Topics

Spindle register issue

carbure2003
 

About. a year ago, I bought a 10K spindle on ebay.

As I have not used much the lathe where I fitted the spindle, ( only with collets) I never noticed that the register was under sized. (1.495 in dia), quite likely machined by a previous owner.

I trialed a chuck with freshly re ground jaws on it and it was defenitely off centered by many thou.

Register defenitely has importance when yo want to swap chucks from lathe to lathe and keep chuck accuracy.
Did somebody ever attempt to rebuild a spindle register ? (Register is 1.510 in dia on my other SB)

If yes, how did you proceed? (Welding is not an option)

Thanks

Guy Cadrin
____________________________________________________________
70s Millionaire Returns with Surprising Prediction
unrestrictedinvesting.com
http://thirdpartyoffers.netzero.net/TGL3241/5b2c3c71941fa3c711a12st03vuc

m. allan noah
 

I'll buck the conventional wisdom, and state that the register
diameter does not matter at all. The conical face of the thread, and
the flat shoulder behind the register are sufficiently to achieve
kinematic positioning of the chuck.

I daresay the problem is your testing method. Reground jaws is
basically meaningless, unless they were ground on the lathe in
question, properly preloaded, with the diameter set to exactly the
size of the stock you are now holding. Take of the chuck, and put it
back on, and see if it is consistent. That is a true test.

allan

On Thu, Jun 21, 2018 at 8:00 PM, carbure2003 <guycad@...> wrote:
About. a year ago, I bought a 10K spindle on ebay.

As I have not used much the lathe where I fitted the spindle, ( only with collets) I never noticed that the register was under sized. (1.495 in dia), quite likely machined by a previous owner.

I trialed a chuck with freshly re ground jaws on it and it was defenitely off centered by many thou.

Register defenitely has importance when yo want to swap chucks from lathe to lathe and keep chuck accuracy.
Did somebody ever attempt to rebuild a spindle register ? (Register is 1.510 in dia on my other SB)

If yes, how did you proceed? (Welding is not an option)

Thanks

Guy Cadrin
____________________________________________________________
70s Millionaire Returns with Surprising Prediction
unrestrictedinvesting.com
http://thirdpartyoffers.netzero.net/TGL3241/5b2c3c71941fa3c711a12st03vuc

--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"

Davis Johnson
 

HTRL agrees with you (heresy around here, tho).

I'd be interested in an experiment.

Chuck up a short piece of scrap, turn the outside for a bit.

The part you just turned will be exactly concentric. Check it with an indicator.

Unmount/remount the chuck several times without removing the piece of scrap. Each time check it with an indicator.

I really would be interested in the results, and would do the experiment myself except that I don't have a chuck with a loose register.

On 06/21/2018 08:15 PM, m. allan noah wrote:
I'll buck the conventional wisdom, and state that the register
diameter does not matter at all. The conical face of the thread, and
the flat shoulder behind the register are sufficiently to achieve
kinematic positioning of the chuck.

I daresay the problem is your testing method. Reground jaws is
basically meaningless, unless they were ground on the lathe in
question, properly preloaded, with the diameter set to exactly the
size of the stock you are now holding. Take of the chuck, and put it
back on, and see if it is consistent. That is a true test.

allan

On Thu, Jun 21, 2018 at 8:00 PM, carbure2003 <guycad@...> wrote:
About. a year ago, I bought a 10K spindle on ebay.

As I have not used much the lathe where I fitted the spindle, ( only with collets) I never noticed that the register was under sized. (1.495 in dia), quite likely machined by a previous owner.

I trialed a chuck with freshly re ground jaws on it and it was defenitely off centered by many thou.

Register defenitely has importance when yo want to swap chucks from lathe to lathe and keep chuck accuracy.
Did somebody ever attempt to rebuild a spindle register ? (Register is 1.510 in dia on my other SB)

If yes, how did you proceed? (Welding is not an option)

Thanks

Guy Cadrin
____________________________________________________________
70s Millionaire Returns with Surprising Prediction
unrestrictedinvesting.com
http://thirdpartyoffers.netzero.net/TGL3241/5b2c3c71941fa3c711a12st03vuc

Jim_B
 

I have many times removed a chuck with a face plate in it, while threading the face plate, to test the fit on the spindle threads.
When the chuck and face plate were screwed back on registration was perfect.

I am not sure if all my chucks were tight fits on the “registration step” or they used the threads and the spindle stop.

The 9” Workshop and the 10k have a very small stop behind the register.
If the faceplate has any radius on the threaded bore you may or may not properly register on the stop.
The Heavy 10 and larger lathes have a good stop.


