Archive for the ‘Back’ Category

Trimming the keychest

Thursday, October 28th, 2010

I put in the wheel for the first time since gluing on the back. I needed to check the fore-aft keychest measurement, because I thought I had the side pieces slightly too long, so that they extended past where the sides of the body attached to the head block.

The instructions say the center of the 7th key has to be exactly 6 15/16″ from the bridge. And the bridge has to be about 7/16″ from the wheel. So, checking all that with the pieces in place, I found that the sides were in fact too long by 1/8″ to 3/16″.

KeychestFitCheck1

Chopstick serving as 7th key to measure proper spacing from the bridge

In the process, though, I discovered something else a little more bothersome — I had the whole keychest way too high. When putting a straightedge on the angle of the wheel, it rested right on the keyshafts! [At least it appeared I had cut the bottom of the sides at the right angle.] The best I could tell, the sides and end pieces needed to be cut down on the bottom by about 7/32″ to have the chanter strings the right distance above the keys. That’s almost a quarter of an inch. How’d I get so far off?

  1. When cutting the bottom edges of the keychest side pieces, I had overcompensated for the curvature of the soundboard. There is hardly any curvature at all to deal with 1 1/2″ either side of the centerline, even though I had doubled the curve amount from that specified. I knew I had to sand the keychest bottom to fit the soundboard curvature, but  I had about 1/8″ extra there — too much to sand.
  2. The wheel seems to sit lower in the body than on the plans. This is not a problem with the plans, but is related to some adjusting I did when making the braces in the body. I had added some 1/8″ thick wood to the tops of the large braces before rounding them. The reason I gave April 15th for this was…

You can see an 1/8″ thick strip of wood has been glued on top of the brace. The short brace is 4″ high, but the two larger braces were 1/8″ shorter. This modification to the larger ones makes all three 4″ high, which is the height of the body. This also makes the threaded hole for the bearing closer to the same height of the shaft hole in the end of the body. I could have sanded down more from the sides of the body and the top of the short brace, but decided to try this.

In hindsight, perhaps I should have made the small brace shorter and sanded down the entire top of the body more. Anyway, this obviously effects the wheel height, lowering it by whatever was left after rounding of that 1/8″ strip. You can see the strips I’m talking about here.

So, this accounts for why I was almost 1/4″ off on the first cutting of these pieces, despite all my attempts to accurately measure the plans. Jerry was good about letting me come over and re-do all these tedious cuts last night. Everything went well, thanks to his careful expertise and excellent tools.

Unfortunately, this necessary shortening messed up the nice double rabbet joint I had on the bottom of the keychest front. Now the base is thinner and weaker than the original piece. I will probably end up adding a second strip on top of the base to reinforce the joint.

KeychestFront12

The front piece after re-trimming, beside original piece

This front piece is now the same height as the original — what a coincidence! I was wondering why it was so much higher before. Hopefully, that’s a positive sign I’m more on the right track, now.

The good news is, if you’re making one of these kits and sticking to the playbook, you won’t have any of these self-inflicted problems. The keychest will be all put together, cut the right size, and everything!

Back trimmed

Monday, September 27th, 2010

Jerry was kind enough to let me use his router table to flush trim the scrap off the edge of the bottom. A stressful operation, but all went well.

BackTrimmed

Portion of bottom edge showing flush trim

The sides haven’t been sanded smooth yet, nor has the edge been rounded, but it looks good!

Back glued on

Monday, September 27th, 2010

I’m getting behind here! The back was glued on a couple weeks ago. To try to catch up quickly…

First, the builder’s label had to be glued in position.

BackLabel

Builder's label in place with ermine border I designed

BackInside

Inside of back with label and center support strip

For nostalgia’s sake, I shot two last views of the inside showing the bracing and bottom of the soundboard, before the back was glued on.

Inside-LastView1

Inside-LastView2

And thanks to Leonard for the use of his clamps…

BackGlued

Back clamped in place, t-shirts protecting top and bottom

The big unwanted surprise during this process was how much the back slid around due to the glue before I could get two clamps tight enough to hold it in place. It was quite unsettling until I got that settled. Hopefully, enough glue got into the kerfing to make a good bond, and there wasn’t too much of it smeared on the label.

Builder’s label

Friday, July 23rd, 2010

I was working on a label design at lunch today. I thought a repetition of the Breton ermine symbol would make a good border. Some lines are included, because the flag of Brittany also has black and white stripes. I was going to print this on parchment-like paper, but decided it needed to be in black and white, like the ermine.

H-G_Label

Shown larger than actual size

Back about ready

Monday, July 12th, 2010

Over the weekend I used a cabinet scraper and sanding block to level the decorative center inlay strip on the back. I had to do this before adding a bulge to the inside, which would make working on the outside more problematic, not being able to lie flat any longer.

The bulge is a center reinforcement strip that the manual refers to that goes over the back seam in the large gap between the braces. No part was included for this and so I suppose it is an outdated step. But I decided to make one anyway. I used a 1″ wide by 1/8″ thick piece of wood I had on hand. The distance between the braces is 8″. I made the strip 7 1/2″ long. After rounding the edges and doing some careful measuring to make sure it would be in the right spot in relation to the braces when it all was put together, I glued it down.

The other two things I did was trace the outline of the body on the back piece, and then trim it closer to this line on my scroll saw.

CenterSupportStrip

Center support strip will span the gap between braces inside the back

Now the back is ready to glue onto the body, except for the inside label. I haven’t made up my mind what I’m doing about that, if anything. One came with the kit, but I might do something else. I went to a label/sign shop today to see about an engraved name tag sort of thing. No rush deciding on that, since I have to first do all the decorative edging around the soundboard first.

Bottom edge rounded

Friday, July 2nd, 2010

Yesterday I got back into the groove somewhat, and rounded the bottom edge of the body. I took out the 1/8″ basswood strips, which were rubber-cemented under the outer edges of the sanding cradle and replaced them with 1/16″ shims, to reduce the curvature. [The recommended curve for both top and bottom was 1/16", but I had increased the top curve to 1/8".] I didn’t have to glue the shims in, due to the springiness of the masonite that is nailed down in the middle. Planing was not necessary, since less was being removed than on the top. So, it went fairly easily. As with the top, the most critical thing was making sure one side wasn’t lowered more than the other due to applying unequal pressure when rocking back and forth.

Back inlay

Sunday, May 23rd, 2010

Tonight I did the back seam inlay. I had a 1/4″-wide strip with a black and white pattern from the local Rockler, which I had bought earlier with one of their coupons prior to the hurdy-gurdy project. It will fit in well with other black and white trim: side stripes, keys, soundboard edge banding, etc.

My Dremel tool has a cone-shaped attachment used for cutting drywall, which made a perfect mini-router. I recently bought a little set of six router bits on eBay, which included an 1/8″ and 1/4″ straight bit.

RouterBitSet1

Drywall attachment with 1/8" bit and the rest of the set of bits

I experimented some on the scrap area of the soundboard, and decided the 1/4″ bit was harder to trust than the 1/8″ bit. So, using my trusty metal rule as a fence, I made two passes with the 1/8″ bit to get the 1/4″-wide groove, and the strip fit in great!

BackInlay1

The mini-router in action, both passes completed

I aligned the inlay pattern in the groove so the edges should be spaced the same when glued to the body and trimmed. The strip was then glued in with wood glue and weight was applied.

BackInlay2

Completed inlay

 It was nice to work on a new part, for a change.

BackInlay3

Inlay detail