Hi all,

Is there a way I can get a mirror like finish on a turned piece of
metal? I know I can use 1000 grit and finer on a piece as it is
chucked and turning in a lather, but how about the bored hole? How
would I get a, say, 1/4" or 3/8" internal surface glass smooth? I am
thinking of some sort of expanding reamer that I could put a 1000 grit
wet/dry sheet around and insert it in the hole as it is turning...seems
like I would just bunch up the paper though ;-)

Anyone ever have to get something "barring" smooth internally....what
did ya use?

Thanks again gang....as always, any help is greatly appreciated

John

I think that the tool your looking for is a lap or hone. You can also ball
size a hole and get a good surface. Some depends on the material your
polishing. For just polishing without worrying about real accurate size you
can charge a bit of cloth with polishing compound and put it in a folded
wire and run it with a drill motor. Describe to us what the material, size
restrictions on finished size, and what the hole is to be used for. then
some more accurate answers can be given.
lg
no neat sig line
"CAMCOMPCO" wrote in message
oups.com...
Hi all,

Is there a way I can get a mirror like finish on a turned piece of
metal?
Anyone ever have to get something "barring" smooth internally....what
did ya use?
Do you mean "bearing smooth"?


Thanks again gang....as always, any help is greatly appreciated

John

"CAMCOMPCO" wrote in
oups.com:

Hi all,

Is there a way I can get a mirror like finish on a turned piece of
metal? I know I can use 1000 grit and finer on a piece as it is
chucked and turning in a lather, but how about the bored hole? How
would I get a, say, 1/4" or 3/8" internal surface glass smooth? I am
thinking of some sort of expanding reamer that I could put a 1000 grit
wet/dry sheet around and insert it in the hole as it is turning...seems
like I would just bunch up the paper though ;-)

Anyone ever have to get something "barring" smooth internally....what
did ya use?

Thanks again gang....as always, any help is greatly appreciated


A burnishing tool is the usual way. Barring that, if it's a through hole
you can "ballize" the hole. In other words, drill and ream the hole
slightly undersize then press the appropriate size ball bearing ball
through the hole. You can also use emory wrapped on a wooden dowel to
polish the I.D. (put a slot on the end to help with the wrap) and then
follow up with a split lap and some lapping compund.


--

Dan

Yes, bearing, 7 years of University studies never taught me to second
guess spell check ;-)

This is as a general skill question...I want the hole to be exactly XYZ
when I am done, in practice, +/- 0.001. Now, I can get the hole that
precise, just cant get it glass smooth. If I am to understand the
ballize description provided by Dan, the hardened ball bearing is
pushed through the hole, essentially smashing the bumps and scratched
flat. Now I have a reason to hunt for ball bearings on ebay.

I'll try the emery wrap, just don't want to sand away accuracy....I
give it a try tomorrow provide update...

Cheers, and thanks again Larry and Dan

John

Yes, bearing, 7 years of University studies never taught me to second
guess spell check ;-)

This is as a general skill question...I want the hole to be exactly XYZ
when I am done, in practice, +/- 0.001. Now, I can get the hole that
precise, just cant get it glass smooth. If I am to understand the
ballize description provided by Dan, the hardened ball bearing is
pushed through the hole, essentially smashing the bumps and scratched
flat. Now I have a reason to hunt for ball bearings on ebay.

I'll try the emery wrap, just don't want to sand away accuracy....I
give it a try tomorrow provide update...

Cheers, and thanks again Larry and Dan

John

"CAMCOMPCO" wrote in
oups.com:

If I am to understand the
ballize description provided by Dan, the hardened ball bearing is
pushed through the hole, essentially smashing the bumps and scratched
flat. Now I have a reason to hunt for ball bearings on ebay.

Exactly right. Kind of a poor man's burnishing tool. Here's a guy on Ebay
that sells gage balls (cheap):

http://search.ebay.com/_W0QQsassZtoolsupplyQQhtZ-1


--

Dan

"D Murphy" wrote in message
...
"CAMCOMPCO" wrote in
oups.com:

If I am to understand the
ballize description provided by Dan, the hardened ball bearing is
pushed through the hole, essentially smashing the bumps and scratched
flat. Now I have a reason to hunt for ball bearings on ebay.

Exactly right. Kind of a poor man's burnishing tool. Here's a guy on Ebay
that sells gage balls (cheap):

http://search.ebay.com/_W0QQsassZtoolsupplyQQhtZ-1


Nice find! But where are his metric-sized gage balls?

