Theory of brazed carbide lathe bits

Bill D · Sep 15, 2020

They used to sell lots of brazed carbide tools silver soldered onto steel shanks. Now for the most part replaced with inserts. Looking at them I do not see any great cutting angles since they just have a flat top with no chip breakers. Similar HSS tools were held in lantern type holders that gave them an up angle of several degrees to promote cutting shear angles. Or does carbide just not need a sharp angle to cut well?
Are these brazed tools supposed to be mounted horizontal like a insert holder or tipped up in an old tool holder. I see folks using them flat in a QCTP.
Bill D

rons · Sep 15, 2020

Every one of those import bits has to be re-cut with a grinding wheel. After that they work ok.
For example, the angle is pretty steep for a 60 degree point threading bit. And the cut on the carbide is not going to line up with the shank of the tool.

Those things can be changed at the grinder. For all those non-mask wearers today it should be another reason to wear one.

Bill D · Sep 15, 2020

I include the older USA made tools in the question. Were users expected to sharpen them before use. That seems to be the way HSS blanks were and still are sold. They come with a generic angled end cut that are different at each end. I have never seem them sold with a 90 degree square end. Of course my experience is limited.
Bil lD

thermite · Sep 15, 2020

Bill D said:
They used to sell lots of brazed carbide tools silver soldered onto steel shanks. Now for the most part replaced with inserts. Looking at them I do not see any great cutting angles since they just have a flat top with no chip breakers. Similar HSS tools were held in lantern type holders that gave them an up angle of several degrees to promote cutting shear angles. Or does carbide just not need a sharp angle to cut well?
Are these brazed tools supposed to be mounted horizontal like a insert holder or tipped up in an old tool holder. I see folks using them flat in a QCTP.
Bill D

They work as well as they work - (not great) - in "lantern" TP, same Armstrong-Williams style forged holders as HSS, and/or the 'flat" ones without the up-angle.

Back in the day, more yet were used in one or more sides of a 4-Way TP, if only because that is what most lathes in industry mounted.

One advantage over HSS is they COULD be used as consumables, no grinding labour required and no need for an operaor / setup person to even be ABLE to grind HSS.

That said, those few we used (they were NOT "popular') were only of use to us because we COULD (also) grind them. Otherwise if not inserted Carbide, we used HSS (Rex 95, Mo-max, Cobra T1 at one day job, Rex AA and AAA at another).

The usual approach was to first cut back the steel mount, under, with an Alox wheel so it didn't bug the fast-wearing green grit so much, then alter the Carbide slab itself with a green grit (Silicon Carbide) wheel.

It was a cheap way of getting Carbide to a special shape or to the ability to"reach in" where an insert of the era could not easily go. We'd also saw off the shanks for shorties in boring bar work - especially if we had hit a nasty HAZ or inclusion in the weld build up we worked so much of.

I still have maybe half a dozen of the old Carbolloy "problem solvers" left in the Kennedy from the dawn of the 1960's.

NO plans to buy any more, though! I think I'd rather have a toothache?

donie · Sep 15, 2020

termite, we are waiting for an explanation, over on the Axelson thread, its your lying about your photos , and everything else problem "again"

thermite · Sep 15, 2020

donie said:
termite, we are waiting for an explanation, over on the Axelson thread, its your lying about your photos , and everything else problem "again"

Your lies are your problem, not my problem.'

Published foto decision is, as has been stated several times, aready, scheduled for 15 September of 2035. Private sharing is private sharing, no concern of yours.

If you are still present, publication will be deferred for a later year.

How hard is it for you to understand an ignorant calendar?

texasgeartrain · Sep 15, 2020

Bill D said:
They used to sell lots of brazed carbide tools silver soldered onto steel shanks. Now for the most part replaced with inserts. Looking at them I do not see any great cutting angles since they just have a flat top with no chip breakers. Similar HSS tools were held in lantern type holders that gave them an up angle of several degrees to promote cutting shear angles. Or does carbide just not need a sharp angle to cut well?
Are these brazed tools supposed to be mounted horizontal like a insert holder or tipped up in an old tool holder. I see folks using them flat in a QCTP.
Bill D

You can grind and shape them the same as HSS to what ever you want including chip breaker. You need a different grinding wheel though. For HSS you would typically use white AO wheels. For brazed carbide you use green silicon wheels, these wheels can also grind HSS. But white AO won't grind carbide.

