Another newbie lathe question

-------------- If possible stick with the TPU/TPG holders.

TPU/TPG inserts are dirt cheap. Unless you are in high volume production using exotic materials the other inserts will not be cost effective. Coatings are also marginal for home shop use. Use C6 grade for steel and C2 for everything else. You can even get mill cutters that will use the TPU/TPG [u = unground, G = ground] inserts.

One place to start is

example price {cheaper on sale and in the 10 pack} ?PMPAGE=164&PMCTLG=00 for the holders see end mills

Unka' George [George McDuffee]

------------------------------------------- He that will not apply new remedies, must expect new evils: for Time is the greatest innovator: and if Time, of course, alter things to the worse, and wisdom and counsel shall not alter them to the better, what shall be the end?

Francis Bacon (1561-1626), English philosopher, essayist, statesman. Essays, "Of Innovations" (1597-1625).

Get a copy of MSC's catalog "the Big Book", which includes tables from at least two makers of inserts in the introduction to the carbide insert portion of the catalog.

You might also find the same information on their web site, or on the web sites of the makers (like Valenite.)

It is all in those tables.

Good Luck, DoN.

You would be better off with HSS and learn to grind you own cutting bits. Carbide has it's uses but there are things you can do with HSS that carbide won't do and you need a quantum leap in rigidity to use carbide without severe problems. Trust me on this!

Paul, I must second Buerste's response. The use of all carbide tools requires power and rigidity in the machine. So, if you are envisioning a small machine, 12" swing and under, stick to HSS. I use carbide on my 18 x 54 L&S, but not on my 13 x 40 or my 10 x 40 SB. I only use HSS on both my small machines. All 3 lathes are in absolutely top condition. When it comes to HSS, always choose a cobalt alloy like M35 or M42. They perform much better with all materials. Steve

Excellent post.

This assumes his machine can take a cut heavy enough to justify carbide

Gunner

interrupted cuts, like cutting over a drilled hole, are the death of carbide.

========= Good point. Big benefit for the newby is this eliminates the need to grind your own HSS tools, which for home shop use are most likely an even better choice.

Unka' George [George McDuffee]

------------------------------------------- He that will not apply new remedies, must expect new evils: for Time is the greatest innovator: and if Time, of course, alter things to the worse, and wisdom and counsel shall not alter them to the better, what shall be the end?

Francis Bacon (1561-1626), English philosopher, essayist, statesman. Essays, "Of Innovations" (1597-1625).

--------- Even here there are differences of opinion. High cobalt tooling is much more expensive, harder to grind, and more brittle than plain M2. While it does offer longer life and allow higher speeds this is seldom a consideration for the typical home/hobby shop. Unless you are wearing more tooling out than you break, M2 is the way to go.

A good combination for the typical home shop lathe is a small [4 X 36 / 6 ] belt/disk sander with "blue" belts and disks, and M2 tool bits. Enco typically has 1/4 square M2 bits on sale for 10$ or less in quantities of 10. Grinding your own tool bits allows you to put the much greater back/side rake the typical home shop lathe is "happier" with on the tools.

Unka' George [George McDuffee]

------------------------------------------- He that will not apply new remedies, must expect new evils: for Time is the greatest innovator: and if Time, of course, alter things to the worse, and wisdom and counsel shall not alter them to the better, what shall be the end?

Francis Bacon (1561-1626), English philosopher, essayist, statesman. Essays, "Of Innovations" (1597-1625).

And, one learns "empathy" with the cut. Carbide is so impersonal.

----------------- For grins, take piece of high carbon steel like a file or a tap and grind a lathe tool, taking care not to "pull" the temper. Run the lathe slow and try taking a cut.

Just as a HS tool will frequently give a better surface finish than a carbide tool, a high carbon tool will frequently give a better finish than a HS tool.

Unka' George [George McDuffee]

------------------------------------------- He that will not apply new remedies, must expect new evils: for Time is the greatest innovator: and if Time, of course, alter things to the worse, and wisdom and counsel shall not alter them to the better, what shall be the end?