- Michael

Just what I was looking for...thanks a bunch

John

Last weekend I made an eccentric strap, similar to a connecting rod, for a
small steam engine. The eccentric strap (follower) needed to fit the
eccentric loosely enough to turn with usu. oil film. First, the strap was
made to outside dimensions with the bolt holes drilled and tapped - flats
were left on 2 sides perpendicular to the split lines, which is the normal
profile for an eccentric strap. Then the rough opening was bored to within
a few thousandths of finished size which was to be 0.806". Next, I made a
pair of go-no-go gauges on the lathe, of 0.806" and 0.808". (Wish I had a
set of gauge rods or balls) The strap was repositioned in the mill with the
flats oriented for splitting. It was split with a 0.020" slitting saw
through each side and the sides tightly bolted together. Next, it was
recentered in the mill and bored to near 0.806". Several boring passes were
made until the 0.806" gauge would just barely "go". The 0.808" gauge would
not "go". That yielded a very round hole (after splitting) of very nearly
0.806", maybe 1/2 to 1 thousandth over, but certainly between 0.806" and
0.808". Measuring with test gauges is a lot less "nervous" than the usu.
small hole gauges, at least for me. One thing to note: When very nearly to
finished size, 1 or 2 tenths can be removed by running the boring tool down
into the hole again, maybe more than once.

Bob Swinney
"CAMCOMPCO" wrote in message
oups.com...
Hi all,

Is there a way I can get a mirror like finish on a turned piece of
metal? I know I can use 1000 grit and finer on a piece as it is
chucked and turning in a lather, but how about the bored hole? How
would I get a, say, 1/4" or 3/8" internal surface glass smooth? I am
thinking of some sort of expanding reamer that I could put a 1000 grit
wet/dry sheet around and insert it in the hole as it is turning...seems
like I would just bunch up the paper though ;-)

Anyone ever have to get something "barring" smooth internally....what
did ya use?

Thanks again gang....as always, any help is greatly appreciated

John

The first thing is to bore the hole properly. You can get smooth surfaces
on the outside of a turning, you can do the same for the inside of a bore
with the right geometry on the cutting tip.
After that, the ball or a rod with a large end will definietely roll over
the sharp edges but will also make the scrapes along the radius of the bore
rather than around the bore. This may be more harmful than leaving a
slightly rougher surface around the bore. Better would be to hone with
either honing cutters or stones to keep the right orientation of the grooves
that are left and get the right size for the hole.
If you're making a split bearing surface, don't forget to use Plastigage on
the bearing to make sure that it is the right clearance that you desire.
The Plastigage is available at any auto machine shop or better auto parts
store. Once you have used the stuff on a bearing and see how well it works,
you'll never go back to any othe method of checking bearing clearances.

--
Why do penguins walk so far to get to their nesting grounds?

Right on, Bob! I totally agree; it is unwise to force anything through a
finished hole. Doing so, may bring the hole "to size", but it will surely
leave minute damage of its own. Thanks for the tip on Plastigage. I will
check on it.

Bob Swinney
"Bob May" wrote in message
...
The first thing is to bore the hole properly. You can get smooth surfaces
on the outside of a turning, you can do the same for the inside of a bore
with the right geometry on the cutting tip.
After that, the ball or a rod with a large end will definietely roll over
the sharp edges but will also make the scrapes along the radius of the
bore
rather than around the bore. This may be more harmful than leaving a
slightly rougher surface around the bore. Better would be to hone with
either honing cutters or stones to keep the right orientation of the
grooves
that are left and get the right size for the hole.
If you're making a split bearing surface, don't forget to use Plastigage
on
the bearing to make sure that it is the right clearance that you desire.
The Plastigage is available at any auto machine shop or better auto parts
store. Once you have used the stuff on a bearing and see how well it
works,
you'll never go back to any othe method of checking bearing clearances.

--
Why do penguins walk so far to get to their nesting grounds?

So is this a vote for not "ballizing" the hole with a bearing.....Dan,
what say you. Have you had success with it? It's interesting to note
how opinions on certain topics can generate both support and
condemnation at the same time...

Thoughts and comments from others...I guess I am going to cram a ball
in the hole, cut the "tube" open and check with a microscope
myself....Once I get my ball bearings in, I'll check and get back to
you all with the findings.

By the way, I never commented on the material....mostly CRS, SS or
Aluminum (mostly fortal these days).

Thanks again all.

