Archive for September, 2011

Head – 90 degree angle

Monday, September 26th, 2011

The horizontal surface of the ‘yoke’ where the head will rest on the neck of the instrument’s body has to be made 90 degrees to the outer flat surface with the two string holes, where the head will join the keychest. This is about 12 degrees off from the square angles of the original block of wood. I routed this area up to the outside edge, but the inside edge needs to be angled by hand.

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Pencil mark shows the needed slope to form the 90-degree angle

This is a critical step, as it determines how the head will align with both the keychest and the body of the instrument.

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Rough chiseling of the angle down to near the pencil line

Another sanding stick was made, and a fine metal file put the finishing touches on it. A combination square was used to check the 90-degree angle.

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Completed smoothing of the angle shown with the tools used

Some more fine sanding was done inside walls.

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The new edge and the pattern used to guide the shaping of it

The original routed edge used to be parallel to the table top, but now slopes down towards the inside.

Head – bottom chiseling & sanding

Sunday, September 25th, 2011

Over the weekend I chiseled out the bottom, mostly using a 3/8″ chisel. This was the next step to smooth out the stair-stepping and scalloped edges caused by the drilling.

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Finished with chiseling - stair steps gone, but still rough

Since it is a very cramped area to sand in, I made a 2 1/4″ wide sanding block that would just fit the width of the cavity to get rid of the chisel marks. Two grits of sandpaper were rubber-cemented on opposite sides.

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Sanding in progress with balsawood block made to fit the width

 

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Sanding flat the scalloped edge from drilling overlapping holes

This intensive sanding was a source of several thumb and index finger scrapes against the rough side edges and corners.

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Sanding mostly complete

Some final sanding will be done after other work, like drilling the tuning peg holes, but the area is essentially smoothed out.

Head – bottom drilling finished

Wednesday, September 21st, 2011

I went back to Leonard’s tonight and spent a couple hours on his drill press drilling out more of the hollow area of the bottom. Since I had routed the area out to a lower level, I was able to lower the drill bit more in the chuck so that it would descend to the depths necessary.

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A much bigger cavity now

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Chanter string holes intersected with the drilling as planned

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Opened up chanter string holes

Now to smooth it all out!

Head – bottom routing finished

Monday, September 19th, 2011

Saturday I routed down to the level of where the ‘yoke’ will sit on the neck. This is 1  1/2″ deep on the flat end of the head. However, that bottom surface is not yet at the right slope for the head to sit properly on the neck. This will probably have to be filed by hand, after more drilling is done. You can see this on the paper glued to the side of the block in the following photo, how that bottom edge tilts upward slightly.

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Beginning the deepest cut with the router, starting in the middle

The depth of the routing is also as deep as necessary on the opposite side of the depression, nearest where the carved head will be  [see the final picture, compared to paper plan glued on the side]. It still needs to be deepened closer to the body, and that will be done with the drill press.

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Finished with deepest level of routing, showing bit

The two masking tapes in the photo are guides marking the stopping points on back-and-forth passes, since the bit is hidden inside and you cannot otherwise tell where to stop. One setting of the fence is mirrored by running the piece through from both directions.

Since this was the last of the routing, I made much smaller movements of the fence, necessitating more passes on the router to give a straighter edge to the internal end of the hollowed out area seen to the right below. Originally, this edge was more scalloped from the round bit and bigger increments between passes. This will mean much less chiseling.

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Close-up showing completion of the routing phase

Head – more bottom routing

Thursday, September 15th, 2011

I’ve spent some of the last two evenings outside until it got too dark routing out the bottom of the head, using a 3/4″ straight bit. I’ve gone down 1 1/8″. I’ve been deepening the cut about 1/8″ at a time. I still have about 3/8″ more to go until I get to the top of the ‘yoke’ where it will rest on the body’s neck. From there, the cavity where the tuning pegs go will need more hollowing with the drill press.

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Progress as of Wednesday, September 14

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Progress as of Thursday, September 15

Head – router work started

Tuesday, September 13th, 2011

I don’t know what real hurdy-gurdy makers call it. I’m calling it a ‘yoke’ — the bottom of the tallest part of the head extending down on either side of the ‘neck’ of the body, like a ‘yoke.’ I got a start on that tonight, using my router table and a 3/8″ straight bit to notch out the part that will straddle the neck. It is not yet the proper width. Same with the depth, of course, which needs to go down to the horizontal mark on the white paper — the level of the soundboard.

