Spindle Bore specification question
 

When spindle bore is specified as (say) 1", does that mean I can pass
a typical piece of 1" stock through it?

The tolerance on standard stock is, say +/-0.002" so the actual
hole would have to be a few thou bigger than nominal. Is it that
way or is the bore size usually just the nominal size?

I'm talking bout Griz import lathes if it makes any difference.

Spindle Bore specification question
 

On 2010-06-08, Spehro Pefhany wrote:
When spindle bore is specified as (say) 1", does that mean I can pass
a typical piece of 1" stock through it?

The tolerance on standard stock is, say +/-0.002" so the actual
hole would have to be a few thou bigger than nominal. Is it that
way or is the bore size usually just the nominal size?

That depends on the machine. Usually it is slightly oversized
with US made (or European made) machines -- except that the nominal
diameter on the European machines will likely be a metric dimension, not
inch.

If the dimension is too close, you could hit problems with
runout in a 3-jaw chuck causing interference.

I'm talking bout Griz import lathes if it makes any difference.

It probably does. Those were probably actually made to metric
dimensions (Chinese and Taiwanese machines). The closest integer
dimension to an inch is 25mm (lacking 0.4mm of full inch size), so it
depends on just how oversized the spindle bore really is.

I have heard stories of spindles which were the nominal
dimension at the ends, but which necked down in the middle. This would
call for a gun drill driven by the carriage to open it up full length,
letting the to-size part at the chuck end act as a pilot for the drill.

If the spindle won't quite clear your workpiece diameter and the
workpiece is the nominal size of the spindle bore, I would just make a
gun drill and take off those extra few thousandths. (Ask here if you
don't know what a gun drill is.) However, I would *not* consider taking
it up to the next size up. :-)

And, of course, this would almost certainly void your warranty.

And, BTW, what would be nicer is a bore of 1-3/8" 34.9mm, which
means that 35mm would be the nearest integer size). The reason for this
being a particularly desirable bore is that this will pass the drawbar
for 5C collets, the most common (and thus the most affordable) size of
collets.

So -- you have my thoughts on the matter.

Good Luck,
DoN.

--
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--- Black Holes are where God is dividing by zero ---

Spindle Bore specification question
 

On Jun 8, 5:48*pm, "DoN. Nichols" wrote:
On 2010-06-08, Spehro Pefhany wrote:

When spindle bore is specified as (say) 1", does that mean I can pass
a typical piece of 1" stock through it?
...

* * * * And, BTW, what would be nicer is a bore of 1-3/8" 34.9mm, which
means that 35mm would be the nearest integer size). *The reason for this
being a particularly desirable bore is that this will pass the drawbar
for 5C collets, the most common (and thus the most affordable) size of
collets.
....
* * * * * * * * DoN.

Looks like the 1" spindle bore is the 11" lathe for $1700 and the next
larger one with a 1-7/16" bore costs $1000 more.

I like 5C a lot but perhaps not THAT much. Most of what I make from
ground drill rod is 1/2" or less and a 3C collet would be enough. A
collet isn't as useful for non-precision rolled stock, even if it
fits. Out-of-round pieces can wobble.

Right now the lathe has a 4 jaw Sherline chuck on a 5C mount in it,
holding a 6mm replacement choke shaft for my string trimmer that
needed a rectangular cut for the lever on one end. The 5C chuck also
fits in a spin index on the mill.

jsw

Spindle Bore specification question
 

On 2010-06-09, Jim Wilkins wrote:
On Jun 8, 5:48*pm, "DoN. Nichols" wrote:

[ ... ]

* * * * And, BTW, what would be nicer is a bore of 1-3/8" 34.9mm, which
means that 35mm would be the nearest integer size). *The reason for this
being a particularly desirable bore is that this will pass the drawbar
for 5C collets, the most common (and thus the most affordable) size of
collets.
...
* * * * * * * * DoN.

Looks like the 1" spindle bore is the 11" lathe for $1700 and the next
larger one with a 1-7/16" bore costs $1000 more.

Ouch!

I like 5C a lot but perhaps not THAT much. Most of what I make from
ground drill rod is 1/2" or less and a 3C collet would be enough. A
collet isn't as useful for non-precision rolled stock, even if it
fits. Out-of-round pieces can wobble.

I was lucky that my 12x24" Clausing came with a lever style
drawbar and nosepiece for 5C collets. (I actually just received a 5mm
collet today -- ordered from MSC yesterday for a current project.)

Right now the lathe has a 4 jaw Sherline chuck on a 5C mount in it,
holding a 6mm replacement choke shaft for my string trimmer that
needed a rectangular cut for the lever on one end. The 5C chuck also
fits in a spin index on the mill.

Those Sherline chucks on 5C collet mount are nice. I've got one
which Sherline put on eBay to boost the number of people who know about
them.

I also got a small 3-jaw chuck on a similar mount -- but from a
different maker, and the 5C drawbar threads are a bit oversized, making
it a pain to get on and off the lathe. (Maybe I should try skimming the
threads a bit in the lathe.)

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

Spindle Bore specification question
 

On 10 Jun 2010 02:48:15 GMT, "DoN. Nichols"
wrote:

On 2010-06-09, Jim Wilkins wrote:
On Jun 8, 5:48*pm, "DoN. Nichols" wrote:

[ ... ]

* * * * And, BTW, what would be nicer is a bore of 1-3/8" 34.9mm, which
means that 35mm would be the nearest integer size). *The reason for this
being a particularly desirable bore is that this will pass the drawbar
for 5C collets, the most common (and thus the most affordable) size of
collets.
...
* * * * * * * * DoN.

Looks like the 1" spindle bore is the 11" lathe for $1700 and the next
larger one with a 1-7/16" bore costs $1000 more.

Ouch!

I like 5C a lot but perhaps not THAT much. Most of what I make from
ground drill rod is 1/2" or less and a 3C collet would be enough. A
collet isn't as useful for non-precision rolled stock, even if it
fits. Out-of-round pieces can wobble.

I was lucky that my 12x24" Clausing came with a lever style
drawbar and nosepiece for 5C collets. (I actually just received a 5mm
collet today -- ordered from MSC yesterday for a current project.)

Right now the lathe has a 4 jaw Sherline chuck on a 5C mount in it,
holding a 6mm replacement choke shaft for my string trimmer that
needed a rectangular cut for the lever on one end. The 5C chuck also
fits in a spin index on the mill.

Those Sherline chucks on 5C collet mount are nice. I've got one
which Sherline put on eBay to boost the number of people who know about
them.

I also got a small 3-jaw chuck on a similar mount -- but from a
different maker, and the 5C drawbar threads are a bit oversized, making
it a pain to get on and off the lathe. (Maybe I should try skimming the
threads a bit in the lathe.)

Enjoy,
DoN.

Ive got an older, but rather good condition Hardinge TFB that Id let go
for hummmm $1800, give or take a little here and there
Cuts VERY nicely, but doesnt do threading.

Cuts very nicely to .0002 G

Gunner

One could not be a successful Leftwinger without realizing that,
in contrast to the popular conception supported by newspapers
and mothers of Leftwingers, a goodly number of Leftwingers are
not only narrow-minded and dull, but also just stupid.
Gunner Asch