John

On 26 Sep 2005 15:09:01 -0700, "CAMCOMPCO"
wrote:

So is this a vote for not "ballizing" the hole with a bearing.....Dan,
what say you. Have you had success with it? It's interesting to note
how opinions on certain topics can generate both support and
condemnation at the same time...

Thoughts and comments from others...I guess I am going to cram a ball
in the hole, cut the "tube" open and check with a microscope
myself....Once I get my ball bearings in, I'll check and get back to
you all with the findings.

By the way, I never commented on the material....mostly CRS, SS or
Aluminum (mostly fortal these days).

Thanks again all.

John
John,
You will find that gummier metals, like crs, will give you a better
finish than harder materials. Be sure to use the correct lube.
Cheers,
Eric R Snow,
E T Precision Machine

On Mon, 26 Sep 2005 16:16:06 -0700, Eric R Snow
wrote:

On 26 Sep 2005 15:09:01 -0700, "CAMCOMPCO"
wrote:

SNIP

John,
You will find that gummier metals, like crs, will give you a better
finish than harder materials. Be sure to use the correct lube.
Cheers,
Eric R Snow,
E T Precision Machine

Hey Eric and John,

Owwwwww...gotta diagree with THAT Eric. The harder the metal, the
better the surface will get, if done properly. Mirror, and I mean
MIRROR finishes in say D-2 are done by "hand men", whose job it is to
polish (and keep with-in size) the suface left by mill or lathe. They
start off with what-ever is rerquired in nthe 40 to 80 grit range, and
finsih with diamond paste, usally with a Foredom or Dumore hand-piece.

Take care.

Brian Lawson,
Bothwell, Ontario.

I could be wrong Brian, but, I think Eric may have been referring to
the Ballizing part from above, Correct me if I am wrong Eric. Now,
given that, Brian, you might still be absolutely correct :-)

Cheers

Ballsizing is a fairly common commercial method of sizing and finishing
holes. Should be lots of references to in on the web.

Dan

On Mon, 26 Sep 2005 20:20:29 -0400, Brian Lawson
wrote:


On Mon, 26 Sep 2005 16:16:06 -0700, Eric R Snow
wrote:

On 26 Sep 2005 15:09:01 -0700, "CAMCOMPCO"
wrote:

SNIP

John,
You will find that gummier metals, like crs, will give you a better
finish than harder materials. Be sure to use the correct lube.
Cheers,
Eric R Snow,
E T Precision Machine

Hey Eric and John,

Owwwwww...gotta diagree with THAT Eric. The harder the metal, the
better the surface will get, if done properly. Mirror, and I mean
MIRROR finishes in say D-2 are done by "hand men", whose job it is to
polish (and keep with-in size) the suface left by mill or lathe. They
start off with what-ever is rerquired in nthe 40 to 80 grit range, and
finsih with diamond paste, usally with a Foredom or Dumore hand-piece.

Take care.

Brian Lawson,
Bothwell, Ontario.
Brian, I meant that gummier materials will look better with ballsizing
than hard materials. My experience with ballsizing and roller
burnishing is limited, but that's the way it always worked for me, and
was what I was told would happen. Like form tapping. gummier, to a
point, is better, Of course, harder materials will polish up better.
Eric

"DeepDiver" wrote in
:

"D Murphy" wrote in message
...
"CAMCOMPCO" wrote in
oups.com:

If I am to understand the
ballize description provided by Dan, the hardened ball bearing is
pushed through the hole, essentially smashing the bumps and
scratched flat. Now I have a reason to hunt for ball bearings on
ebay.

Exactly right. Kind of a poor man's burnishing tool. Here's a guy on
Ebay that sells gage balls (cheap):

http://search.ebay.com/_W0QQsassZtoolsupplyQQhtZ-1


Nice find! But where are his metric-sized gage balls?


Don't know, but he must have bought a dump truck full of "inch" sized ones
at an auction or something. He's been selling them on ebay for some time
now.


--

Dan

"CAMCOMPCO" wrote in
oups.com:

So is this a vote for not "ballizing" the hole with a bearing.....Dan,
what say you. Have you had success with it? It's interesting to note
how opinions on certain topics can generate both support and
condemnation at the same time...

Thoughts and comments from others...I guess I am going to cram a ball
in the hole, cut the "tube" open and check with a microscope
myself....Once I get my ball bearings in, I'll check and get back to
you all with the findings.

By the way, I never commented on the material....mostly CRS, SS or
Aluminum (mostly fortal these days).


