Thread: Tempering 01 steel in the Kitchen oven

same steel as here, by the way. .4 carbon, 1% manganese (bit time hardenability, so it doesn't need an all fast quench), 1% chromium and some molybdenum and silicon.

It will definitely take an edge, but think of it as something like a machete edge or like a commercial hatchet and not like a fine knife edge.

Originally Posted by auscab

.....And yours being Mild steel . Id forgotten that. Ive read it here before when you told us. I was just thinking last night when typing that mild steel would probably work just as well. And so does cast iron it seems.,,,,

Rob, tbh, I think a couple are mild steel, but that inch tap above has machined so nicely it might be something else. But it was done by my mate who has a far better handle on driving metal lathes than I'll ever achieve!

Incidentally, you said you had a bad time with carbide tools - I use them all the time now. I started out with HSS, but the only time I use HSS tools now is for parting tools and making special shapes. The quality of the tool is paramount - I tried a set of el-cheapo carbide-tipped tools early on, and they were rubbish, all I managed to make with them was a big mess. My mate took one look at them & fell about laughing, so on his advice I bought a small set with good quality replaceable inserts & it was day vs night!

Originally Posted by auscab

..... The Red cedar clamp you made. Was it cut with thread box ? I'd be interesting to see that clamp.

Yes my Redgum bench threads are going fine. Just a bit of damage from things hitting the thread but the wear through the nut is like new. Just a bit polished. ......

I misled you - the jaws of the clamps are red cedar, not the screws, they are crows ash (an excellent wood for screws, it's self-lubricating...):

Cr Ash Cedar.jpg

I was making the point that even soft wood like Toona will take internal threads that are strong enough to be practical, but I don't think it would last 5 minutes as screws!

For some reason I remembered your screws as jarrah, not red-gum. I reckon red-gum & jarrah are probably both about as tough a wood as you could successfully thread with a threadbox, There's a bloke in Toowoomba (Frank Weissner) who makes traditional wooden book-presses with giant 3" screws, he favours Tas. oak/mountain ash, which also threads well with a threadbox; Frank certainly makes very clean screws with it.

As I said, I cut all screws with a router & home-made jigs. The jig came from a FWW article back in the early 80s - I'd been having no end of trouble with threadboxes (due no doubt to ignorance & impatience!) and when I saw that article, I decided to give it a go. It worked beautifully first try, which was pure luck, as even now, I don't always get it right first go & it may take several tries to get it cutting a clean thread - had that happened to me the first time, I think I would have abandoned the idea of wood threads completely, which would have been a pity. They've given me a lot of fun & interest over the years, not to mention being extremely useful!

The router can cut near-perfect threads in just about any wood from balsa to bone-hard stuff like Belah, which is what the screws for this pair of small (1/2" diam.) clamps are made from:
Clamps small ed.jpg

Bull oak is often claimed to be the hardest wood on earth - it isn't, but Belah (casuarina cristata) possibly is - it's appreciably harder than bull oak and I doubt you would ever cut a decent thread on it with a threadbox. I think you'd struggle to thread bull oak too, but it peels reasonably well off a skew (one of my criteria for judging if a wood will take a good thread), so it would probably work if your threadbox is in top shape.

I'm rather ashamed to have to admit I was defeated by threadboxes early on. I have subsequently used someone else's that was properly set up so I know they can do a fine job. Some day I must revisit them & find out what the heck I was doing wrong. I was very chuffed to get the old 'primitive' style taps working (the one I wrote about for AWR), and it would be good to feel I could make screws as well without burning electrons....
Cheers,
Ian