Sent from my iPhone-8
Jim B,

On Jun 21, 2018, at 8:28 PM, Davis Johnson <davis@...> wrote:

HTRL agrees with you (heresy around here, tho).

I'd be interested in an experiment.

Chuck up a short piece of scrap, turn the outside for a bit.

The part you just turned will be exactly concentric. Check it with an indicator.

Unmount/remount the chuck several times without removing the piece of scrap. Each time check it with an indicator.

I really would be interested in the results, and would do the experiment myself except that I don't have a chuck with a loose register.


--
Jim B

carbure2003
 

I will do the experiment tomorrow night. I have 3 SB in the basement ( one is not powered, being in storage)

I will turn a piece and move it from lathe to lathe and take measurements.

I am quite sure the lathe with altered register will always be off.

We will see how repetitive readings will be.

I am a strong believer that the altered register has an effect on chuck Alignment. We will also see if the high point repeats as well.

I will publish results tomorrow.
In the meanwhile, the question about register rebuild is in the air.

Worst case scenario, the original 9A spindle will be back in commission until I find a viable solution

Guy Cadrin


---------- Original Messagea ----------
From: "Davis Johnson" <davis@...>
To: SouthBendLathe@groups.io
Subject: Re: [SouthBendLathe] Spindle register issue
Date: Thu, 21 Jun 2018 20:28:43 -0400

HTRL agrees with you (heresy around here, tho).

I'd be interested in an experiment.

Chuck up a short piece of scrap, turn the outside for a bit.

The part you just turned will be exactly concentric. Check it with an
indicator.

Unmount/remount the chuck several times without removing the piece of
scrap. Each time check it with an indicator.

I really would be interested in the results, and would do the experiment
myself except that I don't have a chuck with a loose register.

On 06/21/2018 08:15 PM, m. allan noah wrote:
I'll buck the conventional wisdom, and state that the register
diameter does not matter at all. The conical face of the thread, and
the flat shoulder behind the register are sufficiently to achieve
kinematic positioning of the chuck.

I daresay the problem is your testing method. Reground jaws is
basically meaningless, unless they were ground on the lathe in
question, properly preloaded, with the diameter set to exactly the
size of the stock you are now holding. Take of the chuck, and put it
back on, and see if it is consistent. That is a true test.

allan

On Thu, Jun 21, 2018 at 8:00 PM, carbure2003 <guycad@...> wrote:
About. a year ago, I bought a 10K spindle on ebay.

As I have not used much the lathe where I fitted the spindle, ( only with collets) I never noticed that the register was under sized. (1.495 in dia), quite likely machined by a previous owner.

I trialed a chuck with freshly re ground jaws on it and it was defenitely off centered by many thou.

Register defenitely has importance when yo want to swap chucks from lathe to lathe and keep chuck accuracy.
Did somebody ever attempt to rebuild a spindle register ? (Register is 1.510 in dia on my other SB)

If yes, how did you proceed? (Welding is not an option)

Thanks

Guy Cadrin
____________________________________________________________
70s Millionaire Returns with Surprising Prediction
unrestrictedinvesting.com
http://thirdpartyoffers.netzero.net/TGL3241/5b2c3c71941fa3c711a12st03vuc

m. allan noah
 

I have repeatedly done this experiment on a couple different lathes,
and the work always repeats to within a tenth, even in cases where the
register bore the the chuck backplate is several thou oversize. The
only time i see any variation is if I tighten the chuck differently,
and that seems to be corrected by the first good depth cut. Thats why
I feel confident enough to suggest heresy :)

If I were dead-set on enlarging the register, i would probably turn it
further undersize, and shrink a ring onto it, and then turn the ring
in situ. I'd try to avoid heating the spindle, don't want to mess with
any heat treatment, or cause any warping.

allan

On Thu, Jun 21, 2018 at 8:28 PM, Davis Johnson <davis@...> wrote:
HTRL agrees with you (heresy around here, tho).

I'd be interested in an experiment.

Chuck up a short piece of scrap, turn the outside for a bit.

The part you just turned will be exactly concentric. Check it with an
indicator.

Unmount/remount the chuck several times without removing the piece of scrap.
Each time check it with an indicator.

I really would be interested in the results, and would do the experiment
myself except that I don't have a chuck with a loose register.



On 06/21/2018 08:15 PM, m. allan noah wrote:

I'll buck the conventional wisdom, and state that the register
diameter does not matter at all. The conical face of the thread, and
the flat shoulder behind the register are sufficiently to achieve
kinematic positioning of the chuck.

