Indexable tool insert replacements

Thank you John.

I was simply being impartial!

Oh, and I do use HSS tools as well, probably as much as carbide.

Neither am I.

I've wandered all over the place buying turning inserts, but have settled on Korloy from Cutwel for CCMT and CCGT inserts, plus parting off ones. I've buy metric threading inserts from Cutwel but have to be more flexible for fine pitch Whitworth as they're becoming difficult to get.

Andrew

Just buy the cheap ones and don't forget to get them for aluminium, usually labeled H01. For hobby use they are very good.

If you want to pay more, but don't want to buy inserts in boxes of ten, then check out APT, they sell a selection of singles for hobbyists, and their laydown threading inserts are always available singly.

It was started by Taylor and White in the early 20th century and test methods are now encapsulated in ASME standards.

I think that figures of 15 and 20 minutes come from ASME standards for testing of single point tools. The tools are run at a range of speeds and feeds such that tool life is assessed as being 15 or 20 minutes. This allows results for different tools, and from different laboratories, to be compared. It does not mean that the feeds and speeds are recommendations for use in a production environment. That's up to the individual planner. I suspect that the cost of changing a tool (labour and machine downtime) is larger than the cost of the tool itself. So there is some incentive to maximise tool life by reducing speeds.

I have made measurements of surface roughness that show that, for some materials, high speeds are needed to get a good finish with inserts.

Andrew

I am only purchasing CBN inserts in quantities lower than 10.

All inserts for general work I was buying in boxes of 10 for some time until one particular type was identified as outstanding.

At this point I have negotiated with Chinese manufacturer and purchased 1000 of them at very significant discount.

They will probably last for rest of my life, I believe, so issue of " general purpose good turning insert suitable for ferrous and many nonferrous alloys which gives good finish and last reasonably long" is probably setled for good.

Cannot say which particular Chinese brand it is and from whom it was bought due to forum policy but inserts are really good indeed.

think there is a great advantage to sticking with vendors who cater to the bobby market. They are unlikely to carry inserts unsuitable for hobby machines. The chip breaker design is extremely important. One designed for heavy roughing will be unusable in hobby size machines. The cutting edge will be deliberately rounded over or honed to present a very negative edge to the work. This works well on rigid machines with adequate horsepower but probably will not cut at all on a hobby machine. Look for chip breakers designed for light finishing as they will present a sharper edge to the work. Polished inserts for aluminum work extremely well on hobby sized machines. They have a dead sharp cutting edge.

Ideally one should choose inserts for which a depth of cut - feed per rev. chart is available. That allows choosing an insert to to suit your operating parameters.

For hobby work properly ground HSS tools are probably the best choice. They last nearly forever if resharpened as soon as the cutting edge breaks down. I have HSS tools that have lasted since the 70s. I especially like the tangential tools. Resharpening is a breeze, only one surface needs to be ground and/or honed.

On my larger lathe, 16" x 40" with 6kw motor, I used carbide almost exclusively. On my 9" lathe I alternate between HSS and carbide but mostly HSS.

+1 for that. A while back I posted about difficulties making a coarse thread with carbide inserts I'd bought off the internet - I thought my technique was at fault. Someone (JasonB I think) suggested JB and it was night and day - good inserts and not Sandvik prices. I was skeptical but they really did make a difference. I did have to nudge about tardy delivery, but that was compensated for by the inclusion of a free left-hand threading insert, which will no doubt come in handy one day. Perhaps. But it's the thought that counts!

Robin.

Edited By Robin Graham on 27/02/2021 02:43:42

Edited By Robin Graham on 27/02/2021 02:44:54

I buy the commercial brands mostly. The country they are made in is not relevant actually. It is the materials used and how they are produced. I have found that the better ones, not only last longer, but on machines like a Myford S7, I can cut a huge range of materials and hardness from one insert or insert type. Kyocera , Mitsubishi , and Summitomo, are my main 1st choices in that order. This website for NZ people is I think the best place for Kyocera inserts and some other's that he gets in stock. Will also sell a single insert as well. As an example, This insert https://www.carbidenz.co.nz/ccgt060202mp-ck-stainless-and-steel.html I use for cutting back bearing outer races, making Ti parts, Brass, copper, Al( 2011, 2024, 7075) , variuos steel grades as well . Softer grades of AL can build up, so I use the AL specific insert for 6061 and for commercial extrusion alloy. The other all rounder insert is this one that he calls a wonder insert, Although not on your holder list, is a very eccanomical all rounder available in lots of nose radi. https://www.carbidenz.co.nz/tngg160402r-s-pr1125-wonder-insert.html

I find that using what industry often use in their standard sizes, and geometry types, will give you the best selection for the best prices. I very rarely use any of the general industry turning inserts, as they often tend to need too many rpm and quite a lot of hp to make them work well. I don't run my lathe any faster than the top speed of the low range from the motor pulley to the clutch. So in the 700 rpm is around the max I run for anything. The new to NZ users, Blaser CSF35 cutting oil will extend hard turning insert life by a factor of 10. From tests done at work on hard milling and my own turning experience at home. It will also give improved surface finishes on all materials I have cut so far, and is a really good no smell tapping oil too.

The inserts are not cheap, but do last very well. The 2 I have shown are the most used for most things I make. The ccgt I have in both the 06 and in the 09 sizes. Evan sells the holders in 12mm shank for the ccgt09 inserts and for the tnmg16 inserts. The ccgt 06 inserts, has an 8mm and 10mm shank option. I got the 10mm shank. I have his series of bore bars for the ccgt 06 inserts and ccgt09 inserts as well.

Neil

I bought a box of ten polished inserts at the last Doncaster show from JB Cutting Tools. Good price and they are quality items as far as my limited knowledge and experience allows. I use them not only on aluminium but on BMS and brass, too. They give a good finish, but wear out faster in my opinion, than the "ordinary" carbide ones. For the amount of machining that I do, I consider that acceptable.

John

I've just bought some from chesterfieldmachinetools.co.uk (Kieran Blackwell-Bespoke toolmaker) The tools made in the UK, I don't know whether the tips are but I will say they are superb and give an excellent finish and seem to keep their edge which is more than I can say for the Chinese ones. He advertises on his web site, Ebay. etc.,

I have accumulated a large quantity of insert toolholders over the years, and the advantage of this is that there may be, for instance, 4 tools with TNMG inserts, all with different grades which can be chopped and changed to find which works best with a particular alloy. Inserts can be picked up at less than £1 each on ebay, even if there are some people trying to sell them at more than the large commercial companies charge. As I have said frequently before, the quality of cheap Chinese inserts has got so good that for home use, you don't have to break the bank.