Cutting with inserts

[PEU]

Browsing a local company website I found this picture that shows almost all options in cutting inserts and how they are commonly used, I was looking for something like it for some time, so now that I found it, Im sharing it

If I find the english version of it, I replace it


Pablo

 

[SafetyBob]

Pablo, do you have the link from the company. I am having problems printing this nicely.

Nice find and thank you for sharing it.

Bob E.

 

[ICUDoc]

Thanks Pablo. These inserts make it a lot easier- and on Al they last and last.

 

[PEU]

:mecry:The picture came from this page: http://www.latintools.com.ar/latintools2.htm but Im sure its from a Korloy catalog, I searched the ones I have but didn't found it.

When you are learning these inserts don't last as long as one would wish... Already broke the one that came withthe parting tool I purchased last week, there is a sweet spot in the cutting feed rate, too slow the lathe chatters like an earthquake, a little faster and the finish is not good, a little slower and it breaks :mecry:


Pablo

 

[Anglepoise]

When you are learning these inserts don't last as long as one would wish... Already broke the one that came withthe parting tool I purchased last week, there is a sweet spot in the cutting feed rate, too slow the lathe chatters like an earthquake, a little faster and the finish is not good, a little slower and it breaks :mecry:


Pablo

Interesting point you bring up. Although most of us use inserts, I would bet that HSS tools, correctly ground with positive rake, would give us all better results as far as aluminum is concerned. Very few carbide inserts that are available to us in small quantities are ground all over , and there are not many positive inserts as well. Most inserts are pressed not ground and if you look at an edge with 10x , they are just not sharp.

For aluminium, I find myself going back to HSS more and more.

 

[precisionworks]

Already broke the one that came withthe parting tool

Two ways (at least) to avoid that, which is caused when the tip gets pinched between the two parts. Easiest is to back the tailstock center out (away from the tool) as the tool is fed closer to the parting point. It takes just a little practice, but when done right, the parted off piece stops turning at the instant it is cut through.

Second way (don't laugh) is to stop when the tool is 99.9% through - you'll see a line inside the bore if the part is hollow. Stop the machine, whack the cutoff with a soft-faced mallet (wood, lead, etc.) & the part will come right off. If your lathe is already worn out, you won't hurt anything. If not, method one is better

Very few carbide inserts that are available to us

Quite a few companies now make Al specific inserts, with a highly polished rake face & an angle of cut that makes a neg rake (CNMG) into a positive cut. Slick as butter, 10x better than anything else I've ever used.

I saw this recently on the Practical Machinist site:

CCGT's are razor sharp with high positive rake, fit the same holder as the CCMT's. Very free cutting. Mostly for aluminum, but okay for light passes in steel.

On a CCGT a number 0 rad will be between .000 (sharp) to .008 again depending on manufacture and whether or not it's honed. Sometimes called out as a CCGT 32.5.006R for a .006 radius.

 

[wquiles]

Muchas gracias Pablo

Will

 

[VanIsleDSM]

I imagine the carbide insert tools are great for harder materials like steel and titanium, and I've only played with aluminum so far, which the HSS tools seem to do an excellent job of cutting. For less than $1 each you can get the HSS Asian tool blanks, $65 for my 8" bench grinder, and $12 for a machinist's protractor. With that I've been able to make every tool I've needed so far, I'm a complete novice and I haven't broken anything yet. I don't think I'll be getting into the carbide insert stuff any time soon, HSS seems great for what I'm doing. I suppose if I went CNC or was playing with harder material then I would be looking into it, but I seem to remember back in grade 9 shop class cutting steel no problem with HSS tools.