# HSS tool blanks



## Aukai (Sep 7, 2017)

My PM 1228 will be at Matt's shop soon for QC, and prep for shipping. Since the subject of HSS bits was brought up in the other thread, and I did not want to high jack it, here is my question. For the AXA QCTP, do you need, or should you have  1/2", and 3/8" blanks on hand, is one better suited than the other for jobs?


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## mikey (Sep 7, 2017)

Either one will work, although the 1/2" bit will be stiffer. 3/8" will definitely work and will be cheaper, easier to find and quicker to grind. As long as you do not overextend the 3/8" tool, I do not see an advantage for a 1/2" tool. I have both and pretty much only use 3/8" tooling. Buy both and see for yourself.


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## Aukai (Sep 7, 2017)

Good to know, one thought other than stiffer was that possibly able to tolerate/pull more heat out of the cutter, just guessing. Thank you....


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## mikey (Sep 7, 2017)

Aukai said:


> Good to know, one thought other than stiffer was that possibly able to tolerate/pull more heat out of the cutter, just guessing. Thank you....



Hmm, no not really. You want the heat from the cut to go out with the chip and not heat up the tool. With proper side and back rake angles ground into the tool, efficient chip ejection is exactly what happens.


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## darkzero (Sep 8, 2017)

Not that I have a lot of experience grinding my own tools, I do know that 3/8" tools are much quicker to grind than 1/2". I hated grinding 1/2", I just wanted to start machining already. I guess that's why I pretty much only use indexables now & a QCTP. For us hobby guys 3/8" should be perfectly fine. At least that's how it seemed for me.


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## mikey (Sep 8, 2017)

darkzero said:


> Not that I have a lot of experience grinding my own tools, I do know that 3/8" tools are much quicker to grind than 1/2". I hated grinding 1/2", I just wanted to start machining already. I guess that's why I pretty much only use indexables now & a QCTP. For us hobby guys 3/8" should be perfectly fine. At least that's how it seemed for me.



You wouldn't think it would take a lot longer; its only 1/16" bigger all the way around but a 1/2" tool takes me twice as long to grind as a 3/8" tool does - go figure.


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## Aukai (Sep 8, 2017)

AAAH, I'm all about simple.
Looking at the middle of a product graph, I'm seeing  M 2,4, 42, T 15s
How far up the scale do we need to go? Not all HSS if I'm reading it right.


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## mikey (Sep 8, 2017)

The most common HSS tool bit is M2 and will do for almost all common materials we work with. M35 has 5% cobalt and M42 has 8% cobalt. These cobalt steels can be used for all common materials but tolerate higher cutting temperatures and more abrasive materials; they are useful for higher carbon steels, cast iron, etc. All the M-type HSS contain Molybdenum. 

T-type steels contain Tungsten, hence the T-designation. They are more abrasion tolerant and handle high heat better than the M-type steels. AR Warner uses a lot of T-15 for their inserts. While you can find T-15 tool bits, they are less common and more expensive than the M-type bits. 

I use M2 most often but for tools that see a lot of use and require better edge retention, I use cobalt steel. The best cobalt steel bits I know of are the Mo-Max cobalt steels (M35) and Super-Mo-Max (M42). They are really excellent, with a price to match.


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## Aukai (Sep 8, 2017)

Mo-Max M42 is 17 bucks vs Mr Warner's 8 buck M42s thoughts


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## mikey (Sep 8, 2017)

Aukai said:


> Mo-Max M42 is 17 bucks vs Mr Warner's 8 buck M42s thoughts



You gotta' watch for deals on these things rather than pay retail. In the meantime, buy some plain M2 HSS tools and use them. I think most guys wouldn't know the difference (in terms of cutting performance) between an M2 vs M42 when cutting common stuff.

One bit that I like is Crucible's Rex 95. This is a T-8 bit and makes a really nice tool. Here is an ebay BIN for about 6 bucks and he has four of them for sale. For this tool bit, that is a fair price: http://www.ebay.com/itm/1-New-HSS-R...261050?hash=item25ddc1e23a:g:dPAAAOSwcj5ZPuex

It might help to know what to look for. Makers of good HSS tool bits are: Cleveland (M0-Max, Super-Mo-Max are the best), Crucible (Rex AAA = T-4, Rex 95 = T-8), ETM M2 HSS bits and Vasco Supreme. There are others but these are top shelf and common.


