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Mirage416
03-30-2009, 09:05 PM
I'm having an issue with my new K&M neck turner. It's after hours, so I figured I would ask here.

I have the locking screw loosened, and the cutter depth adjustment will not turn in any more. That is, it gets very tight before the tool gets close to the mandrel. Stuck somewhere around 14/1000s or so neck wall thickness, and the forward neck area is not getting touched by the cutter.

Is there some way to reset the adjustment so that the cutter can be made to bottom on the mandrel?

I'm using a .277 mandrel, by the way.

f d shuster
03-30-2009, 09:21 PM
Mirage416: You've run out of depth on the cutter. You need to screw-out/ remove the 2 piece cutter, and lengthen it by screwing the "bottom" section further out in the larger top section. Just takes a very small adjustment. Just back out, all the way, the hex head nut 'til the entire cutter can be lifted out, and you'll see what I mean.

Mirage416
03-30-2009, 09:26 PM
OK, great. ;)

I turned the outside nut out all the way and took it off, but obviously I did not catch on to the simplistic design while I had it apart. :o

Thanks

janderson0
03-31-2009, 07:17 AM
I often get caught fine on the first pass, and then run out of adjustment for a second pass.

I just back the nut out, being careful to turn just enough to go one turn more, which will advance the cutter. If you go even just one extra it will be too much.

The thing lists 440 turns per inch of travel.

Jim

Jay, Idaho
03-31-2009, 07:31 AM
They use a clever concept known as a "differential thread". One screw is like 32 TPI and the other is 36 TPI or so. As the outer screw moves forward the internal screw goes deeper into the outer member. The actual net forward movement is the difference between the two thread pitches.
I once used a boring head that had the same system. It allowed very fine adjustment of the cutting tool but was quite expensive. It had ground threads, IIRC.

Jay, Idaho

anyrange
03-31-2009, 07:47 PM
When I change mandrels I have to reset the cutter. I use a .034 feeler gauge to start screwing the two adjustment screws. The cutter is .034 off the mandrel when the two screws start engaging. This seems to give me all the adjustment I need for turning necks in the .012 range.

J. Pendergraft
03-31-2009, 10:19 PM
When I change mandrels I have to reset the cutter. I use a .034 feeler gauge to start screwing the two adjustment screws. The cutter is .034 off the mandrel when the two screws start engaging. This seems to give me all the adjustment I need for turning necks in the .012 range.

That's a great idea. I'll have to try that. Will be the heck out of the trial and error procedure.