[smokediver576]

So, I'm getting ready to purchase some threading tooling for my lathe and wanted to know the pros and cons of a tool holder that uses the tri surface insert or the dual surface (sort of like a cutoff tool) insert.

I was going to purchase the Rapid Turn on the day the issues popped up. So I'm on hold with that until Tormach resolves the issues. Right now I'll be using my Emco PC Turn 105 which limits me to a 3/8" or 1/2" shank size.

Thoughts on which would be best.

[tmarks11]

Advantage of the triangle inserts (16 IR AG 60 or 16 ER AG 60) is that you can buy them in full (A60 or G60) or half thread form (AG60). Full thread form tools require two inserts to cover all the pitches (A60 is 16-48 tpi, and G60 is 8-14 tpi), and it actually will cut the roots and the crest of the thread, so you get a more accurate thread form. Half thread (or partial profile) covers the full range with one insert. To make matters worse, the internal (16 IR) and external (16 ER) cutting triangle shapes are different. So you aren't using the same insert for both tools.

BTW, the above assumes you are using at least a 1/2" tool with a 3/8" insert (the 3/8" tools with a 1/4" LC insert only support 16-48 tpi).

The "cut off type" tool only does half the thread form, and I think it is less prone to chatter than the triangle, but that is just a guess, since I only have the triangle type.

What type of material are you primarily cutting? Make sure you buy the right coating. Aluminum doesn't cut great with the wrong carbide coating, especially with no coolant.

With the emco cnc, since it is a lower power and no coolant, I would actually tend to pick a HSS insert. Look at Arthur Warner for insert-type HSS tooling if you don't like to grind your own threading tools.

Arthuir Warner HSS Threading Tools

[smokediver576]

Advantage of the triangle inserts (16 IR AG 60 or 16 ER AG 60) is that you can buy them in full (A60 or G60) or half thread form (AG60). Full thread form tools require two inserts to cover all the pitches (A60 is 16-48 tpi, and G60 is 8-14 tpi), and it actually will cut the roots and the crest of the thread, so you get a more accurate thread form. Half thread (or partial profile) covers the full range with one insert. To make matters worse, the internal (16 IR) and external (16 ER) cutting triangle shapes are different. So you aren't using the same insert for both tools.

BTW, the above assumes you are using at least a 1/2" tool with a 3/8" insert (the 3/8" tools with a 1/4" LC insert only support 16-48 tpi).

The "cut off type" tool only does half the thread form, and I think it is less prone to chatter than the triangle, but that is just a guess, since I only have the triangle type.

What type of material are you primarily cutting? Make sure you buy the right coating. Aluminum doesn't cut great with the wrong carbide coating, especially with no coolant.

With the emco cnc, since it is a lower power and no coolant, I would actually tend to pick a HSS insert. Look at Arthur Warner for insert-type HSS tooling if you don't like to grind your own threading tools.

Arthuir Warner HSS Threading Tools

Hey Tim,

Thanks for all the info! I feel better now. I'm cutting Delrin, Aluminum and Mild Steel.

[300sniper]

Advantage of the triangle inserts (16 IR AG 60 or 16 ER AG 60) is that you can buy them in full (A60 or G60) or half thread form (AG60). Full thread form tools require two inserts to cover all the pitches (A60 is 16-48 tpi, and G60 is 8-14 tpi), and it actually will cut the roots and the crest of the thread, so you get a more accurate thread form. Half thread (or partial profile) covers the full range with one insert. To make matters worse, the internal (16 IR) and external (16 ER) cutting triangle shapes are different. So you aren't using the same insert for both tools.

BTW, the above assumes you are using at least a 1/2" tool with a 3/8" insert (the 3/8" tools with a 1/4" LC insert only support 16-48 tpi).

The "cut off type" tool only does half the thread form, and I think it is less prone to chatter than the triangle, but that is just a guess, since I only have the triangle type.

What type of material are you primarily cutting? Make sure you buy the right coating. Aluminum doesn't cut great with the wrong carbide coating, especially with no coolant.

With the emco cnc, since it is a lower power and no coolant, I would actually tend to pick a HSS insert. Look at Arthur Warner for insert-type HSS tooling if you don't like to grind your own threading tools.

Arthuir Warner HSS Threading Tools

PARTIAL profile inserts will cover between 16-48 and 8-14 TPI. FULL profile requires an insert for each specific pitch or thread form.

[tmarks11]

PARTIAL profile inserts will cover between 16-48 and 8-14 TPI. FULL profile requires an insert for each specific pitch or thread form.

that's what I get for answering after a really long day.

It would be hard to get a full profile off the same shape for 16 pitch and 48 pitch, since the teeth are SLIGHTLY different sizes....

To the OP: delrin and aluminum cut well with HSS.