Could someone help me out with some info. (I am asking for someone else who has asked for my help, & I don't have any experience with this). When using old band saw & circular saw blades to make knives, how can they be softened so that they can be drilled & worked. Then how high should they be heated & how quenched to make them hard again. What would be the apx. Rockwell ?? Thank-you!!
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Heat treating Band Saw Blades
- Thread starter BCK
- Start date
- Joined
- Mar 2, 1999
- Messages
- 666
BCK,
I'm pretty new to this but have done some reading and made a couple of bad knives. A rather low-tech article can be found at:
http://pioneerpc.com/primitivearcher/articles/drawknif.html
This is how I plan to start. I don't think that it gives Rockwell hardness information, but that should vary based on the steel used, the temperature it's at when quenched and the material it's quenched in (as well as the material's temperature - i.e. hot oil versus cold water.) And other factors, I'm sure.
Good luck.
I'm pretty new to this but have done some reading and made a couple of bad knives. A rather low-tech article can be found at:
http://pioneerpc.com/primitivearcher/articles/drawknif.html
This is how I plan to start. I don't think that it gives Rockwell hardness information, but that should vary based on the steel used, the temperature it's at when quenched and the material it's quenched in (as well as the material's temperature - i.e. hot oil versus cold water.) And other factors, I'm sure.
Good luck.
- Joined
- Oct 4, 1998
- Messages
- 427
Most of the time old band and cirsular saw blades are made of L6 a simple oil hardening carbon steel...
I anneal my L6 by taking it up to a non magnetic point in a gass forge and then burrying it in a metal trash can full of vermiculite, it stays hot for about 2 days in there so dont rush it, just let it cool until it can be handled bare handed, it should be as soft as you are going to be able to get it without higher tech equipment..
As far as getting it hard again, its like a reverse of the hardening proccess, take it to non magnetic, and quench it edge first in oil...do not remove it from the oil till you can handle it bare handed, that should be fully hard, to test it, take a file and run it over the edge, the file should skate off with little or no damage, this means the stock is harder than the file...remember this blade is fully hardened, it needs to be tempered to make a usable blade... you can get charts that will tell you what temperature and how long to soak it at that temp to get a certain hardness on L6...
For L6 I usually do a clay temper when I am doing the heat treat myself...Just build up a few coats of fireplace cement on the spine of the knife... The only problem with a clay temper is because of the excess mass thats heated on the blade, you have to use something to cool it faster, so instead of using oil, water is normally used, so the chances of cracking the blade from the shock is greatly increased..
I guess thats more than you actually asked but what the hell I was on a roll..
If theres anything else I can help ya with just email me or post it here, I may be able to help..
Alan Folts...
I anneal my L6 by taking it up to a non magnetic point in a gass forge and then burrying it in a metal trash can full of vermiculite, it stays hot for about 2 days in there so dont rush it, just let it cool until it can be handled bare handed, it should be as soft as you are going to be able to get it without higher tech equipment..
As far as getting it hard again, its like a reverse of the hardening proccess, take it to non magnetic, and quench it edge first in oil...do not remove it from the oil till you can handle it bare handed, that should be fully hard, to test it, take a file and run it over the edge, the file should skate off with little or no damage, this means the stock is harder than the file...remember this blade is fully hardened, it needs to be tempered to make a usable blade... you can get charts that will tell you what temperature and how long to soak it at that temp to get a certain hardness on L6...
For L6 I usually do a clay temper when I am doing the heat treat myself...Just build up a few coats of fireplace cement on the spine of the knife... The only problem with a clay temper is because of the excess mass thats heated on the blade, you have to use something to cool it faster, so instead of using oil, water is normally used, so the chances of cracking the blade from the shock is greatly increased..
I guess thats more than you actually asked but what the hell I was on a roll..
If theres anything else I can help ya with just email me or post it here, I may be able to help..
Alan Folts...
- Joined
- Oct 16, 1998
- Messages
- 24
Alan Folts, Just read your reply to the saw blade question. I've been working with power hacksaw blades. The ones that have the saw teeth welded on to the backing I can drill through with no problem. It's the older ones that are all one metal that I'm having problems with. These are extremly hard. RC tested between 66-68. I've tried all kinds of drill bits, diamond,titanium,cobalt, and carbides. The closest I've come to success is with the carbides, but they tend to brake at the punch through point. I've been using a friends plasma cutter to blow holes in the tangs, but I can't keep bugging him to do this for me. Even though he's a great guy and is always willing. Other than going to stainless, do you have any suggestions for softening and/or putting holes in these things. Got a little long winded there but I hope you get the idea.