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Removing this middle part will allow more drill bit clearance for further hollowing. I will probably go a little deeper on it with the router before going back to drilling. I ran out of daylight tonight. I was working out on the driveway.

Last night I hand-sanded off the circular marks from the disc sander.

Head – initial hollowing

Monday, September 12th, 2011

I went over to Leonard’s tonight and used his drill press to start hollowing out the bottom. I drilled three rows of holes at different depths, opening up an area 2  1/8″ x 1  1/8″. I used a rather small bit due to the steep angle of the interior curve. A bigger bit would have cut more area out, but would require more chiseling on the bottom because of bigger stair steps.

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I also sanded flat the foot of the piece that will attach to the keychest on Leonard’s disc sander. It was only roughly cut initially on the bandsaw, until the string holes were cut.

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It will take another session or two of drilling to get the area completely opened up.

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Head – chanter string holes

Sunday, September 11th, 2011

I decided to tackle the 3/4″ holes for the chanter strings first. Those strings are 1″ apart. Holes 3/4″ in diameter will be 1/4″ apart, slightly wider than the rosewood spacer between the nuts. These holes should have their bottoms tangent to the top of the nut block, according to my calculations. So that should look good. The tops of these holes should be slightly above the top edge of the keychest, that is, the height with the lid open.

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Markings for positions and angle of chanter string holes

I don’t have plans for any of this part, so I’m making it up as I go along! Actually, I see something slightly off, looking at the above picture, which will make the holes turn out a little lower than desired, due to their downward angle.

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Re-enacting the head-stand position for drilling the holes

I went to Jerry’s this afternoon and we cut the 3/4″ holes. I wasn’t sure he could even do it because not only was the girl standing on the back slope of her headcovering, the large holes themselves were to be cut on an angle. Though her head-stand was performed on a flat section, it wasn’t very wide, and wouldn’t stand that way by itself, so I braced it with scraps from the bandsaw and held it in this position while Jerry drilled.

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Top view of head-stand for drilling angled string holes

What was very fortunate about this position flat position on the back of her head was that it just so happened to align the holes in  a perfectly vertical position. No, I didn’t plan it that way! The depth was set on the drill press so that the holes will reach the main cavity that will be created from the bottom.

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Chanter string holes seen from a more normal angle

Despite the slope they were cut on, the holes both ended up the right height. Laterally, the first one came out the right distance from the centerline, but the second hole came out 1/32″ closer. I can probably compensate when I narrow the width of the head, slightly shifting the centerline to be more evenly located between the holes. About 1/4″ needs to come off each side to bring the width down to that of the keychest.

Head – rough cut

Saturday, September 10th, 2011

I was able to make some “headway” on the 3.5 x 4.25 x 8″ block of mahogany that is to become the head of my hurdy-gurdy today, thanks to Eric, who has a great 1950s bandsaw. He was interested in my marquetry and inlay, as he would like to incorporate some of that into his handcrafted electric guitars. So I brought him some samples to explain the steps in the process.

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I will miss my handy sanding block

I worked on the pattern some more in Corel DRAW last night, focusing on the inner and outer edges of the body, to get ready for the big day.

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Patterns glued on both sides the night before

It was neat meeting Eric and seeing his shop and the beautiful woodwork he does on his electric guitars. If you want a finely-crafted custom guitar, check him out.

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Action shot of Eric rough cutting the block on his bandsaw

I didn’t want it cut too precisely at this point, because it has a lot of rough handling ahead. Also, there are many steps to making this, and if you do too much all at once it could make some other step more difficult.

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Things can hopefuly get rolling with this breakthrough, thanks to Eric

I needed to maintain the flat “feet” on the top, because I will be drilling into the bottom to begin hollowing it out, and standing it on the flat edges will keep the piece level and steady. That will be one of the earliest operations, as well as working on the edge that mounts to the keybox. The carving will come later.

Split nut – new spacer

Sunday, September 4th, 2011

I didn’t like the ebony spacer I made when I split the kit nut in two. I had used some of the ebony from the striped edging on the body. It was too thin, short and tapered towards the top. Furthermore, there was a gap between the nuts and the sides of the keychest.

So today I made a new one out of some 1/4″ rosewood, the same wood I used for the chanter selectors at the other end of the keychest. I made a tongue along the botton to fit in the narrower groove that I had cut for the ebony one. Not only is it the same wood, it has a rounded front and top like the chanter slectors for a similar appearance. And as an added bonus, the nuts now fit snugly between it and the keychest sides.

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Test fit of new spacer for nuts