Question about Heat

[copper]

Ok,, I have a couple of knives that I want to polish with my buffing wheel and compound.... I know that heat will mess up the temper... question is "how much heat"?
The blade gets hot pretty quick. do I need to be really careful and keep it cooled off or not?

 

[grunt soldier]

it takes a bit but the easiest way to make sure its not a problem is just keep a big cup of water next to you when it starts getting hot just dunk it wipe it off and, if your holding it in your hand and its not burning you, your probably ok

 

[tyler34]

light passes with black compound and dip it frequently like after 1-2 passes.

 

[IndianaResident]

Got lucky, getting the key responses before the rest of us could make stuff up.

 

[cubby]

just keep dunking it. don't let it change color.

"hot" is relative. the blade will heat up. but to get to a temp that will ruin a heat treatment, you need to really be leaning on a buffer. just take your time, and keep dunking.

 

[ATOMonkey]

It's actually pretty easy to get buffing and/or grinding burns in steel. Localized hot spots that look like cat-eyes after etching. We do a lot of grinding here at work with constant coolant flow over vitrified wheels at very low pressure and feed and still get burns sometimes.

Keep the pressure light. There's no reason to EVER lean on a buffing wheel when doing any job.

Just stay patient.

 

[Kart29]

I think tempering can start in the 400F range for some stainless steels. Not sure about carbon steel.

I wish I knew more about metallurgy. It's fascinating but really complicated, too.

 

[tmkr]

If its too hot to hold comfortably then its too hot,tempering of steel depends alot on what alloy it is,(carbon steel)Just be very patient and go slow.Rough polish as long as you can,leave as little as possible to finish polish.Also cats eyes when grinding can be caused by a wheel that needs dressed,especially when grinding with the side of the wheel

 

[Hotrodkelley]

Tom Krein is a custom knife maker who does alot of re-grinds on all sorts of blades and I don't believe he re-heat treats the blades, so you should be fine.

 

[cubby]

Tom Krein is a custom knife maker who does alot of re-grinds on all sorts of blades and I don't believe he re-heat treats the blades, so you should be fine.

tom doesn't reheattreat any regrinds. he also isn't doing regrinds for the forseeable future.

the name of the game is COOL. as in "keep it...."

 

[jsharmon7]

Like little Fonzies...

 

[Fergy35]

The other guys have pretty much nailed it. Keep it cool.

The one thing I would like to add is that a buffer can be a dangerous tool. It can snag a blade right out of your grip and then bad things can happen. So use light pressure and be careful.