Tap and die material question

[paker]

I read several threads on tap and die and got a question about the tap/die material. I always thought tungsten tool steel (high speed steel) is the best cutting tool material, but surprisingly Gearwrench, one of the recommended here, is made of carbon steel (apparently high carbon steel). But it has a lifetime warranty. So my question is if carbon steel is OK for occasional use? Harbor Freight taps and dies are also rated PASS in this forum and are made of carbon steel with lifetime warranty.

On the other hand Astro homepage stresses that their taps and dies are made of tool steel, NOT carbon steel. Thank you.

 

[Indexmill]

I read several threads on tap and die and got a question about the tap/die material. I always thought tungsten tool steel (high speed steel) is the best cutting tool material, but surprisingly Gearwrench, one of the recommended here, is made of carbon steel (apparently high carbon steel). But it has a lifetime warranty. So my question is if carbon steel is OK for occasional use? Harbor Freight taps and dies are also rated PASS in this forum and are made of carbon steel with lifetime warranty.

On the other hand Astro homepage stresses that their taps and dies are made of tool steel, NOT carbon steel. Thank you.

That's a good question. I am sure some will disagree; but, let me get the ball rolling. Of course, HSS is the best material for taps and dies. That is for long life and for cutting harder material. However, a good carbon steel tap or die will work just fine especially for occasional use. This has been my experience with carbon steel taps and dies.

 

[MattT]

The mechanics tap & die sets are ok for the intended purpose. Mostly cleaning & repairing threads with occasional thread cutting if you're careful. Not much use for serious metalworking though and hardly anyone doing that uses hand taps these days either.

Regards Astros "tool steel" I found this:

Machined and forged from an imported Japanese tool steel alloy chosen for its ability to withstand the types of abuse that High Carbon Steel and TiN coated alloy sets would shatter from

It almost certainly has carbon in it, probably in the mid to high range. Tool steel is a pretty vague term and I'm not aware of any carbon free ones. And it has to be an alloy. TiN is just a surface treatment. So there's a lot of marketing **** in their statement.

That said the japanese do make some very good steels. It sounds like they've selected one tougher than is typically used for mechanics taps. Very good idea because carbon steel taps are kinda fragile and broken taps ****.

 

[paker]

Thank you for the explanation. I have done some occasional machining at work and broken a few #4 HSS taps on aluminum, most likely because of my inexperience. So I always had a negative view on anything less than tungsten tool steel. Now I know better. Thank you.

 

[MushCreek]

Like a lot of tools, the name brand stuff will usually out-perform the cheap stuff. I worked with tool steels for my entire career, and you'd better bring the good stuff when tapping tool steel. Taps are easy to break, though, regardless of what they're made of. The usual culprits are misalignment, chip build-up, or lack of lubricant. Aluminum can be tricky. WD-40 makes a good tapping fluid for aluminum. When tapping any material, back the tap up frequently to clear chips, especially in a blind hole. I have an air gun with a small needle threaded on to it to clear chips as I tap holes.

 

[davethorik]

Like a lot of tools, the name brand stuff will usually out-perform the cheap stuff. I worked with tool steels for my entire career, and you'd better bring the good stuff when tapping tool steel. Taps are easy to break, though, regardless of what they're made of. The usual culprits are misalignment, chip build-up, or lack of lubricant. Aluminum can be tricky. WD-40 makes a good tapping fluid for aluminum. When tapping any material, back the tap up frequently to clear chips, especially in a blind hole. I have an air gun with a small needle threaded on to it to clear chips as I tap holes.

Spiral flute bottoming taps
They push the chip up and out, so you have 1 chip per flute. No reversing needed until you're done.
We use Greenfield taps at work for production machining. They are made in Japan, but we use 95% SAE threads...which I thought was funny...i believe they are HSSCo. Have a dark green/black finish. In a cnc machine can tap hundreds of holes. We tend to avoid spiral flute taps in really tough stuff, A2/D2 and CPM.

 

[Dave455]

I think the quality of the tool, and the exact material it’s made of, is more important than the generic terms ‘carbon steel’ of ‘HSS’.

You would think HSS would be superior, and if you are doing repetitive tapping it certainly would be, but I have used imported (Far Eastern) taps marked HSS and they were barely fit for the purpose.

Conversely, I have used good quality carbon steel taps regularly (primarily because a local stockist kept them on the shelf - British made Apex) and they have been superb - easy cutting, nicely finished, and seem to hold an edge well! But, I only use them occasionally, and by hand, as soon as that changes, I’m buying something more suitable!

 

[CobraRed]

The mechanics tap & die sets are ok for the intended purpose. Mostly cleaning & repairing threads with occasional thread cutting if you're careful. Not much use for serious metalworking though and hardly anyone doing that uses hand taps these days either.

Regards Astros "tool steel" I found this:



It almost certainly has carbon in it, probably in the mid to high range. Tool steel is a pretty vague term and I'm not aware of any carbon free ones. And it has to be an alloy. TiN is just a surface treatment. So there's a lot of marketing **** in their statement.

That said the japanese do make some very good steels. It sounds like they've selected one tougher than is typically used for mechanics taps. Very good idea because carbon steel taps are kinda fragile and broken taps ****.

