Yellow cutters - any good

I got these with my lathe. Anyone ever use them? Any good? I’m planning on going with a QC post. Was thinking of having an adapter/insert made the cutter could slide into then get mounted in post? Thoughts? Pictures to follow.

mwill135 said:

I got these with my lathe. Anyone ever use them? Any good? I’m planning on going with a QC post. Was thinking of having an adapter/insert made the cutter could slide into then get mounted in post? Thoughts? Pictures to follow.

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"Brazed Carbide" is the tribe. Colours are meaningful only within "some" of the maker's product lines. Others do them in all one colour. In general, they are considered obsoleted, and loooong since by far superior "inserted" Carbides and exotic cousins alike in astonishng variety of optimizations to various alloys and tasking.

Can't recall a time I didn't have at least TWO brazed Carbides in my Kennedy. Nor ever more than six. And that was half a century ago. Back when HSS/Cobalt was still the main go-to, and the available Carbides were "negative-rake" and of limited advantage. Modern inserted Carbides are stronger and all-around MUCH better in every respect that matters.

OTOH ... a lathe hand needs to be able turn any material as can BE turned, and now and then a few that ain't known to be possible. Yah need LOTS of options for that. But will not HAVE them. So yah make-do.

These ones can actually be hand-ground for gnarly special needs. ALL of mine had been. No other need of them where I was working.

Doubt that you will ever LIKE them very much. Or ever buy any MORE of them.
But neither would I throw them away.

They make a fair-decent throw-away scriber for marking badly corroded metal surfaces that would f**k-up yer GOOD scriber, for instance...



FWIW.. make yer QCTP installation easily "swappable". The other thing yah learn is need of more than one style of toolpost. Gnarly tasking and weird shapes that can be hard to set tool to WILL cross your plate.

The / A other TP should deal with these - and a lot MORE. As can a(ny) "HSS holder" for a QCTP - which can already hold the shanks of this tribe as well. No need to re-invent that.

And yah can saw 'em SHORT for a boring-bar, given the shanks are only soft steel.

"Short" applies to stick-out in general. These don't "do" vibration nor interrupted cuts all that well. Tend to chip and crack.

2CW

mwill135 said:

I got these with my lathe. Anyone ever use them? Any good? I’m planning on going with a QC post. Was thinking of having an adapter/insert made the cutter could slide into then get mounted in post? Thoughts? Pictures to follow.

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They work great until the edge chips which usually takes about a strong 4 seconds. I'm going to assume your lathe is not the world's best so what you should do is throw them in the garbage and buy some insert tooling, what I would do is put them in the bottom drawer and bitch and moan every time I used one.

Depeds on the quaity and grade of the carbide, best sharpened with a diamond wheel running with coolant. Carbide cuts harder materials better than HSS but likes higher RPM..and a solid machine.
We called them TCT tungston carbide tipped..Nowadays insrets have much taken over that market. Still in a shop that has sharpenig at perhaps .040 taken per sharpening they can be a cost savings..but yes they don't repeat same size like an insert can.

McMaster-Carr

They are usable although you will probably want to upgrade to larger inserted carbide bits in future along with a more rigid tool post.

They can be resharpened by hand using diamond paddles such as the inexpensive 3-grit set from Eze-Lap.

https://www.amazon.com/dp/B000UVS62S?tag=duckduckgo-d-20&linkCode=osi&th=1&psc=1

Inserts are nice for being able to instantly fix a chip'd or worn cutting edge, but I think it's important for new guys to learn to grind their own cutting tools. It saves money, but more importantly, you learn a lot about cutter geometry and how it relates to your job. Not all sharp edges are going to cut the same.

Another mistake often made is that "carbide is better than HSS." It depends what you are doing. For common materials on older slower lathes HSS will cut and last much better. Carbide is needed for cutting hard and some exotic material, and you need higher speeds to cut mild steel and other common materials.

but I think it's important for new guys to learn to grind their own cutting tools. It saves money, but more importantly, you learn a lot about cutter geometry and how it relates to your job

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Or, in other words, it is AT LEAST as important to have SOME understanding OF WHY a tool cuts - as it is to know something about making a lathe go.

To optimize results needs optimization of BOTH sets of understanding. Very little of this takes place over the counter at the machine shop supply - or its modern "on line" counterpart

These folks knew something about what they were doing 105 years ago when carbide was some outlandish future improvement undreamed of yet

michiganbuck said:

Depeds on the quaity and grade of the carbide, best sharpened with a diamond wheel running with coolant. ...