It's a crude form of burnishing. Thousands upon thousands of parts are
burnished everyday. This type of thing would be a big no-no in a medical
implant where impurities can get "rolled in", or in a critical
application where surface integrity was important, say in a tool steel
that was to be heat treated later. On materials that work harden it may
raise the hardness slightly. In all likelyhood the Aluminum might not
work as well as the stainless or CRS.

The trick is to get the hole straight, to the right size, and finish to
start with. That might take a little experimentation.

As far as burnishing a bearing surface, It's done all of the time. It's
how .0001" diameter tolerances are held on Swiss screw machine on the
tiny shafts inside clocks and watches. It's also how many manufacturers
of power tools size the shafts that run in race bearings.

The downside to using a ball is that it will happily follow a crooked
hole, and a big high spot in the hole will tend to push the ball over to
the lower side.


--

Dan

In article , spamto154
@comcast.net says...
"DeepDiver" wrote in
:

Exactly right. Kind of a poor man's burnishing tool. Here's a guy on
Ebay that sells gage balls (cheap):

http://search.ebay.com/_W0QQsassZtoolsupplyQQhtZ-1


Nice find! But where are his metric-sized gage balls?


Don't know, but he must have bought a dump truck full of "inch" sized ones
at an auction or something. He's been selling them on ebay for some time
now.


Cheaper, and metric sizes as well, from McMaster-Carr.

Ned Simmons

I used to manufacture an aluminum valve that had a polished bore.
I mounted a small permanently-lubricated ball-bearing assembly (sealed
both sides) on a stiff rod and clamped that in the lathe turret, and
clamped the valve body in the chuck. Spun the body and fed the bearing
slowly into the bore using power feed and some pressure, and got a
usable surface. I got the best finish when I had ground the bearing's
outer race to a barrel shape, and polished that.
Minimum bore size will be limited by the bearing OD, of
course, and for smaller holes there are proper roller-burnishing tools
available. They cost plenty, and only fit given sizes.

Dan

In article .com,
says...

I used to manufacture an aluminum valve that had a polished bore.
I mounted a small permanently-lubricated ball-bearing assembly (sealed
both sides) on a stiff rod and clamped that in the lathe turret, and
clamped the valve body in the chuck. Spun the body and fed the bearing
slowly into the bore using power feed and some pressure, and got a
usable surface. I got the best finish when I had ground the bearing's
outer race to a barrel shape, and polished that.

How much undersized from the bearing OD did you leave the
bore to start?

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

Ned Simmons wrote in
:

In article , spamto154
@comcast.net says...
"DeepDiver" wrote in
:

Exactly right. Kind of a poor man's burnishing tool. Here's a guy
on Ebay that sells gage balls (cheap):

http://search.ebay.com/_W0QQsassZtoolsupplyQQhtZ-1


Nice find! But where are his metric-sized gage balls?


Don't know, but he must have bought a dump truck full of "inch" sized
ones at an auction or something. He's been selling them on ebay for
some time now.


Cheaper, and metric sizes as well, from McMaster-Carr.

True, but not the same grade/material.


--

Dan

jim rozen wrote:
In article .com,
says...

I used to manufacture an aluminum valve that had a polished
bore. I mounted a small permanently-lubricated ball-bearing assembly
(sealed both sides) on a stiff rod and clamped that in the lathe
turret, and clamped the valve body in the chuck. Spun the body and
fed the bearing slowly into the bore using power feed and some
pressure, and got a usable surface. I got the best finish when I had
ground the bearing's outer race to a barrel shape, and polished that.

How much undersized from the bearing OD did you leave the
bore to start?

Jim

On a related subject I was making a cross slide stop for my Southbend lathe
http://www.rupert.net/~solar/SOUTHBEND13.html.
The materials at hand where a salvaged chunk of cast iron (broken Record
vice) and some string trimmer shafting.
BTW - string trimmer shafting is high quality, precision machined carbon
steel more or less equal to drill rod - NEVER THROW IT OUT and if you come
accross some - grab it.
I wanted a hole (actually two) drilled in the cast iron that would give a
sliding, no shake fit for the shafting.
I forget which number drill gave the loose fit but the next smaller size was
a somewhat too tight fit - light press?
I drilled the smaller size and then used a length of the shafting in this
manner.
I chucked it in the lathe and applied a vibrating engraver to the rotating
shaft.
Then I chucked the (now modified with vibrator warts) shaft in my drill
press and jammed that through the undersized hole in the cast iron - rerady
for disaster that never came.
The result was a *perfect fit*. Pushing the shaft through the hole felt like
pushing against a well tuned dashpot (and still does after several years of
use).

