I love to thickness tops, backs and sides with hand planes. It’s quiet, challenging and a good physical workout. If all goes well the surface of the wood will be just about ready for finishing.
That being said, to produce instruments for sale in a reasonable amount of time most luthiers will use a thickness sander to prepare the wood.
I decided to give this a go but I didn’t want to invest a lot of money on a machine nor did I want to add a relatively large item to my small shop.
Until recently commercially available thickness sanders were large and expensive. Many instruments makers cobbled their own machines together. Though smaller and more affordable thickness sanders are now available I decided to make one out of what I had lying around.
The heart of most homemade thickness sanders consists of a drum sander spinning over a hinged board. When one end of the hinged board is raised the distance between the board and the sanding drum narrows providing an easy way to determine how much wood will be removed with each pass.
To make this machine I used a 1/3 HP motor salvaged from a cheap drill press destined for the scrap heap, some plywood, an old end table I was trying to give away, a 6 inch sanding drum and a few odds and ends from the local hardware store.
There is a knob on a threaded rod underneath the hinged board that doesn’t quite show up in the photographs. This knob makes it easy to open raise or lower the height of the table by small increments. The two brackets on the sides of the table keep it from wobbling from side to side. They work but if I was making this again I would use something more substantial.
The dust hood was made out of some scrap lumber and plywood. At first I just fit a shop vacuum hose into a hole drilled in the top of the dust hood. After the third or fourth time it fell out I screwed on a hose adapter and it works much better. The machine produces surprisingly little dust as long as the vacuum is running.
I use 60 grit sandpaper on the drum.
The sanding drum is mounted to the motor leaving the other end of the drum free. Using the 6 inch sanding drum I can sand a board up to 12 inches wide in two passes.
The machine works quite well as long as I take light passes. I leave the sanded wood a little on the thick side. I then vacuum and wipe off as much dust and abrasive as I can.
A few passes with a scraper removes any grit left behind and I do the final thicknessing by hand.
I’m currently working on a dulcimer in Cherry but I thought I’d get started on the next in line. That one will have Walnut for the back and sides and a Cedar top.
Here is some of the wood that has been up in the attic. This was resawn about a year ago.
I take what I am going to use and keep it in the shop for a few weeks so that it can get acclimated to the environment in which the instrument will be built. I keep the humidity in the shop at around 40%.
Here’s a two piece Walnut back that is about to be joined. The wood is sawn in two consecutive slices off the same board so that the grain is book matched. When joined the two halves will be a mirror image of each other.
To start I clamp the two boards together against the bench. There is a spacer under the two halves of the back elevating them a bit so they are within reach of the planes blade.
I then shoot the joint with a long jointer plane (for you old tool aficionados I’m using a Stanley #7 type 11 with a Hock A2 blade honed with a 10 degree back bevel.) For those of you who are not old tool aficionados (in other words, normal people) I’m using a long plane with a good blade sharpened and set up to take a very fine and smooth cut.
After the joint is shot true I edge glue the two pieces together using a few cam clamps. I weigh down the ends of the clamps to keep everything stable. I usually use a few planes as weights because they live right under the bench. I tamp down the joint with a mallet to make sure everything is lined up evenly and then I go do something else while the glue dries.
Does anyone else find this interesting? Let me know!
When I was 15 I played piano in a rock and roll band. I became involved with a community theater group that rented a storefront and paid the rent by having a coffee house with an open mic every Friday.
I got to meet a lot of interesting performers and heard a diverse range of musical styles. I gained experience as a performer and I started writing songs.
Around this time I met a a guy named Glenn who was to become a dear friend. Glenn played guitar and sang folk songs. He was the person who introduced me to traditional folk music and the singer/songwriters of the 50’s and 60’s.
I started playing autoharp so I could play with Glenn as the piano was kind of hard to lug around…
One night a man named Ed Badeaux played the open stage. Ed played guitar in a finger style I had not heard before. He had a very expressive, soulful voice.