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Go over that part again please: "Diamond Wheel."

Unless the shop *has* a diamond wheel, these tipped tools are basically disposable. Use until they chip or wear, and then throw away.
They can be done on a 'green' wheel but not nearly as good as a diamond wheel. This is one reason why HSS makes a good deal more
sense than tipped carbide tools in a home shop.

I'd say use 'em until you chip the cutting edge (can be as little as the first instant you touch the work piece) and then throw the thing away unless you have a diamond wheel and know how to sharpen them. Or, you could just throw them all away and study how to grind HSS tooling which will work better for you anyway. I have a little plastic box full of those brazed carbide bits, all with chipped cutting edges, left over from when I thought they'd be the answer to my tooling prayers. I'm not sure why I keep them.

Perhaps the fastest way to ruin one of them is to try to cut a thread with one of the ones with the 60 degree point.

johnoder said:

Or, in other words, it is AT LEAST as important to have SOME understanding OF WHY a tool cuts - as it is to know something about making a lathe go.

To optimize results needs optimization of BOTH sets of understanding. Very little of this takes place over the counter at the machine shop supply - or its modern "on line" counterpart

These folks knew something about what they were doing 105 years ago when carbide was some outlandish future improvement undreamed of yet

View attachment 287723

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I'll see your "big chips" and raise you a year. To 1916;

Panama Canal - Wikipedia

Dobermann said:

I'm not sure why I keep them.

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They are actually right useful...

At reminding yerself WHY the tedious bizness of initial-shape grinding of a Rex 95 or a Tatung-G virgin blank is going to become WORTH it ... as they do the next forty-days.. or forty-years - on nought but touch-up grinds!

Bill, after a while, all it is is touch up grinds, unless there is some weird profile you need to cut.

Rudd said:

Bill, after a while, all it is is touch up grinds, unless there is some weird profile you need to cut.

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I'm lazy. I even LIKE it that way!

The goal.. is to tilt the blanks.. add the chip BREAKER as part of the clamping... . so the TOP of a blank has NO grinding done to it.

"Built-in" tilt was what Armstrong & Williams "made their bones" with, back in the day of transitioning to standardized blanks and off tooling hand-forged right in the shop. Some block-type toolholders (Hardinge, but not-only) and some 4-ways, (same again..) the tilt is also built-in.

So this is "not new".

Common turning, it is then grind "front", ONE side, their junction shape. ONLY,

Threading tool is two fronts or two sided - semantics thing - and yah generally DO have to put a belly in the top, otherwise they are messy when fed "straight in".

Parting-off, the blank is Tee-top, wedge-shaped, or both so it wants a "feature" of one kind or another at the front and "may" need another on top.

NB: Some of the new Carbide part-off tools are sooo VERY nice.. I might even break down and adopt one of 'em.



However yah "get there", by altering fewer surfaces, yer touch-up grinds are easier. And yah get better mileage outta the blanks as well.

See also skiving. See also tangential.

HSS, HSS-Cobalt / the Stellites, even a few items of HCS or "tool steel"? Works for me... over 60 years at the tool-tip and counting.

Mind. A good deal of whether yah NEED inserted Carbides isn't so much about cutting speed, nor exotic alloys, either one.

It has more to do with speed and ease of toolsetting and cutter changes, all a part of throughput for high unit volume, and supporting the level of automation, if any.

Hand-ground HSS is NO FRIEND of CNC. Surely not where a toolchanger & magazine are involved. Generally not worth messing with at all.

HSS can still work, but.. standardized store-bought goods, such as drills, saws, endmills, and milling cutters of predictable size and shape. Most CNC "drivers" don't like even the very BEST of re-grinds. Dimensions have changed, extra work to use them can eat-up the alleged savings.

Highly repeatable inserted carbides very much ARE beloved of CNC. "Essential, even".

OTOH, for a hobbyist, retiree on an all-manual machine, light-duty and/or older era, especially? And sometimes even a "for revenue" job shop / repair shop, even R&D or engineering support?

Anywhere the machine is all-manual, and most of all "Old Iron" with lower speeds and feeds.... HSS & cousins are still a very good fit, flexible in use, and very economical as well.

After all.. if yah NEED it for dealing with "the hard stuff"?

Yah can always buy some "yellow" brazed Carbides, yah?



(ducks.. waddles away.. stage left..)