Where do shaft sizes like 0.1545" come from? There's a few small diameter
ones like this that don't match any fraction I'be come across.

On Wed, 18 Aug 2021 20:35:17 -0000 (UTC), Cydrome Leader
<presence@MUNGEpanix.com> wrote:

>Where do shaft sizes like 0.1545" come from? There's a few small diameter
>ones like this that don't match any fraction I'be come across.
>
>
About as close to 4mm as Damn is to swearing.

"Clare Snyder" wrote in message
news:lesqhg5mq2ts3i4gd5bdkeerhua25i8jj0@4ax.com...

On Wed, 18 Aug 2021 20:35:17 -0000 (UTC), Cydrome Leader
<presence@MUNGEpanix.com> wrote:

>Where do shaft sizes like 0.1545" come from? There's a few small diameter
>ones like this that don't match any fraction I'be come across.
>
>
About as close to 4mm as Damn is to swearing.
---------------------
It's even closer to 5/32". Maybe the shaft was meant to be a running fit in
a reamed hole? It's easier to make a custom OD than a small custom ID,
though I've found second-hand reamers 0.001" over and under standard
fractional size.

Jim Wilkins <muratlanne@gmail.com> wrote:
> "Clare Snyder" wrote in message
> news:lesqhg5mq2ts3i4gd5bdkeerhua25i8jj0@4ax.com...
>
> On Wed, 18 Aug 2021 20:35:17 -0000 (UTC), Cydrome Leader
> <presence@MUNGEpanix.com> wrote:
>
>>Where do shaft sizes like 0.1545" come from? There's a few small diameter
>>ones like this that don't match any fraction I'be come across.
>>
>>
> About as close to 4mm as Damn is to swearing.
> ---------------------
> It's even closer to 5/32". Maybe the shaft was meant to be a running fit in
> a reamed hole? It's easier to make a custom OD than a small custom ID,
> though I've found second-hand reamers 0.001" over and under standard
> fractional size.

It doesn't seem to fall into the over or under by 0.001 range though. I
can't find the motor now, but I think 0.178" is another small inch shaft
size that I come across.

On 18/08/2021 21:35, Cydrome Leader wrote:
> Where do shaft sizes like 0.1545" come from? There's a few small diameter
> ones like this that don't match any fraction I'be come across.
>
>
>
Maybe a wire gauge but I can't find a better match than the 4mm or 5/32"
already mentioned even amongst obsolete wire gauges. Traditional Meccano
shafts are 8SWG (0.160")(4.06mm). I got into work one day some years ago
and a couple of the designers I worked with were discussing why another
designer who was no longer with the company would have called up a
spacer of 0.065", I pointed out that 0.065" was 16SWG and commonplace
when the design was done, much less so after metrification in the UK, I
don't know what they did to resolve the issue I left that to them as I
was working on software.

"David Billington" wrote in message news:sfk8hu$a08$1@dont-email.me...

On 18/08/2021 21:35, Cydrome Leader wrote:
> Where do shaft sizes like 0.1545" come from? There's a few small diameter
> ones like this that don't match any fraction I'be come across.
>
>
>
Maybe a wire gauge but I can't find a better match than the 4mm or 5/32"
already mentioned even amongst obsolete wire gauges. Traditional Meccano
shafts are 8SWG (0.160")(4.06mm). I got into work one day some years ago
and a couple of the designers I worked with were discussing why another
designer who was no longer with the company would have called up a
spacer of 0.065", I pointed out that 0.065" was 16SWG and commonplace
when the design was done, much less so after metrification in the UK, I
don't know what they did to resolve the issue I left that to them as I
was working on software.
----------------------------------------

The hardware store inch-size washers I buy come in a range of almost random
thicknesses, which helps when I need a shim. I suppose they were punched
from whatever sheet stock was available cheaply, perhaps because it was out
of spec. Their aluminum and steel rod stock is also loosely sized and
doesn't always fit 5C collets. I've had better luck with CRS shafting which
machines much better, but it's not as easily available.

