Recovering from palpitations having priced a replacement Sandvik parting insert holder having had a minor prang on the lathe. After all they are only a profiled piece of spring steel but are going for the 70-90 quid mark - horrendous!
It's a sandvik 151.2-21-20 - memo to self, when holding 1/2 whit stud in a nut in the chuck to part off the stud, split the nut first so it grips or the stud WILL unscrew and take your parting tool with it faster than you can react!!!
AWEM
Quicker and simpler is two put two nuts on, assuming the length allows, and lock them together using two spanners.
Steve
Sadly not Steve, there is a hole in your method. When locked together tight enough the hex flats of the nuts will not align, then when held in the chuck as you tighten it the hexs move into alignment slackening the stud! It would work if one nut could be out of the chuck jaws but I couldn't do that. Silly as I keep a box of various nuts with axial saw cuts in them just for this purpose.
AWEM
I bought a box of 151.2-200 inserts for a good price and was dismayed to find that although they looked like 151.2-250 inserts in the photo, they were actually rather smaller and wouldn't fit the holder. I too was horrified at the price of a Sandvik holder so I made my own from a bit of gauge plate. After hardening and tempering it works fine, and cost less than a pound.
I too was considering such a move. The profile looking sideways would be a doddle on my wire eroder, however the mouth where the insert pushes is profiled as well in the other axis - I suppose a touch with a diamond file would do it though.
AWEM
Wayne
In message , Andrew Mawson writes
Actually Andrew, I believe that you will find that if you choose the correct pairs of flats the chuck jaws will tend to separate the apexes and thus to tighten rather than loosen the joint. Ne'er a failure in sixty years - but it could happen tomorrow. :)
Mike
Interesting Wayne - I've always fought shy of changing brands as nobody ever says if their product is compatible with the oppositions inserts. Do you happen to know if the CTC holders are compatible with the Sandvik parting inserts?
AWEM
I made my own too. I did not harden and temper but it has served me well for a couple of years. Parting off Aluminium bar at 1000 rpm is magic!
I keep an eye on EBay.
Mark Rand RTFM
Well, it could, but let's be honest, it's not going to, the hole is not there. What you said about the tightening is correct. I've used this method for many years to cut bolts or studs with a hacksaw or angle grinder. I've only recently acquired a lathe, so I've been out to play this morning and done this with a couple of M12s. Works a treat. I also (re)discovered that the start of the thread isn't always in the same place relative to the flats, so they may line up if you change one of the nuts.
Steve
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