MadModder
The Shop => Tools => Topic started by: Will_D on April 12, 2016, 07:10:06 PM
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Is it possible to buy tool steel blanks in an unhardened state to make milling cutters, hobs, taps, woodruff cutters and the like?
I know most of us can/have to machine silver steel and harden and temper it to our requirements but what about some harder steels more suitable for stainless (303 / 304)?
Tools steel blanks as supplied i.e. 6 or 8 mm square by 100 mm or 8 mm dia by 100mm are pre-hardened and are meant for grinding.
There are a LOT of tool steels available from the metal merchants but do I really need or can afford a stock length?
I assume these can be machined with TC tooling in the annealed state and subsequently heat treated. Any ideas?
Other than annealing the supplied blanks!
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I'm under the impression that the steels used in those blanks (M42 HSS?) would be difficult to harden appropriately on your own.
In contrast, the most common tool steel in my region, O-1, is very forgiving with home shop heat treatment methods.
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I'm under the impression that the steels used in those blanks (M42 HSS?) would be difficult to harden appropriately on your own.
Sparky is correct.
Can you not get a tool bit and grind it to suit?
But do you really need carbide instead for your SS application?
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HSS comes in many various compositions,but because of the need for precisely controlled heat treatment processes and equipment to carry it out it isn't generally deemed suitable for amateur shop hardening.
Some general info on different grades and their uses in link below.
I generally look for M42 Cobalt blanks when purchasing as it is very robust stuff. OZ.
Link: https://en.wikipedia.org/wiki/High-speed_steel
Also see article below to give some info on process involved in heat treating HSS.
http://www.totalmateria.com/page.aspx?ID=CheckArticle&LN=EN&site=kts&NM=57
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There are a lot of other tool steels other than siver steel and HSS.
The O series and A series all can be machined readily in their annealed state with HSS tooling. They are also able to be heat treated in the home shop. The heat treatment and tempering is a bit more involved, but quite doable with a suiable heat source and an infrared thermomenter and a clock - oh, and patience :)
On the other hand, hardended toolsteels can also be machined: for turning and milling I use Cermet inserts (not carbide). They will cut anything up to HSS but do NOT like interrupted cuts. So you need a rigid machine. ANY chatter and the tip is chipped.
I've turned ball bearings for example on a number of occasions and modified high carbon steel tooling a few times that way. They are surprisingly inexpensive by the way, in some sizes cheaper than carbide tips.
Lastly, if you get a Cubic Boron Nitrate (CBN or Borazon) grinding wheel, you can shape HSS very quickly into any shape you like. NOT damond! It dissolves in the steel at grinding speeds. It is purely for tungsten carbide or ceramics (or any metal as long as you make no sparks - think hand finishing only).
Cheers,
Joe
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O1 is classified near on the same as silver steel.
There are loads of other steels, the chances of getting small amounts highly remote.
D5 ok but not that hard.
Vanadis great to work with and gets hard.
Still got what I reckon is EN19T from 24 yrs ago, not recommended hacksaw blade bald just cutting every 1/4" depth on 3/4" thick, milling cutters not much better even roughing cutters, its an animal in annealed state as hard as O1/silver steel hardened.
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Thanks for the replies. I am thinking of building* a 'Lil Bertha electric tool oven. I know there's a thread running about Bertha but a swap in PCs at the moment makes posting links difficult.
I need to machine and not grind at the moment!
* well I have e-prayed Kanthal-A wire, a 1400C rated thermo. couple and a Pid !
What could possibly go wrong?
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Will, maybe you could give us an example of what you intend to do in SS?
We might be able to suggest more specifically and appropriately.
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Well recently (2 years ago) I decided to restart some machining on my old ML7. Thanks to this group :bugeye: I have upgraded the shop a bit. Expense: Don't tell SWMBO
A Long time ago when working on a small live steam loco (Rob Roy 3 1/2" gauge). I made a lots of jigs/fixtures/etc from mild steel and subsequently watched them rust!
Nowadays thanks to modern tooling machining SS 303/304/316 is as easy as En1a was in the 70s with HSS Tooling.
Reason for this thread is that I cannot find the correct sized milling cutters to cut T slots to my spec.
Also the 'Lil Bertha may just be used for melting stuff