I got it from James Howel's book "Modern Gunsmithing" (circa 1950's) it is one of my go to sources. In the first book he has three or more chapters on gun stocks, stocking, and finishing. He has some oil/varnish formulas that are variations of slacum that work well. He recommends applying an oil finish with a muslin wheel coated with rotten stone and a few drops of finish added. The rotten stone does indeed polish the wood and completes the final filling of the wood as you cant, entirely wipe it off. I do the wheel treatment and then after 15-30 minutes I hand rub the finish. If the stock still feels oily then wipe it down with a clean cloth. Not sure if this is necessary but it looks good afterwards. Usually the film is so thin that 24hrs. is enough curing time before another application. I usually use a hand drill or if on a bench wheel set the RPMs pretty low and be careful of edges they can get torn loose. Too high on the RPMs and it can burn the finish.
This method only works with slower drying oil or oil varnish mixes. You could use any finish and add oil and turpentine to it to use the wheel finish method. If the surface of the wheel glazes over or gets hard just cut it back and start over and use less finish on it.
I treat the wood with artist linseed oil after the alkanet then fill with straight varnish or a paste filler if the wood is open grained or both with varnish first as a sealer filler. Then sand back to wood and start the wheel finish. This will not build up much if any surface coat so if you want that finish with another application method.
Get a hold of his book if you can, they are getting a little pricey but still worth it.