Francis Bacon (1561-1626), English philosopher, essayist, statesman. Essays, "Of Innovations" (1597-1625).

Lots of good advice here. Thanks.

The lathe will be arriving in a few weeks, so I still have some time to study before beginning production of metal shavings.

A small mill is on its way as well. At some point, I will take a whack at making tool holders and other jigs when I get bored of simple turning.

The crystal structure is different, high-carbon will take a finer edge...I think. Why are people obsessed with carbide? For us, we get more speed and heavier cuts but we are under time constraints. And, I've got a big, lathe with 10 hp and very ridged QC tooling. I still use HSS for intricate work other than facing and hogging diameters.

I bought a few carbide lathe bits , wasn't impressed . I can hand grind a

1/4 inch cutter to perform bettter , longer . Only place I prefer carbide is in the flycutter in my mill . Higher cutter speeds due to the larger diameter are pretty tough on even cobalt .

I used them for years on a 10" and later a 12" Atlas lathe, no problem. You DO want positive rake tooling, though. the negative rake is definitely for the heavy, production machines.

Jon

Well ... that depends. I use negative rake holders, but inserts with the special chipbreaker groove which turns that negative rake into positive rake. This on a 12x24" Clausing lathe.

And I particularly like the threading inserts with the angled support anvils to adjust for the helix of the thread being cut.

I go to small (55 degree diamond) uncoated inserts with a very sharp edge for finish cuts on steel where I care about the finish. (These were purchased originally for my little Compact-5/CNC lathe, but turn out to be very nice for certain things on the larger Clausing as well.

Of course -- when I need to cut something special, I do grind appropriate tools from HSS or the like.

Enjoy, DoN.

Part numbers???

How many of these things do you want the part number from. I've moved your question to the top, so I can make what I can supply interleaved with my original text.

[ ... ]

My most commonly used holder is the Aloris BXA-16N -- a double-ended holder for negative rake inserts -- one for turning, the other for facing. This fits (of course) the BXA style wedge type toolpost which I got made by Phase-II.

Insert numbers (from a box I keep on the lathe) -- TNMG-322 C6.

Iscar or Carmex IIRC -- interchangeable lay-down inserts, and interchangeable angled anvils between the two. The numbers are a function of the shank size among other things. I use 5/8" shanks to fit the BXA tool holders.

I can't give you a working part number for these. The holders are labeled "Tizit", and the inserts are positive rake 55 degree diamond shaped with 1/4" IC (I think). Before I ran out of the ones which came with the lathe (but was getting low) someone here on the newsgroups offered some samples for free. Once I got them, I realized that they were just exactly what I had hoped, and since nobody else had shown any interest in them, I bought the whole lot from him. Some ground only for right-hand turning, some only for left-hand turning, and some for both.

Sorry that I have no part numbers -- they came in plastic bags. :-)

Enjoy, DoN.

Thanks. The last time carbide came up 'micrograin' was suggested for light cuts on old lathes. I have the 1/4" and 3/8" TT sets which I use on stainless and hard cast iron, but they fail quickly by chipping.

These are the sets of five (right, sorta-right, center, sorta-left, and left) which come with allen head screws (round/countersink combo head) and no carbide anvils under the insert? I've tried these, and found them to be fairly useless for exactly the reasons you give. And the price of the inserts is typically greater than the price of a set of five with inserts).

The good ones -- AXA-16 or BXA-16 if you have the right toolpost

-- even better with the 16-N version of the proper size for your lathe and the right inserts to match -- give a lot better results.

The presence of the anvil makes a big difference, and the 16-N holder combines the part which fits the toolpost dovetail with the insert holders in one hefty lump of forged steel. Toss in the carbide anvil and you have proper support for the inserts, so they don't tend to break.

And there are various styles of carbide (C-2 and C-6 are the most commonly mentioned) one of which is for tough ferrous and hardened workpieces, and the other better for non-ferrous.

But still -- if the cross-slide and/or the compound flex, you can have chips from that. I forget whether you mentioned what your lathe was -- size and make.

Good Luck, DoN.