Archive for July, 2011

Lid design

Tuesday, July 26th, 2011

Well, the lid of a hurdy-gurdy is ideal for decorating, I think. Time for some more marquetry! I have thought of all sorts of things over the months: more folk dancers, a breton landscape, different gothic cathedral designs, various symbols, and so on. But those all seemed too complicated or I wasn’t completely sold on the idea. Many just didn’t fit well in a narrow rectangle.

The one I kept coming back to was a floor design on a landing of the Golden Staircase in the Doges’ Palace in Venice, Italy. The picture is from a Newsweek book from the series Wonders of Man that I’ve had since 1973. Glad I hung on to it four almost four decades to help solve this design need.

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Golden Staircase in the Doges’ Palace, Venice, Italy

Based upon the size, this is probably marble, not a parquetry wood floor, but it also would look great done in wood. I like the trompe l’oeil 3D effect. It is also a pattern that looks good extended horizontally in a narrow vertical space. And it looks equally good vertically, if the instrument is standing up.

I scanned the page and warped the perspective out of the floor until the edges were square again.

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Floor section of picture all squared-up using Photoshop

Then I just had to repeat it to fit the lid and computerize it into a pattern. That was the hardest part, getting the angle right and the widths of the pieces to make it repeat correctly, ending at the proper place in the pattern at the sides.

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Design created to the proportions needed for the lid using Corel DRAW

Lots of pieces, but at least they’re uniform strips. Yes, the ‘height’ of the 3D pattern is a little short. I may adjust that when cutting the veneer strips. On the ‘top’ pieces I decided to add a basketweave effect, which will require extra cutting. If the ‘bottom’ diamonds were a dark color, it would look like holes were were cut in the lid, but I think the contrast would be too glaring. I want it to be fairly subtle. To give it a little breton flair, I plan to inlay some black-white-black edging around it, as on the front of the keychest, and around the edge of the soundboard.

The next step is picking the veneers to use.

Lid ends

Sunday, July 24th, 2011

Because I made my own end pieces for the keychest, and had to heavily sand the side of the keychest for the marquetry, the width of the keychest is 1/32 narrower than the intended 3 inches. So, now the lid is a bit too wide, and needs adjusting to match.

The lid is also too long. This could be partly the way I trimmed the keychest sides, but I have seen other hurdy-gurdies where the lid hangs out over the keychest front towards the wheel. I checked the keychest and wheel cover on the body, and I don’t have room for that overhang on mine.

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Lid on keychest before adjusting length, width and front angle

The third thing is the two ends of the lid need to be angled, because the lid sits on the sloped keychest, but the keychest ends are vertical. I am tackling the last two issues first. I have glued sandpaper to the side of the head block, and am going to see how that works to get my vertical edge. When you don’t have all the nice tools, you have to improvise.

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Angled head block with different strips of sandpaper for beveling ends

I am taking enough off so that the inside lip on the front of the lid is the same width as the front piece of the keybox. When you open the lid, they will match. I rough-cut this with the miter saw, because it was too much to sand off by hand.

Lid02

Initial beveling of front end of the lid

The extra length will be taken off the head-end, which will mean the inside lip on that end will be removed entirely. I decided to make it easy on myself and have the head-end flush with the keychest and at the same angle, too. I’ve seen pictures of them done different ways, but I want to simplify shaping the head to fit the keychest.

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Pencil marks where I needed to cut the head-end of the lid

It turned out —fortunately— that the length I needed [13"] was just in front of where the lip was on the head-end!

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Cutting off head-end of lid at a slight slant from vertical

Then came a lot of sanding — running the lid back and forth along the head block sander, being careful to keep it perpendicular.

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Head-end of keychest with trimmed and angled lid

It took some experimenting with different thicknesses of wood strips under one side of the block to put the right bevel on the ends of the lid to match the vertical ends of the keychest.

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Wheel-end of keychest showing the lid is slightly too wide

I may do something to modify the straight edge of the front lip.

The width still needs narrowing, but I intend to wait on that until I finish doing any inlaying on the top, which will take a lot of handling, with the chance of bumping an edge.

Leveling front and top of keychest

Tuesday, July 19th, 2011

My custom-built front piece for the keychest had two tips which needed to be angled on top to match the slope of the keychest sides. The second thing was that it was impossible to get it glued in perfectly flush with the vertical ends of the side pieces. It ended up sticking out past them a little, which meant that the whole front piece had to be slightly reduced in thickness. You can also see beads of glue sticking out from the seam.

KeychestFront19

Before and after views showing sanding of top and front of keychest

Black keys 10 thru 13

Saturday, July 9th, 2011

The plot thickens! Things are getting rather crowded down at the end of the row, and it is taking much more head-scratching before cutting. I don’t think I’ve messed anything up so far.