Having the right tool grinder helps. I went through a pretty good tool grinder here:
Hammond Machinery Builders, Tool Grinder Model CB-77

I have white AO and green silicon for both sides of this machine. You can see the green silicon wheel here:

Same side of grinder, but white AO. This side of machine is where most of the tool grinding is done for angles. The table is degree-d and tilts. The miter gauge is another way to set degrees.

This other side of machine you cut chip breakers:

dian · Sep 16, 2020

rons said:
Every one of those import bits has to be re-cut with a grinding wheel. After that they work ok.
For example, the angle is pretty steep for a 60 degree point threading bit. And the cut on the carbide is not going to line up with the shank of the tool.

Those things can be changed at the grinder. For all those non-mask wearers today it should be another reason to wear one.

that is simply not true. it depends on where you buy them from, probably. i have plenty of brazed tools that are ready to go as they come. i mean, you dont have to get them from ebay.

i suspect that in many parts of the world they still are the go to tools for smaller shops and toolroom. just look at some russian videos. any table on cutting geometry will show carbide needing smaller or no top rake, depending on the material. and as to sharpness, you dull the edge on hss tools, so where is the problem? most carbide grades can be ground razor sharp if needed. and you would grind carbide on a wet diamond wheel anyway.

all the threading bits i have seen are flat.

btw, the recent paranoia about a bit of fumes or dust killing you is ridiculous. i cant even laugh any more when i read about people wearing a mask when using epoxy paint.

Winterfalke · Sep 16, 2020

Always avoided the junk brazed carbide we had laying around for general use on the manual lathe, but I know Micro 100 still sells good brazed carbide tools in a good number of shapes ready to go, we used them almost exclusively in our swiss machines. There were actual piles of them on each machine, I believe they got honed when the finish started to degrade. Not my department, so I couldn't tell you much more.

thermite · Sep 16, 2020

dian said:
all the threading bits i have seen are flat.

+1

Might not be yer first choice, but they could get 'er done.

Flat, no compound ordinarily on the cross, Big 4-Way. So straight in. Pay attention to setting the height. Soon done. On to the next ball-buster!

Decent ones aren't hateful. I just like Rex 95 or Tantung-G BETTER!

By about ten to one....

But there you have it. Lot of it is what yer most comfortable with.

Milland · Sep 16, 2020

dian said:
btw, the recent paranoia about a bit of fumes or dust killing you is ridiculous. i cant even laugh any more when i read about people wearing a mask when using epoxy paint.

The "paranoia" isn't just recent, concerns over chemical hazards from a variety of paint types goes back decades. While in general I'd agree that epoxy paints aren't the worst, it's still a very good idea to minimize exposure to their uncured constituents.

SUIT UNVEILS 9-YEAR COMPANY DEBATE ON WARNING FOR TOXIC PAINT ADDITIVE - The New York Times

So maybe your "can't even laugh" is due to your lungs being damaged from long-term exposure?

thermite · Sep 16, 2020

Milland said:
The "paranoia" isn't just recent, concerns over chemical hazards from a variety of paint types goes back decades. While in general I'd agree that epoxy paints aren't the worst, it's still a very good idea to minimize exposure to their uncured constituents.

SUIT UNVEILS 9-YEAR COMPANY DEBATE ON WARNING FOR TOXIC PAINT ADDITIVE - The New York Times

So maybe your "can't even laugh" is due to your lungs being damaged from long-term exposure?

No s**t. G'Dad & his elder Brother both prominent printers, Pittsburgh, PA. Pre-War ONE ... and onward.

G'Uncle Pete a prominent Ripofflican, "biznessman", non-Union, worked P.R. Connell from a desk, had a stroke or two, died of old age.

G'Dad was a staunch Democrat, Union Shop if ever was, worked his "New Era" printing's exotic German-made multicolor web-offset lithography press AT the press. Tumour he was carrying when he died young about volleyball size. One of several litho printers of my acquaintance who fell to the same killer.

"Glaze Breaker"

AKA Benzene.

Galis, we had a half-55 gal drum trough to wash the coal dust, grease, zinc-chromate paints, white lead, off our chip-welted bare arms. Chlorothene-NU.

'nam we scrubbed the Oxygen plant floors, laundered our uniforms, washed oil off our own selves with 55 gallons a month worth of Trichlor to prevent pure Oxygen and 100 degree-plus temps flaring us like flashbulbs.

