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Carbon Steel Cutting Tools


Nov 6, 2021
In the days of yore, there was no HSS; all cutting tools were of forged and quenched carbon steel.... Or so I'm told.

Does anyone here make and use their own carbon steel cutting tools?

In a couple of my old planer & shaper manuals, there are data tables for carbon steel cutters. They seemed to have ran them at about ½ the speed of HSS.
Actually ,the trickiest part was grinding them ......had to be ground on a sandstone wheel to avoid drawing the temper ....a slow process ...........a lot of cheap drillbits are still high carbon steel ,and are suitable for wood only.
I have "forged" a small boring bar from O-1 rod, then quenched and tempered it. I have also made quite a few parts from A-2, some of which had cutting/scraping function. And if I wanted a big tap (over 1") I would see if Sam Mesher Tools in downtown Portland still had their barrel of WW2 vintage carbon steel taps. They held on to them into the 2010's; they probably still have them if they're still in business.
But generally, I use HSS or carbide tools. If I have to grind a tool bit, it will be from a HSS blank. I suppose some of my stash of older Thurston slitting saws might be carbon steel, but everything remotely recent will be HSS if it's not carbide.
I have made some form tools from drill rod and flat stock, but only for shapes that were difficult to grind from hss. Otherwise some woodworking tools such as chisels for a router plane. Do a search for “clickspring” on youtube. He regularly makes cutters for clockmaking from drill rod.
Actually ,the trickiest part was grinding them ......had to be ground on a sandstone wheel to avoid drawing the temper ....a slow process ...........a lot of cheap drillbits are still high carbon steel ,and are suitable for wood only.
A lot of cheap taps and dies, too... which makes them mostly suitable for cleaning up previously cut threads.
Lotta years ago ,place I worked for had drums of ex WW2 surplus carbon steel dies ......used to use them on the lathe with a pull off holder ........they were intensely hard ,and cut a nice thread.......but it was very easy to break them by pulling out a big chip of the hard steel........no thought ever given to sharpening ......just get another one ......the surplus stuff would never end .
In the pre-HSS era, machinists in smaller shops were expected to forge, harden, temper and grind their own lathe, shaper & planer tools. Shops had a forge, anvil, and blacksmith tools for that purpose. In forging a carbon steel tool, a machinist who was skilled at blacksmith work would forge the carbon steel tool to very nearly its finished geometry. While in the annealed condition, the tool could be filed to bring it even closer to its finished geometry. After hardening and tempering, the tool would be ground to create the cutting edge and other finer features.

I suspect the carbon steel used for lathe and other cutting tools was something on the order of a 1090 steel, about like a W-1. Nothing fancy, but properly heat treated, would be a good hard tool. Just not up to the kind of high temperatures and running at higher cutting speeds that HSS is able to handle. The beauty of a forged tool is strength due to the grain flow in the forging. Another nice benefit is that a forged tool could be re-forged when too worn for re-grinding, or to change its geometry if needed for another job.

At Brooklyn Technical HS which I attended 1964-68, we still had some line-shaft driven machine shop classrooms. In the classroom where I studied advanced machine shop in my junior and senior year, we had heavy pedestal grinders made by Blount. These were single-wheel grinders, driven from the overhead line shaft. The wheels were a wide and fairly large diameter aluminum oxide wheel, vitrified bond. These grinders were built to run 'wet', having a coolant pump, trough around the wheel, and coolant pipe to flow water on the wheel when grinding. Brooklyn Technical HS was built in 1924, so machine tools and overhead lineshafts were what was in widespread use at that time in industry. By the time I attended 'Tech, we were using HSS cutting tools. The school book store sold "Rex M-2" HSS tool bit blanks for small money. Each student in their sophomore year, took two semesters of basic machine shop. They were required to purchase two (2) 5/16" square HSS toolbit blanks. These were ground freehand at both ends, so a student had four (4) possible lathe tools. At least one of the blanks was ground as a turning/facing tool, and one end was ground as a thread cutting tool. Since we were in the HSS era, the old Blount grinders were run dry. I could see where having a deluge of water on the wheel would allow the grinding of carbon steel tools on the aluminum oxide wheels. The old Blount grinders had wheels that seemed to me (as a kid of 15 or so) as big as a millstone.