I daresay the problem is your testing method. Reground jaws is
basically meaningless, unless they were ground on the lathe in
question, properly preloaded, with the diameter set to exactly the
size of the stock you are now holding. Take of the chuck, and put it
back on, and see if it is consistent. That is a true test.

allan

On Thu, Jun 21, 2018 at 8:00 PM, carbure2003 <guycad@...> wrote:

About. a year ago, I bought a 10K spindle on ebay.

As I have not used much the lathe where I fitted the spindle, ( only with
collets) I never noticed that the register was under sized. (1.495 in dia),
quite likely machined by a previous owner.

I trialed a chuck with freshly re ground jaws on it and it was defenitely
off centered by many thou.

Register defenitely has importance when yo want to swap chucks from lathe
to lathe and keep chuck accuracy.
Did somebody ever attempt to rebuild a spindle register ? (Register is
1.510 in dia on my other SB)

If yes, how did you proceed? (Welding is not an option)

Thanks

Guy Cadrin
____________________________________________________________
70s Millionaire Returns with Surprising Prediction
unrestrictedinvesting.com
http://thirdpartyoffers.netzero.net/TGL3241/5b2c3c71941fa3c711a12st03vuc



--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"

Paolo Amedeo
 

Unfortunately, if the shoulder of your backing plate is not cut correctly and making proper contact with the shoulder on the spindle, your results won't be very meaningful: the chuck could mount fairly repeatably on the spindle you ground the jaws on, even with the shoulders not making contact at all and just the threads being jammed. But, as soon as you mount it on practically any other spindle, it will be off. By using the unthreaded portion of the spindle to align the backplate (sorry, I won't call it a register, since it is not intended to be it), the backplate will be crocked the amount of play between internal and external diameter.

I agree with Jim that the shoulder on SB 9" is ridiculously tiny and that you need to make sure to cut a very sharp shoulder on the backplate.

Paolo
Damascus, MD

On 6/21/2018 21:47, carbure2003 wrote:
I will do the experiment tomorrow night. I have 3 SB in the basement ( one is not powered, being in storage)

I will turn a piece and move it from lathe to lathe and take measurements.

I am quite sure the lathe with altered register will always be off.

We will see how repetitive readings will be.

I am a strong believer that the altered register has an effect on chuck Alignment. We will also see if the high point repeats as well.

I will publish results tomorrow.
In the meanwhile, the question about register rebuild is in the air.

Worst case scenario, the original 9A spindle will be back in commission until I find a viable solution

Guy Cadrin

carbure2003
 

I machined a piece of steel.

On my 10K, it repeats within less than half a thou.

Same chuck transferred on 9A with intact spindle, it repeats within 3 thou.

On the 9A with altered spindle, it is off centered by 7 thou.

3 thou is acceptable, 7 is not.

Guy

---------- Original Message ----------
From: "Jim_B" <@Jim_B>
To: SouthBendLathe@groups.io
Subject: Re: [SouthBendLathe] Spindle register issue
Date: Thu, 21 Jun 2018 21:44:12 -0400

I have many times removed a chuck with a face plate in it, while threading the face plate, to test the fit on the spindle threads.
When the chuck and face plate were screwed back on registration was perfect.

I am not sure if all my chucks were tight fits on the “registration step” or they used the threads and the spindle stop.

The 9” Workshop and the 10k have a very small stop behind the register.
If the faceplate has any radius on the threaded bore you may or may not properly register on the stop.
The Heavy 10 and larger lathes have a good stop.


Sent from my iPhone-8
Jim B,

On Jun 21, 2018, at 8:28 PM, Davis Johnson <davis@...> wrote:

HTRL agrees with you (heresy around here, tho).

I'd be interested in an experiment.

Chuck up a short piece of scrap, turn the outside for a bit.

The part you just turned will be exactly concentric. Check it with an indicator.

Unmount/remount the chuck several times without removing the piece of scrap. Each time check it with an indicator.

I really would be interested in the results, and would do the experiment myself except that I don't have a chuck with a loose register.




--
Jim B


____________________________________________________________
We Say Goodbye To Lara Spencer
risingstarnewspaper.com
http://thirdpartyoffers.netzero.net/TGL3241/5b2da6b340efa26b323b4st03vuc

m. allan noah
 

So, if you turn that piece of steel on the 9A with the altered
spindle, it will run true. If you then remove and reinstall the chuck
without removing the workpiece from it, does it repeat well?

allan

On Fri, Jun 22, 2018 at 9:46 PM, carbure2003 <guycad@...> wrote:

I machined a piece of steel.

