Linear07 Plane Iron Metal Type
I have an old Stanley/Bailey No. 7. The last patent date is '02'. The iron has the label "Pat Appl'd 19 92" (or something like that...I don't want to have to go out to the garage to check it unless I need to). I am assuming that this is oil hardened steel and that I should be able to harden/anneal it in a standard fashion. When I hit it with the mapp gas torch I got a lot of blue and straw colors waving under the torch flame, but it didn't continue to quickly escalate to the cherry red (it's not very thick) that I am used to with O1 tool steel. I shut the torch off quicky because I didn't want to find I was trying to anneal some air hardening type of metal and was just making it harder. I can't believe that a blade this old is air hardened, but I wanted to make sure before I hit it with the torch again and tried to anneal it. Can anyone tell me, with any certainty, what type of tool steel this old blade is made of. Thanks for your help.
07 Plane Iron Metal Type
The steel is either water hardening or oil hardening. Either way it's thin enough to quench in oil. I don't think a MAPP torch will spread heat evenly enough to uniformly heat an iron that big.
07 Plane Iron Metal Type
lwllms,
Thanks for the reply, and thanks for confirming my suspicions. I was starting to think along the same lines about heat treating this iron with a torch. The width, length and thin-ness of the iron is giving me trouble keeping any type of uniform heat. I was thinking about clamping it to a thin piece of mild steel to, hopefully, help hold and distribute the heat and then just heating it from the edge up to the slot opening. If I actually manage to pull that off (I have my doubts also), do you think just hardening the front 1-1/2 inches will cause any problem? Thanks again for your help.
delsur777
07 Plane Iron Metal Type
I don't think hardening just the first 1 1/2" to 2" is a problem. I don't know what to say about using the MAPP torch for this. My experience is that it is very difficult to get uniform results on even a 1 1/2" wide iron. Both excessive distortion and over heated sections are likely with a MAPP torch but I haven't tried what you're talking about.
07 Plane Iron Metal Type
lwllms,
I believe your experience is definitely worth listening to. These wide, long, thin blades act as their own heat sinks and they make it extremely hard (if it's even possible) to keep an even heat with a mapp torch. I tried the method that I had suggested, which seemed to make it a little (very little) easier to even out the heat, but after quenching it...I still have soft metal.
This brings me to a new question. How was the quality control at the turn of the last century? It looks, for all the world, like I have a piece of cold rolled steel masquerading as a plane iron. I can easily believe that I screwed up the heat treat, but it should have at least been a little hard...most likely, too hard with cracking and razzing, but it isn't hard at all. It's also pretty clean after the quenching. I usually get a little "blacking" on the blade, but this one came out nice and clean...just oily. What's the possibilty that I have a low/no carbon blade?
If that is the case, that brings up another question. Who do you like as a supplier for replacement blades? 
))
Thanks again,
delsur777
07 Plane Iron Metal Type
If I were replacing a Stanley iron, I think I'd prefer a Hock O-1 iron.
My experience is that you're far more likely to get a tool with heat treating problems with the modern tools, heat treated in batches, than with the old tools that received individual attention. The old furnaces were quite capable and if you read Ashley Iles Memories of a Sheffield Tool Maker you'll read about how a single case of bad heat treating could put a company out of business.
To heat treat bench plane irons, where uniform heating of larger pieces of steel is difficult with a torch, we use a computer controlled furnace. We're pretty careful with the calibration of the furnace. That said, I'm confident I can heat treat smaller pieces, like molding plane irons, more accurately with a torch. The idea is simple, with the furnace you're depending on averages based on a range of tolerances and with the torch you're following the visible phase changes in each individual tool. We use a large propane torch that heats a much bigger area than the smaller hand-held bottle/torch units. The propane torch also heats at a lower temperature than the pencil-point flame of MAPP torch. This lower temperature reduces the likelihood of overheating portions of a tool and makes burning the steel much easier to control.
07 Plane Iron Metal Type
lwllms,
What you're saying makes sense. I'm just not making it happen with the Mapp torch, and I do like the sound of a Hock Blade. I think I'll just do that.
I will have some need in the future for some heat treating on special made irons (I have a crazed notion to make my own carriage plane from a #4 Craftsman.) You are, obviously, extremely knowledgeable of both old planes and heat treating...do you take in contract work to do heat treating of this sort?
Thanks, once again, for your excellent advice,
Delsur777
07 Plane Iron Metal Type
I'm not sure when we'll heat treat bench plane irons again. We have more irons for bench planes than we have beech for bench planes. I haven't been able to find any 16/4 beech for nearly 2 years. You never know, we may start using googaboola or some other crappy wood better suited for mantle jewelry than hand planes.
You'll have to excuse me for being a little blunt but I'm pretty disgusted with wood suppliers right now. We heated the shop part of last winter with the World's most expensive fire wood and are now trying to get a supplier to pick up the garbage he sent at twice what he quoted and we can't even use the stuff. I'm not going burn anymore high-dollar wood.
07 Plane Iron Metal Type
lwllms,
Now that you mention it, I haven't seen any Beech in awhile either. I tried to get some Lignum Vitae for a plane sole on Saturday, and all the guy had was a small piece you could wrap your hand around. He says LV is endangered and he doesn't carry it anymore. I bought some purple heart instead, but I read somewhere that it tends to chip out around the mouth if you use it for a plane sole. Oh well..I guess I'll have to make fret boards out of the purple heart and use your googaboola for plane soles. ))
We're probably missing out on a marketing opportunity. We should buy up a load of cherry and soak it in stain for a few months. Then we can sell it for $25 a board foot as Dark African Googaboola or South American Amazon Stinkwood. As we start to run out we can claim it's endangered and we're down to the last of it and triple the price. I think I'm on to something here. ))
I can joke about it, but I couldn't actually pull it off. With my kharma, the best I could hope for would be legal indictment for "The Great Stinkwood Scandal of '09"
Delsur777
07 Plane Iron Metal Type
Hi Larry, It's the same in the UK, most of the time the sawyers need you to explain what you mean by quartersawn. I've recently bought some 4" square billets which were 5 foot long. When they arrived they were all split in various places, mostly along the medullary rays. Suffice to say, a few heated emails asking why he didn't think it was relevant to mention the wood was cracked. Saying that i did get a partial refund and the Beech can still be used for MP wedges and maybe the odd number 2. I've also recently tried to solve the Beech problem by resawing some flatsawn thick boards. Last week a piece actually cracked just after i made it into a D handle and fitted it into a jointer. The woodyard guy told me it was quite common for beech to crack when quartersawn due to dried in stresses, which become released when you resaw. I've got several promises of quarted stock from UK yards, so as and when it comes in they'll give me a call.
Best of luck with the heat treatment on the Stanley. With thin stock, even with modern non-distorting o1, things can go wrong. I had a small skew rebate blade 'hump' in the middle of the front section after double quench and then spending 1 hour in the oven. I'd love to know a simple method of flattening a tempered blade without it springing back. It was a real shame because the iron had been perfectly bedded before the torch got to it.
All the best, Nick.
