Slab vs. Quarter, wide vs. fine

[Ken McKay]

I have a stock of quartersawn Big Leaf maple that I have made bass backs from. It is fairly plain looking but is very stable and moderately dense (about 45 lbs/bd ft iirc). These are big wedges that are suitable for a fully carved back with a center arch height of 1.75 inches. Once carved and graduated these backs are very stable and no worry. Good stuff.


I have some very fancy looking eastern red maple that is slab cut but is beautifully flamed all the way across the 15 inch board. I sawed the plank into slices a little over 1/4 inches thick to make two two-piece backs. This is very tricky to work with. Once the book set was glued together it started to potato chip when sitting on a flat bench. I recongized this movement and compensated in the construction of the back by letting air get to both sides at all time. This let moisture escape equally from both sides. I also kept the shop humidity at around 40 to 50% RH. I worked very slowly and let the back wood acclimate over two seasons before I glued the braces in the flat back. I also made an X pattern brace so as not to confine the natural wood movement that I recognized over the seasons of watching the wood. I also curved the braces so the back would be domed. This dome is around 5\8 inch and serves to allow the back to gain a little structural strength as well as move and vibrate the way I wanted.

I am in the process of sawing two large logs of white pine into top wood for double bass. Michigan grown, standing dead for over a year as I watched it turn gold and now ready to be sawn. Most will be quartered.