Thanks, Dave
Thanks, Dave
- Joined
- Feb 9, 1999
- Messages
- 6
Heat the metal before working it. The As-1 point(about 1350 -1400 for plain steel) is usually close to the point where the knife becomes non-magnetic. Then cool very slowly, take at least 4 hours to go from As-1 to Ms (about 500 deg).
- Joined
- Oct 4, 1998
- Messages
- 427
David, I got a couple tips for ya on those band saw blades...
The first is they ARE hardened, I wouldnt recomend trying to drill them without fully anealing the peice of steel first..
But if you have to take on the imposible here are a couple of tips...
When I started out using saw blades for steel I used to grind them fully hardened, but where I wanted a hole I had a problem..
First tip, if you have an oxy acetaline torch just heat up the area you want to drill to a nice cherry red and cool it off slowly, aka the vermiculite trick posted earlier...
Second tip, if you dont have a torch try getting a peice of drill rod, just round carbon steel rod, chucking it in the drill press at the highest speed possible you can clamp your blade in the press and bear down with the drill rod and cause enough friction to heat up that one spot real hot...
Use a bigger drill rod than you will use a drill bit to actually drill the hole...
These are just a couple tips to try before going out and blowing $15 on a carbide bit just to snap it off drilling a hole in a hardened blank..
If ya have any other questions email me and I will see if I can explain my thoughts on getting past them..
Always like to help..Alan Folts
alanfolts@sprintmail.com
The first is they ARE hardened, I wouldnt recomend trying to drill them without fully anealing the peice of steel first..
But if you have to take on the imposible here are a couple of tips...
When I started out using saw blades for steel I used to grind them fully hardened, but where I wanted a hole I had a problem..
First tip, if you have an oxy acetaline torch just heat up the area you want to drill to a nice cherry red and cool it off slowly, aka the vermiculite trick posted earlier...
Second tip, if you dont have a torch try getting a peice of drill rod, just round carbon steel rod, chucking it in the drill press at the highest speed possible you can clamp your blade in the press and bear down with the drill rod and cause enough friction to heat up that one spot real hot...
Use a bigger drill rod than you will use a drill bit to actually drill the hole...
These are just a couple tips to try before going out and blowing $15 on a carbide bit just to snap it off drilling a hole in a hardened blank..
If ya have any other questions email me and I will see if I can explain my thoughts on getting past them..
Always like to help..Alan Folts
alanfolts@sprintmail.com
- Joined
- Oct 16, 1998
- Messages
- 24
Alan, Justin
I've tried heating it up to the point of non-magnetic and letting it slow cool, and still had no success. I'll give the vermiculite trick a try and let you know how it comes out.
Thanks,Dave
I've tried heating it up to the point of non-magnetic and letting it slow cool, and still had no success. I'll give the vermiculite trick a try and let you know how it comes out.
Thanks,Dave
- Joined
- Dec 14, 1998
- Messages
- 4,870
For those that have a ht oven with a ramp control To anneal the L6 take it to 1400-1450 hold for an hour, then ramp down to 1000 deg at a rate of 40 degrees per hr.
For hardening bring the steel to 1475-1500 deg for 15 mins, quench in warm oil.
Temper at about 450 for two hrs then take it out let it cool and temper again for two hrs.
This will give you a rc of about 57-59 rc.
One other thing if your using vermiculite or lime (they both do the same job) Pre heat the area you are going to stick the blade into to anneal.
If the annealing media is cold (up north here) the steel will harden back up. So take a slab of steel and stick in there first to heat up the
anneal media..
Another way to get a nice temper line on this material is to get a flat pan with oil in it(tranny fluid works good for me) . Set some blocks on the bottom of the pan as a gage for
the place you want to temper line on your blade . Perheat the oil a little. Then just take your blade roll it in the oil (TIP FIRST) when you quench it
gage blocks. When the edge is dark . .. it takes 15-30 seconds put the whole blade in the oil edge down and hold it there until you can touch it for 10 seconds (do not move the blade side ways it will warp). Then air cool for a few mins. Temper the blade then (always within 20 mins of the quench)...