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## Aukai (Sep 8, 2017)

Thank you for your help here. This quote from one of the pages is saying Crucible is not producing... Is that a different subject?
Crucible Steel Selector (No longer producing products but very good information)


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## darkzero (Sep 8, 2017)

mikey said:


> One bit that I like is Crucible's Rex 95.



I like Crucible also & use them quite often. Not tool bits though. Many of my knives have blades made from various Crucible CPM alloys. I almost always carry a knife on me.


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## mikey (Sep 8, 2017)

Aukai said:


> Thank you for your help here. This quote from one of the pages is saying Crucible is not producing... Is that a different subject?
> Crucible Steel Selector (No longer producing products but very good information)



Not sure if they're making bits or not but you will find them for sale on ebay. 

My best advice - buy some mild steel keystock in the size you plan to use and learn to grind tools with that. When you can grind a tool shape you are satisfied with then change to M2 HSS. When you have M2 tools that work as you intend, try cobalt or the Tungsten tools.  Trust me; grinding cobalt as a first tool does not usually work out well. They take more skill to grind well.

Clearly, Chinese bits are the cheapest way to go. My experience is that they do not hold an edge as long but they work pretty well. When I experiment with a tool, this is what I use until I get it exactly right. Then I grind one from a blank I trust.


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## Aukai (Sep 8, 2017)

Good idea on the key way material.


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## Tozguy (Sep 8, 2017)

To the original question I would say get both 1/2 and 3/8th blanks. Don't limit your tool choices prematurely and try to use the largest tool available unless a smaller one is required for the job.

No one I know wants to do more grinding than they need to (with two exceptions maybe). But we must not develop an aversion to grinding. If grinding becomes a chore it is usually because the grinding equipment used is not adequate. I would not compromise on the quality of steel in a tool because of grinding difficulties. Upgrade your grinding equipment as necessary. There is no better feeling than being able to solve the grinding issue and not have a hesitation to grind any HSS or carbide tool.

Likewise I would not waste time grinding anything that is not going to be used. If you start with a quality blank and practice on the real thing then you don't have to start over when you are finished. It is way easier to change the profile or sharpen a tool than it is to start from scratch.

Unless you have much experience grinding with precision, avoid grinding freehand. That approach will have you hating grinding lathe tools forever. With a way to control angles consistently you will minimize effort and frustration. Just my $.02.


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## Aukai (Sep 8, 2017)

Thanks Toz, I did pick up an 8" grinder, and a change of wheels, hopefully I'll get the hang of grinding the shapes needed.


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## Tozguy (Sep 8, 2017)

Sounds good, enjoy the fireworks.


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## Reeltor (Sep 8, 2017)

One thing that you might want to consider is to use an angle grinder to rough in the bit before taking it to your bench grinder.  I never though of using an angle grinder on a tool bit until I saw a YouTube video series between Adam Booth-- Abom79 and Tom Lipton--OxToolCo entitled Chip Control on Adam's youtube and Chip Control to Major Tom on Tom Lipton's site. 
Good luck and have fun, (remember this is supposed to be fun  )


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## tq60 (Sep 8, 2017)

A good source for bits are estate sales as often you can find a box of them for a buck.

We use carbide for everything but have boxes of the other for tinkering someday.

Sent from my SAMSUNG-SGH-I337Z using Tapatalk


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## Aukai (Sep 8, 2017)

Thank you for the videos, we were out on a call, and I checked in, I'll watch them when the sun comes up.


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## benmychree (Sep 8, 2017)

mikey said:


> Not sure if they're making bits or not but you will find them for sale on ebay.
> 
> My best advice - buy some mild steel keystock in the size you plan to use and learn to grind tools with that. When you can grind a tool shape you are satisfied with then change to M2 HSS. When you have M2 tools that work as you intend, try cobalt or the Tungsten tools.  Trust me; grinding cobalt as a first tool does not usually work out well. They take more skill to grind well.
> 
> Clearly, Chinese bits are the cheapest way to go. My experience is that they do not hold an edge as long but they work pretty well. When I experiment with a tool, this is what I use until I get it exactly right. Then I grind one from a blank I trust.


