Sunday, August 28, 2016

Day 129: The Cheeky Brace

While speaking with Owen Daly of Owen Daly Early Keyboard Instruments about lower and upper bracing, Owen mentioned to me that he found the upper bracing scheme in Mr. Miller's eBook Most Excellent to be a bit on the heavy side. While I in no way question Mr. Miller's motivations for his directions or reasons for giving them, I decided to pause for a couple of weeks to look at drawings and photos of Ruckers instruments. Paul Irvin, a builder with over 200 instruments under his belt, was also instrumental (pun intended) in introducing me to drawings and ideas from different builders and their national traditions.

Sometime last year, I attended a Western Early Keyboard Association performance in which the instrument being used had some "cheek curl." I've since come to learn that this can be quite common in harpsichords due to string tension and that it is also quite preventable. One thing Owen recommended was to put a brace into the area where the bentside meets the cheek. Thus I have dubbed it the Cheeky Brace. Owen says this structure will prevent cheek curl, so I proceeded with this idea by cutting and installing one in the instrument earlier today.

First, I started with a new piece of 3/4" poplar. I purchased the darkest material I could find because it has been my experience that dark poplar is quite hard. Whether it's heartwood or not is neither here nor there. I simply know it's good and hard and what I wanted to use for the Cheeky Brace. Interestingly, I found a piece that was nicely figured, which I had never before seen in poplar.

I took some measurements in the bentside/cheek joint corner and cut a piece to fit snugly under the cheek and bentside liners. I also cleaned it up quite a bit using a No. 7, a No. 4, and a small block plane.

It was so nice to put the Roubo to work; its leg vise performed flawlessly. Once I had the piece into shape, I assembled the glue-up parts and did a little planning.

Because I had mounted the case to the bottom earlier, I was forced into making small blocks that I could pound in as wedge clamps between the bottom of the Cheeky Brace and the bottom of the instrument - another reason to hold off on gluing the sides to the bottom until a little later in the game. You can see where I covered the business ends of the wedges with painter's tape to prevent them from becoming permanent parts of the instrument (plastic glues won't stick to painter's tape).

I gingerly tapped them into place and they are setting up in the shop as I write this. The final photo I'll share below is the space between the flat spot on the end of the Cheeky Brace and the spine that will be filled in tomorrow with a nice upper brace (the Cheeky Brace is in the bottom of the photo).

I'm excited to get these braces into place, as well as an "upper belly rail stiffener," so I can move on to making the registers and, I hope soon, the jacks.

Until next time...

Saturday, August 13, 2016

Day 128: Liners and Gifts

Once the lower braces were completed, along with their attendant trenails, I could start preparing and gluing up the soundboard liners. What are liners? Well, they're pieces of wood 1/2" thick and 1 1/2" wide of varying lengths that run around the inside of the body 1 7/8" below the top of the case sides. Ultimately, the liners serve two functions: 1) To support the soundboard and 2) To hold various hitchpins that are the distal termini of the strings. More about those later.

Given the fact they run around every side of the case, they're referred to as the tail, spine, bentside and cheek liners. First,  I started by trimming a 1/2" piece of poplar to a couple of 1 1/2" pieces.

I started with the tail liner as recommended by Mr. Miller in his eBook Most Excellent. One of the reasons for this is to mount it so that the spine and bentside liners butt up against it when they're mounted later. This helps buttress the end of the case against the enormous amount of string tension presented when the instrument is strung.

I used good, old Titebond for all of the liners, along with a wet rag to help clean up during the glue-up process. And it was a process, mainly because it's been in the 90s (Fahrenheit for my European friends) this past week. I really don't mind the heat when using Titebond because it helps cure the glue quicker. If I were using hot hide glue, it wouldn't be too terribly bad, either, but for a completely different reason - it would help extend the setup time of the glue.

Once the tail liner was in good and solid, I proceeded with cutting and gluing up the spine liner.

Next, I worked on the bentside liner. This one was interesting because I chose to kerf it (rather than laminate on the lamination form and hope it fits) to help make the bend in the bentside. What is kerfing? In this case, I cut 7/16" slots into the 1/2" (8/16" for my mathematically challenged friends) piece starting at 1/4" spacing and then gradually spreading them farther apart as I neared the tail.

You'll notice I put a stop behind the band saw blade that provided a perfect 7/16" depth for every cut. The miter gauge helped support the wood at 90 degrees. I also did this one in two pieces, which helped make both the kerf cutting and glue-up a little (okay, a lot) easier.

It doesn't look like much of a bend in the photo above, but it is and the kerfing allowed me to match the liner up perfectly with the bentside. Then, I glued on the tail end of the bentside liner.