In days of old, a machinist apprentice learned a lot of 'bench work', the use of files, hammers and cold and cape chisels, and basic forge work and heat treating of plain carbon tool steels. Forging a tool was not a special thing or a rare activity for the old machinists. I suspect they spent a lot of time forging and heat treating carbon steel tools when machining rough iron castings or scaly alloy steel forgings.
Grand pa is pretty pleased with his giant 85 ton locomotive - no doubt machined entirely with carbon tool steel cutting tools at least somewhat before 1900 at the Brooks plant in New Jersey (Joe says Dunkirk, NY - THANKS). Those are 80" drive wheels


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So then the old carbon steel tools would be the equivalent of W, O, and perhaps A & D as well?
I've made some custom taps and even a die of carbon steel. Folks say they are "useless", but they cut fine. I am pretty sure that some of the taps and dies I have in obscure thread pitches/sizes are carbon steel, and they work just fine also.

You just have to be aware that while they are as hard as HSS, they are not as tough in that condition, so you want to be easier on them. Knowing how to temper them right for what you need is essential to getting good use out of them.
John Oder:

Not to dispute you, but Brooks Locomotive Works was in Dunkirk, New York. Brooks, along with a number of other steam locomotive builders, were all combined into The American Locomotive Company, better known as ALCO. Alco kept the Dunkirk works open for many years after the merger.

Steam Locomotives were built in New Jersey by two other firms: Cooke, and Rogers. Rogers is best known as the builder of the locomotive on which Casey Jones met his death. Like Brooks, Cooke and Rogers were also folded into Alco.

I am currently working on the engineering for extensive boiler repairs to Arcade & Attica RR's locomotive number 18. Number 18 was built in 1920 at the Cooke works, in Paterson, NJ. By that point in time, Alco had pretty much dropped the Rogers name and still included "Cook Works" & Paterson, New Jersey on the builder's plates.

Arcade & Attica Number 18 was originally built for a Cuban sugar mill railroad, and was ordered with an oil fired boiler. The sugar mill backed out of the purchase, and Alco/Cook sold the locomotive to a railroad in the USA, converting it to coal firing for the sale. I designed some very extensive repairs which are considered as 'alterations' to the boiler. In the process of inspecting the boiler and then the repairs, I cannot help but appreciate the work the boilermakers did back in 1920, and then the work the current generation of boilermakers did for the repairs/alterations. Anytime I am around old machinery, whether it is machine tools, steam engines, locomotives, or anything else in the way of old machinery, I always reflect on what it took to build it back 'in the day'.

Machine work on steam locomotive parts was heavy machine work for its time. Boring & facing the cylinder castings and machining the smokebox saddle on the cylinder casting was a feat of heavy machine work in itself. As superheated steam came into use along with higher working pressures, cylinders began to be cast out of semi steel rather than gray cast iron. A steam locomotive's frames have pedestals (guideways) for the driving axle 'brasses'. Early locomotives had 'built up' frames, fabricated by forming steel members, machining the members then assembling with reamed and fitted body bound bolts. This gave way to casting the side frames, making them as steel castings. These frames were planed off and then stacked as a pair and the pedestals for the axle boxes were machined on a multi-head slotter. In the days of carbon steel cutting tools, locomotive builders machined cylinders, frames, axles and so much else. In the big locomotive works, I am sure they had blacksmiths assigned to do nothing but forge and heat treat cutting tools, as well as reforging tools that were too worn for regrinding. SImilarly, they no doubt had an extensive toolroom which made the form cutters, tapered reamers, and ground the forged cutting tools for the lathes, shapers, slotters and planers.

