Is there a difference between threaded bolsters and fluted bolsters? Also, what is meant by mill relieved liners?
Many thanks to all!
Threaded bolsters have narrow, usually shallow, lines cut across them -- normally two or more lines. Fluted bolsters have a wider, deeper round bottomed cut across them - normally just one. Fluted bolsters are also traditionally called "rattail" bolsters, since the flute is often cut using a rattail file -- a thin, round file. You can have bolsters that are both fluted and threaded.
Mill relieved liners have been cut down several thousandths of an inch depth - usually in a partial circle - on the inside of both liners a short distance from the pivot pin. This basically creates an integral "washer" for the rear part of the tang to ride on -- it also creates a region that doesn't contact the stamped/etched portion of the tang - thus avoiding marring the finish and the stamping. Done right, it also makes the blade action a bit better, since there is now less of the liners in contact with the tang. Here's a walkthru of how it's done:
http://boseknives.com/liner-milling/ Sometimes a maker without access to a mill will create the same relieved effect by deep etching liners -- works fine, it just takes more time and aggravation -- it can even be done by a small hand scraper and a lot of work if you're *really* determined (I think Ron Lake did a lot of his earlier knives that way).
Note: there is an old purely decorative liner treatment that's also called milled liners -- a small, knurled wheel is applied with a lot of pressure to the edges of the liners, creating an effect rather like a coined edge that goes around the whole liner edge typically.
-- Dwight