"Cydrome Leader" wrote in message news:sfk3t3$gi1$1@reader1.panix.com...

Jim Wilkins <muratlanne@gmail.com> wrote:
> "Clare Snyder" wrote in message
> news:lesqhg5mq2ts3i4gd5bdkeerhua25i8jj0@4ax.com...
>
> On Wed, 18 Aug 2021 20:35:17 -0000 (UTC), Cydrome Leader
> <presence@MUNGEpanix.com> wrote:
>
>>Where do shaft sizes like 0.1545" come from? There's a few small diameter
>>ones like this that don't match any fraction I'be come across.
>>
>>
> About as close to 4mm as Damn is to swearing.
> ---------------------
> It's even closer to 5/32". Maybe the shaft was meant to be a running fit
> in
> a reamed hole? It's easier to make a custom OD than a small custom ID,
> though I've found second-hand reamers 0.001" over and under standard
> fractional size.

It doesn't seem to fall into the over or under by 0.001 range though. I
can't find the motor now, but I think 0.178" is another small inch shaft
size that I come across.

------------------------------

There are bearing clearance standards, in fact lots of them, so pick the one
you like.

https://www.plantengineering.com/articles/sleeve-bearing-clearance-depends-on-many-factors/

On 8/18/2021 1:35 PM, Cydrome Leader wrote:
> Where do shaft sizes like 0.1545" come from? There's a few small diameter
> ones like this that don't match any fraction I'be come across.
>
>
>

I guess the first question would have to be is it really a "precision"
shaft or just a piece of round bar? Even if it is precision shaft what
are the tolerances of manufacture. Look at the notes on most any
size/shape stock on the McMaster Carr website to see what I mean.
Sometimes its right up on top, and sometimes you have to click on the
individual product information link.

The next question is how much does the exact size matter?

--
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https://www.avg.com

Bob La Londe <none@none.com99> wrote:
> On 8/18/2021 1:35 PM, Cydrome Leader wrote:
>> Where do shaft sizes like 0.1545" come from? There's a few small diameter
>> ones like this that don't match any fraction I'be come across.
>>
>>
>>
>
> I guess the first question would have to be is it really a "precision"
> shaft or just a piece of round bar? Even if it is precision shaft what
> are the tolerances of manufacture. Look at the notes on most any
> size/shape stock on the McMaster Carr website to see what I mean.
> Sometimes its right up on top, and sometimes you have to click on the
> individual product information link.
>
> The next question is how much does the exact size matter?

It's precision and common on small motors shafts. They make matching
radial bearings and reamers for this size. I just can't figure out where
these bizarre sizes originated.

To be specific, C-frame fan motors have sizes like this as do some fairly
expensive DC motors. If you just throw a ruler on these motors, you get
darn close to x/32nds. If you have to make mating parts, you'll run into
some serious problems.

In the metric world for shafts, they seem to have nice clean ODs even on
ground and polished shafts, even in the sum 1/4" range. 2.0, 2.5 3mm etc.
The sleeve bearings may have more clearannce, but no big deal there.

One servo motor in my hand has the shafts turned down to 0.1545" and it's
no fluke. The shaft inside the motor and bearings are bigger and likely
metric, but this number is no accident and common practice.

"Cydrome Leader" wrote in message news:sfopag$24h$1@reader1.panix.com...

It's precision and common on small motors shafts. They make matching
radial bearings and reamers for this size. I just can't figure out where
these bizarre sizes originated.

--------------

Motor manufacturers' catalogs might tell you.

