The best way I've come up with is, I only mark the side to side location, across the key with a line. Then take the key, mount it in a machinst's vise, and, without marking the entry with anything, use a stub bit, and the Bridgeport's xy table to locate the hole and drill it without wandering. With a tight quill, machinist's vise and stub bit, if you don't like the start of the hole centering-wise, you can move it a tad to find center. The trick is the key is held in a vise clamped to a table, stub bit, and tight quill.
If you dont have an xy table for your drill, its a really good investment, as long as you have a tight quill. Many drill press quills have so much slop, it makes the tool useless, so the machinery is important. Using the technique I use, I can move the capstan small amounts without the bit wandering back to the original location, or somewhere else where you don't want it to go.
Actually just an x axis slide is all you need for this job, as long as the slide is tight .
The trick in clamping a key whose sides are not guaranteed to be 90 deg to the bottom of the key, is for the vise to only clamp the key in the middle of the key. With double stick tape, apply a small 3/16" or so piece of wood so the vise jaws don't impose a screwy angle off of un-square sides.
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Jim Ialeggio
grandpianosolutions.com
Shirley, MA
978 425-9026
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Original Message:
Sent: 09-11-2020 11:08
From: Edward McMorrow
Subject: Centering capstan in key
I scribe a line across the keys for the capstans with them carefully clamped in place at the rest position. I then set the stack on the frame and move it left or right as needed to best center the whippens above the keyends. (Sometimes a little more whippen spacing is done to build higher uniformity at this time). Then use a pencil to mark under the whippen in the capstan groove. Then use an awl to mark the key ends and use a spur tip bit in a drill press to drill the holes.
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Edward McMorrow
Edmonds WA
425-299-3431
Original Message:
Sent: 09-11-2020 10:55
From: William Truitt
Subject: Centering capstan in key
Does anyone have a method or jig to center your index marking on the key so ask to locate the capstan hole?
It would be easy enough to make an indexing jig if all the keys were the same width, but they are not.
Will Truitt
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William Truitt
Bridgewater NH
603-744-2277
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