homebrew plane irons

[Stephen Pereira]

Hi all,

I spent most of today trying to make a plane iron and chipbreaker. The chip breaker once the edges are rounded off and the business end lapped flat will work . The shop built screw came out OK but the iron was a complete failure. I made the iron from discarded planer blades scrounged from a local wood plant. The planer blades were hard as blazes so I annealed a few pieces in the woodstove. I figured I could harden them again after I machined the slot and made a preliminary 30 degree bevel.

The hardening part didn't work. I heated the iron until it wasn't magnetic and quenched in warm oil.. still soft. I heated it again and quenched in water.. still no go. I have no idea what kind of steel the planer blades are made of and apparently I am going about the rehardening process completely wrong. I gave up after a few more attempts and ordered some Starrett oil hardening flat stock from ENCO. I made a burnisher from the same steel so I know my hardening procedure works.

Kind of a bummer to work all day and not accomplish much.

[Bob Barkto]

I know the feeling. Been flatteninig chisel and plane blades for days now. Got to get 'em sharp!

Most solid steel planer blades are high speed steel.
It's typically air hardened and the heat treating process is quite involved. Including high hardening temperatures, long soak times at various temperature stages, forced air cooling to a specific temperature quite a bit above room temp. and several temperings.
Optionally add cryo treatment for best grain structure and carbide distribution, IMO it's essential for hand tools that need a keen edge.

O1 is simple in comparison! It's a good compromise for those of us without the resources to work the exotic stuff.
I think it's about the best choice, all things considered.

[Stephen Pereira]

Bob,

Thanks for the reply. I did a little research after my hardening fiasco. You are correct, most planer blades are HSS and the working of HSS is out of the range of most amateurs. I should have read Tubal Cain's book before starting on this project.

Cain, in his book on heat treating steel, recommends high carbon steel over HSS for whom he calls "model engineers".. that us. He says high carbon steel imparts a better finnish on the work and is much easier to sharpen. My heat treating facilities are crude at this point.. propane fired weed eater and a magnet. If I continue to make plane irons I will have to invest in an electric kiln of some sort.

[Pam Niedermayer]

Why not buy some O1 steel? Would probably be cheaper than a new kiln.

Pam

[Bob Barkto]

Stephen,

That's what makes O1 so nice. Even I can deal with it!
Among easily worked steels it offers the best edge retention and other characteristics that make it ideal for woodworking tools. Easy to sharpen too.
The other alloys like A1, D2 M2 etc. do offer much better edge retention but are difficult to sharpen properly. You'll need diamond abrasives to really create a good edge on them. Otherwise they get craggy real fast and leave rougher surface compared to a well honed "plain" carbon steel.


If you really want to use them you might consider farming out the heat treating. A lot of custom blade makers do. Most heat treaters offer cryo treatment as well, which as I said is pretty much a necessity to get that good edge needed for woodworking hand tools.

Good luck on your project!

[Jeff Wittrock]

I may be way off on this. Honestly I know nothing about metallurgy. I remember being told that the leaf springs on a car suspension would be a good tool steal. Any chance thats true, or just a load of horse excrement.

-Jeff

[Barry Vabeach]

Stephen, I was not sure if you ordered, but if you haven't, check out Victor Machinery www.victornet.com (http://www.victornet.com) - they are having a clearance sale on odd sizes, like 7/32 and an2" wide by 18 inch long costs only $9.10 . Barry

[Ron Brese]

Actually if you really study the process of heat treating irons for hardness you will find that O-1 tool steel does not benefit from cryo treatment, A-2 does in fact gain benefit from the cryo treatment, the amount of benefit realized from the cryo on the A-2 is disputed by a lot of metallurgist. A good many are of the opinion that what benefit there is does not justify the cost especially in a hand tool application where the cutting edge is moving relatively slowly as compared to a machine tool. The conversion of austenite to martensite in the heat treating process is more complete in O-1 tool steel, however this conversion process is not as complete in A-2 steel and the cryo treatment is thought to help this conversion take place at a faster rate in the A-2 steel.

Ron

[Stephen Pereira]

Thanks for all the replys,

Barry, i checked out Victor Machinery and they are cheaper than ENCO.I just placed an order.. thanks for the heads up.

