not straw but violet....

B

brymway

Joined
Jan 6, 2005
Messages
7
Hey guys- need some help
I roughed two blades out. One is OF-1 and the other is MSB-1. (masonary saw blade) I used a blow torch to heat them both to non-magnetic and then quenched them in a gallon of used motor oil for about fifteen minutes. I then washed them off and put them in my wifes oven at 450 for 1 hour. When I took them out, some flakes from the outside brushed off and revealed a blue or violet color. Did I leave them in too long and too high a heat? And do I have to re-temper them and go thru the process again?

Thank you for your time
Brock
 
Color is dependent on the alloy and how clean the surface is ..BTW when using an oven [of any kind] it is always best to check with a thermometer to see if the temperature is accurate.
 
try 400 ish with the 0-1. The discoloring could be coming from surface dirt / oil crap on the blade. Sand off a clean spot and use a thermometer. Go by the temp rather than the color and watch that temp closly so you will know if it spiked at some point.
 
dark straw to violet is best, imho. If it's blue, you did go too high. In my limited experience, thinner saw blade material goes to violet/blue very easily (at lower temps) than others. I think that's becuase it's a low-alloy steel. Also, if you put a thermometer in that oven, you'll see it's a lot hotter than 450.

Try it again at 350-375 and go for a medium straw to brown range. If you want the blade to have some flex to it, shoot for brown. Might take a few more tries until you and the oven "become one". ;)
 
sharpen the blade and flex the edge over a piece of 1/4" round bar or drill bit.

If it bends, the temper is too high, if it chips, the temper is too low. If it springs back, the temper is just right.

Do some cutting and chopping next and see how the edge holds up.
 
I might be mistaken, but I'll bet that the OF1 is an old file?

There's a somewhat useful temper color chart available here:
color chart

Hope that helps!

Tony
 
yes the "OF" is old file. Should I re-heat it to non-magnetic again and then try cooking it?
 
Test the edge with a file, if it cuts easily then reheat treat, if it skates or just barely cuts you are probably alright. Even though I'm using digital HT ovens I still find myself checking the edges with a file, just an old habit I've always done.

Don Hanson lll
 
I will agree with DON, I still use a file to make sure. Get rid of that Damn motor oil.nasty stuff. use vegetable oil heated to 120 - 130 degrees. blades are cleaner and won't stink up the kitchen....... :cool:
 
You must log in or register to reply here.
Back
Top