A buddy, and my maching guru came by later that day for a rum and coke
session.
I dragged him down to the shop to show off my latest triumph.
As soon as I said "no shake" he got that "total BS" look in his eye and
grabbed the protuding shaft.
Try as he might he could not detect *any* play!
This guy had forgotten more about machining than I will *ever* learn.
Essentially, I guess, I sort of 'burnished' that hole.

Regards.
Ken.

In article , spamto154
@comcast.net says...
Ned Simmons wrote in
:

In article , spamto154
@comcast.net says...
"DeepDiver" wrote in
:

Exactly right. Kind of a poor man's burnishing tool. Here's a guy
on Ebay that sells gage balls (cheap):

http://search.ebay.com/_W0QQsassZtoolsupplyQQhtZ-1


Nice find! But where are his metric-sized gage balls?


Don't know, but he must have bought a dump truck full of "inch" sized
ones at an auction or something. He's been selling them on ebay for
some time now.


Cheaper, and metric sizes as well, from McMaster-Carr.

True, but not the same grade/material.


See McMaster page 3394, exactly the same grade and material - Grade 25,
52100 steel. For example 100 1/4" balls from McM are $3.97 (p/n
9528K15), on ebay $9.99 (Item number: 4578478224).

Ned Simmons

wrote:
I used to manufacture an aluminum valve that had a polished bore.
I mounted a small permanently-lubricated ball-bearing assembly (sealed
both sides) on a stiff rod and clamped that in the lathe turret, and
clamped the valve body in the chuck. Spun the body and fed the bearing
slowly into the bore using power feed and some pressure, and got a
usable surface. I got the best finish when I had ground the bearing's
outer race to a barrel shape, and polished that.
Minimum bore size will be limited by the bearing OD, of
course, and for smaller holes there are proper roller-burnishing tools
available. They cost plenty, and only fit given sizes.

Dan

Thanks for the tip

I can visualize you forcing the bearings into the hole and the outer race of the
bearings picking up the same RPM from the hole as the two meet. So the relative
positions of the bearing race and the hole remain constant throughout the push
and withdrawal. Now, if my understanding of what you are doing is correct,
then is there any particular advantage drawn from having the chuck rotating?
The operation appears not unlike swaging a barrel.

A

According to Allen :
wrote:
I used to manufacture an aluminum valve that had a polished bore.
I mounted a small permanently-lubricated ball-bearing assembly (sealed
both sides) on a stiff rod and clamped that in the lathe turret, and
clamped the valve body in the chuck. Spun the body and fed the bearing
slowly into the bore using power feed and some pressure, and got a
usable surface. I got the best finish when I had ground the bearing's
outer race to a barrel shape, and polished that.
Minimum bore size will be limited by the bearing OD, of
course, and for smaller holes there are proper roller-burnishing tools
available. They cost plenty, and only fit given sizes.

Dan

Thanks for the tip

I can visualize you forcing the bearings into the hole and the outer race of the
bearings picking up the same RPM from the hole as the two meet. So the relative
positions of the bearing race and the hole remain constant throughout the push
and withdrawal. Now, if my understanding of what you are doing is correct,
then is there any particular advantage drawn from having the chuck rotating?
The operation appears not unlike swaging a barrel.

The impression that I got was that the OD of the bearing was
smaller than the ID of the bore, so it rolled around the bore as the
workpiece rotated. (The "some pressure" would be pressure of the roller
against the side wall of the bore, not axial pressure. Thus, it became
a form of roller burnishing tool. Not as stiff as one with three
rollers pressing into the bore at 120 degree spacing, but for a soft
workpiece material, it should suffice.

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 ---

DoN. Nichols wrote:
According to Allen :

wrote:

I used to manufacture an aluminum valve that had a polished bore.
I mounted a small permanently-lubricated ball-bearing assembly (sealed
both sides) on a stiff rod and clamped that in the lathe turret, and
clamped the valve body in the chuck. Spun the body and fed the bearing
slowly into the bore using power feed and some pressure, and got a
usable surface. I got the best finish when I had ground the bearing's
outer race to a barrel shape, and polished that.
Minimum bore size will be limited by the bearing OD, of
course, and for smaller holes there are proper roller-burnishing tools
available. They cost plenty, and only fit given sizes.

Dan


Thanks for the tip

I can visualize you forcing the bearings into the hole and the outer race of the
bearings picking up the same RPM from the hole as the two meet. So the relative
positions of the bearing race and the hole remain constant throughout the push
and withdrawal. Now, if my understanding of what you are doing is correct,
then is there any particular advantage drawn from having the chuck rotating?
The operation appears not unlike swaging a barrel.