Jeff,

According to my blacksmith friends, leaf springs once annealed make good knives and other cutting tools. So do files. I made a few marking knives out of small files. The reason I want oil hardening flat stock to make plane irons is that it is a lot less work.. annealing, machining and re hardening.

Pam,

O1 steel needs to be heat treated to be made into cutting tools. I could use a propane weed burner but oven or kiln will produce better results.

I'll post pictures when I'm done and let you know how my home brew irons compare to Ron Hock's.

[Bob Barkto]

The "them" I was referring to are the A2-M2 class of steels.:)

Not O1. Which I'm of the opinion does not need cryo treatment, or double tempering for that matter, for most cutting tool applications. It is useful where critical dimensional tolerances must be maintained.



Actually if you really study the process of heat treating irons for hardness you will find that O-1 tool steel does not benefit from cryo treatment, A-2 does in fact gain benefit from the cryo treatment, the amount of benefit realized from the cryo on the A-2 is disputed by a lot of metallurgist. A good many are of the opinion that what benefit there is does not justify the cost especially in a hand tool application where the cutting edge is moving relatively slowly as compared to a machine tool. The conversion of austenite to martensite in the heat treating process is more complete in O-1 tool steel, however this conversion process is not as complete in A-2 steel and the cryo treatment is thought to help this conversion take place at a faster rate in the A-2 steel.

Ron

[Pam Niedermayer]

O1 steel needs to be heat treated to be made into cutting tools. I could use a propane weed burner but oven or kiln will produce better results.

My point was that you can use propane burners, or other "amateur" set ups, to heat treat O1, whether or not it's ideal. If you really want to have fun, build a fuigo, make some pine charcoal, buy some wrought iron and miso, and make laminated blades.

Pam

[Stephen Pereira]

My point was that you can use propane burners, or other "amateur" set ups, to heat treat O1, whether or not it's ideal. If you really want to have fun, build a fuigo, make some pine charcoal, buy some wrought iron and miso, and make laminated blades.

Pam


Pam,

That sounds like fun.. oh boy, here we go. What is a fuigo? Miso as in miso used for soup?

Steve

[Pam Niedermayer]

A fuigo is a wooden box bellows (http://www.twinoaksforge.com/BLADSMITHING/BOX%20BELLOWS.HTM ).

Miso as in soup, used as flux in this case.

Pam

[Marcus Ward]

You're better at it than I am. I made a plane blade last weekend and cutting the slot was a mother of a pain. 9.10 for 18" of 2" wide is a good price, I paid double that from mcmaster carr. Good luck.

[Dave Burnard]

Hey Pam!

That nice toasty miso smell we all remember came from the hardening stage, when the miso plus salt mix was applied to the faces of the hammers we made.

I don't think it would work so good as a flux - but then again I've never tried it. ;)

Amateur smiths should note that 1095 is a nice easy to work with blade steel as well and is available in flat bar/sheet stock. Check with a knifemakers supply site.

[Ron Petley]

You can make a small heat treat "oven" from pottery kiln bricks, about $4 each. You can buy them at a pottery supply store. You can heat it with a basic propane torch, I think you would need a bernzomatic brand tip. You can quench it in vegie oil and temper it in the kitchen oven. cheers Ron.

http://i50.photobucket.com/albums/f333/mookie098/th_P7280225.jpg (http://i50.photobucket.com/albums/f333/mookie098/P7280225.jpg)

[Pam Niedermayer]

Hey Pam!

That nice toasty miso smell we all remember came from the hardening stage, when the miso plus salt mix was applied to the faces of the hammers we made.

I don't think it would work so good as a flux - but then again I've never tried it. ;)

Many thanks, Dave. I had to stop for about 10 minutes to remember it incorrectly. (: What did Yataiki use for flux when he laminated that blade?

Pam

[Dave Burnard]

good one Pam. :) I've already forgotten more than I ever knew...

Most smiths have their own favorite recipe for forge welding flux. The ingredients are basically the same but the proportions will vary, or how fine the flux is ground will vary depending on what type/size of things the smith makes and what kind of forge he welds in.

Borax, boric acid, iron/steel filings or powder, forge scale (black iron oxide) , rust (red iron oxide) are common ingredients.