After this, the only piece left was the cheek liner. You'll notice in the photo below that I cut a 3/4" x 3/4" notch into this one on the upper belly rail side to allow some extra space for a 4' hitchpin rail that will be mounted to the underside of the sounboard - more on this later, as well.

Installation of the soundboard liners represents something of a milestone for me. Over the last couple of weeks, stuff is starting to get real. Though I still have a ways to go, I inch a little closer every day. It's a good thing.

On a couple of completely unrelated notes, Random Roger Green presented me with two gifts when I visited his cavernous shop a few days ago. The first was an aluminum planing stop that I will mount into the workbench in a recessed notch (to prevent hand plane blade damage) and the other is a vise spacer used principally for the tail vise. The spacer helps prevent the vise from wrenching sideways when I put a thin board into it and tighten it down. I did not know such a thing existed until Random put it in my hot, little hand.

At this point, I really should be showering Roger with gifts for his help and guidance with the bench. Of course, there is always the problem of deciding what to do for a guy who already has everything. I'll think of something (please email me suggestions).

The other note is related to hand plane restoration. For the first time, I submerged really rusty plane parts in a white vinegar bath for 24 hours. Unfortunately, I didn't take too many photos of the process (not really sure why not), but I did snap the one below of the parts gurgling away in a plastic container.

These parts are from a Stanley Bailey No. 5 and I must say the amount of rust that was removed was truly remarkable - and with a minimum of effort on my part, which I like very much. Once I wire brushed the parts down, I rinsed and bathed them in a solution of water and baking soda to halt the stripping process. I'll post more photos of the plane as I put it back together later this week.

Until next time...

Sunday, August 7, 2016

Day 127: Fish Glue and Trenails

Once again, there's been so much happening at Tortuga Early Instruments Worldwide Headquarters I've no had time to post. Time to remedy the situation. First, I want to wrap up one of my mistakes so we can move on. The photo below illustrates my faulty nameboard center window cut.

As I said on Facebook, I'd like more of whatever I was on when I made this cut. Not only is it off, all three of the windows are of insufficient height. Okay, in my defense, it was one of the first things I worked on after completing the keyboard. Yeah, I know, lame. Regardless, I'm going to need to work on all three windows, but, at Owen Daly's (of Owen Daly Early Keyboard Instruments) suggestion, I'll be waiting until later to clean them up.

Random Roger Green also asked the salient question, "Aren't you veneering it? If you are, why not fix the holes and just put another layer of [astonishingly thin] veneer over it?" Once again, Owen and Roger have shown me the way - and the way is down the road weeks or months from now. Okay, enough with the mistakes, let's look at a few things done right.

First, I finished up gluing the remediated upper belly rail (UBR). You can see in the photo below where I created some small clamping blocks covered with blue painter's tape. This prevented the blocks from being glued to the case, and I used the blocks to keep the clamps from marking the wood during glue-up.

All measurements are good, everything is square and all dados and parts line up where they should. Now that I've fixed all of the mistakes I baked into the UBR, I'm proud to say I've instituted a new cutting program at Tortuga Early Instruments Worldwide Headquarters. When cutting the parts and pieces below, I literally wrote the dimensions on the wood with checkboxes to ensure I made the correct cuts. The first parts cut using the new program were the lower braces. Before I cut the pieces, though, I had to mark out the upper and then lower brace lines onto the case sides.

Upper Brace Lines

Lower Brace Lines

Once I lined everthing out, I carefully proceeded with the cutting and shaping of the lower braces.

I cut all to dimension and drew on the cut lines of the curves. The idea is the have a 1 1/2" bar with two inches of a full three inches in width at each end. You can see in the photo above that I once again used the trusty, old magnetic screw dish to make my angles.

I then cut the pieces on the band saw (sorry about the poor quality of the photographs - I broke my cell phone and have not yet replaced it, relying, instead, on my little Samsung tablet's camera and it sucks) and shaped them on the Ridgid oscillating spindle sander. I know, I have kind of a Darth van Beethoven thing going on there. I don't care - it's safety first at Tortuga Early Instruments Worldwide Headquarters!

As you can see in the bottom photo above, I left a little leg room on each end as suggested by Mr. Miller in his eBook Most Excellent. The longest one requires angle cuts on both ends and all the others have them only on one end, yet it's been my experience that these things are best left a bit rich because it's frankly kinda hard to cut an angle perfectly on the table saw the first time. I did, though, get them all cut and put in for a quick dry fit.

All was well, so I went ahead and glued and clamped them in.

