Is this a really dumb idea? Metalworking using a kitchen

I want to make some fingerplanes for guitar bracing, mandolins, violins, etc.
After looking at commercial blades (pricy, at $14-$20 per blade at japan woodworker), I was thinking of making some out of O1/W1 steel.

While I know that plenty of people have done metalworking (particularly George Wilson), has anyone used the kitchen stove for heat treat?
In the apartment where I live, there's a gas stove and a metal (nonflammable) sink.
I don't suppose that I can heat treat some blades with it, and anneal it in the kitchen oven.

Anyways, I'd appreciate if someone could tell me if it's doable....or a really, really dumb idea.

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Originally Posted by Matt Lau

I want to make some fingerplanes for guitar bracing, mandolins, violins, etc.
After looking at commercial blades (pricy, at $14-$20 per blade at japan woodworker), I was thinking of making some out of O1/W1 steel.

While I know that plenty of people have done metalworking (particularly George Wilson), has anyone used the kitchen stove for heat treat?
In the apartment where I live, there's a gas stove and a metal (nonflammable) sink.
I don't suppose that I can heat treat some blades with it, and anneal it in the kitchen oven.

Anyways, I'd appreciate if someone could tell me if it's doable....or a really, really dumb idea.

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that's one of those things where in theory, no problem. in practice, you may run into some problems. stoves don't generally put out enough heat to get a very big blade up to temperature, but a finger plane blade might be small enough. you'll need to concentrate the heat a bit, a stack of fire brick or a sheet metal shield might get you there. off gassing of the sheet metal shield or the fire brick could stink up your kitchen, or even pose a hazard- DO NOT use galvanized sheet. you'll be operating the stove to produce higher heats than it is designed to do- there is a risk of damaging the finish of the stove top, nearby objects, etc. presumably you can control the lighting in your kitchen well enough to judge incandescence colors, but handling glowing hot steel in a darkened room in a residential space has hazards of it's own. I'd have the quench sitting right next to me on the stove top for such a small piece. if it will be oil hardening, make sure the quench bucket is large enough that you won't get the oil close to it's flash point, and make sure that the bucket of hot oil cannot be spilled on your lit stove top. the sink will be ideal for wet and dry sanding to expose bright metal to watch the temper colors, just clean up well when you are done.

me, I'd probably rather do it out in the yard, on the barbecue.

I'd just buy a small mapp or propane torch at HD for any blades an inch or narrower. You can use it in the kitchen if you want to, though.

If you haven't worked with metal before, beware the lingering smell
and wail of smoke alarms.

There's got to be someone with a furnace nearby, maybe a ceramics place?

If you must do this at home, have a fire extinguisher handy
and someone to dial for help if it gets away from you.

http://www.hocktools.com/diyht.htm

I'm guessing you are not married?
Jim

I use my oven for tempering, it works just fine. It can be stinky as pointed out. David's suggestion for a torch is a good one. On larger blades I may use two torches and have even made a crude oven with a section of steel pipe an oxy acetelyne kit brings the BTUs to the party!

A Mapp gas torch is fine for small blades. In fact That's all I had for some years when I had a tiny little workshop. Get some firebricks and lay 3 down. Do this on the top of the stove,and NOT on your counter!!! Take the other 2 and stand them on edge to make a corner to lay your blades in. This makes a remarkable difference in retaining enough heat to get larger blades up to hardening temperature. If you have 2 Mapp gas torches,you can really get things like full size plane blades orange hot for 2 or 3" on the cutting end.

