Turning Bolts with HSS?

ErichKeane said:
My lathe is from 1941, so it only cuts imperial
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Metric threads existed well before 1941. Most any lathe that can take change gears will cut both metric and imperial threads. That said, sometimes it is a lot easier to find somebody who already has a lathe with features and/or extra tooling that will do it easily. It might be a good idea to find and ask a local volunteer on H-M to help you with that...

It is quite possible for hobby machining to be a social sport...
 
Do try some known good HSS. Just in case you happened to get junk. A Cobalt bit would be nice to have too. If you don't have a set yet, we can get you a set of model tools.

You don't need speed for carbide, but it does help. Having one or two tools is probably a good idea to help identify issues and cut things you have issues with. I use HSS 90% or more of the time, but it's nice to have options.

I bet you could get transposing gears for metric threading. I don't have that lathe though, so I can't say for sure.
 
Bob Korves said:
Metric threads existed well before 1941. Most any lathe that can take change gears will cut both metric and imperial threads. That said, sometimes it is a lot easier to find somebody who already has a lathe with features and/or extra tooling that will do it easily. It might be a good idea to find and ask a local volunteer on H-M to help you with that...

It is quite possible for hobby machining to be a social sport...
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*Shrug*, perhaps. But mine is a made-in-USA-cut-iron-on-a-battleship lathe, so it was never well concerned with metric. I could perhaps spend a few hundred on change gears (or learn to cut them some day), but cutting metric threads seems like a pain if I cannot use the thread dial and have to keep it engaged.

Either way, for $10 on Zoro I found some cheap all-thread that I'm hoping will work better.

ttabbal said:
Do try some known good HSS. Just in case you happened to get junk. A Cobalt bit would be nice to have too. If you don't have a set yet, we can get you a set of model tools.

You don't need speed for carbide, but it does help. Having one or two tools is probably a good idea to help identify issues and cut things you have issues with. I use HSS 90% or more of the time, but it's nice to have options.

I bet you could get transposing gears for metric threading. I don't have that lathe though, so I can't say for sure.
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Not sure how to find some "known good HSS", everywhere I look to buy seems to be imports these days. I'll keep an eye out though! Perhaps I'll invest in a quality carbide holder (I have a drawer with some inserts that I was saving for a pass around box, perhaps I'll just use those) or make one sometime soon.
 
You could try some of this stuff: http://crobalt.com/index.htm Comes standard with the Eccentric Engineering Diamond Tool and the only thing I've found it doesn't like is a Blue plastic stuff that is used on some electric motor armatures. Good value.

 
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Look for known brands like mo-max, Latrobe, etc.. They are available on eBay all the time, but generally cost more than they probably should. Cobalt tends to be about $10/ea for 3/8 pretty much all the time, with occasional deals. I would pick one up if you are in a hurry and then just watch for deals. M2 is a bit cheaper.

Not all the Chinese stuff is bad, most of it is probably fine. In the tool grinding thread some of us picked up a pack of 50 M2s for $65ish. It's going to take a while before I use them up, as you can hone them a little and have them good as new. It's nice to have some inexpensive ones to test different angles and such on as well.

rover.ebay.com

50pcs 3/8 x 3" HSS Square tool bits for $189.00 #HS-2BT-38---new | eBay

Find many great new & used options and get the best deals for 50pcs 3/8 x 3" HSS Square tool bits for $189.00 #HS-2BT-38---new at the best online prices at eBay! Free shipping for many products!
rover.ebay.com

Found it in my history. They have worked well for me.
 
I picked up a stash of 3/8 and 1" at one point, just haven't broken into it yet! But both are eBay specials.
 
If you're patient, you can get 3/8 Mo-Max for $2-3 a stick on fleabay. That's cheaper than chinalloy by the piece at Shars.

I find the chinalloy HSS to be good for general purpose. It heats up fast, so going with cobalt is better if you go that route. China cobalt is slightly inferior to old USA M2 class HSS. One thing I notice about Chinese tool steel is how unevenly it heats up during grinding. It's almost like the steel is in pellets like rice and cemented together. Hot spots come through in this "grainy" material in blue way before they should. YMMV.
 
I second Norton's post above about Crobalt cast steel bits using a tangential holder.
Mine get used a lot.
 
Hmm, well, I ground a new bit today that made orange sparks. So I think that means its M2 HSS? it is a 3/4x 3/4 piece, though chinese as well.

I was cutting cast iron and couldn't seem to stop messing up the tip. Even one pass of ~2" would wear the end off and turn it blue/grind off the tip. I tried a radius, I tried no radius, I tried everything I could think of! While it WAS an interrupted cut (there is a keyway cut through it), it seems strange that it would do this. I even turned down the powerfeed speed, and it still happened.

I'm at a bit of a loss...
 
Chilled Cast Iron is incredibly hard, even when turning freash castings you normally need to cut deep enough to get under the 'skin'. Hard spots in Cast Iron will damage Carbide even the grades made specifically for it.
 
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