For the longest time I have used nothing a HSS cut off / parting tool and have never had any real problems. That is until I was working some titanium a couple of months ago and ever since the HSS parting blade has just never been the same requiring seemingly constant resharpening and touching up with a stone.
To be fair the HSS steel parting blade mounted in a AXA QCTP holder had always worked very well and after a sharpening or touching up would without so much as whimper part of leaded steel, CRS, 4140, brass and aluminum. The constant resharpening become a bit of a chore.
I had read of many having a go with carbide insert cut off tools and all to a one with very high praise for their new found bit of tooling.
This sold me but finding the right cut off tool was quite an adventure in reading, asking questions and poking around the internet. There where the wide thin bars which tool an insert which just slide in and required either a special holder or a holder which in turn was held in a regular tool holder. In either case these all seemed too big for any of my AXA size holders and on the expensive side. There where also insert holder that had 1/2" shanks which also fit a regular AXA size hold and these seemed to be the choice but the maximum recommended size to cut off was generally on the smaller side and usually less one inch. I do a lot of work with 1 to 1-1/2" stock so I set these aside for the time being as well.
The local "toy store" Busy Bee Tools (kind of like a cross between Grizzly and Harbour Freight) started to carry some of the newer offerings by Glanze. Now Glanze is an import brand as most will know but not from China but rather from India. I have several Glanze lathe cutting tools already and their quality is usually quite good - generally speaking, good fit and finish. The store was now carrying one of the Glanze brand cut off tools (see the first photo). This design was very typical of what you might find offered by Iscar or Kennametal and used a readily available style insert (GTN I think, can't find my notes but something like that). So I bought one. It comes with the holder that in turn is held in standard AXA holder and overall fit and finish are quite good.
However, I did not like the way it sat in any of my standard AXA holder (see photo 2). It did not sit flat (partially a problem with the AXA holder) nor did it sit tight up against the AXA holder. In any case the parting blade itself is quite a ways of center and not sitting flat or tight up against AXA holder is just poor and not for me - it looked like it was asking to not be very rigid and start to chatter just when you least expected. I returned the tool unused and continued my search.
Aloris themselves make a couple of AXA size holders to take this style of cut off tool blade directly AXA-77 is one such holder. Aloris also sell the blades and the holders are compatible with other brands of similar design and size. I decided to bit the bullet, spend the cash and something I know will be of excellent quality and of which I will never be sorry to have bought. Made a few phone calls, found a couple of sources, buying in Canada was out of the question - at least double the US price, and the couple of US sources I called would gladly sell me what I wanted but they would only ship via UPS. UPS! No way, I will not accept anything shipped by UPS from the US to Canada. UPS charges an arm and a leg for "customs clearance" plus taxes plus... I would be better off buying in Canada.
Disappointed I starting looking again for a couple of other sources when I made happy accidental discovery. Iscar makes cut off bars specifically to replace HSS cut off tools. Instead of the bar needing to sit level in order to ensure the proper relief angles for the insert they are instead made to sit at a 4 or 5 degree angle from the horizontal - guess what anglethe AXA cut off tool hold the HSS blade at - 4 degrees! (at least the AXA size).
http://www.iscar.com/Ecat/familyHDR.asp/fnum/376/app/51/mapp/TG/GFSTYP/M/type/1/lang/ENThe problem was the width of the smallest blade I could find is 17mm - a bit too wide to fit a holder which takes 1/2" blades. Not a problem - just cut it down in size to fit.
So, I bought one - and ISCAR SGFS 4-17-2 (4 degree 17mm wide 2mm thick inserts).
Once I recieved the bar and inserts it was a matter of an hours work with a dremel cut off wheel, a bit of work on the grinder and presto - one modified insert holder made to work with the AXA cut off tool holder. The metal the ISCAR bar is made of is very hard, a hack saw would only scratch it hence the cut off wheel and grinder work.
Photo three shows the original ISCAR SGFS 4-17-2 bar and Photo four shows the modified bar mounted in the AXA cut off tool holder.
Tests where just great - ran the lathe at 550 rpm and it just sliced through a piece of 1" leaded steel and the same for a piece of 1.25" 1144 stress proof and the finish of end of pieces was considerably better than I ever got with HSS. I could probably have run the leaded steel even faster, with the HSS for that size of steel I would run about half that speed.
I'm sold.
And so ends my last little project for 2009. Seasons Greetings to all and best wishes for yourself, family and friends and may the New Year be prosperous.
cheers, Graham in Ottawa Canada
