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Carbon Steel Cutting Tools

I've read that, for shaper and planer work, high carbon tools will give a better surface finish than hss. I intend to test that out someday. In my older books, they mention 'emery wheels', are these the same as sandstone wheels? I had assumed they were emery paper pasted to a metal wheel for grinding.

since i use and sometimes used to make a lot of carbon steel tools for both hand and machine powered woodworking, i once set up, trued, and used a 2-1/2" wide x 24" sandstone wheel with water flood for a while, adjacent to my regular grinding facilities. It was sort of fun, slow as can be, and tended to burn the steel if you were not careful. (If you got impatient with the interminableness of the process and pressed hard under the water) Emory is not sandtone, i believe it generally refers to corborundum? Silicon carbide. The best way to sharpen carbon steels is with AlO open pore(8 or better) coarse (46g) wheels around J hardness with water mist or coolant and then hone/lap them on hard fine india or Arkansas stone. SiC stones are a good intermediate lap.

I might revisit carbon steel on the shaper or planer sometime as a play project, but as i mentioned, HSS works better.
If you only need to do a small area at a slow speed; a carbon tool might get through. But if you are doing something big, it does not matter how nice the original honed edge cut, it goes away too fast. HSS is almost imperceptible to tell the difference on powered machinery (as opposed to say hand taps).

I would not bother making a carbon form tool for the planer or shaper, for instance. The way they wear takes too much off the shape (need to grind the face back too far to regain the clearance). HSS is just as easy to grind a form tool initially, and it lasts longer and erodes less. I've posted projects with shop made HSS form tools sharpened on the face only, for fairly long run shaper jobs, and a few for the planer. CPM C4 HSS is the best tool steel i've experienced on either machine (Thanks, John Oder) & it is my go-to steel for most work, especially for planing steel. OTOH, Carbide works well for CI, depending on geometry. Most of the "smoothness" of any type cut but especially on recip cutting machines is down to appropriate geometry for the substrate and the shape of the intended cut (flat or form) and then tweaking that geometry and edge detail.

Stellite is a wonderful cutting material, but it is at least as brittle as carbide. The advantage of making brazed on bits and form tools of Stellite or Tantung is that they can be shaped and sharpened by normal AlO wheels, no diamonds needed. I've posted articles about making and using stellite tools, mostly for wood working.

For long running edge tools with the ability to be somewhat productive, you need heat resistance and toughness.
HC tools can be honed very sharp,.some are sort of tough, but they have no heat resistance and the way the edge fails in cutting steel or CI requires that a large amount of edge material be carefully ground back on the tool to regain the edge.

Stellite is easy to shape with normal wheels and can be honed as sharp as HC or maybe even keener. It has excellent heat resistance and durability, but is brittle/no toughness.

Carbide has excellent heat resistance, good abrasion resistance, and can have fair toughness. But it cannot be sharpened to as keen an edge as other materials though gains are being made.

Some grades of HSS have excellent heat resistance, good to excellent toughness, and can be honed as nearly sharp as HC as you can't really tell the difference shaving.

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On a similar note, does anyone know how carbon steel and hss slab milling cutters were produced? I can imagine they were turned on a lathe or planer, but I can't find any actual info on their manufacture on google.
Hard as it is to imagine, there are vast tracts of knowledge that are not available on the Internet. This is why I have a shelf of (mostly reprints of) century-old manufacturing and machining texts.
The short answer is "gashed on a horizontal milling machine, relieved on a lathe with a special relieving attachment."
There is a chapter on making milling cutters c. 1900 here,
They show the a type of form tool and a couple of methods of form relieving the cutters that were used for gear cutting or fluting helical cutters and drills with a rudimentary relieving attachment here
or an alternate simpler but slower and perhaps a bit less accurate setup that would have been easier for most small shops to accomplish here .
Ive found lots of the old machine tool books online for very cheap prices .......generally they are unopened ,ex library clearouts .........only catch is postal costs now generally exceed the price of the book.
Indeed. I've got a lot of books for 5$, and then paid 10$ for shipping. For the knowledge, it's still a good deal I think.