Resetting didn’t work, and then when I removed the dust hood, a mangled spring and a metal screw fell out. Don’t know where they were supposed to be, but I decided to take it back and exchange it.

I took it back a week ago, and got a replacement, but I couldn’t bring myself to open the box and use it until I had a good stretch of time this past weekend.

I opened the box, set it up following the instruction book, and gingerly set to work, expecting the same thing to happen. It didn’t; the machine worked beautifully. I planed a piece of maple that I had resawn fairly neatly, and with the exception of a couple of lines of snipe, it came out very well-dressed. Pleased!!