Thread: Annealing steel

Great, I'll give it a try.

Originally Posted by JoshEarl

I recently forged a blade out of O1, and once it was ground I was unable to drill the hole in the tang.

What I generally do is to punch the holes at red heat with a pritchel. It is the traditional way in the cutlery industry - holes were rarely drilled in the old days before stamped out blanks and stock removal - just look at the dot (pivot) holes of old Sheffield razors.
If you use a pritchel with a flat, round end of about the right diameter rather than a pointed one, you can start the punching on the face of the anvil before moving over the pritchel hole. This will punch out a little disk, distorting the surrounding tang less than if you simply poke a hole through with a pointed pritchel.
I hope this is of some use. If I have just taught your granny to suck eggs then I apologize.

Duncan.

Duncan,

I'd like to try that, actually. I tried to use a punch from Home Depot, and it just bent.

The trouble is that I don't use vintage-style pivots, so a precise hole is desirable.

Does the tang get bent at all when you do it this way?

Josh

Originally Posted by JoshEarl

Duncan,

I'd like to try that, actually. I tried to use a punch from Home Depot, and it just bent.

The trouble is that I don't use vintage-style pivots, so a precise hole is desirable.

Does the tang get bent at all when you do it this way?

Josh

Forge your own pritchels from old car coil springs then harden & temper them. Cheaper & better than shop rubbish. Make them fairly long & you will keep your fingers away from the red hot steel.

Yes, punching distorts the tang. Tapping in the pritchel from the other side after the hole is formed evens up the hole and straightens the tang to some degree. You then just flatten the tang on the face of the anvil. If you punch the dot hole dead centrally in the tang then you should not get too much curling up or down of the tang (as opposed to the side-to side bending which is just hammered flat) using the "punch out a disk" method.

If you require a precise hole, it might be worth considering punching it undersize then drilling or reaming it.

Good luck,

Duncan.

Good idea Duncan. Some of the pins being used are 0.062 inch and that's a small hole to punch. Since the material being work is hot anyhow, any deformation is easily corrected.

Another method, if you have a heat treatment oven, is to do a subcritical anneal. Get the blade up to 1300 F and hold it for two hours, then let cool slowly. This will spherodize the carbides and while slightly harder than a complete annealing, the material will act like free machining steel and be much easier to drill.

O-1 can air harden. Look around the working shop for air blasts from the furnace that warms the building or a fan that's moving air. That may be all it takes to put a piece into the hard-enough-to-be-a-PITA to drill stage.

It's all a grand experiment to find a way to play with fire...