Burnishing Dowels to Size
Really quick and easy
This is one of those peculiar Martin arch top guitar bridges from the 1930s. They have plastic guide rods and plastic adjusting screws:
This one's rods had become so bent with time and tension that the bridge was in danger of collapsing.
Not having either the time or the inclination to chuck up a piece of phenolic rod and turn a replacement on my lathe, I figured I'd measure it and substitute a nice strong wooden dowel:
Of course, the size turned out to be nowhere close to a standard dowel diameter.
I ran to my number drill index and grabbed the one that matched my measurement:
Chucked it up and quickly drilled a hole through a piece of scrap ebony:
I suspect any hardwood can do this job, but I had the ebony handy.
Then I chucked a piece of 1/4"birch dowel in my Makita and ran it against the small belt sander to rough it down to a smaller diameter:
With the drill running in reverse and the belt speeding by, it was very quick and easy to make a lumpy approximation of what I needed. I went too far with the end of the dowel, and simply chopped it shorter, leaving plenty enough for the job at hand.
Running the dowel at full speed, I was able to jam it through my newly drilled hole:
Viola! (This spelling always seems more musical. . .) I had a dowel of exactly the right diameter for a tight press fit in the top of the bridge and a loose fit in the base:
A few quick strokes with the infamous "Steinway Touch-up Kit" and my new dowel was black and shiny:
Here it is, doing its job:
You might be tempted to use this technique for precisely sizing dowels to use for other purposes. I was, and I've found it necessary to break the glaze on the surface before using the dowel for gluing.
Some judicious sanding does the trick quite well, and I believe that the water in the glue tends to swell the burnished dowel a bit, tightening its fit in the hole. I've tried burnishing the dowel into the actual hole in which it will be glued, but that's a dead end street because of the difficulty of breaking the glaze down in the hole!