A totally wild machine to see a youtube of is the specialized planer used to machine the smokebox saddle on the cylinder castings. This saddle is machined to a given radius to seat the boiler smokebox. The planer for this job moves the cutting tool in an arc, advancing a small amount with each stroke of the table.
Locomotive works were in business to produce locomotives as rapidly and economically as possible. Heavy hogging cuts were the rule on most parts being machined. Carbon steel tools did the job, but much slower cutting speeds were the rule as well. When I see old steam locomotive frames and cylinder saddles and bores, I look at the tool marks from the machining. It is obvious the sides of the frames were planed off with a broad-nose tool, and there are no chatter marks. It was also an era when a lot of machining was done using spring or firm joint calipers and a machinist rule rather than micrometers, let alone the niceties we now have like DRO. Machining the drive wheel 'centers' and tires for the shrink fits was a feat without the kind of measuring instruments we have today. The tires were cast or forged alloy steel, and the wheel centers were castings. Even in today's world, those would be less machineable metals than mild steel. Those old shops were not pleasant or healthy places to work. Natural light was often the primary source of light, with high windows and 'sawtooth' roofs having glazing, but soot and dirt from the shops soon blocked a lot of that natural light. Heat, noise, smoke, and fumes all were present as well. It took a hardy breed to work in those shops, and shorter life expectancies were inevitable. Anytime I am around steam locomotive work, I find myself reflecting on what the men who designed and built those locomotives had to do to accomplish it. Like the carbon steel cutting tools, those men had a shorter life.
So then the old carbon steel tools would be the equivalent of W, O, and perhaps A & D as well?
W1 is pretty close to 1090/1095. Carbon tool steels might range from 1070 (mostly for tough work) to 1095. "Low alloy" or "plain carbon" tool steels like O1 would have been introduced pretty early, too, long before that designation was standardized.
I do not consider A and D to be plain carbon tool steels. They are not high-speed steels, but they have significant chromium and other alloying elements.
Without leaving the era of carbon steel tooling, there were some exotic non-ferrous alloys like Stellite for jobs plain carbon tools just wouldn't cut. Stellite is primarily an alloy of cobalt and nickel, with minimal iron. It was patented in 1907 with development starting about 20 years earlier, and it's not the only early proprietary "super alloy" tool material.
I have a 1907 copy of "Hardening, Tempering, Forging, and Annealing of Steel" by Woodworth. It is intended for toolmakers and makes mention of self hardening (i.e. air hardening) tool steels. So apparently they had air hardening tool steels fairly early.
Yeah, "Mushet" steel was on the path to modern high speed steels and also air-hardening, but I don't know offhand where it would fit in the modern classification. Since tungsten is a main alloying element, it could be considered a T family wannabe.

When I run boiler calculations and fill out the "Form 4" (Boiler registration document) and the "Form 19" (boiler alteration and repair report) for the US Federal RR Administration, the locomotive is always referenced by it's builder's boiler number. A locomotive could have had several different owners with different numbers on their roster, and railroads sometimes re-numbered locomotives following modifications or some other administrative reason. To add to the confusion, when a number of steam locomotives of a particular 'class' or design were ordered, each locomotive got a 'builder's number' (such as B 720 that you refer to in your post). The boilers always got another separate number. A locomotive builder might get an order for a number of locomotives of a particular design from a railroad. They'd start building those locomotives, with the frames, cylinders, drivers, running gear, etc coming through one set of shops heading for the erecting floor. Meanwhile, in the boiler shop, the boilers for that order were being built. The boilers were (hopefully) interchangeable from one locomotive to the next in a particular class and order. To really confuse matters, if a steam locomotive went in for heavy shopping after hard service, a railroad backshop might remove the boiler from the frame and running gear. That boiler might wind up in the railroad's boiler shop for repairs or alterations (such as adding thermic syphons, modifications to the firebox, etc). A boiler for the same class of locomotive that had already had repairs and modifications done would be put on the next frame and running gear to complete shopping. The result was locomotives often finished their working life with different boilers than they left the original builder's shops with. Large railroads like the NY Central and the Pennsylvania RR used to change boilers on locomotives of the same class and builder's order number.

An interesting case is some of the Alco 2-8-0 locomotives delivered to the Lake Superior and Ishpeming (L S & I) RR. These were ordered new around 1910, and were ordered as saturated steam locomotives, slide valves, but ordered with Walschaert's valve gear (many slide valve engines had Stephenson's Link motion, with the valve gear located inside the locomotive frames). This order was assigned by Alco to its Pittsburgh, PA works. By the early 1920's, the LS & I wanted to move heavier iron ore drags, but did not want to buy new locomotives. During the winter months, when iron ore shipping on the Great Lakes was stopped, the LS & I had plenty of locomotives laid up. They changed the locomotives from the 1910 order from saturated steam to superheated steam. To do this, the L S & I got with Alco and ALco furnished new fireboxes with Thermic Syphons, and new front and rear tubesheets with 5" superheater flues, superheater elements, and a whole new cylinder block with piston valves. By 1920's Alco had closed the Pittsburgh works, and the new cylinders and boiler parts came out of either Schenectady or Dunkirk. The builder's number and original boiler number stayed the same on each locomotive, but those locomotives were quite different from how they were ordered and delivered when new.

