Tool Steel Question

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After getting an email from a fellow Witherby, Ruggs and Richardson jointer owner off the OWWM website, I kind of got a boot in the rear to continue with the restoration of this 1865 machine. To make a long story short I finally got the old blades out of it by using the heat and water trick, and now its time to order steel to make the cutting edges.

Now in looking through Mcmaster Carr, I got a ton of options, but mostly it boils down to A1 Oil Hardened Tool Steel and A2 Air Hardened tool steel. Both come in the annealed state so I must harden it after I machine the steel into the proper cutting edge configuration. I am thinking the A2 Air Hardened steel would be easier to heat-treat after the machining, but the price is about double than the A1 Tool Steel.

So I guess the question is pretty simple. What is the best choice for steel to make the cutting edges for this 18" jointer? Unfortunately I cannot get m2 tool steel in the thickness I need.

(Cutting edge dimensions: 18" long, by 3" wide, by 5/16 thick for this machine)

Jointer-New_Paint-403x572.jpg
 
Just a thought....... could you have a set or two of knives made up that have a 1/4" thick by say 1" wide piece of the M2 steel put into a piece of softer metal?

My blades are like that.............

knife_opening2.jpg

Sorry I don't have a better pic than this.

Might be cheaper too?

I would think any good machine shop could do this, no?

Cheers!
 
That is a possibility. The thing is, I can only get M2 in steel 1/4 inch thick, and this is critical because of the way the cutterhead clamps down onto the knife. In other words 1/4 inch wont get the same bite as a blade made out of 5/16.

I would jump through hoops to get the M2 steel if I really felt it would make a difference, but if A2 steel means I have to sharpen say once more per year versus M2 steel, well why jump through hoops? I am not trying to argue with you here, or myself for that matter, I just wonder if the extra effort is worth it. At the same time I have to think about safety. This machine is going to have a lot of horspower and torque on it (25 hp disel engine) and the size of the jointer scares me already.

One more thing to keep in mind, I am a machinist by trade so I am just trying to order the right steel. The machining, welding and heat treating are all going to be done at my companies machine shop, after hours of course.
 
It's been years since I worked with tool steels. But I do remember the guys had problems sometimes with oil hardening stock warping when quenched in the oil. So I would tend to lean toward A2. If I remember correctly it doesn't want to warp.

We used A2 for a lot of applications and I don't think you will go wrong using it.

Jeff
 
I am a machinist, but my work consists of 90% stainles steel (316L) and 9%marine grade alumimum. Brass and mild steel make up the 1%. I know there are big differences in steels, but like you I do not use them enough to know.
 
Travis, out of the two choices you listed, you should go with the A2 air hardened. A1 won't hold an edge for very long. A better choice might be M42, a very durable tool steel, but I’m not sure about availability. I assume you have looked at the blade suppliers like infinitytools.com? That would be a better way to go in my opinion.
 
I would try to find someone to make them for you, like Infinity would probably be able to do so.

Not trying to discourage you from doing it, but you'll find that tempering them is not so easy. Not only do you need to have heat that exceeds most ovens and such, you'll have a hard time getting the edge evening heated on a 18" piece of edge, so that you can temper it.

This is where a forge comes in very handy, and a propane forge would be best as it can heat steel up to the same temp. for the entire forge.

You still need to be able to quench in oil for 18" of edge, and that could be done in a tray of such with oil (old motor oil, transmission oil, or similar work well). And finally, you will need to burn the oil off to really get a decent edge. A solid fuel forge is preferable for that step, IMO.

Because of this, it's not so easy for most people to temper their steel, but some are successful using a rosebud torch or similar, and others say they're successful in using their oven...but I consider that a joke since ovens get about 500 degrees, and a forge gets up to 2000+ degrees, I think 2300 degrees is bright yellow. You would need to get it to bright orange, which is about 2000 degrees I believe (I might be wrong).

Seeing folks reccomend tempering in your oven at 350 degrees is humorous. Tempering is not like cooking a batch of cookies, 350 degrees just wams the steel, it doesn't really heat it, IMO.

The real test is trying to file the steel after it's tempered, you should not be able to get any bite from a file if it's done properly. IOW, you will not be able to file it at all and the file will just skate off the steel.

The other thing I will tell you is this...I was trying to forge some HSS steel, old 24" Oliver planer blades which someone sent me, I wanted to make some scorps out of them, even though they're narrow. I couldn't prevent the steel from shattering and/or cracking, no matter how slow I took it, eventually as I forged it it would shatter/split/crack and after a few pieces of hot white steel were flying around the smithy, I decided to put that effort on hold. I tried 4 different ways. My blacksmith instructor told me he has never been successful at forging HSS steel, and everyone he knows says it's a PITA to work with.

Same goes for A2 and O1, they're even that much more difficult to work wtih.

Long story short, find someone to make you the knives/blades and consider yourself ahead.

Wow, 1865, that must have a square head cutter on it, huh?
 
Alan is right about tempering steel of any kind. There is a specific "recipe" for each type of steel. We heat treat many types here for gears. Some stays in the furnace for up to 8 hours and then the entire cycle time is close to 12 hrs including oil tembering and then quinching. I don't do the tempering but have a working knowledge of it and it is a science in itself. Like he said buy them
Reg
 
We have a Blacksmith lucily at work and he is also knowledgeable in heat treating steel. He was the one that suggested air hardening as he thought it would be easier than oil hardening steel. I have a lot of confidence in his ability as he has been a Blacksmith for years and years.

The reason I am looking at McMaster Carr for the steel is because we get shipments from them every two days and I can use the company discount to get my steel. They do have some pretty decent deals and they are great to work with.

As for buying the blades, that just plain goes against my grain. I machine parts for 15 million dollar yachts so I figure machining out blades for a scrap-ironed saved jointer can't be too difficult. At the same time, whatever I make has got to be an improvement over what they had for orginal blades. I am sure tool steel was in its infancy in 1865. Besides its no fun to buy something when you can make it yourself.

Again I am not trying to argue with anyone here, its just that I take these kind of projects on to learn and try new things. That is the fun part of it for me, the rebuild itself. After the thing makes chips, its onto another old tool to rebuild.
 
Oh I guess I made a boo boo. It is good you have the tools to grind your own blades. Getting the tool steel and gridning them is great. Some don't have grinders to do that type of work.
I understan the yatch bussiness I use to do mirrors on yatch in fal. Browards, Burgers and such
Reg
 
No mistake on your part Reg, you did not know. The problem with posts like this is that all the posts are short in the interest of brevity. Besides with liability these days, its rare for a company to hand an employee a key to a machine/ fab shop and say "use it on the weekends if you want."
 
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