carbide inserts and lathe holders for same

You might look at Plastools

Speaking of cheap inserts try Carbide Depot

Speaking of bucks What's the difference between beer nuts and deer nuts?

Beer nuts $1.49 a bag. Deer nuts are always under a buck!

Errol Groff Instructor, Machine Tool Department H.H. Ellis Tech

860 774 8511 x1811

Make your own. I did.

I do NOT like the price! It took me a couple hours to make two sets of my design. I keep one set loaded with inserts for ferrous and one with inserts for non-ferous. I've broken a few inserts when I've really screwed up but have yet to break or bend a holder.

Do read my article. Ted

I bought some of the "USA" holders from MSC around 8 years ago, the style that use the TCMM32x inserts. This is a slightly different insert (different screw hole) from the "Borite" MSC sells for slightly more. The holders are fine, they get used on a 15" lathe, really should be using 3/4" shank tools but these are what I already had. These get used for the quick & dirty work, they generally don't give me a great surface finish.

Two years ago I decided to complete the set with the "Import" set from Enco/MSC that uses the same inserts.

I cant' comment on the grade of steel, but the finish of the insert seats looked like they had literally been cut by hand with a belt sander. The inserts didn't even sit tight against the back of the seat. Went right back, Enco's satisfaction guarantee is that I got to pay shipping both ways.

My lathe, and surely your Sheldon, should do just great with negative rake tooling. I haven't done enough turning lately to explore further into it.

Bob

Thanks. I think I will make a couple of holders that hold the triange insert "backwards", with the flat side almost parallel to the spindle axis. One just a little left, one just a little right. With these, I could cut both left and right faces, turn the diameter, and make steps to one side of the cutter. (I had a project that needed this done on 50+ parts, and doing it with one tool instead of two would have been a great improvement.) The holder needs to be a little narrower than the face of the insert.

Jon

The advantage to negative tooling is you can turn the insert over thus you double the usable edges. The problem with negative holders is you have to have a very rigid setup. They don't work well on long skinny work or thin stuff. Trying to decide on what geometry tooling you use by deciding what type of work you do mostly.Than pick the tooling that is optimal for what your doing and you'll be set up. Ebay is a great place for bargain tool holders and inserts. I had some trangle shaped insertable tooling on some 1/2 inch tool holders for my lathe. I don't like them it seems the edge strength is bad on the insert. My favorite is dnmg 431,432,or 433. I also like vnmg 331,332,or 333 for working up close to profiles

Charlie

The Borite turning tools are hardened tool steel and are very tough. MSC sells them in all the standard shank sizes. The inserts that come with them are good general purpose types. Watch

Randy

recommendations

Did you read the whole article and check out the pix?

shows a set of three. I have never missed having any different angles but I have a square tool post can swing at any angle to the compound slide. This lets me set up for both turning and facing without moving or changing the tool.

Indeed! A sharp point 3/8" IC insert is 0.650" on the face. A TNMP321 is a little less due to the rounded point but still wider than 1/2".

Ted

That is why I am using what are called negative-positive inserts, TNMP-321s. What _looks_ like a chip breaker groove isn't. The grove goes right to the edge giving the insert a ten degree positive rake. My holders

have a five degree "droop" on the nose. This results in five degrees clearance and five degrees positive rake. And six points for ~Cdn$5!

Ted

Ive been using negative rake tooling quite a bit recently. While its not for every material..if used properly on a solid rigid machine..it cuts damned well and with a very smooth finish.

Gunner

"A vote for Kerry is a de facto vote for bin Laden." Strider

You can harden your "tool steel" tools to Rockwell bazillion and it doesn't matter a tinkers Dam except on the cutting edge which you say comes from an insert. Rigidity is determined by shape and eleastic modulus and the elastic modulus of all steels is about the same. A mild steel holder is just as rigid as an expensive "Hardened Tool Steel Holder".

The hardened steels generally have a higher yield strength. How many tool holders have you broken or put a permanent bend in?

Make your own holders for pennies a piece out of mild steel and, as the commercial says, "Save your money!"

Ted

The reason hardened tool holders are desirable is that under hard use the insert pockets don't wear and the shanks aren't deformed by the QC holder set screws. Also, in case you screw up, the insert breaks with less chance of damaging the tool holder nose or the retaining screw hole(ask me how I know). Tool holder failure was one of the complaints the original poster had about his Enco set. And yes, Ted, I am well aware that all steels have nearly the same modulus of elasticity. And no, Ted, not everybody is as "thrifty" as you are.

Randy

I started this thread when I *DID* break a toolholder! But, it clearly was

Jon

Cast iron, if indeed it was cast iron, is extremely weak in tension. A toolholder works as a cantilever beam, tension on top, compression on the bottom. There are grades of cast iron that aren't too bad but I wouldn't expect to see them in a cheap toolholder. Also, IIRC, you said

Ted

I have yet to see the first and fail to see why the second matters. Appearance?

Again, while I have broken a few inserts in my time, I haven't damaged my mild steel holders.

I'm happy for you that you have miney to burn. Not all of us are so fortunate. :-) Ted

Right. I've got a 1/2" set coming. As for the Enco holder, I don't know the actual material. But, the break is characteristic of something with high carbon and quite brittle. A very granular surface, and no sign of any flow or deformation, just a very rough, cracked surface. Amazingly, it didn't break the insert or screw!

Jon

I've always wondered how so.. I seem to remember seeing gray iron as at least 30KSI, equal to mild steel.

Tim

-- Just remember, Man was made in God's image. Woman was created out of a rib, which, quite honestly, is a cheaper cut of meat." - toon Website:

Even worse, while looking up some stuff, I noticed that cast iron was a lower modulus of elasticity than steel. Depending on the grade, it can vary from 12E6psi to 20E6psi compared to steel at 30E6psi. References: MH and Blodgett.

Ted