Inspector
Nyuck, Nyuck, Nyuck!
Paul Hannaby":1g4gn88m said:Catches can happen with any tool and it isn't always due to poor or incorrect bevel contact because in the case of normal scrapers, there isn't usually any bevel contact.
Going back to your earlier statement about files - they are hardened "glass hard" and are brittle so any shock loading (which can happen in turning) could result in the file breaking or possibly shattering, resulting in shrapnel travelling at high speed. Traditionally, turning tools were hardened and then tempered to reduce their hardness while increasing their toughness so they don't snap when receiving a shock load.
I put this to the test once by deliberately hitting a file which someone had made into a turning tool with a "shock load" - it snapped!
If you really know what you are doing and can correctly heat treat a file or other piece of metal to make a turning tool, that's fine but advocating that anyone should use a file without correct heat treatment is downright irresponsible.
You can temper the file in your oven so it isn't so brittle. Turn the oven on to 400F to 450F (205C to 230C) and when warm put the file in. Heat it for a couple hours and remove it. When cool repeat. Turn off the oven and hide the evidence of you being in the kitchen. The file should take the shock loads you are worried about.
Pete