I had to do a bunch last year, both Oak and ash broke too easily as did ebony so I ended up with beech, boxwood and despite its faults almond. Making them with 3 woods makes them stronger I suppose that the joints prevent the splitting. I also found that CA glue finish is not good so I stuck to cellulose sanding sealer and standard Tripoli, white diamond and carnauba wax finish. The carnauba wax will rub off in about 2 days (its just good for first presentation) but the rest will stay and their own hands will continue the patina and polish.
I made mine by drilling undersize and then sanding to size, turning to outer size and finished sanding then parting and using the part turned holding piece as a jam chuck (to finish the parted side). If you do use a buffing system then turn a friction fit stick to hold it because the wheels burn!!
The important this is that the inside should be sanded down to very fine with micromesh and water used to raise the grain whilst sanding (this does of course play havoc with the sanding and getting the sizes right). I sand to 12000 micromesh and also make sure that the inner edge does not catch on the web of the fingers.
Here are some ideas http://www.objetsbois.com/fr/20-bagues-en-bois-alliance-en-bois-a-offrir-en-cadeau .
And if you are going to make a business out of it then you will need one of these http://www.cooksongold.com/Jewellery-Tools/Durston-Showroom-Ring-Sizer-Set-prcode-999-ST13
Have fun they are fun to make.
PG
