Build Diary| Jack Spira | Ditson Style Part 1
Please Click on the pics for fullsized view!
Jack Spira is a really talented Australian based luthier who trained at the London Collage of Furniture. He established Spira guitars in 1991 and I have known with Jack for over 5 years. In this time, he was made some fantastic guitars and his knowledge of Native Australian woods has invaluable in our quest for alternative tonewoods. (see his article on Australian Tonewoods here.).
I have been enthralled by Jack’s Ditson style guitars as the originals had a certain old world charm and in the latter years sounded rather good, especially with silk and steels. Their smaller size mean they could be played very comfortably with a quick response and an intimate tone.
Resources: 1. Read Jack’s article on Australian Tonewoods here.
2. See another 1-45 style guitar buy Gary Demos here.
My fate was sealed when I saw the 45 style replica pictured above. The little jewel of a guitar bewitched my eyes and senses and I began to plot a order from Jack! We agreed on a set of specs which came very close to the originals with some modern amenites. They would have adjustable truss rods and also be X braced for light guage steel strings.
Jack has very kindly agreed to document the build process of a pair of Ditson style 1-45s: one in Brazilian rosewood and another in Acacia for us! So without further ado, here starts the build diary:
Please Click on the pics for fullsized view!
The red spruce tops as they came from Old Standard wood. They gave me some very good grade Adirondack. I think because of the small size i was able to get some good tops.
I join them with the No 7 jointer plane on a shooting boards, then glue them with the old spanish method of rope and wedges. I’ve tried a few different joining methods and cant beat this one for speed and accuracy. Then the tops are rough thicknessed down to 3mm thick. This is not the finished thickness, but is a bit over. I put the rosettes in and then I can run them through the thicknesser again to clean up the rosettes and finish the thicknessing by hand.
The three ring rosette I put in with the Greven rosette jig. I hardly ever use this tool as most of my rosettes are the wide classical type, and of differing thicknesses, and some are oval, so need to be cut by hand. This tool is ideal for the three ring rosette though and does a beautifull clean cut with the thin slots.
The rosette itself is moslty made up of 0.3mm poplar veneer. The black veneer is also poplar, dyed black. I cut the sheets into strips with a scalpel blade. A strip of teflon is used in the centre section where the shell will go, and the wider white lines around the shell border, which were probably originally ivory, are white plastic I got from Martin guitar, the same stuff they use on the contemporary rosettes. Its a fiddly job getting it all in.
The two outer rings don’t have to join up at the top end as they are cut away later, but the inner ring has to join neatly at the top. The next job is to pull out the teflon strip which will leave a slot exacly 1.6mm wide ready for the abalone strips.
Jack Spira http://www.jackspiraguitars.com/
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Hallo, Jack.
I have been recommanded by a luthier that you have knowlegde of vintage guitars.
i am an starting guitar builder and now the next project will be an vintage Mid-19th century Martin Guitar.
You can find the plan by Guild of American luthiers plan 57.It is about the same Ditson Guitar you have built.
Now mine question is i love the early blues sound,delta/raggtime blues.
I have heard that ladder bracing on the top honduras mahogany back and sides produced the blues sound.
How i can modified the guitar like a steelstring guitar.Hopely you can help me.
Nice Day, Erik van Minde/Netherlands.
Hello Erik
I had a look at the plan ( number 57) and it looks like a great project, a beautiful style of guitar. I’d be happy to help as much as I can.
My knowledge of vintage guitars is actually not very broad I’m afraid. I have a specific interest in the Ditsons and love early Martins in general.
I think you are right that a ladder braced top, and/ or a mahogany top would give the kind of sound you’re after.
The guitar in the plan you have has a simple fan brace of three struts by the look of it, and that’s a pretty common one for that period I think. The Ditson has a slightly more complex fan brace of five struts, three of which fly over the bridge plate. Both these designs are very good at keeping the bridge area flat under string tension without adding too much stiffness across the grain of the top. Allowing that flex across the grain on a small top seems to improve the lower frequencies and get a more balanced sound from a very small box. That’s not what you’re after though, so stiffening the top across the grain with ladder struts should give the small boxy sound you are after.
I’m not an expert with ladder braced tops, but I think they can be prone to distorting under string tension and the bridge rolling forward with the back of the bridge bellying up the soundboard. So if it was me I would start with this in mind.
Positioning two ladder braces immediately in front and close in behind the bridge might help a lot. Also I would consider adding one or two short braces going along the grain of the top right underneath the bridge ( I think the Selmer’s did this ) just to keep it flat around the bridge plate area.
Another option might be to go over to an X brace, flatten the X out so its closer to a single ladder brace in terms of stiffening across the top, and put another ladder brace behind the bridge. This would create quite a good stable triangle around the bridge plate I think.
You may need to consider something like that if the piece of Mahogany you have for the top is not very strong along the grain, which is sometimes the case with Mahogany when its thinned down to top thickness. Spruce is generally much stronger along the grain, so I would expect less trouble from spruce in regard to distortion around the bridge.
Bear in mind my experience with ladder braced tops is very limited, so I’m not drawing on specific experience. With any luck, someone with better knowledge of ladder struts will leave a comment as well
Cheers!
Jack
hi there, i have a really old dreadnought guitar with the traits of an early/martin chicken guitar. i am searching for folk who can help identify it! hope you can help? all the best martin gaughan roberts – artist.
Hi Martin, thanks for your email. Feel free to pop some images into the email to us and we’ll do anything we can to help.
Hello Jack .i really like your guitars How did this little beauty end up sounding? Will anything like this be for sale at the next melbourne guitar convention in may?
Hi Jack – just a modest update on the Ditson tenor Guitar you built for me a few years ago … in one word, remarkable! For such a small bodied guitar, it has a room filling sound and which is a delight to both me and who ever is listening. Thanks again for the terrific instrument(s). I am still trying to come up with what I’d like you to build for me next.
- for others reading this, this is a 22. inch scale, 4 string tenor with a floating bridge rather than a pin style. It is all OZ woods with a very successful King Billy top and an amazingly rich Tasmanian Blackwood back and sides. The King Billy top works will with the floating bridge as the flex and tension are all in one direction; down, rather than the torque twisting which happens in a pin bridge. I had this built as a rhythm instrument and it is superb … the real surprise is the way it has matured into a very rich finger style instrument. Fun instrument to play and a real crowd stopper.
Pix of this gem are http://www.mandolincafe.com/forum/showthread.php?57186-Spira-Tenor&highlight=Jack+Spira
Thanks again Jack for a remarkable instrument.
Dion – Chicago