Using metric threads

[John RutzenParticipant @johnrutzen76569]

[John RutzenParticipant @johnrutzen76569]

Hi just a hint I thought I would pass on after wasting an hour today trying to thread some 8 BA studs. I was trying to grip 3/32 stainless, first in a chuck- no good, it wouldn't grip it. Then I tried a collet, worked but with difficulty. Then the die wouldn't cut the thread. I remembered then that I had 50 stainless steel M2.5 screws I had bought on eBay for very little money. They fitted the 3/32 holes in my Lion frames just great. The problem is the nuts are big and ugly but you can tap out 8BA nuts to M2.5 no bother. So problem solved. It works very well too with M3 cheap screws and tapped out 6BA nuts.

[JasonBModerator @jasonb]

You can buy smaller hex head metric fixings from Polly and GHW which look more in keeping

[John HaineParticipant @johnhaine32865]

A tip which might work for threading out small nuts – I have used it to drill out M2 nuts to make short spacers.

Chuck a socket that fits the hax in your 3 jaw or better a collet. Stack a row of the nuts into the hex and feed the drill into the threaded hole in the tailstock. As each nut gets drilled out it slides on to the drill. You can do as many as will fit in the socket in one go.

To thread I guess you'd drill out like this if needed, then put the nuts back in the socket and feed in the tap.

[Clive Brown 1Participant @clivebrown1]

Posted by John Rutzen on 13/02/2019 12:41:10:

Hi just a hint I thought I would pass on after wasting an hour today trying to thread some 8 BA studs. I was trying to grip 3/32 stainless, first in a chuck- no good, it wouldn't grip it. Then I tried a collet, worked but with difficulty. Then the die wouldn't cut the thread.

3/32" dia. material is a bit big for an 8BA die, especially stainless. 7BA would be a better thread which I've often used in conjunction with 3/32 dia. rod.

[John RutzenParticipant @johnrutzen76569]

Hi, yes I tried turning it down to 2.2mm but still found I couldn't get the die to go on well. Maybe my die isn't quite what it should be. I wasn't suggesting buying 8BA nuts and re-threading them , it's just that I had about 200 of them from decades ago when they were cheap. The re-threaded 8BA nuts look very neat with the M.5 studs.

[thomas oliver 2Participant @thomasoliver2]

Blunt dies are relatively easy to sharpen. Fit a grinding burr into your Dremel or drill which is slightly smaller than one of the holes. Figure out which is the cutting edge and run the burr through a few times. You can see the fresh surface which is ground and continue until it reaches the cutting edge. Repeat for other edges. Tapas can also be easily sharpened. A conical burr is best – fractionally less in radius than the flute radius.or the same. The trick is to run the burr in each flute TOWARDS the tip, then if it jumps it will not damage the cutting edge..The other way up, one slip and the tap is ruined.

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