The impression that I got was that the OD of the bearing was
smaller than the ID of the bore, so it rolled around the bore as the
workpiece rotated. (The "some pressure" would be pressure of the roller
against the side wall of the bore, not axial pressure. Thus, it became
a form of roller burnishing tool. Not as stiff as one with three
rollers pressing into the bore at 120 degree spacing, but for a soft
workpiece material, it should suffice.

Enjoy,
DoN.

That makes sense. Good call. I was thinking more of a swaging operation but I
can see I was wrong.

A

Ned Simmons wrote in
:

In article , spamto154
@comcast.net says...
Ned Simmons wrote in
:

In article , spamto154
@comcast.net says...
"DeepDiver" wrote in
:

Exactly right. Kind of a poor man's burnishing tool. Here's a
guy on Ebay that sells gage balls (cheap):

http://search.ebay.com/_W0QQsassZtoolsupplyQQhtZ-1


Nice find! But where are his metric-sized gage balls?


Don't know, but he must have bought a dump truck full of "inch"
sized ones at an auction or something. He's been selling them on
ebay for some time now.


Cheaper, and metric sizes as well, from McMaster-Carr.

True, but not the same grade/material.


See McMaster page 3394, exactly the same grade and material - Grade
25, 52100 steel. For example 100 1/4" balls from McM are $3.97 (p/n
9528K15), on ebay $9.99 (Item number: 4578478224).

I stand corrected. I did a quick search and found the ones on page 3404.
You would think that there would be more of a price difference between
the two. I guess since 52100 is used for bearings, the quantities they
are made in offsets the price for the extra precision.


--

Dan

"CAMCOMPCO" wrote in message
oups.com...
Hi all,

Is there a way I can get a mirror like finish on a turned piece of
metal? I know I can use 1000 grit and finer on a piece as it is
chucked and turning in a lather, but how about the bored hole? How
would I get a, say, 1/4" or 3/8" internal surface glass smooth? I am
thinking of some sort of expanding reamer that I could put a 1000 grit
wet/dry sheet around and insert it in the hole as it is turning...seems
like I would just bunch up the paper though ;-)

Anyone ever have to get something "barring" smooth internally....what
did ya use?

Thanks again gang....as always, any help is greatly appreciated

John

I haven't visited the newsgroup in quite a while, and you have probably
already finished your project but here is how I would do it.

I would use the same basic procedures that are used in making a custom rifle
barrel. First drill the hole undersize, ream and polish for a good finish
leaving the hole slightly undersize. Then silver solder a button (ball
bearing) to the end of a rod that is smaller than the hole size. Using a
good high pressure lubricant such a moly powder, or even anti-seize compound
that contains a fair amount of copper I would push/pull the button through
the barrel. Doing this with the hole about 0.005" undersize to start with
should leave a good finish.

Clean the inside to remove the moly or copper with a good penetrating oil
(such as Kroil) and very mild soft abrasive such as "J-B Bore Compound".
This is what is used by some shooters to clean the moly and brass from their
rifle barrels, without causing any extra wear. The J-B is a soft vegetable
based abrasive and will not remove any steel.

In article , DoN. Nichols says...

The impression that I got was that the OD of the bearing was
smaller than the ID of the bore, so it rolled around the bore as the
workpiece rotated.

And it seemed to me that the bearing was oversized by some amount
for the hole, and it was a sort of dynamic ball burnishing
effect.

I would be interested to know the details of the operation
because it sounds like it works pretty well.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

Thanks, project still in progress....it seems that alot of these
methods require making things a "normal" size...I gueass that's the
key. If you wander out of "normal" you enter tha land of cutom tooling
(cutum reamers....yikes).

Thanks for the info...

John

"Ned Simmons" wrote in message
...
In article , spamto154
@comcast.net says...
"DeepDiver" wrote in
:

Exactly right. Kind of a poor man's burnishing tool. Here's a guy on
Ebay that sells gage balls (cheap):

http://search.ebay.com/_W0QQsassZtoolsupplyQQhtZ-1


Nice find! But where are his metric-sized gage balls?


Don't know, but he must have bought a dump truck full of "inch" sized
ones
at an auction or something. He's been selling them on ebay for some time
now.


Cheaper, and metric sizes as well, from McMaster-Carr.

Ned Simmons

Thanks Ned for the tip!