When I took a machine shop class in high school, we were given a piece of key stock to grind into a roughing tool with ground in chip breaker; when we could show the teacher we were capable of grinding an acceptable tool, we were given a new tool bit to keep for the year's classes; that and a round nose tool were our cutting tools for the class.  He also had U shaped adaptors so that the 1/4" square tool bits could be used in the Armstrong tool holders for the larger lathes that used 3/8 square tools.
I had one of the best teachers ever, this back in 1962-3 at Napa High School Ca., Paul Goldberg, later changed to Kreuger. He apprenticed at Mare Island Navy Yard in the 1930s and was an apprentice school teacher after that until after WW2 when he taught in the public schools.  Nothing went on in HIS shop that he was not aware of; he had a finely tuned ear to noises that meant trouble, and was on top of everything, and no screwing around in class!


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## Aukai (Sep 8, 2017)

Sounds like a remarkable experience, I love the older guys.


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## tweinke (Sep 8, 2017)

Funny story about key stock, my boy came over one night to make a part for one of his projects and grabbed one of the pieces of key stock I had practiced on and proceeded to attempt to cut down a piece of cold rolled shaft. about the time he found that it wouldn't cut I walked in. He said to me that he thought I better keep practicing grinding tools because even though this one looked pretty it didn't cut worth $#!#. We both got a good laugh when I told him it was just key stock I practiced on. and an even bigger laugh when he told me he had used that same "tool " to cut some delrin two nights before!


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## mikey (Sep 8, 2017)

Reeltor said:


> One thing that you might want to consider is to use an angle grinder to rough in the bit before taking it to your bench grinder.



I've not used an angle grinder to rough in tools but I have used one with a cut off blade to rough in threading tools. Threading tools often have one side with a lot of material to take off and I tried cutting the bulk of it off with an abrasive cut off wheel. It worked but that tool got HARD. It took some grinding to get past that hard surface but it did save a little bit of time.


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## Dan_S (Sep 8, 2017)

In my opinion , you will need a range of different tool blank sizes, even if you are using carbide tools. Sometimes you use a small bit because you don't want to spend a day grinding a 1/2" one. Other times you need a 1/2" bit because you need the extra cross sectional  area to minimize flex because of the stick out required. I keep 3/16", 1/4", 3/8" & 1/2" blanks in my tool box, but I use 3/8" the most.


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## Aukai (Sep 8, 2017)

Thanks Dan, good thoughts.


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## Glenn Brooks (Sep 9, 2017)

Once a year or so I go shopping on eBay for HSS tooling.  Often you can buy a large batch of  tools, formed into all sorts of shapes, for pennies on the dollar.  I've never worried about what grade they are, as some really old bits have been the best cutters. Wouldn't hurt to take a look and buy a batch for $10 or $15 bucks that have already been ground for left and right hand turning, plunge cutting, rounded edge for yellow metal, etc.

Glenn


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## Aukai (Sep 9, 2017)

Glenn I will keep my eye open there, I need to learn what to look for, and the strategies involved.


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## Glenn Brooks (Sep 9, 2017)

Aukai said:


> Glenn I will keep my eye open there, I need to learn what to look for, and the strategies involved.


One good resource is south bends old " how to run a lathe" book.  Plenty copies around on eBay.  The book has several pages dedicated  to HSS tool geometry.  Pictures and description of use.  Also available on line.  

Basically you will want to explore which tool shape to use for left and right hand cutting, also what to use to the face off the work mounted in the lathe.  The next stage will get you into looking at the subtle differences in the  tiny little rounded edge that contacts the work, and honing the sharpness of the tool edge.

Jump in and have fun!  
Glenn


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## Aukai (Sep 10, 2017)

HAHA Glenn living in Hawaii since the 50s I learned to swim, surf, dive, no problem. I feel like I'm at the kiddy pool now.


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## Dinosaur Engineer (Sep 11, 2017)

You can get good bargains on the larger 2nd hand HSS bits as the professionals don't want them ( they use inserts) and they are considered too large for most of the hobby users. I agree that 1/2" bits take longer to grind from scratch but once they are ground to the correct shape they can be be sharpened quire quickly.


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