Another Professional Machinist Story

[rake60]

We had run a set of 30 threaded pins through our CNC machine.
The thread was 1-3/4 - 12
Somewhere in the process someone replaced the threading insert and misread
their mics by a revolution leaving the thread .025 on the pitch diameter too heavy.

I tried to run a die over one to take it to depth. That wasn't happening.
A coworker suggested setting them up in a manual lathe and chasing the threads
to depth. To a hard shoulder??? I didn't think so!

He did them. I've never seen that done before, and I'm quite sure I couldn't do it.
I wish I would have had a camera there to video it. He did bump the shoulder on
one piece. One out of 15 isn't bad!

To Steve :bow: :bow: :bow:

I'm SURE the praise won't go to his head! :-\

Rick

 

[lathe nut]

rake60, looks like there is getting less and less manual machinist in the business, I live in SW Louisiana, went to an oil field machine shop a few weeks ago to see something that our company was getting made, the shop must cover 4 acers, I have never seen that many machines in one place most of them are the CNC, dummy me, I asked the shop forman how machinist work here, he said about 20, I looked around and seen 100 people, he seen the stupid look on my face, then he said define what you mean by machinist, just what you are describing, they are actually housed in a different building, then he took me in there, they do the real work, It was a dream to see, glad we still have some, take care, Lathenut

 

[d-m]

There was a really good article in machinist work shop a few months ago explained how to do a thread repair it would be quite similar to what he had to do but against a shoulder I know I would have wrecked more than one : I just re read the article needing to do some threading on the lathe soon it was really good info.
Dave

 

[rake60]

I've only been a CNC operator for 2 years.
For the 28 years before that I was a manual machinist.
I've done my share of single point chasing threads, but never to a hard shoulder.
On my best day I would have never been able to do what Steve was doing once,
let alone 16 times.

After each one he'd offer to let me do the next one.
I declined every time.
He said: "That shoulder isn't that hard." :

Rick

 

[zeusrekning]

Rick, Why didn't you fix it on the CNC. I had a guy do the exact same thing on a 2-3/16" SS pump shaft that was about 10ft long. Only threaded about 4" on the end but for some reason he didn't run the gage on it till he took it out of the machine. So I had to put it back in the lathe and chase it.
Tim

 

[rake60]

Setting the Z axis for each part to line the threading tool up would have taken
much more time than on a manual machine. If you missed it the part would be
junk and you wouldn't know it until it was happening until it was too late.

Once you press the Cycle Start button, the coolant starts flying and there's no
seeing the part until that cycle is completed. The machine is going to do what
you told it to do. Right or wrong.

And they wonder why I'm bald! :big:

Rick

 

[rake60]

Here's another one for you.

A machinst was standing on the ways of a lathe turning a large tap with a wrench.
The wrench slipped and he did an back flip hitting his ribs on the way.

A guy at the other end of the shop held up a legal size tablet with a big 9 on it.
When asked why he replied: "Well I couldn't give him a 10, the dismount wasn't clean.
He hit the ways on the way down."

Yeah, that's where I work! :

 

[zeusrekning]

Yeah it sucked. I had to offset the tool up and run it a couple passes with the coolant off then offset Z to try and match the tool to the thread. I kept doing this till it looked like it would track correctly. I was not very happy with this guy that day.