Replies

1. 
   oldusty | Jan 11, 2013 06:20pm | #1

   drill bits

   Imola ,

     Most doweling jigs have steel sleeves the bit guides through , the jig may

      be aluminum but not the part the bit goes though usually .

      I used them for years and I learned that often the bits get smaller by a matter of thousandths

      each time they get sharpened so ultimately they get sloppy in the sleeves .

     I have a few dedicated 3/8" bits that work great with the doweling jig , BTW a round point  seems the

     most forgiving for dowel holes for me  .

             regards dusty , boxmaker

       

2. 
   roc | Jan 11, 2013 11:40pm | #2

   Not over thinking. You have good questions.

   Here are my thoughts:

   If you like the bits you have I would suggest trying to order more bits from the same manufacturer in the dowel sizes you will use.  That way you can keep your set complete and fresh.  That is probably only two or three bits.  Keep those with your doweling jig just for doweling. Protect the ends of the bits for all you are worth. If you can not buy more bits individually I wouldn't worry about using the good bits in the doweling jig as long as you very carefully place the bit in the jig so the cutting edges on the END of the bits do not get dinged on the jig.  That is what is going to kill the bit.  Unless you are cutting dowel holes all day every day I would not worry about wearing out the sides of your bits.

   The sharp edges on the side of the bit:

   Lets call them the flute edges.

   I have sharpened a boat load of drill bits in my time, for metal working and wood.  I have never ever sharpened the side flute edges.  I have never found a reason to.

   The edge is sharp to help keep chips from getting caught while the flutes convey the curls out of the hole.  They don't cut they just maintain a close fit to the side of the hole.  Since they don't cut they stay sharp enough to do their job for the life of the bit (unless used on house construction where there is grit contamination from dirt and concrete etc.).  For your cabinet making I wouldn't worry about this in the least.

   I also wouldn't let some body sharpen the flute edges on the doweling bits that way they won't get reduced in diameter.

   Now about sharpening :

   It is a bit of a confusing thing to learn but you can learn to sharpen the actual hole cutting edges of your drill bits your self.

   The hole cutting edges are just short little areas on the end of the bit.

   I can help you learn this if you like.

   I would recommend you get a practice bit to . . . well . . . practice on until you are confident with your drill bit sharpening skills then you can touch up  the edges on your good bits.  It isn't like you take off much metal at all; just a light stroke or two now and then.

   You don't need any fancy tools, just a couple of little diamond files that don't cost much.  Some of the brad point bits you can even sharpen with a file.

   Now, there are things that look like drill bits but are cutting tools that are designed to cut side ways such as router bits and metal milling bits.  Those get dull in the flute edges and need to be very sharp and very accurately ground to work right.

   A drill bit is not the same animal.

   One thing that will make your doweling bits happier in the doweling guide and for drilling deep holes in general is a bit of candle wax rubbed on the bit.

   This cuts down on friction in the jig or hole and makes the bit cut the wood a little easier/faster/quieter (the wax melts down the bit and onto the cutting edges to a very minute degree) and it makes the bit heat less while it is in the dowel hole.

   One would ask . . . does the wax inhibit the adhesion of the glue to the hole ?

   I will leave that up to the pros here to answer.  I use candle wax on my plane soles and plane blades and have no glue adhesion problems or finish problems.

   I will now drop the bomb and say I don't do much doweling.  I do a lot of drilling though and have since I was six or eight years old.  Always making stuff.

   As far as taking your bits in to be sharpened or mailing them.  I can and you can sharpen a drill bit or two in less time than it takes to find a box and package up your bits let alone the time wasted sitting in traffic, twice (going and then picking up the bits).

   Nah, you sharpen your chisels and plane blades and hopefully your hand saws . . . sharpen your drill bits as well.

   Once you have the "ah ha" moment you will wonder why it ever seemed like a big mystery.