Tekno_Cowboy
Flashlight Enthusiast
Does anyone know of a good pro/con type comparison of the different shapes of indexable carbide inserts, and their applications?
Insert shape comparison
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gadget_lover
Flashaholic
Not I.
The shape of the insert makes a difference in several areas. Number of cutting edges is one consideraton. So is the size of the cutting surface.
A square insert has the most possible corners (8), but it takes a wide bite in relation to the depth of the cut. A triangle has fewer edges but also has a smaller cutting area so it takes less force to cut the same depth.
That's all (that I think ) I know on the subject.
Daniel
The shape of the insert makes a difference in several areas. Number of cutting edges is one consideraton. So is the size of the cutting surface.
A square insert has the most possible corners (8), but it takes a wide bite in relation to the depth of the cut. A triangle has fewer edges but also has a smaller cutting area so it takes less force to cut the same depth.
That's all (that I think ) I know on the subject.
Daniel
The strength of an insert varies according to the angles of it's cutting corners. As an example, a square insert is stronger than a triangular insert assuming other factors are equal (e.g. corner radius, thickness, insert size).
What's more important than the basic insert shape is the cutting edge geometry, e.g. positive / negative rake, chipbreaker shape etc, that is not a simple subject.....
What's more important than the basic insert shape is the cutting edge geometry, e.g. positive / negative rake, chipbreaker shape etc, that is not a simple subject.....
precisionworks
Flashaholic
That's a tough one. Most distributors figure that their customers already know that they want a certain ANSI shape, and provide tech support only for grades & types of coatings. PGS Tools does have a well done tech page, and they ship free if the order is $100 or more:
http://www.pgstools.com/servlet/the-template/technicalinfo/Page
Carbide Depot has a brief section on choosing an insert shape:
http://www.carbidedepot.com/formulas-insert-shape.htm
Discount Tools also has a short section:
http://www.discount-tools.com/catalogs/gen/239.pdf
Before you settle on a shape & size, make sure the insert is readily available from a number of manufacturers. I bought a nice Seco indexable end mill on eBay, about $20 delivered, and it came with 5 inserts. But only Seco made that shape/size, and the next 5 inserts were going to cost $125 - back on eBay it went
Some insert shapes can be used for turning, facing, boring, and end milling.
Tekno_Cowboy
Flashlight Enthusiast
Thanks for the links, the Carbide Depot one was just what I was looking for. :thumbsup:
Looks like the 55 degree diamond is pretty versatile, and the Trigon is a jack-of-all-trades, but a master of none. From what I keep hearing from the sales reps though is that trigon inserts are the hottest thing since sliced bread.
Can anyone shed some light on their pushing the trigon shape?
Looks like the 55 degree diamond is pretty versatile, and the Trigon is a jack-of-all-trades, but a master of none. From what I keep hearing from the sales reps though is that trigon inserts are the hottest thing since sliced bread.
Can anyone shed some light on their pushing the trigon shape?
Anglepoise
Flashlight Enthusiast
I think this is very important. For example, Sandvik do not make a small
1/4" Trigon insert so if you want to use this shape, you might not find it satisfactory for boring.
For my use, I want my preferred shape ( triangle ) and size to fit as many of my holders as possible.
precisionworks
Flashaholic
Every body and their mother offers a WNMG insert, and there are lots on eBay as well - an eBay search shows 73 listings for this shape. The 80 degree corner, while not as narrow as a 60 degree triangle, will still be able to cut to a 90 degree shoulder without problem. One big selling feature of the WNMG is three edges on top & three more edges on the other side. It's a popular shape, very strong, and easy to find holders for.
I use CNMG because it is even more popular - an eBay search shows 178 listings, more than twice as many as for the WNMG. You get four corners, two on top plus two on the other side, but they are so inexpensive that this is seldom an issue. There are face mills that use the "unused" corners of the CNMG, so the inserts are free if you use them first on the lathe. This one on eBay is almost identical to the 2" face mill that I use:
http://cgi.ebay.com/CNMG-2-0-FACE-M...ding?hash=item1e5789ecc4&_trksid=p3286.c0.m14
NOTE - that face mill has a 1.000" shank. That's fine if you use an ER-40 collet chuck in your mill, but very few places sell an R-8 collet in 1" - this company does list it:
http://www.engineering-supplies.com/subcat.asp?id=257
wquiles
Flashaholic
Don't buy a Trigon holder/inserts yet - I have one set at home with 9 un-used inserts, and I will make you a smoking deal if you want it :devil:
Tekno_Cowboy
Flashlight Enthusiast
It looks like you used it on your HF 8x12, so I'm assuming it's 1/2" shank?
I'll take you up on that offer if the price is right. Thanks Will, PM incoming :thumbsup:
Edit: Now that I think about it, is that the one you tried using without an insert?
I'll take you up on that offer if the price is right. Thanks Will, PM incoming :thumbsup:
Edit: Now that I think about it, is that the one you tried using without an insert?