All steels have carbon in them. High carbon steel relies on high carbon content for hardness but can be lacking for toughness.
Tool steels like HSS and others certainly have carbon but are alloys with other properties to acheave hardness and ideally toughness. I assume the astro set is not hss otherwise it would say, but still a tool steel like M2 HSS is so should be a better choice than high carbon steel. And sourcing from Japan likely means it probably starts off decent

 

[paker]

Thank you for the notes. I will go by brand name as advised.

 

[04chase]

i like the irwin tap and die set with mm and sae. its got the tap holders for a socket wrench and those are my go to.

i do mostly threrad repair and chasing along with occasional cutting.

i do have thread chaser and repair kit from s/o also that i will use depending on the job

i will say that i have had the irwin set for about 7 or 8 years and all the sae taps are now hss . when i break one , i didnt worry about warranty just bought a single quality HSS .

this has been the best way for me , vs buying an entire set of HSS most of which youll never use.

 

[theoldwizard1]

From Wikipedia



T1 pretty much been replaced my M2.

 

[toplessHO]

Ive got a set of Craftsman Kromedge over 40 yrs old and it still works fine.
Yes its not a garage queen I use them.
I also bought an expansion set for my metric set that included much larger sizes.
That is a disappointment,works ok but every piece has rust on it,stored properly etc.
So I guess the Kromedge finish isnt what it used to be.

 

[seber]

HSS as it's name would imply is good for automated work. It's main advantage is it's ability to withstand heat. For hand taps and dies that advantage is useless. M2 and other tool steels have better properties for the purpose. In any case most tool steels have the advantage of better toughness than high carbon steel.

 

[MattT]

HSS as it's name would imply is good for automated work. It's main advantage is it's ability to withstand heat. For hand taps and dies that advantage is useless. M2 and other tool steels have better properties for the purpose. In any case most tool steels have the advantage of better toughness than high carbon steel.

M2 is a grade of HSS

 

[Professional Tool User]

I read several threads on tap and die and got a question about the tap/die material. I always thought tungsten tool steel (high speed steel) is the best cutting tool material, but surprisingly Gearwrench, one of the recommended here, is made of carbon steel (apparently high carbon steel). But it has a lifetime warranty. So my question is if carbon steel is OK for occasional use? Harbor Freight taps and dies are also rated PASS in this forum and are made of carbon steel with lifetime warranty.

On the other hand Astro homepage stresses that their taps and dies are made of tool steel, NOT carbon steel. Thank you.

The Gearwrench set is not lifetime warranty if you look carefully at the packaging. The taps and dies are not covered. Only the tap handle and the other bits that are not the taps and dies are covered. Unless you want to spend big bucks on machinist grade taps and dies, carbon steel taps and dies will work for occasional use.

 

[pstemari]

Yes, M2 is definitely HSS: in fact, it's the most common variety.

High carbon steel, eg 1095, can fall under the "tool steel" category. IIRC, 1095 and W-1 are about the same thing. However, it's fussy stuff and doesn't make very good taps.

Sent from my Pixel XL using Tapatalk

 

[MShaw]

And, just for the record, cpm is not a grade of tool steel. It stands for Crucible Powder Metallurgy and is a processing method not a grade.

 

[DFB]

The Gearwrench set is not lifetime warranty if you look carefully at the packaging. The taps and dies are not covered. Only the tap handle and the other bits that are not the taps and dies are covered. Unless you want to spend big bucks on machinist grade taps and dies, carbon steel taps and dies will work for occasional use.

Yup old Craftsman warranty on their Kromedge was the exact same way. I had questioned the company on that once long ago and the response was the tap and dies were cutting tools and not warranted.

 

[theoldwizard1]

Carbon adds strength and Molybdenum add "toughness" (resistance to shock loads which is why it is necessary in impact sockets). Cobalt increases heat and wear resistance.

 

[Maui]

The better quality taps and dies are manufactured from tool steels and high speed steel alloys that were produced domestically. If you run across any vintage Starrett or Greenfield Tap and Die taps, they should have been manufactured from good domestic quality high speed/tool steel.

Maui

 

[Steve_P]

Thank you for the explanation. I have done some occasional machining at work and broken a few #4 HSS taps on aluminum, most likely because of my inexperience. So I always had a negative view on anything less than tungsten tool steel. Now I know better. Thank you.

4-40 is the size to avoid on new designs as this is the most apt to break taps because of the amount of material being removed vs root diameter of the tap. Years ago I went to a design for manufacturability class and the machinist instructor said to not use #4 in new designs unless absolutely necessary .

 

[MushCreek]

I used to repair a variety of molds that were full of 4-40 fasteners. They would break frequently. Great fun trying to remove a broken 4-40 screw that's rusted in place. 6-32 is a close second for breaking. We learned on tool steel you can go significantly bigger with your tap drill and still have strong enough threads. On really tough materials we used a 65% thread depth chart instead of the usual 75%.

 

[FrancisJ]

Ditto what Maui said about Starrett, Greenfield.

99% of the tap and die sets out there today are marginal at best. If you hope to achieve Class 2A, 2B or even higher in the Class 3A, 3B area these won't cut it. Even the so-called Irwin and Greenlee Industrial tap and dies barely get you close to Class 2A, 2B.