Cleared the adjacent paddy to clear fields of fire for our gunnery with 500 gal de-con trucks filled with an herbicide called Agent Orange.

WTF did any of us know at the time?

And how is it one's skin ends up uglier than the patchy hide on God's alcoholic Uncle-in-Law?

Pay attention, kids:

Humans may be tuff critters, but yah don't HAVE to be in Kaliphoneyah for this s**t to kinda ..

..welll .... "push yer luck" might fit?

No fuss the five packs of menthol smokes a day. Lung cancer will just have to take a damned number and run it's puny ass off trying to catch up!

DDoug · Sep 16, 2020

thermite said:
+1

Might not be yer first choice, but they could get 'er done.

Flat, no compound ordinarily on the cross, Big 4-Way. So straight in. Pay attention to setting the height. Soon done. On to the next ball-buster!

Decent ones aren't hateful. I just like Rex 95 or Tantung-G BETTER!

By about ten to one....

But there you have it. Lot of it is what yer most comfortable with.

….and nothing saying you can't bend the steel shank, just back of the carbide, a wee bit in the vice
to get the wanted "positive rake" while being installed in the 4 way.....

thermite · Sep 16, 2020

digger doug said:
….and nothing saying you can't bend the steel shank, just back of the carbide, a wee bit in the vice
to get the wanted "positive rake" while being installed in the 4 way.....

Not that easy, size of the shanks on our ones! Stick-welds very niceley, though.

So does Rex 95, believe it or not. Made the planer tooling for the inside of Lee-Norse continuous miner chain guides that way.

Not really an issue. Folks go on about not wanting to have to mess with "shims" in a 4-Way. but we were glad of 'em - they were actually beloved!

Most all of us had our pet "collections" of angles and wedges we had made-up and come to rely on.

Plenty of space when the toolblock was made to take 1 1/2" or anything lesser as either a HSS/Cobalt blank or an insert's heavy steel shank.

Tilt a(ny) smaller blank up, down or angled as to top tilt to save "some" of the grinding in a New York Minute of familiar setup, depending on the need.

Herr Pelz had been a ball-buster as to never wasting good alloy nor time with a chip-breaker ground into an HSS tool. Set the heel clearances only, leave the top as-issued flat.

Simply TILT the blank, CLAMP on another piece of shaped alloy just back of the working edge, and yah could adjust all of it to suit the needs of the task, make the chip do whatever it needed to do, change your mind in not much more time than the C. Allen Peyser mandate:

"Try it! If it doesn't work? Fix it. But fix it FAST".

Blanks took FAR less time to touch up. High-grade alloy bought for good money goes a looooong way further!

Brass & Alpaca metal, the tools we made for volume production were no more complicated than a slice of Timken Graph-Mo tool steel!

donie · Sep 16, 2020

mr termite, there may be a break in the case of your stolen Medusa photos, apparently they have caused many to go bezerk, and people have spread outrageous lies. These people have been cremated, and put deep in the ground, as per your instructions.
Keep up on the Axelson thread for updates. thank you

DDoug · Sep 16, 2020

donie said:
mr termite, there may be a break in the case of your stolen Medusa photos, apparently they have caused many to go bezerk, and people have spread outrageous lies. These people have been cremated, and put deep in the ground, as per your instructions.
Keep up on the Axelson thread for updates. thank you

……..………………………(ten characters....)

donie · Sep 16, 2020

Thank you duck of Zamak, the termite needs your undying support as it seems the "termite" was exposed as a "bull shitter" on the Axelson thread, by an "eye witness."
As the termite would say Good fer Yah!

I am relieved you have not seen the termite Medusa photos, gone bezerk, spread outrageous lies!

camscan · Sep 16, 2020

Brazed carbide tools were used regularly on Swiss type cam screw machines. Absolutely nothing wrong with them, you get what you pay for.

Screwmachine · Sep 16, 2020

camscan said:
Brazed carbide tools were used regularly on Swiss type cam screw machines. Absolutely nothing wrong with them, you get what you pay for.

Yes, I have a bunch and it's what I use for lathe work in general. Handy to have an Agathon grinder to modify and touch them up for sure.

Orbital77 · Sep 16, 2020

One good thing about brazed carbide is heat dissipation. Or so I was told and don't know if it matters and how much. Food for thought.
By the way, where does one buy carbide pills for brazing ? Cheap, I mean.

Theory of brazed carbide lathe bits

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