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Buttons ten and eleven are done, still designing twelve and thirteen

The clearance between keys ten and eleven is 11/32″ and between eleven and twelve is 5/16″.

No need —or room— for any plugs on these small keys. I’ll have to see what the outside of button thirteen ends up looking like. That will  show, so it may need one. But if I do the straight cut on the inner part of the button near the shaft, then angle outwards like the others, it won’t need one because the slot won’t be exposed.

The next step is angling thirteen’s shaft before cutting twelve’s button to length. Button spacing is getting down close to 1/32″ in this set.

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Shafts twelve and thirteen are done and ready for their buttons

Cutting the 45-degree angle on the shafts is done on my scroll saw in two cuts. The angled cut comes out a bit rough, so a bunch of sanding and filing is necessary. It would be easier with my miter saw, but as you can see in the photo, I do not want to also angle the tab for attaching the button. That would be losing a significant amount of gluing surface, and make the button joint weaker. And this way the 90-degree tab cosmetically fills in the slot.

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Backs of keys twelve and thirteen, showing slot plug on the right

The black keys are now done! I decided to leave thirteen squared on the outer end, and plug the slot, as seen above.

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The last two keys, twelve and thirteen in place

Button number one is squared on its outer end, and so are both the white ones, so I didn’t see the need to angle it like the overlapping keys, and like most hurdy-gurdies seem to do. I can always do that later, if I change my mind.

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View showing all the finished keys

Black keys 6 thru 9

Saturday, July 9th, 2011

The last of the “easy” ones! I plugged the slots on the right end of all of these. The offset between buttons five and six was a little practice for the much harder ones at the far end.

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Buttons six through nine upside down while epoxy hardens

Note that the outer ends of these four buttons had to exactly align vertically with the outer ends of the top three white buttons. The black buttons are quite a bit shorter than the white. It was necessary to customize the lengths to make sure they aligned with the white ones properly. But what I ended up using was always very close to the stated length. Perhaps 1/32″ more on some of them? I also started to narrow the gap between buttons slightly from the 1/16″ inch specified. They are more like 3/64″ gaps here. I was trying to maximize the length of these smaller buttons to give more playing surface.

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Closeup of the offset relationship between keys six and five

Doing these offsets was a challenge, as I wasn’t too sure what the tolerances were. What was the necessary amount of “push clearance” between an activated key and its overlapping neighbor? Enquiring about it, I was told 5/16″ was the goal. Between keys five and six I ended up with almost 3/8″ before key six’s button contacts the shaft of key five.

One of my goals in cutting these overlapping buttons was to remove as little as possible. On the plans, the buttons all have a simple 45-degree cut. Mine are more zig-zaggy, with a straight cut initially to clear the straight part of the adjacent shaft, then an angled cut to clear the angled part of the other shaft. It was hard mentally figuring out how to do these at all, so doing this two-step process actually made it easier for me to understand, even though it made cutting the buttons a little more complicated.

Black keys 1 thru 5

Saturday, July 9th, 2011

I wanted the tops of the black buttons flush with the tops of the shafts. I think that was the intention, but I had to adjust the slot in the button stock to move the bottons up to match the top of the shafts. Also, I had to deepen the slot some to accomodate the width of the tabs on the shafts.

As with the white buttons, I rounded the first end of the button on my router before cutting the button to length with my plastic miter box. These buttons are much shorter than the white ones, so all of the second ends were rounded by hand with a file and sandpaper.

BlackKeys1

First five black buttons and plug stock for slot ends

Note fifth shaft with offset triangle in above photo. Part of the shaft opposite it had to be angled at 45 degrees to match the triangle.

As on the white buttons, I wanted to “plug” the ends of the slots on some of the buttons. So, I cut up an extra shaft to fit the slot. Cutting the wenge across the strong grain into little plugs was problematic. It would want to splinter.

BlackKeys2

Using a knife to cut plugs prevented splitting better than sawing

For this reason, I ended up making the plugs a little longer, and only did this on button ends that stood out from the shaft enough to bother. These buttons are under the white ones and therefore it is harder to see an exposed slot, plus the fact that they are black which further disguises a slot from showing. I made sure to put the plugs in so that the grain was angled the same direction as on the button.

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Backs of first five buttons showing plugs, and plug stock

I used sanding dust from shaping the buttons to dye the epoxy glue. It is five minute epoxy so usually I only glued two or three buttons at a time.

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First three buttons glued on, turned upside down while epoxy hardens

Once I had them on the shaft correctly horizontally to allow for proper spacing, I turned them upside down to harden, so the tops would be flush with the shafts. [The buttons are thicker than the 1/4" shafts by about 3/32", so the extra is on the bottom.]

BlackKeys5

First five buttons completed, with remaining button stock

You will notice in the photo that the fifth button offsets slightly towards the fourth. Also that it aligns vertically with the end of the fourth white button. Similarly, the ends of the second black and white buttons line up vertically.