How to anneal bandsaw blades and other hard metal?

HMF

HMF

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If I need to drill into a bandsaw blade after shortening it, and want to anneal the metal to reharden it, or simply to harden a piece of metal, what is the procedure?

Thanks!


Nelson
 
Annealing isn't out of reach of a home shop, Heat the part up to cherry red and let it cool sloow. Hardening isn't out of reach either just takes a bit more knowledge and anyone willing to spend the time to learn can do it. Having drill rod or similar metal is a definite advantage and a small furnace is too which is what puts it out of all but the aggressive home shop machinist. What hardening I've done (six 1" dia pistons for a John Deere hydraulic pump for instance) were done with oil hardening stock, my oxy/acetylene torch and some fire brick to help hold the heat and a picture book beside me for correct color of heat range, then dumped in the bucket of oil and stirred around a bit. Far as I know the backhoe is still working ?? As for drilling Slooow is one of the key words turned by hand at times is about the right speed, also sometimes a different (shallower) angle on the drill bit cutting end can help depending on the material being drilled. Stainless Steel especially needs a shallow angled drill and slow cutting speed. It's amazing what you can do with a properly ground HSS bit if you drill slow enough. ;)
Never say Never, cause you Never know what you can Never do ;) ;)
If somebody else can build it I can tear it up ;D And occasionally fix it :) :)

Don't forget the "air hardening" materials that are also available
 
Oh Well Dave join the crowd :) :) I'm pretty lazy myself at times but there is a lot we can do if we simply put our minds and heart into it ::) :) I just don't want to see anyone discouraged from "trying" something. There is a dizzying array of fancy stock out there that is way beyond my limited comprehension but there are also simple things that are well within our simpler capabilities. This is after all "home shop" so we have to do the best we can with what we have and I do agree with you there is a time and place to take it to the pro's !! There is also a time to learn and that is sometimes trial and error other times with the help of teachers of various abilities. AND with ANY HEAT TREATING there ARE inherent dangers so know your risks and act accordingly. If you don't have basic safety gear and sometimes other safety gear some of these ARE better left to the professional shops.

There Dave does that cover me ? ;)

;) :)~Chris
 
8) Relief wish I could come to South Africa to meet you in person :) :) I've got a feeling we've got quite a bit in common ;D

It would be interesting to go around and meet everyone in person and tour all the shops, see all the skilled crafts done by everyone and just absorb the friendly nature of this community. Whew just think of all the coffee, tea and beer it would take for such a visit !! Somebody else can have my beer though ;)
~Chris
 
:) :) :) :)Thanks for the offer :) :) Now that is the best offer I've had all day. :) :)
I'd love to come, never been to Africa before but my wife has, she spent about a year or two in Mozambique with her folks leveling land for Senna Sugar Co.
 
Some real good info in here...

Always wondered about the hardening process, such as "hardened ways" on my SouthBend Heavy 10.

Nelson
 
I believe that lathe ways are usually induction hardened. Flame hardening takes many forms, some of which are beyond home shop, some not so much. That is, as long as you aren't required to hit some very specific conditions.
 
Tony do you have an entry level explanation of induction hardening ?? I'm assuming heating by electrical induction am I close ?? :blank: I've never looked that up yet ?? Don't need a lot of technical details just a basic what is it ? Also aren't bandsaw blades induction welded ?? Maybe I've been dropped on my head too many times and getting things confused in my mind ?? :blank: :blank:
~Chris
 
Basically, the heating is done by electrical induction. That works on a simple principle. Think of a transformer with a very low resistance secondary resistance winding; a short, for all practical purposes. The primary coil of an induction heat is energized and the part, being the shorted secondary get rather hot. Imagine what would happen if you clamped your welder's ground and stinger together. The cables would melt if nothing else failed first. The object being heat treated is the secondary of the transformer. It's a easy to control way to heat a material very evenly. Of course, most materials still need to be quenched, and then tempered....but that's a whole new subject.

Here's a link that shows a simple, home made high frequency induction heater. Induction heaters have advantages of working clean. They can be run in a vacuum, and inert atmosphere furnaces.

http://www.richieburnett.co.uk/indheat.html

Bandsaw blades are resistance welded, as far as I know, but they do use induction hardening to take care of the teeth while leaving the backing softer. They may use induction for welding them, but I haven't seen it.
 
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