On Fri, 20 Aug 2021 09:07:20 -0700, Bob La Londe <none@none.com99>
wrote:

>On 8/18/2021 1:35 PM, Cydrome Leader wrote:
>> Where do shaft sizes like 0.1545" come from? There's a few small diameter
>> ones like this that don't match any fraction I'be come across.
>>
>>
>>
>
>I guess the first question would have to be is it really a "precision"
>shaft or just a piece of round bar? Even if it is precision shaft what
>are the tolerances of manufacture. Look at the notes on most any
>size/shape stock on the McMaster Carr website to see what I mean.
>Sometimes its right up on top, and sometimes you have to click on the
>individual product information link.
>
>The next question is how much does the exact size matter?
Sometimes the shaft is unsersized to provide clearance in a
"pricision" bearing. The shaft is 3.924mm - providing just under .003"
running clearance in a 4mm bearing.

Jim Wilkins <muratlanne@gmail.com> wrote:
> "Cydrome Leader" wrote in message news:sfopag$24h$1@reader1.panix.com...
>
> It's precision and common on small motors shafts. They make matching
> radial bearings and reamers for this size. I just can't figure out where
> these bizarre sizes originated.
>
> --------------
>
> Motor manufacturers' catalogs might tell you.

Dear lord you fuckers are dense and out of touch.

There is no story about where this or 0.2175" shafts come from in
catalogs, and they are extremely common items.

On 20/08/2021 22:59, Cydrome Leader wrote:
> Jim Wilkins <muratlanne@gmail.com> wrote:
>> "Cydrome Leader" wrote in message news:sfopag$24h$1@reader1.panix.com...
>>
>> It's precision and common on small motors shafts. They make matching
>> radial bearings and reamers for this size. I just can't figure out where
>> these bizarre sizes originated.
>>
>> --------------
>>
>> Motor manufacturers' catalogs might tell you.
> Dear lord you fuckers are dense and out of touch.
>
> There is no story about where this or 0.2175" shafts come from in
> catalogs, and they are extremely common items.
>
>
Because of how close the sizes are to fraction inch sizes, 0.2175" being
near 7/32", I wonder if the dimensions pre-date the common tolerance
system we use today and the bush bores were made to the fractional inch
size and the shaft suitably undersized to give the needed running
clearance.  The fact that the sizes are still in use today may just be a
legacy thing to maintain compatibility like happens in so many other fields.

On Friday, August 20, 2021 at 7:15:10 PM UTC-4, David Billington wrote:
> On 20/08/2021 22:59, Cydrome Leader wrote:
> > Jim Wilkins <murat...@gmail.com> wrote:
> >> "Cydrome Leader" wrote in message news:sfopag$24h$1...@reader1.panix.com...
> >>
> >> It's precision and common on small motors shafts. They make matching
> >> radial bearings and reamers for this size. I just can't figure out where
> >> these bizarre sizes originated.
> >>
> >> --------------
> >>
> >> Motor manufacturers' catalogs might tell you.
> > Dear lord you fuckers are dense and out of touch.
> >
> > There is no story about where this or 0.2175" shafts come from in
> > catalogs, and they are extremely common items.
> >
> >
> Because of how close the sizes are to fraction inch sizes, 0.2175" being
> near 7/32", I wonder if the dimensions pre-date the common tolerance
> system we use today and the bush bores were made to the fractional inch
> size and the shaft suitably undersized to give the needed running
> clearance. The fact that the sizes are still in use today may just be a
> legacy thing to maintain compatibility like happens in so many other fields.

Is it a standard inch size less a little bit? Sort of like a 2x4?

John

On Thursday, August 19, 2021 at 5:35:51 AM UTC-7, Jim Wilkins wrote:

> The hardware store inch-size washers I buy come in a range of almost random
> thicknesses, which helps when I need a shim. I suppose they were punched
> from whatever sheet stock was available cheaply, perhaps because it was out
> of spec.

