Lathe turret clearance

[gregormarwick]

Seymour, can I ask why the reluctance to go up a size on the machine and spec with 8" chuck?

Footprint, spindle speed... - are there obstacles beyond the obvious financial aspect?

 

[Ox]

Distance from (lower turret) tool tip to main turret tool tip is a long way.
I wonder how many people punched a hole in the metalwaork behind the chuck while turning with the lower turret....!
Interesting concept tho

I believe that most of those type machines have an extended pocket above for the long tools.


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Think Snow Eh!
Ox

 

[DDoug]

I believe that most of those type machines have an extended pocket above for the long tools.


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Think Snow Eh!
Ox

I've seen them with "not much" sheetmetal up there, more like just the sliding door for the operator.
Warner & Swasey Engine Lathe 400 RPM SC32 Slant Bed
This one has the sheet metal all enclosed. a bit higher up:
J&L Slant Bed Lathes Project - Peiffer Machine Services

 

[Vancbiker]

I believe that most of those type machines have an extended pocket above for the long tools.


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Think Snow Eh!
Ox

A feature too frequently overlooked by some builders.

 

[SeymourDumore]

Seymour, can I ask why the reluctance to go up a size on the machine and spec with 8" chuck?

Footprint, spindle speed... - are there obstacles beyond the obvious financial aspect?

Gregor, 2 reasons.
First, typically the 8" and 10" machines are only different in spindle bore size. The turrets are either the same on both, or the 10" version offers a 10 station turret.
Second, there is no way to downsize a chuck, only up. IOW you cannot get a typical 10" machine with an A2-8 spindle taper and put an 8" chuck on it.
There is no such adapter in existence as the interface differences are too large.

 

[Ox]

Well, you could very easily roll your own adaptor.
Only catch is that it will chew up an additional 1.5" (?) of daylight.
On the flip side tho - the smaller chuck may be about that much shorter too?

A2 adaptors are not rocket science.


With that said tho - once your tools get past the Z length of the smaller chuck - they will still need to clear the spindle casting behind it.
The adaptor may not be bigger than the chuck tho?


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Think Snow Eh!
Ox

 

[SeymourDumore]

Well, you could very easily roll your own adaptor.

Think Snow Eh!
Ox

Not really Ox.
The size differences are so large that the drawbar adapter ( the threaded part ) of the chuck has to be separate from the chuck itself, and it will have to be
captive by the taper adapter.
There is a reason they don't exist.

 

[Ox]

What?


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Think Snow Eh!
Ox

 

[chad883]

Not really Ox.
The size differences are so large that the drawbar adapter ( the threaded part ) of the chuck has to be separate from the chuck itself, and it will have to be
captive by the taper adapter.
There is a reason they don't exist.

I wish someone would have told me this before I did it. I am running a 8" chuck on my Mori SL-25Y that has an A2-8 mount.

I had to make an adapter for the drawtube also.

 

[Ox]

Well, you could very easily roll your own adaptor.
Only catch is that it will chew up an additional 1.5" (?) of daylight.
On the flip side tho - the smaller chuck may be about that much shorter too?

A2 adaptors are not rocket science.


With that said tho - once your tools get past the Z length of the smaller chuck - they will still need to clear the spindle casting behind it.
The adaptor may not be bigger than the chuck tho?


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Think Snow Eh!
Ox

I just quick checked the bolt pattern on my 10" chuck, and it looks like the bolts will fit inside an 8" diameter, so no worries there.

Both - my 8" Hardinge and my 10" Kit chucks are 4" thick, so add 1.5" (?) adaptor and you have 5.5" before you get to anything bigger'n 8".

Again - you doo however lose that adaptor thickness, which apparently is NOT made up via the smaller chuck.



Edit:

I guess there is no reason that the adaptor couldn't be 1" thick.
It would still be 1.5" total - incl the male taper, but that doesn't add to the daylight value.


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Think Snow Eh!
Ox

 

[SeymourDumore]

I wish someone would have told me this before I did it. I am running a 8" chuck on my Mori SL-25Y that has an A2-8 mount.

I had to make an adapter for the drawtube also.

I'm not asking you to take your chuck off to show the adapter, but I can't picture how you did it...
I am holding a threaded drawtube adapter for a Royal 5C collet chuck with an A2-8 mount.
This adapter is larger than the taper end on the A2-6 ...
What am I missing?

 

[Ox]

You are puting a smaller tube into a bigger hole, not the other way around.


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Think Snow Eh!
Ox

 

[SeymourDumore]

You are puting a smaller tube into a bigger hole, not the other way around.


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Think Snow Eh!
Ox

Opposite Ox, it is the other way around!
Bigger tube ( A2-8 drawtube ) + an internally threaded adapter into a smaller hole ( A2-6 taper )

 

[Ox]

I dissagree.
I obviously don't know what you have there, but the 3jaw chucks and collet chucks that I have here for my CNC lathes, all have male threads.

Meaning that my draw tubes have female threads.

A smaller chuck would need a bushing - for my equipment.


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Think Snow Eh!
Ox

 

[Ox]

You may be standing too close to this...



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Think Snow Eh!
Ox

 

[Ox]

Crickie - worst case is that you make your own draw tube.
DOM isn't THAT expensive that you can't pony up for 4' of 3.25 OD x .500 wall and send it to your C/L grinder chum around the corner....



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Think Snow Eh!
Ox

 

[SeymourDumore]

Meaning that my draw tubes have female threads.


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Think Snow Eh!
Ox

Really?
I have 4 different spindles, each of them have OD threads on the drawtube.

 

[Ox]

I have 1 that has that way too.

But - again - if that;s the biggest issue, Mr. Dumore is Shirley capable of making a draw tube that will work.
Even if it involves trashing the OEM tube and mod'ing that.

Then when you buy a chuck, order it for an external thread.
They have several different shanks to put on them.
Tell them that you have a Hardinge T51. (1990's) (for an 8" chuck)

I mean, come_on man....
Outside the box!


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A Factory Tool is a Good Place to Start!
Ox

 

[Ox]

I just skimmed a calipers over the (OD) threads for the 3 jaw for the Hardinge T51 setting on the flat spot, and it read 2.355, which I ass__u_me is prolly 60mm?

That gets you an 8" chuck with a 2.0x" through hole.


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Think Snow Eh!
Ox

 

[SeymourDumore]

I just skimmed a calipers over the (OD) threads for the 3 jaw for the Hardinge T51 setting on the flat spot, and it read 2.355, which I ass__u_me is prolly 60mm?

That gets you an 8" chuck with a 2.0x" through hole.


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Think Snow Eh!
Ox

Interesting ...
Perhaps that is the reason why some of the machines ( current models ) with the very same A2-6 nose have a 2" through capacity, while others are 2.5"..
Them 2" machines might all have internal drawbar threads and the 2.5" ones are external....

In that case though, there should be a way to make step-down nose adapter for internally threaded drawtubes...