Machines v. Handtools
Woody has touched on the value of each of the few machines that he has in the shop. The truth is, home-shop luthiery is primarily a hand-tool operation. Hand and eye skills are still the dominant tools in this sport. Some readers will be disappointed to hear that. Hand tools do not, perhaps, come with the adrenal rush that heavy machines might bring. If that is your interest, Woody suggests furniture or cabinet making, or some other woodcraft where the primary processes involve some sort of machining. This is not the case with home-shop luthiery.
There are luthiery-process exceptions, however, that are better accomplished with semi-expensive machines like thickness sanding, side bending and compressed air for applying a finish to your guitar. Machines that assist with these operations might only be used a few times during the course of building a guitar. They can make the entire process of guitar building more controllable and, hopefully more satisfying.
Sitka Re-Saw and Grade
0:07:10
https://www.youtube.com/watch?v=1DTY2bUoxwo
Carved instruments, like mandolns and violins, are ideally quarter-split as opposed to being quarter-sawn. If the grain is straight, billets of wood split radially will appear as shown in the photo below. If the tree twisted as it grew, the split will not be flat but will show waves or twists as the grain 'runs out' across the face of the split. Nearly all quarter-sawn wood must deal with run out to some extent. Most spruce trees, however, do not twist severely as they grow, i.e. run out is minimal. Run out, however, is a feature in grading the quality of the tone wood that you buy from a supplier. (A, AA or AAA)
The Sitka spruce billet in the photo below has been split radially forming two wedges of spruce on the left and right. The grain in this billet is very straight. The split surface is so flat that it looks as if it was sawn. These billets were harvested and split by Woody himself in 1982 from discarded bridge stringers on Prince of Wales Island, Alaska. Woody has about 40 of these left. Let me know if you are interested.
Woody@WoodyStrings.com
July 2020 Luthier's Journal
Shop Machines
Hand Tools
Tone Wood
By comparing the information in the tables one can see that Brazilian and East Indian Rosewood have the same density, but Brazilian is stiffer and has significantly less tangential shrinkage.
More on shrinkage below.
Play Safe, stay healthy. Come back next month.
Woody
TONE WOOD Below are the URLs to 4 interesting videos put out by Taylor Guitars. The videos are about harvesting and grading music-grade wood. They really are very interesting. To view them you will have to copy the URL and paste it into the address line of your browser.
Tone Wood Suppliers
If one Googles "Tone Wood", one will see that the list of tone wood suppliers is very long. A few of these 'luthiery supply' houses are authentically catering to the growing number of luthiers around the U.S. and abroad (LMI, Stew Mac, and a few others). Woody has found that authentic luthier supply houses have objectively graded wood, friendly and knowledgeable customer service, and clearly defined return policies.
Other tone wood suppliers actually sell all types of musical merchandise from ukelele wood to guitar stands, amplifiers and, of course, musical instruments. These are not actually tone-wood retailers but are distributors for tone-wood wholesalers. You pay your money and take your chances.
Still others are luthiers who buy wood in bulk, mill it in their backyard and sell it to you_ keeping the best quality wood for their own personal stock. Sometimes one gets good wood and sometimes...
Over the years, Woody has dealt with tone-wood suppliers in each of these categories. With small outfits one has to be sure of, and agree with, their return policies before purchasing anything.
For example: The wood that you want should be less than 15% moisture content and air-dried for at least a year. If you're not sure, call the seller and ask. Wood that comes off the truck, gets milled immediately, and is sold to you a month later_ is green.
Because one never knows for sure when the wood was harvested and milled, the best solution is to assume that the wood is from a tree harvested in the last 12 months, then milled in the last 6 months, then packaged and sold to you. Once in your shop, check the quality of the wood on the day it arrives.
Is it cut and milled to the proper dimensions? (including thickness)
Does it have obvious visual flaws? (knots, pitch pockets, run out, etc.)
Tightness of grain? (A, AA, or AAA)
Is it truly book matched?
Does it have consistent color? (back and sides wood the same color and approximate grain)
What is the moisture content? (moisture content meters are not expensive)
If satisfied that the wood is what you ordered:
Mark (number) the wood so that book-matched plates stay together.
Keep a record in your 'Wood Inventory' spiral notebook. Record date, supplier, type of wood, moister content, weight, seller's grade, costs and your in-house ID number for that wood.
Sticker and store the wood for at least another year in your own shop to make sure that it is dry.
It's easiest to do this record keeping and storage in the first few days after the wood arrives. Otherwise, it could easily lay around for a year and when you need it you might not remember what you've got or where you put it.
Generally when wood cures, the tangential shrinkage is about double that of radial shrinkage. That's why we want to only use quarter sawn wood for the top, back and sides of the guitar. Quarter sawn ensures that shrinkage along the grain (tangential) is in the shortest dimension, i.e. across the plate thickness which is only about 1/10 of an inch.
Flat-sawn (aka Plain sawn) wood in a guitar back, for instance, means that the tangential shrinkage will take place across the width of the back (15 inches or so). That's a recipe for disaster.
The luthier wants quarter-sawn wood at approximately 15% moisture content (or less), preferably air dried.
Some distributors of tone wood advertise and sell flat-sawn wood because it shows those interesting cathedral patterns as one can see in the bottom half of the 'Milling Tone Wood' picture on the left.
By comparison, quarter-sawn wood is not as visually dynamic as flat sawn. Those cathedral peaks are an indication that the wood has been flat-sawn which is really the most common and efficient way to mill lumber out of a tree.
All commercial construction "two-by" lumber is flat sawn. Check it out the next time you're in one of those big-box lumber stores like Lowe's or Home Depot. There is nothing wrong with lumber cut this way... unless you're building a musical instrument.
wJs SHOP HAND TOOLS
By far, more hours are spent with hand tools than on machines. Luthiery is a hand-tool sport. In discussion, it is hard to pin down every use of every hand tool. Suffice it to say that when one needs a specific hand tool, you will know it. Let me give you one example.
When fretting a bound fretboard one does not want to cut the fret slot through the binding. You want the crown of the fret to extend over the binding to about 3/4 the binding's thickness. To do this the fret tang needs to be removed perhaps an 1/8" back from the end of the fret. Looking something like this.
Koa Wood
0:02:57
https://www.youtube.com/watch?v=AQXnvK8GkjY
SHOP MACHINES
There is little that Woody can say about the machines in the wJs shop that he has not already written here (somewhere). There are some succinct comments, however, that might help you decide if buying a certain machine will be useful and priced right for your shop. Again, every luthier is different. Please take Woody's information objectively and filter it through your personal needs and home-shop capabilities.
Fiddle Back Maple
0:06:20
https://www.youtube.com/watch?v=jJMLE7G2IIk
Sitka Harvest, Prince of Wales Island, Alaska
0:07:30
https://youtu.be/5EpVIEyYiSs