At about 600 grit finish you will start seeing a temper line in the blade.
If you go higher in the sanding (about 1000 or so) it will show more temper line. The higher you go the better . Some swords and such are 6000 grit.
When the blade is finished rub it down with semichrome polish . I use a rag wrapped around a block of wood . Rub it hard . When the semichrome is done you will know.
Then clean the blade with acetone..
Take vineger and on a soft cloth.
Wipe the blade down with it until fully wet.
Let is stand for 30 sec..
The wipe with water sevral times.
The temper line will pop out and knock your eyes out.
Also the back of the blade will be a bit springy.. Thats the way I like um.
Test before sanding take the blade out and chop the hell out of a RR tie..
There most often oak and soaked with that stinky stuff that makes then tough.
A good steel for this type of knife is 5160.
I had a 12 in camp knife and a 12 in bowie blade ready last weekend
I chopped until my hand had blisters.. Then shaved my arm . with one swipe after chopping my hairy arm was bald like my head.... after all that chopping hahahhahah
If you really like to check them try chopping antler. That will seperate the men from the boys.
If they survive this test they are excellent.
One other nice thing about this type of quench is that the blades were 12 x 1 3/4 x 3/16 thick wide. Total lenght 18 inches
I did a full flat grind on them. The edges before heat treat were .02 thick. Almost finished. After this type of heat treat there was NO WARP...and the edges were not wavy..
L6 is a good steel for salt bath marquenching also..
------------------
Web Site At www.infinet.com/~browzer/bldesmth.html
Take a look!!!
For hardening bring the steel to 1475-1500 deg for 15 mins, quench in warm oil.
Temper at about 450 for two hrs then take it out let it cool and temper again for two hrs.
This will give you a rc of about 57-59 rc.
One other thing if your using vermiculite or lime (they both do the same job) Pre heat the area you are going to stick the blade into to anneal.
If the annealing media is cold (up north here) the steel will harden back up. So take a slab of steel and stick in there first to heat up the
anneal media..
Another way to get a nice temper line on this material is to get a flat pan with oil in it(tranny fluid works good for me) . Set some blocks on the bottom of the pan as a gage for
the place you want to temper line on your blade . Perheat the oil a little. Then just take your blade roll it in the oil (TIP FIRST) when you quench it
gage blocks. When the edge is dark . .. it takes 15-30 seconds put the whole blade in the oil edge down and hold it there until you can touch it for 10 seconds (do not move the blade side ways it will warp). Then air cool for a few mins. Temper the blade then (always within 20 mins of the quench)...
At about 600 grit finish you will start seeing a temper line in the blade.
If you go higher in the sanding (about 1000 or so) it will show more temper line. The higher you go the better . Some swords and such are 6000 grit.
When the blade is finished rub it down with semichrome polish . I use a rag wrapped around a block of wood . Rub it hard . When the semichrome is done you will know.
Then clean the blade with acetone..
Take vineger and on a soft cloth.
Wipe the blade down with it until fully wet.
Let is stand for 30 sec..
The wipe with water sevral times.
The temper line will pop out and knock your eyes out.
Also the back of the blade will be a bit springy.. Thats the way I like um.
Test before sanding take the blade out and chop the hell out of a RR tie..
There most often oak and soaked with that stinky stuff that makes then tough.
A good steel for this type of knife is 5160.
I had a 12 in camp knife and a 12 in bowie blade ready last weekend
I chopped until my hand had blisters.. Then shaved my arm . with one swipe after chopping my hairy arm was bald like my head.... after all that chopping hahahhahah
If you really like to check them try chopping antler. That will seperate the men from the boys.
If they survive this test they are excellent.
One other nice thing about this type of quench is that the blades were 12 x 1 3/4 x 3/16 thick wide. Total lenght 18 inches
I did a full flat grind on them. The edges before heat treat were .02 thick. Almost finished. After this type of heat treat there was NO WARP...and the edges were not wavy..
L6 is a good steel for salt bath marquenching also..
------------------
Web Site At www.infinet.com/~browzer/bldesmth.html
Take a look!!!