On my 10K, it repeats within less than half a thou.

Same chuck transferred on 9A with intact spindle, it repeats within 3 thou.

On the 9A with altered spindle, it is off centered by 7 thou.

3 thou is acceptable, 7 is not.

Guy



---------- Original Message ----------
From: "Jim_B" <@Jim_B>
To: SouthBendLathe@groups.io
Subject: Re: [SouthBendLathe] Spindle register issue
Date: Thu, 21 Jun 2018 21:44:12 -0400

I have many times removed a chuck with a face plate in it, while threading the face plate, to test the fit on the spindle threads.
When the chuck and face plate were screwed back on registration was perfect.

I am not sure if all my chucks were tight fits on the “registration step” or they used the threads and the spindle stop.

The 9” Workshop and the 10k have a very small stop behind the register.
If the faceplate has any radius on the threaded bore you may or may not properly register on the stop.
The Heavy 10 and larger lathes have a good stop.


Sent from my iPhone-8
Jim B,

On Jun 21, 2018, at 8:28 PM, Davis Johnson <davis@...> wrote:

HTRL agrees with you (heresy around here, tho).

I'd be interested in an experiment.

Chuck up a short piece of scrap, turn the outside for a bit.

The part you just turned will be exactly concentric. Check it with an indicator.

Unmount/remount the chuck several times without removing the piece of scrap. Each time check it with an indicator.

I really would be interested in the results, and would do the experiment myself except that I don't have a chuck with a loose register.




--
Jim B


____________________________________________________________
We Say Goodbye To Lara Spencer
risingstarnewspaper.com
http://thirdpartyoffers.netzero.net/TGL3241/5b2da6b340efa26b323b4st03vuc


--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"

Earl White
 

Just a thought and It's probably way off, but if that is a scroll chuck, you might have put the wrong jaws in the wrong slots.  Each jaw is different depending on the number stamped on the jaw.  In other words the #1 jaw has to go back in the #1 slot and so on, other wise the jaws will not center at all and your work will be way off center.  

Earl

On Fri, Jun 22, 2018 at 7:44 PM, m. allan noah <kitno455@...> wrote:
So, if you turn that piece of steel on the 9A with the altered
spindle, it will run true. If you then remove and reinstall the chuck
without removing the workpiece from it, does it repeat well?

allan

On Fri, Jun 22, 2018 at 9:46 PM, carbure2003 <guycad@...> wrote:
>
> I machined a piece of steel.
>
> On my 10K, it repeats within less than half a thou.
>
> Same chuck transferred on 9A with intact spindle, it repeats within 3 thou.
>
> On the 9A with altered spindle, it is off centered by 7 thou.
>
> 3 thou is acceptable, 7 is not.
>
> Guy
>
>
>
> ---------- Original Message ----------
> From: "Jim_B" <jim@...>
> To: SouthBendLathe@groups.io
> Subject: Re: [SouthBendLathe] Spindle register issue
> Date: Thu, 21 Jun 2018 21:44:12 -0400
>
> I have many times removed a chuck with a face plate in it, while threading the face plate, to test the fit on the spindle threads.
> When the chuck and face plate were screwed back on registration was perfect.
>
> I am not sure if all my chucks were tight fits on the “registration step” or they used the threads and the spindle stop.
>
> The 9” Workshop and the 10k have a very small stop behind the register.
> If the faceplate has any radius on the threaded bore you may or may not properly register on the stop.
> The Heavy 10 and larger lathes have a good stop.
>
>
> Sent from my iPhone-8
> Jim B,
>
>> On Jun 21, 2018, at 8:28 PM, Davis Johnson <davis@...> wrote:
>>
>> HTRL agrees with you (heresy around here, tho).
>>
>> I'd be interested in an experiment.
>>
>> Chuck up a short piece of scrap, turn the outside for a bit.
>>
>> The part you just turned will be exactly concentric. Check it with an indicator.
>>
>> Unmount/remount the chuck several times without removing the piece of scrap. Each time check it with an indicator.
>>
>> I really would be interested in the results, and would do the experiment myself except that I don't have a chuck with a loose register.
>>
>>
>>
>
>
>
> --
> Jim B
>
>
> ____________________________________________________________
> We Say Goodbye To Lara Spencer
> risingstarnewspaper.com
> http://thirdpartyoffers.netzero.net/TGL3241/5b2da6b340efa26b323b4st03vuc
>
>
>



--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"