I am just wondering if anyone has attempted hardening there own stationary gears by heating them up evenly with a blow torch and then quenching them in oil? Thanks, Mike

 

uhh... no.





www.rotorsportsracing.com offers cryogenic treating of those and most other parts though......

 

in order to harden things the right way you need to start heating it up a little and dip the object that you are trying to harden in rat poison.. ther is something in it that i cant remember the name of it for **** right now.... but if its realy importent i can just ask my teacher at college.... but you need to heat it up enough to make the powder stick to your gear.. you might need to heat it and dip it a cuple of times to get the intire thing coverd good enough that no air can touch any metal.... an once you have it fully coverd you can now heat the gear up to roughly around 500 degrese and all the powder will turn to a liquid.. still make sure it is fully coverd thats importent.. the strict-9 or rat poison what ever it was that we used in class(cant rememebr) will start to glow bright red like as if it was metal that is realy hot.. but its not that hot to turn metal red just yet.. in order to know that you have it hot enough have a magnet in your hand or easy to grab at this time and put the magnet to your gear, if you can feel the magnet want to pull, its not hot enough yet.... whin you got it hot enough all metal will lose ther magnetic force or pull or what ever you want to call it at about 500 degrese..(this wont work on metals that are non-magnetic to begine with).. once you feel that the magnet no longer pulls to it.... dip it in a bucket of water and wigle it around fast as you can and cool it down fast as you can.... now all the powder that turned into liquid whin it was hot, will now be hard and crispy and i think it tuners black or gray, cant remember becuz i havnt done this in a while... but chip all that stuff off and the gear you are trying to harden will be all shiny like new.. if you see any little black spots or bloches on it.. thoughs are the spots that air got to it.... and if most or all of it is a light gray or brand new looking, then you did a good job....



ohh i almost fegot... you need something to hold it with.. we used somekind of bailing wire. i forget what it realy was though but it worked good and held up to the heat and didnt take up any or too much space where you can get the powder nicely coverd all around it....



but i have never tried this with a gear from a rotary motor. but i have done this to some gears as a project in class and it worked realy good.... the only thing kinda bad about it is, it makes the metal shrink just a little soo that might be a prob. for some stuff

 

i think you were just using the rat poisen as an air barrior so the part doesnt oxidise to much during the hardening,..



heating the steel to the austenitizing temperature (where it goes non magnetic) is how you start to heat treat most steels,..this temperature is mor elike 1500 degrees then 500,..



however you wouldnt want to quench the gear in water,.. it would almost surley crack, masot hard steels require oil,.. or even air quenching..



If you really want to do it right you need to use temperature controlled salt baths to quench,.. if you do it this way its possible to harden the steel into a bainite which is very durable





If you really wanted to do this, take it to a place specializing in heat treating.



just so you know,.. to save you trouble,.. S5 and up gears are all factory hardend

 

we had to quench ours in water becuz that was the prosses of case harding things.... and i've never seen metal crack unless it was cast iron, becuz the fact that the carben in the iron shinks alot slower and will force the iron apart.... if you cool the metal down slowly it makes it soft.. there is sooo many defrint ways of heat treating stuff and its all a process of annaeling, yes the best way would be having a shop do it.. ohh and that 1500 degrese. my bad.. i kinda dont remember.. been a while since i was in my metalurgy class... but yea it might be good to try if you got some junk parts laying around that you wouldnt mind trashing if it turns out bad.. but i would much reather just pic up some s5 an up parts..

any ways it was all a good thought.. cant blame people for trying

 

if your going to properly harden anything, you should get a furnace get it up to about 780*f let it sit there for 15 mins then quence it vertically in oil, then after it come back down to room temp you want to temper it, throw it back in the fernace at about 300*f and quench vertically in oil.

 

More likely just the teeth are induction hardened by a second or so of insertion in a high current electrical coil. Years back from time to time you would find one where the bearing would be tighter on the tooth end than the other. I would remove the bearing and hone the bore a bit to take out the taper, then reinstall the bearing.



I have not seen that in ages, but if you see a bearing that is shiny on the tooth end, and the engine has not been screamed, check the ID with a snap gage.





Lynn E. Hanover

 

Well i just had another idea, my dad was hardening his 9 inch ford gears today and what he did was stick them in dry ice for 6 hours, and supposidly that hardens gears so i think i will try this on a test engine