Must Stop Agreeing to dumb jobs

[Kato]

I know there are some of you lot that like to play with a lathe or mill occasionally, and I am definitely in that number, well until this week anyhow,
the lesson learned for me is to ASK “what is it made of” and I don’t mean steel, alloy, Ti etc I mean specifically

I had thought a small modification on a small alloy part would take me a max 20min’s in fact probably longer to set up the job than to machine it

Having broken seveal inserts scartched my head a lot drank a lot of tea and a visit to a mate who knows

This innocuous looking light alloy part turns out to be made of something called Haynes 188 a cobalt-nickel-chromium-tungsten alloy, apparently used extensivley in gas turbine engines the stuff work hardens as soon as you look at it and required the ordering of crazy expensive inserts, and I was right job took 15 mins but nearly broke my lathe and my sense of humor

must learn to stop helping people

ASK “what is it made of” and DO NOT AGREE to machine it for anybody

[Mr Gazza]

Wow. That's the best one of those I've ever see.
What is it?
Have you flipped the photo or is your lathe the opposite hand to all the others I've seen?

[Bitza]

This reminds me of when I was a self-employed landscaper, during a lean period I accepted a job for a friend of my sister to fell a tree in their field. The price I accepted was based on seeing the tree from a distance, big mistake, it turned out to be bloody huge, multi stemmed, plus it was some weird species full of resin. The whole job turned into an absolute nightmare, it took ages, wrecked the saw blade, ruined a pair of boots, in all it knackered me, cost me, and the customer realised what the situation was yet still used the friend of a friend situation to get me to shift the wood back to their barn. I have hated them ever since.

[utopia]

I have sympathy with your situation and indeed I've been in similar myself but it would be a shame if your generosity of spirit were to become hardened too much by this.
On the other hand it is quite common for folk who don't do such work themselves to totally underestimate the time that most machining jobs take.
As you suggest, the set-up time nearly always massively outstrips the actual machining time and while commercial operations can recoup this over large batch quantities, on-offs are a different kettle of fish entirely.
The mere mention of cobalt strikes fear in my personal machinist heart though ... but much like titanium, I'd guess that slow speed and heavy feed with plenty of cutting oil would be the way to go.

[Kato]

Exactly right Jeff, slow and heavy but you need a machine with huge torque to avoid chatter, I'd take Titainium all day long over this stuff its evil

Gazza: it's a coupling from jet engine that sits in a drag car

[Mr Gazza]

Originally Posted by Kato

Gazza: it's a coupling from jet engine that sits in a drag car

Wow! Well some kudos in that even if it was a swine to do.

I still can't figure out which way round your lathe works, unless the tool post is wound out right past the workpiece?

[Kato]

Not my lathe as had to borrow time on a way more powerful one than I own, plus pic taken from a weird angle and somehow got scewed