I always head my calculations sheets for the locomotive boilers with the name of the railroad owning/operating the locomotive, the railroad's 'road number' on the locomotive, and the builder's boiler number. The Form 4 and Form 19 are also filled out in this same way as the 'builder's boiler number' is the one that counts.
Alco absorbed quite a number of locomotive builders, closing most of the smaller ones and consolidating at their main works in Schenectady, NY and at Dunkirk.
For quite some years, when we'd travel from our 'home' powerplant to two smaller hydroelectric plants a bit north of Albany, we'd cut thru Schenectady. We'd go right past the old Alco plant. The boiler shop building and many of the other buildings were intact. American Locomotive COmpany's name was still visible on the side of the high boiler shop building. Locomotive boiler barrels were assembled by stacking each course vertically, so the boiler shops had a tall building and often a pit in the floor to handle long boiler barrels. The boilers for the UP 'Big Boy' locomotives were built at the Schenectady works. I considered the site 'hallowed ground', and always felt a twinge when I drove past it. Eventually, the real estate was sold for redevelopment. Condos, office space and similar now occupy the site where some of the greatest steam locomotives were designed and built. In 1978, I attended a week of training on the Alco 251 series diesel engines. Training was given in the Auburn, NY plant where Alco had built their diesel engines. This was the former McIntosh & Seymour engine plant. By 1978, it was "Alco Power', unrelated to the original Alco, and building the 251 series engines for stationary and marine applications. They'd get 251 engines in from railroads that still ran Alco diesel locomotives, but had delivered their last diesel locomotive in 1968. The last steam locomotive built by Alco happened around 1948. I've lost count of how many steam locomotive boilers I have done engineering work for. Plenty of locomotive built by Baldwin and Alco, a few Chinese built engines, and two Swedish steam locomotives that wound up in the US and Canada. I've never been a 'foamer' (a rabid rail fan). Just an old time engineer handling locomotive boiler calculations and design work for alterations, evaluations and repairs. I've never worked on anything built by Lima, though I'd like to work my way through a Lima built boiler.
When I studied traditional clockmaking, we were taught how to make things like fly cutters and d-bits using what the Brits call gauge plate and silver steel (ground flat & round stock). I don't remember any discussion of the different types of tool steel, just the file test and tempering colors. Of course this is far away from any kind of production environment making cutters for one-offs usually cutting brass. It can be very useful to shape the cutter using hand tools and then harden, temper and sharpen.
As I wrote, the old time machinists and toolmakers were expected to be able to forge, heat treat and grind their own cutting tools. Sometimes, when a heavy or large cutting tool was needed, the body or shank of the tool might be forged from a 'machinery steel' (a low carbon steel) and a high carbon steel cutting edge would be forge welded to the shank. The cutting edge and surrounding portion of the low carbon steel shank would then be hardened by water (or brine) quenching, followed by tempering. Low carbon steel can be water or brine quenched and will not 'take hardness'. Getting a heavy piece of tool steel sufficient to forge a large cutting tool or boring bar might be difficult, or too expensive. By forging the bulk of the tool (shank or boring bar) out of low carbon steel and using the high carbon tool steel for just the cutting edge, there was a cost savings and the resulting tool might better resist shock loads.

The old time machinists and blacksmiths valued tool steel, and it was not something that was plentiful. Old files were saved for the tool steel, which could be forged into other tools. Plenty of bearing scrapers were forged from worn out files. Plenty of woodworking chisels and gouges for home woodworking projects were forged from old files as 'government jobs'. I've forged a few tools from worn out files. Old file steel water hardens without quench cracking, but I never forged any tools with sharp corners or major changes in size from one section to the next. I could see where a piece of file steel, forge welded to a mild steel shank could make a good lathe tool or shaper or planer tool. If a person had to cut a really hard casting, needing to cut thru a hard outer 'skin', they could harden the file steel cutting edge and temper it to a light straw (about what is used for fine knives or woodworking chisels) while the mild steel shank could handle the shock loads and support the hard cutting edge.

A common thing was to take an old file and some low carbon steel flat stock and combine the two to make knives. Knives for butchering, where some prying or beating on the spine of the knife to separate joints might occur needed to be able to flex and resist shock, yet hold a keen cutting edge. The oldtimers often used old files and low carbon steel to make knives with a high carbon steel cutting edge and the rest being low carbon steel, soft, and able to resist shocks and stand up to prying and beating.

The development and use of high speed steel had to have been a major step up, and probably as significant as the move from HSS to carbide cutting tools. I recall many years ago, an old German immigrant machinist telling me about the development of "Widia" carbide cutting tools prior to WWII. The name "Widia" comes from the German "wie Diamant" (meaning "like a diamond", a reference to the hardness of cemented carbide cutting tools).