Years later I learned that Ed had recorded a few albums in the 1950’s and had been the editor of Sing Out magazine for some time.
Ed would perform at the coffee house now and then. It was always a treat.
I was very moved by his playing and singing and this was a turning point for me. Sometimes the nature of an influence can’t be explained.
One night Ed showed up with a dulcimer and sang “Pretty Saro.”
I had never heard a dulcimer before but I had an overwhelming draw to the instrument.
This was around 1973 or so. I could not find a music store in New York City that sold dulcimers and it was rare to find a store with someone who knew what a dulcimer was!
A year or so later I came across a store in Greenwich Village that shall go nameless. This store had all sorts of exotic instruments including a bunch of dulcimers. They asked how much I had to spend and sold me a dulcimer that was worth at least half of what they charged me! Of course I didn’t know this at the time but it got me started as a dulcimer player.
There were very few books and recordings featuring the dulcimer back then. I was able to learn the tunings and the basics but I had to take it from there on my own. I knew enough music theory to figure out where the scales and chords were.
I did not know what was considered possible or impossible to play on the dulcimer and this lack of knowledge served me well. I knew the dulcimer was not chromatic but other than that I assumed that anything I could not play was a limitation of my ability and not a limitation of the dulcimer.
This outlook caused me to try and play anything I thought should work and this included just about everything.
A few years after I started playing mountain dulcimer I heard a man playing hammered dulcimer on the street. Once again I was struck with a strong sense that I had to learn to play this instrument.
Once again I was not able to find an instrument in New York City. Dulcimers and hammered dulcimers just were not that popular in the Big Apple back then.
An acquaintance mentioned he knew a woman who had a dulcimer but she didn’t know how to play it. I went to visit her thinking she would have a mountain dulcimer but what she had was a hammered dulcimer.
She lent it to me so that I could learn to play it and then teach her.
She decided she was more interested in the mountain dulcimer. I had recently begun making mountain dulcimers so I traded one I had made for her hammered dulcimer.
Woodworking tools are useless unless they are sharp. Learning to sharpen is an ongoing process; I have tried a number of methods and find that my technique and the materials I choose to use continually evolve.
There is not a right or wrong way to sharpen tools. If the tool gets “sharp enough to shave with” then all is well.
Sharpening basically involves bringing two edges to such a fine point that they almost disappear into each other. The two surfaces are ground with increasingly finer abrasives until what had been a scratched piece of metal becomes a mirrored surface.
What follows is a very basic overview of my sharpening process. You can find much more detail on the web, in books or by asking me a question. Please feel free to ask questions! The first order of business with chisels and plane blades is to flatten and polish the back. The back of the blade forms half of the edge. If the back of the blade is not flat and polished the edge will never be precise; it will show small imperfections and nicks and the edge will not stay sharp very long.
Flattening the back of the blade is a tedious process but well worth the effort. The back of the blade is held flat against the stone and polished until it is smooth. This is repeated using increasingly finer grits.
Here’s the set up I use most often for sharpening. I use several diamond sharpening stones. They cut quickly and always stay flat. The flatness provides a constant reference and keeps edges and the backs of blades straight and true.
I have a very coarse diamond stone that works so well I rarely use a grinder anymore. I have a few finer grit diamond stones that bring the edge to a usable sharpness very quickly.
I use a fine Japanese waterstone for the final sharpening and polishing. The waterstone brings the edge to a mirror finish. I use the diamond stones to keep the waterstone flat.
On the bench you can see the sharpening guides I use. These are very helpful with maintaining a constant angle when bringing an edge to shape. I use them all the time with plane blades and chisels though I often work freehand when touching up a blade that is beginning to dull a bit.
Last but not least is a hand grinder with a hard felt wheel charged with a fine honing compound. This makes quick work of sharpening a knife, putting a razor sharp edge on a chisel and sharpening various odds and ends around the shop. It isn’t absolutely necessary to use the grinder for these tasks but it is a lot of fun!
In the future I’ll write about different types of bevels and angles for special tasks, blah blah blah….