Thread: Help wanted for tungsten lathe tool inserts

R C, Blu Rock,

I also have a set of these 12 mm insert turning tool holders which came with a lathe. I have not been able to identify the various inserts. Excluding the threading and parting ones there are four normal turning ones, two square and two trigons. I seldom use them because they are very prone to chipping the cutting edges, and because replacements other than the ones in kits like the H & F ones are difficult to identify. They would get more use if I could find a reasonable alternative source of supply for a better quality insert, and I am apparently not alone in this. I use mine mostly on mild steel.

Both the square types are 10mm square. Thickness is 3.50 mm. Hole is parallel, no countersink, and is 4 mm diameter. There is a shallow recessed circle on the bottom of the insert which is 7 mm diameter. They are either zero rake, or very slightly positive - difficult to tell. There is only a very small radius on the corners. One type has a continuous chipbreaker groove about 2 mm wide running around the cutting edge, including around the corners. The other one has four chip breaker grooves open on the cutting end and finishing level with the far side of the centre hole on the other end. Nose radius on these appears to be slightly greater than on the ones with the continuous chip breaker.

The trigons come in two types - for right hand tools and for left hand tools. Hole size, thickness and the recessed circle on the bottom are the same as for the square inserts, i.e. 4 mm, 3.5 mm and 7 mm. There are chip breaker grooves on each cutting edge, open on the cutting edge end and closed where they terminate almost at the short part of the opposite side to the cutting edge. Not sure how trigons are measured, but from one cutting edge to the opposite flat side is 12.88 mm. The longer part of the side opposite to a cutting edge is adjacent to the opposite chip groove, and is about 7 mm long. The shorter part is about 6 mm long. Nose radius, while still small, appears to be slightly greater than on the square inserts.

I have tried to identify these from the link which R C posted, but nothing seems to correspond with dimensions given in the link. I also have an old Seco catalogue, but cannot find anything remotely like the inserts which are used in the Chinese sets, though I might not be looking in the right place. Any identification of an alternative for these insert types would be much appreciated.

Regards,

Frank