The kitchen oven can be used for tempering,though they can be a bit tricky. They can be off as much as 75º. I always found it best to just polish off the blackened surface of the blades,and carefully heat them on the end opposite the cutting edge. Let the tempering colors creep towards the business end,heating very slowly and carefully. When the cutting end reaches a medium brown,quench in oil or water,which ever is appropriate. I'll assume you are using 01 since it is the most commonly available steel. Do not try A2 because it will decarb,leaving a soft skin that you do not want. You can just use vegetable oil to quench 01 steel. It will work just fine to avoid unpleasant smells in the house. If you get practiced enough that you can anticipate reaching the medium brown color,and avoid quenching,it will be even better. But,be careful: When you take the torch away,the colors will continue to develop to purple and blue. If they go to GRAY,your steel will have no temper left,and it will be annealed. You can re heat to hardening ONCE and get away with it,but do not do this repeatedly,or the steel will begin to do crazy things molecularly,and you will not get a good blade. I won't go into technicalities here.

The quench needs to be large enough to not get heated much when you quench. For violin planes,a pint is plenty. For 2" wide plane irons,use a gallon. The oil can flame up when you plunge a large plane iron in. Do you have a hood over the stove? Don't get panicked by the flame up. It will be very temporary. It is MUCH BETTER if you have a pair of LONG HANDLED tongs,blacksmith type,to keep your hands away from the flame up. You will not get a flame up making violin planes though.


it really would be better if you set up your hearth OUT DOORS for quenching larger blades,especially if you are NEW at it. Besides,you don't want to smoke up the ceiling of your kitchen. That MIGHT evoke some loud OATHS from your wife,and suspension of privileges!!:)

Anyhow,ORANGE heat,large enough quench,polish off,heat to medium brown and you'll make quite serviceable blades. OH,be sure you DO NOT grind the bevel on the plane iron before you harden it. The blade will certainly warp hollow if you do,because of the different surface size on either side of the plane iron. Take my word for that,or suffer the loss of your iron.

FWIW, Matt, Diefenbacher has decent prices on the Ibex planes.

http://www.diefenbacher.com/luthier.htm

They're really well made. The finger planes are about $50. More than just a blade, but it's a complete working plane cast out of brass. I have several of them, including the big palm plane. I would maybe make my own palm plane, but I don't think I could make the smaller ones as nice as the Ibex. You probably only need one of them.

George,

Your comments left me with a couple of questions since I know very little about tempering:

1. What temperatures are required to temper a blade?

2. Would an Infrared Thermometer be useful to someone not skilled at tempering?

For you as a beginner,I'm keeping it simple. Just heat your 01 to an orange color and quench in room temperature vegetable oil. You likely have no way to accurately measure the actual temperature. Your application is not super critical(like making airplane parts is!)

You could use a metal magnet fastened to a stick or wire. Don't use a rubber based magnet. When the metal stops being magnetic,the critical temperature MOST of the time has been reached. Try to not let your magnet get too hot,or it will not remain magnetized. Do you have an old speaker you could get the ALNICO magnet out of?

I wouldn't worry about it anyway. For your needs,getting the metal orange will work fine. Test the metal for hardness after quenching,with a finer cut file. The file should just skate on the hardened steel. I just use a SMALL,short stroke on a part of the file that isn't used in normal filing,like right at the tip of the file. You don't need to ruin the file by using a full stroke,which will dub the teeth over. These days,good files are getting harder to get.

I recommend a medium brown color for your blades,though purple will also hold a good cutting edge. That is between the brown color and the blue spring color. In my years using antique plane blades,I found that those that a file would BARELY cut,held the edge better. There is too much emphasis on having 60 Rockwell hardness. That is at the very upper range of practical hardness for 01 steel. In reality,it is TOO hard,and the microscopic cutting edge will break down,making the blade seem dull.

I have said this many times: Tempering steel is a balancing act between edge retention and hardness and wear resistance. Too hard is not good. Neither is too soft. If you can temper your blade so a new,FINE cut file will barely file it,you will get the best edge retention. Yet,everyone seems to think 60 Rockwell is the best hardness. It is not. My best books on steel verify that,plus my many long years of personal experience working with hand tools and making them.

My approach is to do the hardening in my basement shop using peanut oil for the quench and a propane or MAPP gas torch for the heat. Using a vegetable or preferably a nut oil will do much to avoid unpleasant odors and keep SWMBO off your back. I have my own personal cookie sheet for tempering in the kitchen oven. Again, the use of a nut oil when doing your basement hardening avoids marital unrest and a nasty smell in the kitchen oven and kitchen itself. I have a remote probe digital thermometer which I use to verify my hardening temperature since as George said, oven settings are unreliable. I would suggest that going to a steel supplier's website or to McMaster-Carr's site and looking over the tables for tempering temperatures, times, and cross sectional sizes of the steel would give you some good insight into what you want to choose. Temperature, dwell time, and cross section of the piece of steel all effect the Rockwell hardness of the end result. I have never been disappointed in the results from our kitchen oven and I've hardened and tempered probably 5000 pieces of O-1 in the last 10 years of making tools.

Dave, I do it exactly as you describe. The only thing I do differently is for wide irons, I head outside with a weed torch, but it is overkill even for them - so much so that it's hard even with leather gloves to hold the iron in the heat long enough to get it soaked.

Peanut oil for the same reason. I can do them in the oven (and my wife is over the top about certain things, putting something with an inedible oil in the oven would be completely out of bounds), and the oven temperature is easy to check

McMaster here (which may be a different warehouse than ships for you) has always given me starrett steel, and starrett has the tempering temperatures right on the packet. When I temper tools for an hour in my oven, they always have a straw temper temperature and end up working fine (I have overdone them before by hand - and had to reharden and re-temper, as evidenced in the bouvet-ish plane thread a while ago where one got away from me and got too brown). I have an oven rack thermometer that I use to keep the oven honest, but it has so far shown that the oven is honest. Those oven rack thermometers are not expensive, but they do show you that it takes longer for the oven to get to temperature throughout the entire oven than the temperature indicator on the oven suggests. My oven will be uniformly warm about 10 minutes after it says it's up to temperature, but the areas near the front of the oven will still be 50 degrees or more shy at first when the oven says it hit temperature. For that reason, I always just leave everything in the oven 45-minutes to an hour to temper. It's not necessary, but it's cheap insurance. When I turn the oven off to take them out, the oven thermometer and the thermometer sitting on the rack match within a few degrees.

I agree on the keeping it longer in the oven Dave. You open the door to insert the cookie tray and it is probably another 5+ minutes to get back up to temperature.

Very much single.

Thanks for the touch of sanity guys.
I think the MAPP torch may make sense, but I'll ask my knifesmithing guy for a favor.

I'll be building him a guitar in the next year.

-Matt

Quote:

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Originally Posted by Jim Ritter

I'm guessing you are not married?
Jim

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Matt,I forgot to mention that I use a small toaster oven for tempering my parts. They are even used by professional heat treating shops (Well,we were a professional tool making shop!) I bought a high temp. thermometer from Brownell's Gunsmithing Supply. It has a long probe on it. I insert the probe through one of the slots in the back of the oven. Be careful when doing this. Better to drill a little hole in the back to insert the robe. I touched a live wire inside once,and burned a hole in the probe,ruining it.

The accurate thermometer will do a good job of telling you the true temperature,and the small oven costs less to operate. It heats up quicker,too.

I agree with David about leaving the part in the oven for an hour without opening the door.

Straw color means light BROWN. I recommend medium brown or even purple.

To do the very best job,and get the most from your steel,put it in a PRE HEATED toaster oven immediately after you take the blade out of the quench,while it is still so hot you can barely juggle it in your hands. Quickly wipe the excess oil off and get the blade into the oven quickly. The molecules of steel will temper better if you do this. This bit of info is VALUABLE and you should do it. We had two PARAGON furnaces in the toolmaker's shop. Both were accurate pyrometer controlled knife maker's furnaces. We would set one to the hardening temperature,and the other to the tempering temperature. After the part was removed from the quench still good and QUITE warm,it was given a quick wipe off and put into the other furnace. Those furnaces are quite expensive though. I have one at home,and just use a toaster oven for tempering.

David's weed burner will put out a very large flame,enabling you to heat up a whole large plane iron using a trailer size bottle of gas. I found that our weed torch would shut off after 10 or 15 minutes due to a safety valve inside the trailer bottle. The weed burner used gas so quickly,the device thought the bottle was leaking,and a valve would shut off the bottle. I got a special nozzle to screw into the gas bottle that by passes the safety valve,enabling the bottle to burn as long as we wanted. I don't know the name of this screw in valve,but if you go to where they sell trailer supplies,they probably will know. Or go to a welding supply and describe what you want.

It might be that you can get your whole blade hot without the valve though. I think David may be accomplishing this without the valve. It will help if you do use the "corner" I have described,made from 5 fire bricks. KEEP YOUR FIRE OFF OF CONCRETE. Concrete will burst open if it gets too hot,releasing the water that has been chemically retained inside it. It can blow up violently,sending hot shards everywhere. DO NOT FORGET THIS. Your wife MIGHT give you a dirty look if you ruin the sidewalk!!!

Peanut oil as Dave suggested is fine. I just have been using vegetable oil as I'm not doing this in the house. We used a 5 gallon can of automatic transmission fluid at the toolmaker's shop,but in the kitchen you should not use non edible oil to avoid bad smells as suggested. Save this info for the future,whenever you can get a separate shop.

The vegetable oil that stands heat best is grape seed oil,but it probably costs more,and will still not really stand orange hot steel being plunged into it without some flare up,but will stand tempering quenching. Just an extra bit of useless info!

Starrett steel will cost more than other 01 brands. You can order English made 01 from Enco(If you can get their online catalog to work!!) Call 1-800- USE-ENCO and request a catalog. They will be one of the cheapest sources you can find. Another cheap source that might be cheaper than Enco is Victor Machinery Exchange in New York. Tell Mark I sent you. They have a decent online catalog. Google them. I have had no problem with English made 01 steel(but watch out for their hotels!)

If you do want the very best,Starrett is the brand from McMaster Carr,as David mentioned. Enco sells it also. I think Enco might be cheaper than McMaster Carr. You can get quite a few violin blades from an 18" long piece anyway. Enco sends out flyers often,advertising free shipping for a minimum order of $25.00 or so. I forget. But,when I want to order a 6 foot piece of heavy brass,I wait for the free shipping. That saves a good bit of money. I think Enco might be sort of struggling,so numerous are their free shipping,and sometimes 20% off offers. I hope they will be O.K.,as I have done a lot of business with them for many years now. They are owned now by Manhattan Supply Co.,but are much better on prices. Get yourself on Enco's mailing list.

Yeah, on the starrett, mcmaster is very variable. There are times when the starrett price is very similar to any other place, and there are times when mcmaster carr's steel price is like 25% higher than the going rate at the discount parts places.

They are not, however, so competitive on brass that I've ever seen.

I've only bought steel when I've needed it, so I'm not quite as much of a price shopper, but I haven't had any from anywhere that didn't produce a good result.

I read yesterday or the day before that lie nielsen is dumping O1 steel because they've had quality problems with it. I don't know how air hardening steel is done in production, maybe it's done very quickly and that's the difference. Just about any way that you control the temperature reasonably with O1 provides good results. The biggest shame is that their bench chisels in O1 would've been far more desirable than the same thing in A2, and I know derek has opined before that vintage chisels don't hold an edge very well and thus extrapolated that onto oil hardening and water hardening steels, but that is a matter of hardness and not a matter of the alloy (the vintage chisels are certainly less hard by a slight amount).

Edge for edge, the O1 steel is ideal for chisel type stuff and small blades in the shop - and compared at the same hardness and same angle is easily equal to any of the other common steels right now in chisels, but it grinds easier and is more convenient to sharpen on any stone than A2, short of diamonds - especially if you count time to remove nicks. It's certainly adequate for planing, too, if someone is not trying to win a contest of the most 1/2 thousandth thick shavings from a plane blade.

So, anyway, O1 - i've never had any trouble with any type, sometimes mcmaster has about the same price and sometimes they don't, but I like the starrett stuff despite not having any issues really with any of it - even completely unknown stuff that someone has sold in lots on ebay that just says "O1" on it in black marker (presume those are just sellers cutting short pieces off of long stock).

The cost does, though, get appreciable if you start building things like panel planes out of the steel, but that is one place where I will pay for the starrett, too, because I know the stock will be dead flat, which is a big deal to someone who builds metal planes without machine tools.

I am certain that LN is stopping the use of 01 is due to warping issues. Making a plane iron without the bevel pre ground is not a problem. Insert it vertically into the quench,NOT flat or sideways. Cutting end in first,vertical.

But,when it comes to chisels with beveled edges on one side,the side with the bevels has more surface area than the flat(bottom) side. This WILL cause bad warping issues with W1(especially),or with 01. It is not a problem with A2,because it cools in still air at a very slow rate,yet hardens. I have used A2 for many years for the numerous punch and die sets I have made for my wife's jewelry business.It does not appreciably change dimension. The punches have to fit the dies perfectly. It is also much longer wearing than 01,since it has chrome in it. However,there is no free lunch,and the more highly alloyed a steel is,the less keen an edge it will attain. A2 will be fine for chisels,though,except for the most challenging situations,such as skiving the suede leather off of chrome tanned leather. I needed to do that with my LN block plane,and had to put the old W1 blade back into it to get that bit of extra keen ness necessary to accomplish that job.

As for the home shop,A2 is not what you want to buy unless you have the equipment needed to harden it. You need a pyrometer controlled electric(or other muffle furnace) to get the EXACT(within 25º) temperature needed. You need either an inert gas furnace,or wrap the A2 in a high temperature stainless steel foil wrap: It gets a thick,soft skin on it from decarbing if exposed to the air while hot. We were able to use it,but we had the equipment.

Do you have any clue how they harden it in production? (A2). Is it processed continuously by going through an oven and getting up to temperature and then just coming out of the oven and being exposed to the air?

I've hardened O1 with bevels already cut (just slightly shy of the edges) and it has been fine (no real warping issues), but I haven't tried water hardening steel in a similar configuration. That said, the O1 does move a little, and I always reflatten it some after it's been hardened. It's just a minute or two, though (I lap it to close to a polish before hardening it).

It's confusing to me because there's a multitude of other makers making oil hardened tools without issue (lee valley, ashley iles, clifton, etc).

The simpler the steel,the more treacherous it is to warp or crack. W1 is the worst,01 is next. A2 is quite stable.

I don't know how LN might handle hardening A2. Most likely they have an inert gas oven to heat it in,and remove the chisels to cool in still air. They might be sending irons to a hardening service to be heat treated.

Yes,Stanley made,and makes their 750 beveled chisels out of simpler steel,and does it o.k.. I know that for hardening special,critical parts,like the large helical gear used in the differentials of rear wheel drive cars,they placed the gears in special jigs to hold them flat while quenching. Stanley may have done something like that.

I am not sure at all why LN would abandon 01. It could be they can't deal with the problems,they think A2 is better,or they just don't want to be bothered with dealing with 01.

All I can tell you is several years ago,when Ln was apparently still using W1 for their blades,I had noticed that one of my planes had an iron that was not up to the hardness they advertised. I checked it with my Versitron hardness tester just beyond the bevel of the plane. I called LN and got the foreman(guess that was his title). He wanted to know where I tested the hardness. It turned out they only hardened the first ONE INCH of their irons. Due to warping problems,I am sure. They indicated a high reject rate.

I told them their planes were very expensive,and they could go to A2 and though it cost more,they would have no reject problems,and could harden MUCH MORE of their irons' length,as would be proper for longer life for the irons.

The guy told me they had tried A2 and their customers could not tell the difference. Yet,a few months after I was told that,they started using A2 !! THAT really put me off,since I had bought 6 or 7 LN planes that had the old,1" hardened irons in them.

I managed to get LN to send me a FEW A2 irons,but to tell the truth,I thought the fellow I spoke to was not very friendly. And,I felt I had been lied to,because that decision to go to A2 had to have already been planned a long time before that. You just don't make a move like that suddenly,sorry.


So,what does this episode say to me? I think they do not have the expertise to handle 01 steel chisels.

They might not like to see me relating this story,but that is exactly what happened.

Everyone's process and such might just not fit, I guess (speaking of their - LN's - troubles with O1).

They have always been over the top helpful to me. I had one of their earlier A2 irons and thought it felt a bit soft on the stones. I don't know what the difference was, but I told them I thought the iron I had may have been a bit soft, but I didn't buy the plane directly from them. They took it back, tested it (it tested 61.5 - plenty hard enough) and called me and said "it's one of our earlier irons, it's in spec, but if you'd like we can send along a newer iron with it no-charge when we return it to you".

I declined that, the order of process literally would've been I guess wrong on an iron and send it to them, they prove that it's fine, and they send me a free one anyway. Too generous!

I don't know how hard they made their O1 chisels, but they can be made to the same spec as their A2 without problems, and would otherwise have the same edge retention in use. Blue II steel (which is considered a very tough chisel steel) and O1 are little different except for hardness and about 10% difference in carbon content, and blue II at 64 hardness is a very good chisel steel. I've seen some comments that LN's O1 chisels were not as hard as the A2, or implied that based on edge holding, and I think that was a bad move to not harden them to the same level.

That's the primary difference between the old chisels in oil or water hardening steel (which were designed to be easy to sharpen and specified to be used set up at angles, etc, for carpentry vs. fine woodworking) and new stuff made out of A2.

A2 does make a technically better plane iron, though, but the bits about it that are better are insignificant to an experienced user who is doing more than sharpening. Once someone planes with shaving thicknesses deep enough to do both fast and accurate work, clearance on plane irons is more important than absolute holding of initial keenness.

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Originally Posted by george wilson

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I told them their planes were very expensive,and they could go to A2 and though it cost more,they would have no reject problems,and could harden MUCH MORE of their irons' length,as would be proper for longer life for the irons.

The guy told me they had tried A2 and their customers could not tell the difference. Yet,a few months after I was told that,they started using A2 !! THAT really put me off,since I had bought 6 or 7 LN planes that had the old,1" hardened irons in them.

I managed to get LN to send me a FEW A2 irons,but to tell the truth,I thought the fellow I spoke to was not very friendly. And,I felt I had been lied to,because that decision to go to A2 had to have already been planned a long time before that. You just don't make a move like that suddenly,sorry.

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It may have been that higher up the management chain was a decision to 'embargo' the information until the release date.

This is standard business practice whether we like it or not.

My recollection of the biggest disaster in this realm was when Adam Osborne mentioned his computer company would soon be coming out with an IBM compatible computer. Sales of the current line dried up, the cash flow stopped and some say telling the market early about a change caused the company to go under.

Yes, it also ticks me off when something new comes along within days of being assured by some sales person the item of my purchase is not going to be replaced soon.

jtk

To be specifically told that A2 was NOT going to be considered was what I did not like. I did not like being sold a bunch of planes with 1" of hardened iron in them,either.

Wow, I'm fascinated and intimated with the responses.
I'll be saving up for peanut oil and a MAPP torch in the future...but not soon.
Since I last posted, I have the opportunity to buy a dental practice in my hometown.

Because I won't have time to make blades, I bought some 7/8" white steel plane blades from Japan Woodworker.