TCMT insert question.

jarhead jim · Mar 2, 2012

I have a set of 3/4" toolholders that take the TCMT 32.5 inserts. I believe the holders are import. Of course the inserts are cheap, crappy pieces of sh-- and I'd like to get some quality inserts. My question is.....what make would you guys recomend? I found some Iscar, Sandvik, Kennametal, etc. but the numbers following TCMT is 3(2.5)1 or 2. Is this the same as 32.5? Another question I have is.....There are 2 different makes I'm looking at and the numbers and letters following the TCMT ( I know what the letters TCMT stands for) are confusing. What do they all stand for?

Sandvik 32.51 UR 4025
Sandvik 32.51-MM/16T304-MM 2025
Kennametal 3(2.5)0-LF16T302-LF

Would any of the above fit my toolholders and are they the right type of steel/carbide? I'm used to using the rocker style on my lathe so this is all French to me.

I'm going to be using the inserts on grade 8 to regular steel.

Thanks!

Jim

blue35mm · Mar 2, 2012

Jarhead! Love that.
I use those all the time.
The last digit on the numbers is the radius of the tip of the insert in Thousanths of an inch.
the following are the insert grades from the manufacturers. Find out what you would like to cut with them , and go online to the respective manufacturers sites , and cross reference the grade you are looking at, with the ones on there site. They will have a wealth of knowledge on there that will pinpoint what you need.

look at the type of metal, speed you will cut at,type of operation etc.
Good luck

CarbideBob · Mar 2, 2012

The 2.5 means halfway between a 2 and a 3 thickness.(ie:0.156 thick.)
This was added way after the standard was created hence the funky numbering.

Another wacky number is the 3(2.5)0. Technically a 0 radius or sharp corner.
However most of the time on this tool it will mean a .006 radius. Once again there is no number for a .006 rad so a zero is used. Unless you look it up in the catalog there is no way to know for sure.
Sometimes this will be called a TCMT-32.5.006R which makes a lot more sense if you grind inserts like I do.
There is no way to make a TCMT with a zero radius since the M means molded IC.
A TCGT may in fact have a sharp corner.

Letters after the number with no spaces mean edge prep or special corners on milling inserts. They also may callout a chipbreaker style but usually there is a space first. Again, find it in the specific manufacture's catalog or you will be just guessing.

The tail end of any complete insert description will be the grade.
Unless you are one of the few crazy people who really like to keep the 500 or so current grades in your head you have to go to the website or catalogs to have an idea of which grades are best suited to what and which are honed (bad on aluminum) and which are up sharp (bad on cast iron).

The good news on grades is that for occasional light usage on steel you can get away with just about anything.

I know grades like the back of my hand but when I need to turn down one piece on the manual lathe I'll grab the first insert I find of the right shape and corner rad for what I'm doing.
If it has a hone and I want up sharp I'll kiss the top on a diamond wheel to remove the edge prep. Goodbye coating but I don't care I just need to get a part done.

Is tool life really an issue here over large runs?
I'm guessing you are looking at low volume usage here and looking for low cost inserts to use.
.750 shank holders? What machine is this in?

(yeah, I've got carbide in my blood, my dreams are actually filled with this silly stuff) :nutter:

Bob

matt_isserstedt · Mar 3, 2012

If you are first trying I would recommend a larger nose radius, like 1/32". The insert will be tougher and you won't chip so many. Just going from my own experience starting with inserts and watching others learn with them too. They can take a lot of heat/speed etc. But don't like interruptions and things like stopping the spindle with the tool engaged in the cut.

jarhead jim · Mar 3, 2012

CarbideBob said:
The 2.5 means halfway between a 2 and a 3 thickness.(ie:0.156 thick.)
This was added way after the standard was created hence the funky numbering.

Another wacky number is the 3(2.5)0. Technically a 0 radius or sharp corner.
However most of the time on this tool it will mean a .006 radius. Once again there is no number for a .006 rad so a zero is used. Unless you look it up in the catalog there is no way to know for sure.
Sometimes this will be called a TCMT-32.5.006R which makes a lot more sense if you grind inserts like I do.
There is no way to make a TCMT with a zero radius since the M means molded IC.
A TCGT may in fact have a sharp corner.

Letters after the number with no spaces mean edge prep or special corners on milling inserts. They also may callout a chipbreaker style but usually there is a space first. Again, find it in the specific manufacture's catalog or you will be just guessing.

The tail end of any complete insert description will be the grade.
Unless you are one of the few crazy people who really like to keep the 500 or so current grades in your head you have to go to the website or catalogs to have an idea of which grades are best suited to what and which are honed (bad on aluminum) and which are up sharp (bad on cast iron).

The good news on grades is that for occasional light usage on steel you can get away with just about anything.

I know grades like the back of my hand but when I need to turn down one piece on the manual lathe I'll grab the first insert I find of the right shape and corner rad for what I'm doing.
If it has a hone and I want up sharp I'll kiss the top on a diamond wheel to remove the edge prep. Goodbye coating but I don't care I just need to get a part done.

Is tool life really an issue here over large runs?
I'm guessing you are looking at low volume usage here and looking for low cost inserts to use.
.750 shank holders? What machine is this in?

(yeah, I've got carbide in my blood, my dreams are actually filled with this silly stuff)
Bob

This is a 1911 LaBlond 16"x42" lathe. A beauty. And yes, I use it for hobby purposes. I'm not real computer savvy but if you punch in my user name and look at the posts I started I have one entitled 1911 laBlond I believe. I don't have many posts so it shouldn't be hard to find.

Thanks guys on all of the info, I always get great info on this site and value it very much!

Jim

Search

Largest Manufacturing Technology Community on the Web

Search

TCMT insert question.

jarhead jim

Aluminum

blue35mm

Aluminum

CarbideBob

Diamond

matt_isserstedt

Diamond

jarhead jim

Aluminum

Similar threads