Old Saw Blade for making a knife

[Devin]

A friend of mine offered me a couple of old saw blades and I jumped at the chance. Free is good!

I cut out about 10 blanks and started to shape one. After a while I decided to try to drill a hole through the metal. Three bits later I'd barely made a scratch! Any advice re how to drill through something this hard or should I just cut my losses and hang what's left on the wall for a nice decoration?

See link below for a picture if that helps.

Appreciate any advice!

Devin


http://s24.postimage.org/ykxiyeztx/Saw_Blade.jpg

[Ray Rogers]

What you need is called a straight flute carbide drill. Probably can't get them at you local hardware store, you'll need to order from MSC or McMaster_Carr. Any industrial tool supplier would have them.

Or, you could anneal your blade blanks, drill them, and the HT them. That's probably what you should do anyway since that saw blade is probably a little softer than you would want your knife blades to be ...

[chrisC73]

if you use carbide tipped drill bits made for drilling concrete, it shouldhelp with your issues. I have been using the same bit for close to 6 months now.

[bob levine]

Yes free is good, especially if you know what kind of steel it is. Otherwise how do you anneal it and then re harden it. Steel is like cake dough you have to know what you've got in order to cook it properly.

[C Craft]

When I first started I made some knives out an old two man saw blade. I was told by a seasoned veteran, that if I didn't get the steel too hot I probably wouldn't need to harden when finished.
Mainly because the steel had good carbon and in the state that the steel was in at that point (as far as being hardened for use as a two man saw blade), was about as hard as it would get anyway! Thinking this is the best of two worlds I set forth to make some knives from that two man saw blade!

The steel did have good carbon and as long as I didn't get it too hot when working the blade out it would hold an edge that if it began to dull a couple of passes on a stone would bring it back to a honed edge.

However when trying to drill it I found out it would spin a bit and never touch the steel. I found out I could spot anneal with a mapp torch. While red hot the drill bit will cut like hot butter, (at least once). It is very hard on bits! The heat kills the bit after a hole or two!

I tried regular carbide tipped masonry bits and the heat would let them cut the first hole or two and by the third attempt I usually spun the head off.

I tried the straight flute carbide drill bits as suggested by Ray and they work but are very expensive and if you force one, it's usually gonna explode!

So I basically gave up on the saw blade material, not that it didn't make some really decent knives but, the headache of being able to drill it wasn't worth the cost in bits to drill them!

[Ray Rogers]

Just out of curiosity, you did use the straight flute carbide drill on cold steel, right? Actually, the idea behind spot annealing as you did is to wait until the steel cools before you use any kind of drill on it or, as you discovered, it surely will kill that drill bit. The idea behind the carbide drill is to not have to bother with the spot annealing ...

[Devin]

I've never tried (or heard of) spot annealing, but I'm going to give it a shot! This means taking down the latest wall decoration in my shop, but as they say, nothing ventured nothing gained. I apprecaite the advice and will let you know what happens!

[Devin]

Ok metal gods, thank you. I just "spot" annealed the blade with a nail in my drill press. Spun it fast on the spot till it turned blue (x4), let it cool and drilled 4 holes!

After some of the advice I received above regarding using saw blades of unknown origin I may still relegate it to a wall decoration, but what a neat new trick I just learned. Thank you!

Devin

[bob levine]

Free is not good if you dont know what your getting. Knowing the kind of steel you have is crucial in knowing how to heat treat the blade. Heat treating is the heart of the blade.

[C Craft]

Originally Posted by Ray Rogers

Just out of curiosity, you did use the straight flute carbide drill on cold steel, right? Actually, the idea behind spot annealing as you did is to wait until the steel cools before you use any kind of drill on it or, as you discovered, it surely will kill that drill bit. The idea behind the carbide drill is to not have to bother with the spot annealing ...

Ray I haven't revisited this thread in a while. Yes I know you are supposed to let it cool when spot annealing but tried that and was still not able to drill the steel that the two man saw was made from.

Small bits like 1/8" and up to 1/4'' were used originally. They were just regular metal bits. The use of them on the red hot spot was born out of frustration. I had tried to drill the metal and already killed the point on the bit. So I came up with the spot annealing idea. And once frustrated while hot I proceeded to drill a hole with an already dull bit, before letting the spot cool. To my amazement the more pressure I put to the bit on the red hot spot it began to cut a hole, like drilling hot butter. I even found some very hard finish nails I had and found out they would do the same thing. I only had a few of them and they never lasted over a couple of holes till they got so hot and folded!

The carbide bits I tried were actually masonry bits. I got a deal on a dozen and they were just that, "you get what you pay for". And yes I know they are not designed for drilling metal.

My thoughts was this. I once had made a trailer and used some old bed irons for the cross members. The steel was hard enough that I could not drill them with a regular metal bit. I was burning up bits like crazy trying to drill holes to bolt down the floor of the trailer.

I consulted an old friend who was a machinist by trade. He said the steel should not be that hard but perhaps the welding heat had hardened them.

He took an old Masonry bit and reground the angle on the bit and it cut metal like hot butter. I probably drilled close to 50-60 holes with that reground bit! He is dead now and I wish I had payed more attention to how he reground the bit because I could not get it right with the ones I tried.

However they would cut like hot butter if I spot heated and jumped on it while still red hot. Of course about three or four holes and I had spun the carbide point off of the bit!

I was not really recommending my method only saying, in a pinch it will work. Once red hot the bit requires pressure and it will cut through hardened metal and I had already said it was not good for the bit! I have since quit making blades from such steel. It made some decent knives but was a bear to work with.