As you can see in the bottom photo above, it looks exactly like the dry fit except that they're glued in. I suppose this one's for the record. You'll also notice gaps where there shouldn't be gaps. I should have sanded the bentside ends of the braces down to fit the odd bentside angle. The bentside continues to offer opportunities for improvement and I certainly will be addressing this in future builds by making another lamination form or simply bending a 1/2" plank. We'll see.

Once I was satisfied with the glue-up, I pounded two trenails (pronounced "trunnels") into both sides of each brace. I made my own using red oak and gave them a dull point using a bench hook and 1/2" chisel.

A trenail is really just a square peg pounded into a round hole. In many ways, this is a great metaphor for my life, but I digress. In the end, Owen was right - there's something really quite satisfying about pounding them in, especially the "THUNK" when they hit home.

These will hold the braces fast and will be completely covered when I veneer the sides. Yes, I'll cut them off and clean them up. Sheesh.

On a couple of completely unrelated notes, I experimented with fish glue this past weekend. Now, the stories from my luthier pals about fish glue are as varied as they are interesting. As I always say, "Ask five luthiers for their opinions on a build method and you'll get seven answers." This was the case with the fish glue. Mark Roberts of Mark Roberts Guitars and Ukuleles gave me a small bottle, so I experimented with it a bit.

Conventional wisdom among my fellow builders is that fish glue is for temporary use only, when one requires a weak joint. When would a luthier require a weak joint? Well, some builders glue blocks to parts such as case sides, use them to clamp during glue-up, and then remove them with heat. This requires an ostensibly weak glue such as fish or watered down hide.

On the other hand, Mark tells me a story from a luthier pal of his who built a guitar using only fish glue that has traveled on six continents in just about every weather condition imaginable for the last 20 years and it's still as solid as the day it was built (or the fish glue dried, as it were). The photo above illustrates a two-day test I ran on a couple of pieces of scrap using the fish glue he supplied. I cannot get them apart. I even tried cold, room temp, and hot water.

Tomorrow, I'll hit it with the heat gun to see what happens. I can say with confidence the glue is incredibly easy to work with during glue-up; it cleans up quickly using hot water and a paper towel and washed easily off my hands. I suspect the fact that this glue is made from fish air bladders, rather than bones and/or cartilage, makes a difference, as would its final formulation by the manufacturer. More to come on this interesting, sticky new twist.

I also made a couple of little racks to get some of my clamps off of benches, shelves, and other hangy-thingies and up out of the way while remaining easily accessible. My solution:

Yeah, I know it's trivial in the grand scheme, but, sometimes, it's the little things that count.

Until next time...

Wednesday, August 3, 2016

Day 126: Fixing Mistakes...Again

The last couple of weeks have been an intensely interesting study in attention to detail. Mr. Miller's eBook Most Excellent is clear and precise. I am not. I keep making mistakes over and over and over and over. This simply will not stand. So, I've had to come up with a mitigation strategy that includes both a laptop in the shop and checklists for every cut moving forward. It's sad I need to do this, but I need to do this. I've grown weary of fixing mistakes.

Speaking of mistakes, the first one we'll discuss today is the upper belly rail, or UBR. The UBR serves several functions related to support and placement of the soundboard and registers (guides for the jacks). After cutting and then fixing the dado (discussed in an earlier post), I discovered that I had cut the rabbet on the wrong side of the board. I then cut off the rabbet and had a little do-over party.

Because the poplar piece I wanted to use for the fix was not long enough, I created a half-lap joint that I knew would be even more stable once the piece was glued onto the UBR.

Once it was glued up, I cut the rabbet (again), this time on the correct side, and smoothed it out on the new bench using a 1/2" chisel.

All was well...until I tested its placement in the case. I discovered the pinblock supports I had cut and glued up months ago were not dimensioned correctly. Good grief. Rather than start a harpsichord case-fueled bonfire in the backyard, I deliberated a bit (Owen Daly calls this "head-scratching time") and emailed Ernie Miller who helped by clarifying the necessary dimensions. I then decided I should at least try to hog out what needed to go to reach the correct dimensions.

I started by creating a template that was the size of my desired end dimension.

This little template helped me draw some cut lines in a highly constrained space. Once the lines were drawn, checked, and rechecked, I started the exacting process of chiseling out the unneeded material.

Wonder of wonders, it worked! The supports are now dimensioned in the right places and I can get back to gluing in the UBR, Thank goodness for sharp chisels - they saved the day.

After discovering my latest mistake, I decided to throw the keyboard into the case to check its fit.

Fortunately, it's just right. I honestly don't know what I would have done had something been off - probably fix it and live to fight another day.

Until next time...