Use Peghole Reamer for Truly Round Holes
V-0344
Dan Erlewine demonstrates the Peghole Reamer and explains the difference between our musical instrument reamer and a hardware store reamer.
Video Transcription
[on-screen text reads: Stewart-MacDonald - Peghole Reamers]
The difference between musical instrument and hardware store reamers
Dan Erlewine: Peghole reamers aren't the same as a hardware store reamer [on-screen text reads: Peghole Reamers by StewMac]. They're specialized tools that are made for instrument work because they have a two degree taper that matches the taper of friction pegs like those used on ukuleles, old-fashioned banjos, flamenco guitars, some mandolins, and in this case a dulcimer. They're made of hardened steel with hollow ground cutting edges that are really sharp.
Unlike utility reamers, these peghole reamers have cutting blades on only one side, and the other side is round. That rounded side keeps the cutters centered in a hole so when they ream a hole, it stays truly round. Utility reamers have blades all around that will hog into the wood. The hardwood handle has a good shape to it and feels good in the hand when you turn.
Different Peghole Reamer sizes
The standard reamer fits holes up to three-eighths for violins, violas and flamenco guitars. The larger reamer reams holds up to about five-eighths for guitars and cellos or whatever hole you're trying to patch. The small reamer is perfect for this mandolin, for example. I need to enlarge the hole 17 thousandths, and that's not a lot. Here is a tip. As the depth stop, I measured and cut off a piece of rubber surgical tubing and that lets me know right when I hit the face or the back, and that's time to stop. I'm not taking much off.
Benefits of using Peghole Reamers
Using the reamer is faster and more sure than trying to center a drill bit in an existing hole [on-screen text reads: TradeSecrets - Using a reamer in an elecric drill]. Drill bits can wander and create out of round holes also. So I'll kiss in a little bit from the top and a little bit from the back and that'll leave me an hourglass shape that I'll file this center out with a small rat tail file.
I use reamers for patching all sorts of holes. By reaming out a wallowed out jack hole or another small hole, it becomes truly round so it's easier to fix using a round patch that really fits. Like on this old beat up Martin guitar that somebody punched holes through the back, I can ream to a size that fits plugs that I cut with a plug cutter. They're just super valuable tools in my shop and not just for violins and cellos.
