pipeline saw blade knife

brets-ftw

brets-ftw

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Sep 11, 2010
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so i work at the MDT (Marine Diving Tech) building at SBCC, and they throw away a lot of scraps so i have a new habit of dumpster diving and one of the gems i found was an old saw blade used to underwater cutting on pipes,

now i know that its a bi-metal blade as the teeth are far more brittle then the rest after some file work so i was curious if this would be some what suitable material for a knife blade, if i could figure out how to post pics i would, but intil then ill post the dimensions

(1/16in) x (16 3/4in) x (1 3/8in)

as for my plans, i have a forge i can use during the summer and plan to fold the saw blade in half to add some width and pound the teeth into a somewhat usable edge, as the metal isnt laminated i worry that after a few times resharpening itll useless, or at least will be dependent on the back metal,

all thoughts and comments welcome
 
From what you describe you have what sounds like an old hacksaw blade. The teeth are HSS usually M2. The backs are steel and the good ones are high carbon steel. The M2 is very difficult to forge. Very red hard and as you have found brittle on impact. I have not tried to forge weld HSS as it sounds you are thinking about doing. The alloying in it would make it hard to do. It also requires a much higher temp for HT and very controlled temps. I have seen blades made form these blades and are normally in the straight edge design using the HSS as the edge. To be honest the time you will be spending trying to save some $$ would be better spent with a good known steel or at very least some leaf or coil springs. Since you have access to a forge I would recommend that.
 
Alrighty, now would it be possible to heat the blade up and possibly take off the High speed steel and save it for a later time?

And is there any way to test the back steel for what grade it is, preferably in such a way that isn't to expensive?

As to the design i was in fact thinking of making it a wharncliff or a sheepsfoot, and if it is M2 then i would be more frightened of resharpening as ive heard it takes forever to do, and im sure just getting the initial edge on there will take a lot off
 
Normally the HSS portion is only 1/4-3/8 wide. Not worth saving. If you had a bunch of the blades you might want to get a spectrograph done. This would be about $50. Another way is to do a quench test, though it does not tell you what steel it is, it will tell you if it will harden. Or you can do a spark test. You need to get a couple of pieces of known steel, grind them and look at the sparks. Compare the blade to the known material and you will get a very rough idea as to the type of material you have. You will find if you have not already, not many will recommend using unknown steel. Since a piece of known material will cost you less than a spectro. 20' of 1/4 x 1 1/2 5160 is $83 + shipping at admiral steel. Aldo Bruno has great prices but his site is down and I do not have a current price list.
 
well after reading all that it sounds like its going to become a test piece, just to get some ideas into physical form i suppose, as i dont have any good grade knife steel to test it against, nor do i want to do the spectro for it

thanks for the info

now would O-1, 5160, or 1095 be a good steel to start getting serious about knife making? preferably something more mistake friendly
 
5160 is a good all around steel. Many knives have been made from this steel. It is a great steel for beginners IMHO. 1084 is also a great material to use. O-1 is a great alloy steel but needs a little more care than the 5160 and 1095 is a great steel but requires a bit of a learning curve to HT right.
 
brets-ftw said:
As to the design i was in fact thinking of making it a wharncliff or a sheepsfoot, and if it is M2 then i would be more frightened of resharpening as ive heard it takes forever to do, and im sure just getting the initial edge on there will take a lot off
Click to expand...

Once you have it properly shaped, resharpening shouldn't take long. I resharpened my HSS (M2 I think) last night from barely paper slicing to tree topping sharpness on my Sharpmaker in about 15 minutes. Proper shaping is the hard part, as this requires the removal of a lot of material from a piece of very wear resistant material. That said, power equipment is a must for when the edge gets too thick to resharpen in a reasonable amount of time. I use a 12ish degree convex bevel from a belt sander with a 20 degree micro-bevel from the sharpmaker, on 0.055" stock. It can be resharpened several times before the microbevel gets too big to do quickly. Also, for the amount of cutting that can be done with a knife of M2, or other HSS, I think the trade off is worth it for some extra sharpening time. I've cut over 300 inches of cardboard with mine and it would still catch hair above my skin. My blade is all HSS, spine to teeth. Some bi-metal blades have only the tooth tips as HSS. If you grind off the teeth, all the good stuff is gone.
 
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