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wquiles
Flashaholic
It is a SECO 5/8" holder/kit - ENCO Part #SU317-0801 - $112 plus shipping
I have only used one of the ten brand new inserts (6 edges per insert). The whole thing is yours for $25 plus shipping - lets say $30 shipped to you
I no longer have the modified holder for it to fit right in the 8x lathe, but it is not difficult to modify. If you don't have a mill, or a friend that can do the small milling job, mail me the holder, and I will modify it for free if you buy the kit from me :devil:
Will
I have only used one of the ten brand new inserts (6 edges per insert). The whole thing is yours for $25 plus shipping - lets say $30 shipped to you
I no longer have the modified holder for it to fit right in the 8x lathe, but it is not difficult to modify. If you don't have a mill, or a friend that can do the small milling job, mail me the holder, and I will modify it for free if you buy the kit from me :devil:
Will
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precisionworks
Flashaholic
One caution on any negative shape (CNMG, WNMG, TNMG, etc.) is that negative inserts require a machine with more power & more rigidity than the machines in many home shops. Lathes from about 10" swing & up seem to work well, but smaller machines may or may not. Smaller machine users often prefer positive shapes (TPG, TPC, TPGH, etc.)
Will's holder & inserts look to be Seco, which is high end tooling - equal to Iscar, Kenna, Valenite, etc.
Will's holder & inserts look to be Seco, which is high end tooling - equal to Iscar, Kenna, Valenite, etc.
Tekno_Cowboy
Flashlight Enthusiast
"Sounds great!" just seems like an understatement. 
Just shoot me a PM or email on where to send the Paypal.
Thanks a ton! :twothumbs:
Oh, did you happen to have a modded AXA toolholder you'd be willing to sell me too? I can have one modded by the local Carquest machinist, but I'd rather send my money to a fellow CPFer...
Just shoot me a PM or email on where to send the Paypal.
Thanks a ton! :twothumbs:
Oh, did you happen to have a modded AXA toolholder you'd be willing to sell me too? I can have one modded by the local Carquest machinist, but I'd rather send my money to a fellow CPFer...
Tekno_Cowboy
Flashlight Enthusiast
Thanks for the info. I think for the price, I'd be crazy not to try it anyways. If It doesn't work out, I can always pass it on to someone else on the forums for the same great price. :thumbsup:
wquiles
Flashaholic
No worries - send me the holder and I will modify for free. Total for everything is still $30.
These negative inserts work really well for me on the 8x, so they should work well for you as well
Will
These negative inserts work really well for me on the 8x, so they should work well for you as well
Will
No worries - send me the holder and I will modify for free. Total for everything is still $30.
These negative inserts work really well for me on the 8x, so they should work well for you as well
Will
I just purchased that same holder kit from Enco a couple weeks ago. The inserts seem to hold up well in Titanium.
Mac
Tekno_Cowboy
Flashlight Enthusiast
Hmmm... I wonder how it would work for turning some Ti chopsticks :thinking:
Tekno_Cowboy
Flashlight Enthusiast
It'll be interesting to see how they handle 9 inches of 5/16" when cutting a taper. I havn't worked much with long, thin stock. Would I be better off with higher or lower spindle speeds?
Tac
Newly Enlightened
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- Jul 26, 2009
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Given titaniums properties, I'd say a *high* speed with a smaller cut would produce better results. Also, titanium in small cuts just loves to spark and light up, which isn't really a problem with the giant stock I used before. (No expert here!) I rarely do anything over 6" long in Ti, and I'm not the expert at turning anything long and of a fairly small diameter with that metal.
I hope someone else can give you a better answer, but that's just my opinion.
I hope someone else can give you a better answer, but that's just my opinion.
I think precisionworks has covered all of the major points.
One advantage that 80 degree diamond (e.g. CNMG) and trigon (e.g. WNMG) have over other insert shapes (e.g. triangle, 55 degree diamond) is that one tool will both turn and face and will turn up to a shoulder, i.e. you won't have to change tools part way through the job the way you would with some other insert types.
I'm using triangular (TNMG) inserts in my lathe tooling, if I was buying a new set of tools I'd probably be buying CNMG, they're the most easilly available which makes them the cheapest (especially on ebay) and they're more robust than TNMG or WNMG. The advantage of not having to change tools so often is something you appreciate more when you're changing tools in the middle of one of those jobs that's taking longer than it should.
One advantage that 80 degree diamond (e.g. CNMG) and trigon (e.g. WNMG) have over other insert shapes (e.g. triangle, 55 degree diamond) is that one tool will both turn and face and will turn up to a shoulder, i.e. you won't have to change tools part way through the job the way you would with some other insert types.
I'm using triangular (TNMG) inserts in my lathe tooling, if I was buying a new set of tools I'd probably be buying CNMG, they're the most easilly available which makes them the cheapest (especially on ebay) and they're more robust than TNMG or WNMG. The advantage of not having to change tools so often is something you appreciate more when you're changing tools in the middle of one of those jobs that's taking longer than it should.
