# Large Scale Threading



## rake60 (Feb 12, 2009)

One of the machines I run at work is a large vertical boring mill.
It is like a giant lathe stood on end.







The table on that machine is approximately 10 feet in diameter.
The part on the table is an adjusting nut that calls for an internal thread
at 96" minor ID with a 2" pitch.
It is a totally manual machine single point threading.
I thought maybe some of you might be interested in seeing that cut.
(Yes that is me and I AM that bald!)

[ame]http://www.youtube.com/watch?v=q7vw50-ApDc[/ame] 

The table is only turning at 11.3 RPM
At the 96" diameter the surface speed is 284SFM at the cutting point.
.200 depth of cut at a .020 advance per cut.

[ame]http://www.youtube.com/watch?v=fmRkBx_qCqc[/ame]

At home I usually take lighter cuts.  

Rick


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## Stan (Feb 12, 2009)

Two questions Rick. What is the setup time for a job like that? Presumably you don't tap it around with a plastic hammer.
Second: Is that a straight in feed of the cutting tool, cutting both sides of the thread?


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## rake60 (Feb 12, 2009)

The table is basically a big 4 jaw chuck.
It has 4 jaws that adjust in and out in T-slots.
The jaw wrench is a special socket turned with a 3/4" drive ratchet
and a 3 foot length of pipe for extra leverage. After it's indicated in
it gets 4 toe clamps, one over each jack, to keep it from slipping in
the jaws.

Set up time for that job averages 45 minutes to an hour.
The thread ends up being 1.032" deep so you can never
allow a full tool cut. It's actually kind of an entertaining job to run.

Rick


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## te_gui (Feb 12, 2009)

Some big iron there Rick! Back in the day I used to run a Skoda and a couple different Bullard vertical turret lathes or vertical boring mills. I never have figured out which term is correct. I always figured the if the part turns its a lathe, if the tool turns its a mill. Big machines are fun to run, nothing happens really fast but ya still need to be on your toes, cause an 8' dia scrap part gets expensive quick.


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## itowbig (Feb 12, 2009)

all i can say rick is wow  
you sure dont want to mess up those threads.
would like to see the wrench it takes to tighten that nut. :bow:
you dont mess around when you cut threads :big: ;D


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## ChooChooMike (Feb 12, 2009)

Another obvious question (so I think ), what's that huge nut for ? I'd like to see it's mating part too !!

Very cool


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## tel (Feb 12, 2009)

ChooChooMike  said:
			
		

> Another obvious question (so I think ), what's that huge nut for ? I'd like to see it's mating part too !!
> 
> Very cool



I'm pretty sure I won't be making the bolt on the Myford. That's one BIG nut. Thanks Rick.


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## Maryak (Feb 12, 2009)

Rick,

WOW, I'm impressed :bow: :bow:

I thought it was only dinosaurs who had em that big. 
	

	
	
		
		

		
		
	


	




Thanks for sharing.

Best Regards
Bob


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## Loose nut (Feb 12, 2009)

What, you couldn't use a tap for that.


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## BobWarfield (Feb 12, 2009)

Heh, how many folks here are getting chips that blue when threading?

Cheers,

BW


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## steamer (Feb 12, 2009)

GEEEEZ Rick!...............I thought you were going to show some BIG work!....... :

 ;D ;D ;D ;D


Holy nut from a battleship batman!.... ;D


Very nice......and BLUE chips too!

Thanks for sharing that Rick....brings back memories of big machine tools in my youth.


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## Stan (Feb 12, 2009)

> The thread ends up being 1.032" deep so you can never
> allow a full tool cut. It's actually kind of an entertaining job to run.



Do you have time to explain how the tool is advanced into the thread so that you don't take a full tool cut?


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## Holescreek (Feb 12, 2009)

Makes the DeVliegs I ran look puny. Now show a photo of the spanner wrench!


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## rake60 (Feb 12, 2009)

Stan  said:
			
		

> Do you have time to explain how the tool is advanced into the thread so that you don't take a full tool cut?



When cutting the bottom side we move the saddle up and work the tool in
another .200" Then move the saddle back down .020" at a time until the cut 
blends into the previous cut. Same process when cutting the top.
There is a flat at the root so there is a little bit of working room when it
get into depth.

Rick


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## 10K Pete (Feb 12, 2009)

That's one darn big threading job Rick!

Cool stuff! Post some more like that if you have time.

Pete


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## rake60 (Feb 13, 2009)

That nut adjusts a threaded bowl in a cone type rock crusher.
This is a picture of two finished bowls.






We also repair the cones for those crushers. That's sometimes a lathe job.






Now that's a machine I am NOT interested in running!

Rick


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## Stan (Feb 13, 2009)

Thanks for the explanation Rick. I guessed at that but thought you must have an easier way. Stan


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## GailInNM (Feb 15, 2009)

And large in the other direction.

Details at:
http://www.shopswarf.orconhosting.net.nz/bgscrew.html

Actually you should check out:
http://www.shopswarf.orconhosting.net.nz/index.html
for lots of pictures of old machine tools as well as a lot of good bits of information that applies today.
Gail in NM,USA


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## lathe nut (Feb 15, 2009)

Rick, thanks that is impressive, not many people will ever see that or even work at a place like that, that must be a very satisfying job you have, there is no room for mistakes, that would be a costly one, I love to tinker but doing it for a living would to much but guess that easy comes with time, thanks again for sharing, Lathe Nut


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## Metal Mickey (Feb 17, 2009)

Rick, do you keep the chuck key in your pocket? :big: :bow:


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## rake60 (Feb 17, 2009)

Perhaps I should.
I have been known to leave that 3/4" drive ratchet laying on the 
the table. Even at slow speeds, it makes a lot of noise when it 
slides off.

Rick


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