Power Hacksaw Blades

[Zingmo]

I often seem to read that folk find it hard to get hold of these nowadays. Here is an Ebay item that may be of interest.

The blade is 2mm thick so can be used for small knife blades.


I would say I have no affiliation blah,blah..but the chap is one of my neighbours.

Z

[sasquatch]

Are they high speed steel? I have a few in a box of old files, any idea how the heat treat & temper would differ from O1? Or is the idea to not need to heat treat and temper with this stuff? I've always been curious but never asked...

[ged]

Are they high speed steel? I have a few in a box of old files, any idea how the heat treat & temper would differ from O1? Or is the idea to not need to heat treat and temper with this stuff? I've always been curious but never asked...

Very probably HSS, yes They will also probably be all hard, so they'll be brittle all the way through. I still use a couple of broken blades from the donkey saw at the engineering company where I worked over 40 years ago. So they last quite well.

If they're all hard you'd need to temper them for use as a knife blade, otherwise they'd be dangerously brittle. The main reason I've ground an edge on an old hacksaw blade is for when I want an edge which I don't mind abusing, but I'm aware that it will be brittle and take appropriate precautions such as wearing eye protection. The handle would probably be duct tape.

Hardening depends on the steel, there are many types of high speed steel. I don't think it's as forgiving as something like O1 but if you're working with scrap steel you might be happy to experiment. To see what you're up against try a search such as

http://www.bing.com/search?q=high+speed+steel+hardening

Some are air-hardening, some can be hardened in oil or air. One of the things to watch for is soaking too long at high temperature, which can cause the steel crystals to grow too big.

Incidentally that looks like a good price for a blade like that on the auction site, but depending on what you actually want of the finished article I can't help thinking that the old files might provide more suitable material.

The broken edge of a hacksaw blade is about the best thing I've found for striking sparks from a ferro rod.

[Zingmo]

Thanks for that Ged. I have got one of these blades off him to experiment with when time allows. I have also seen somewhere someone using one of these in a bowsaw frame to make a giant hacksaw.

Z

[ged]

... I have also seen somewhere someone using one of these in a bowsaw frame to make a giant hacksaw.

In that case the frame would need to be able to put great tension in the blade, so that it doesn't bend much, or it will easily break. It's also important to avoid twisting (in any direction).

When these blades are used in the machines that they're made for, they'll cut through staggering amounts of steel before they wear out. But one wrong move and ... SNAP.

[sasquatch]

Hmm, looks intense when you read about that stuff! I have a few in a box, I'll be happy to experiment. I've seen it mentioned in the past and heard various things. Thanks for all the info Ged.