What grit belt for bone nut blank?

Not a big deal. 150 will work fine. You'll find that changing a belt is quick and easy if you need to.

Two years ago my workshop at The Music Box down sized when we changed location. All of my nuts and saddles are done by hand as there isn't room for a belt sander. I keep a large selection of bone and corian thicknesses. At work, its a hacksaw and a dremel. Its not terrible. Violin bridges are the worst but I make due.

The last time I made some blanks I used my surface sander to level the nuts and saddles to usable blanks. Final shaping is done by hand with sand paper on a refereance granite block.

Mick, I use 120-grit for roughing out nut blanks, finish with single-cut files, followed by polishing with 1000-grit paper, and then final polish with the back of the 1000-grit paper.  Try it...makes a glass-smooth and shiny bone nut.  Be sure to use a portion of the back that has no printing on it or the ink may transfer to the nut.

If you don't have one yet, get yourself a hand vise.  This not only prevents a nut blank from being launched into orbit around your shop, it also saves your fingertips from getting unintentionally re-shaped by the high speed sandpaper.  It provides precise control over any small part you're working on.  You'll find many other uses for it, so hang it in a handy place at your bench.  This is a tool that comes from model making; not 'models' as used today--but wooden models that served as masters for making molds for metal castings. Gunsmiths, clock makers, jewelers and other tradespeople that shape small parts also depend on them. You can find these cheap at flea markets/boot sales and Junque Shoppes. If you're in a junk shop and spy a crate of old rusty tools, dig around and you'll probably find one.  If it's rusty, soak the parts in vinegar overnight and polish it up.

I have a few hand vises; one that I modified (made smooth) specifically for doing nut work because most hand vises have knurled grippy jaws that will damage the smooth surfaces of nut material.  I know hushnel has a few; we've talked about it.

They look like this:



If you use a vertical belt sander that has a table on it, another handy tool for nut making is a small drill press vise.  These are designed with the jaws, base, sides, and end all 90 degrees from one another.  You can clamp a nut blank in it and lay the vise on its side (or on its end) on the sander's table and get perfectly square sides on the blank.  Same as above: look around for a used one and get a really good price.  



Stooge Mac sells one, but they call it a nut-making vise and that makes it mucho dinero ($50 + shipping).  It does, however, have the added feature of taller, thinner jaw plates that make hand filing/sanding nut material a bit easier:

www.stewmac.com/Luthier_Tools/Tools_by_Job/Tools_for_Nuts_and_Saddles/Nut_and_Saddle_Vise.html