That's not unlikely; a job shop doing stampings will frequently have leftover
parts of whole sheets of material, and can make a bit more money by punching
out washers than from recycling the remainder as scrap for remelting.

whit3rd <whit3rd@gmail.com> wrote:
> On Thursday, August 19, 2021 at 5:35:51 AM UTC-7, Jim Wilkins wrote:
>
>> The hardware store inch-size washers I buy come in a range of almost random
>> thicknesses, which helps when I need a shim. I suppose they were punched
>> from whatever sheet stock was available cheaply, perhaps because it was out
>> of spec.
>
> That's not unlikely; a job shop doing stampings will frequently have leftover
> parts of whole sheets of material, and can make a bit more money by punching
> out washers than from recycling the remainder as scrap for remelting.

hardware store washers are definitely the worst of the worst, if you're
looking for any type of consistency. I make it point to show people the
random thicknesses in of those things. They must be running the worn out
dies on scrap until they finally fail. Might also be the junk from setting
up the machines.

On the other hand, Lawson makes some real nice washers if you don't want
to worry about sharp edges up or down. Some appear to be fineblanked.

On 8/20/2021 4:15 PM, David Billington wrote:
> On 20/08/2021 22:59, Cydrome Leader wrote:
>> Jim Wilkins <muratlanne@gmail.com> wrote:
>>> "Cydrome Leader"  wrote in message
>>> news:sfopag$24h$1@reader1.panix.com...
>>>
>>> It's precision and common on small motors shafts. They make matching
>>> radial bearings and reamers for this size. I just can't figure out where
>>> these bizarre sizes originated.
>>>
>>> --------------
>>>
>>> Motor manufacturers' catalogs might tell you.
>> Dear lord you fuckers are dense and out of touch.
>>
>> There is no story about where this or 0.2175" shafts come from in
>> catalogs, and they are extremely common items.
>>
>>
> Because of how close the sizes are to fraction inch sizes, 0.2175" being
> near 7/32", I wonder if the dimensions pre-date the common tolerance
> system we use today and the bush bores were made to the fractional inch
> size and the shaft suitably undersized to give the needed running
> clearance.  The fact that the sizes are still in use today may just be a
> legacy thing to maintain compatibility like happens in so many other
> fields.
>

I'm just a dense fucker, so I'll reserve any further speculation.

--
This email has been checked for viruses by AVG.
https://www.avg.com

Bob La Londe <none@none.com99> wrote:
> On 8/20/2021 4:15 PM, David Billington wrote:
>> On 20/08/2021 22:59, Cydrome Leader wrote:
>>> Jim Wilkins <muratlanne@gmail.com> wrote:
>>>> "Cydrome Leader"  wrote in message
>>>> news:sfopag$24h$1@reader1.panix.com...
>>>>
>>>> It's precision and common on small motors shafts. They make matching
>>>> radial bearings and reamers for this size. I just can't figure out where
>>>> these bizarre sizes originated.

>>>> Motor manufacturers' catalogs might tell you.
>>> Dear lord you fuckers are dense and out of touch.
>>>
>>> There is no story about where this or 0.2175" shafts come from in
>>> catalogs, and they are extremely common items.
>>>
>> Because of how close the sizes are to fraction inch sizes, 0.2175" being
>> near 7/32", I wonder if the dimensions pre-date the common tolerance
>> system we use today and the bush bores were made to the fractional inch
>> size and the shaft suitably undersized to give the needed running
>> clearance.  The fact that the sizes are still in use today may just be a
>> legacy thing to maintain compatibility like happens in so many other
>> fields.
> I'm just a dense fucker, so I'll reserve any further speculation.

What? Not going to post? Considerations like not knowing for sure or
being totally dense usually don't stop most posters from spouting
their speculations as gospel truth.

My guess would be that manufacturers would buy either 5/32" material
or a wire gauge size about 5/32" or just over, and then grind just
enough off to get a true straight shaft, this size then became the
standard.

Sort of why TGP is common in sizes like 3-15/16". Start at 4" and true
it up.

Randy

On Wed, 18 Aug 2021 20:35:17 -0000 (UTC), Cydrome Leader
<presence@MUNGEpanix.com> wrote:

>Where do shaft sizes like 0.1545" come from? There's a few small diameter
>ones like this that don't match any fraction I'be come across.
>
>