For a long time I've always felt that to do the best possible job on something mechanical, my favorite approach is to break a task down to their separate steps, and have a systematic method for performing each step. So with repivoting, I kind of started with an assortment of different diameters of blued pivot wire, and went from there. My idea is that since I have a wide range of diameters to pick from, one of them ought to be the next size thicker than the pivot I want to duplicate. That's because I like to make a pivot slightly thicker than my final diameter and machine it down to maybe a couple thousandths larger than my final destination diameter. Then I can just stone & burnish to destination diameter.
This first photo shows how I keep my pivot wire organized. I made a cheap wooden stand and drilled for plastic test tubes for each wire diameter. I get my plastic test tubes from Lake Charles Manufacturing in Louisiana. You can find them here: http://www.lcmlab.com/Vol_10ml_Round_Bo ... 1&CartID=0 . You have to scroll down to the size I used for pivot wire...16x150mm. I bought item #58A2 for a pack of 25.
In my wooden stand I drilled holes for three rows of plastic test tubes...the back row has the pivot wire. I got little adhesive round labels for the blue caps, so I printed out the wire diameter for each tube, makes it easy to quickly select a needed piece of pivot wire. In front of the pivot wire row is two rows for smaller plastic test tubes, which I use to hold ONE carbide printed circuit board twist drill. I know twist drills aren't the ideal drill for pivot work, but they're so cheap they're easy to replace and besides, I peck at the spinning arbor so lightly that I haven't broken a drill bit yet. But, I drilled the stand for two of each drill bit to go with each wire diameter. As you can see some of my wire sizes only have one drill bit, but my more common wire diameter have two bits in front of it, in case I break one (and I probably will someday).
Here's another view of my pivot wire organizer. This shows the little labels I made for the drill bits. The top number in bold matches up to the pivot wire diameter behind the drill bit. The middle number is the actual drill bit size, whether it's a metric, wire gauge or fractional or whatever. The bottom number is the drill bit size expressed in thousandths. I picked each drill bit size to be just one or two thousandths UNDER the pivot wire it goes with. That way I can file down the pivot wire piece to just fit tightly into the hole in the arbor.
Here's a closeup of the little test tubes I bought for the drill bits. They're really cheap, only $11.02 for a pack of 500 of them. I don't know what I'll do with them all. Guess what - you have to buy the caps separately! You can find the tubes here: http://www.lcmlab.com/12mm_Polypropylen ... 1&CartID=0 Look for item #51A3 - you can also get the caps in bags of 25 for $2.00 or so...they are item #51A2. The caps I got for the tubes are item #88A3 (pack of 25), you can find them here: http://www.lcmlab.com/12mm_Two_Position ... 1&CartID=0
Here are two more shots of the organizer. The first one shows the diameter labels on the pivot wire blue caps, and the second shot shows a construction detail. The organizer is made from three pieces of plywood with only the top one drilled for holes.
OK, now here's how I hold the drill bits in my tailstock. One thing I like about PCB drills (besides the fact that they're carbide so they cut great) is that all the shanks are perfectly 1/8", or 0.125" diameter. I use a special runner I had made for the tailstock in my Rivett watchmaker's lathe. I took my actual tailstock and a 36" piece of "S"-sized O-1 drill rod to a company in Phoenix that does centerless grinding for the aerospace industry - I figured if they can make little parts that go on the Mars rover, they can make me a tailstock runner! They ended up grinding me 3 separate runners, but the one shown here is drilled with a less-than-1/8" drill hole, then bored with a tiny boring tool just to the point that the shank of a PCB drill just made a nice slip-fit. I also had three tiny holes drilled and tapped for very small allen set screws. The holes are spaced 120-degrees apart so all three set screws are equidistant from each other. Just lightly tightening down on the set screws effectively locks the drill bit very firmly.
Here's two shots of the little knob on the end of the runner. The knob was turned from Delrin.
So how does the runner perform? Like this: