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Thread: Is this a really dumb idea? Metalworking using a kitchen

  1. #1

    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.

  2. Quote Originally Posted by Matt Lau View Post
    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.
    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.

  3. #3
    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.

  4. #4
    Join Date
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    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

  5. #5
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    I'm guessing you are not married?
    Jim
    Ancora Yacht Service

  6. #6
    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!

  7. #7
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    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.
    Last edited by george wilson; 10-16-2014 at 9:05 AM.

  8. #8
    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.

  9. #9
    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?


  10. #10
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    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.

  11. #11
    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 Anderson

    Chester, NH

  12. #12
    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.
    Last edited by David Weaver; 10-16-2014 at 1:01 PM.

  13. #13
    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.
    Dave Anderson

    Chester, NH

  14. #14
    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 Originally Posted by Jim Ritter View Post
    I'm guessing you are not married?
    Jim
    Last edited by Matt Lau; 10-16-2014 at 9:45 PM.

  15. #15
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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.
    Last edited by george wilson; 10-17-2014 at 9:46 AM.

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