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  #1   Report Post  
Christopher Tidy
 
Posts: n/a
Default Another piston ring question

Hi,

As everyone was so helpful with my last question about piston rings, I'd
like to ask another. I unwrapped the new rings for my Wolseley engine
this afternoon ready for fitting. Surprisingly there were four rings in
the pack, whereas there are three on the piston. The first two rings on
the piston are identical plain cast iron rings a little over 1/8" thick.
The third ring is a slotted cast iron oil control ring about 1/4" thick
(the bore is 3"). In the packet I have two identical rings which fit the
first two grooves fine. Then I have a slotted oil control ring which is
narrower that the original (perhaps by 1/16"), and a very thin ring
which is about 1/16" thick. When placed together these two rings are the
same thickness as the original oil control ring, and fit neatly into the
groove.

So it would appear that I am intended to replace the original oil
control ring with two rings. Is this common practice when the correct
ring is unavailable? I bought the rings a few years back and now I have
a vague recollection of some discussion about this, but I can't remember
the details. I just need to decide whether it's okay to fit these rings.
I should point out that this is a big, chugging engine which isn't
highly stressed (1.5 hp at 700 rpm with a 3" bore) so it's probably
going to be more forgiving than modern engines. What do people think?

Any suggestions would be much appreciated.

Many thanks,

Chris

  #2   Report Post  
 
Posts: n/a
Default

If memory serves, the thin ring is a support for the oil control ring
and is fitted below the oill control ring. Remember to stagger the
gaps!

All the best,

Charles

  #3   Report Post  
Larry Jaques
 
Posts: n/a
Default

On Thu, 19 May 2005 16:35:58 +0000 (UTC), the inscrutable Christopher
Tidy spake:

Hi,

As everyone was so helpful with my last question about piston rings, I'd
like to ask another. I unwrapped the new rings for my Wolseley engine
this afternoon ready for fitting. Surprisingly there were four rings in
the pack, whereas there are three on the piston. The first two rings on
the piston are identical plain cast iron rings a little over 1/8" thick.
The third ring is a slotted cast iron oil control ring about 1/4" thick
(the bore is 3"). In the packet I have two identical rings which fit the
first two grooves fine. Then I have a slotted oil control ring which is
narrower that the original (perhaps by 1/16"), and a very thin ring
which is about 1/16" thick. When placed together these two rings are the
same thickness as the original oil control ring, and fit neatly into the
groove.


The overlapped pair, with their openings more often offset than
aligned, probably keeps more oil from escaping into the combustion
chamber.


So it would appear that I am intended to replace the original oil
control ring with two rings. Is this common practice when the correct
ring is unavailable?


Engineers probably found that the pair worked better (or broke less
frequently) than the original single piece.


I bought the rings a few years back and now I have
a vague recollection of some discussion about this, but I can't remember
the details. I just need to decide whether it's okay to fit these rings.
I should point out that this is a big, chugging engine which isn't
highly stressed (1.5 hp at 700 rpm with a 3" bore) so it's probably
going to be more forgiving than modern engines. What do people think?

Any suggestions would be much appreciated.


Dredging up memories from 33 years ago (auto tech school theory), I
believe it provides just slightly better oil control. I remember
having installed 4-pc oil rings. Thin upper and lower chromed rings
and a narrow center ring with www expanded spring below it.

-----
www|]
-----


================================================== =========
Save the Endangered Boullions from being cubed!
http://www.diversify.com/stees.html Hilarious T-shirts online
================================================== =========
  #4   Report Post  
Harold and Susan Vordos
 
Posts: n/a
Default


"Larry Jaques" wrote in message
...
snip-----

I remember
having installed 4-pc oil rings. Thin upper and lower chromed rings
and a narrow center ring with www expanded spring below it.



Yep!

Harold


  #5   Report Post  
Tom
 
Posts: n/a
Default

Christopher Tidy wrote:

Hi,

As everyone was so helpful with my last question about piston rings, I'd
like to ask another. I unwrapped the new rings for my Wolseley engine
this afternoon ready for fitting. Surprisingly there were four rings in
the pack, whereas there are three on the piston. The first two rings on
the piston are identical plain cast iron rings a little over 1/8" thick.
The third ring is a slotted cast iron oil control ring about 1/4" thick
(the bore is 3"). In the packet I have two identical rings which fit the
first two grooves fine. Then I have a slotted oil control ring which is
narrower that the original (perhaps by 1/16"), and a very thin ring
which is about 1/16" thick. When placed together these two rings are the
same thickness as the original oil control ring, and fit neatly into the
groove.

So it would appear that I am intended to replace the original oil
control ring with two rings. Is this common practice when the correct
ring is unavailable? I bought the rings a few years back and now I have
a vague recollection of some discussion about this, but I can't remember
the details. I just need to decide whether it's okay to fit these rings.
I should point out that this is a big, chugging engine which isn't
highly stressed (1.5 hp at 700 rpm with a 3" bore) so it's probably
going to be more forgiving than modern engines. What do people think?

Any suggestions would be much appreciated.

Many thanks,

Chris


The thin ring is only a spacing ring to convert the wider original
ring to the more modern width. The thin ring is fitted above the oil
control ring in the groove.

Tom


  #6   Report Post  
Harold and Susan Vordos
 
Posts: n/a
Default


"Tom" wrote in message
...
Christopher Tidy wrote:

Hi,

As everyone was so helpful with my last question about piston rings, I'd
like to ask another. I unwrapped the new rings for my Wolseley engine
this afternoon ready for fitting. Surprisingly there were four rings in
the pack, whereas there are three on the piston. The first two rings on
the piston are identical plain cast iron rings a little over 1/8" thick.
The third ring is a slotted cast iron oil control ring about 1/4" thick
(the bore is 3"). In the packet I have two identical rings which fit the
first two grooves fine. Then I have a slotted oil control ring which is
narrower that the original (perhaps by 1/16"), and a very thin ring
which is about 1/16" thick. When placed together these two rings are the
same thickness as the original oil control ring, and fit neatly into the
groove.

So it would appear that I am intended to replace the original oil
control ring with two rings. Is this common practice when the correct
ring is unavailable? I bought the rings a few years back and now I have
a vague recollection of some discussion about this, but I can't remember
the details. I just need to decide whether it's okay to fit these rings.
I should point out that this is a big, chugging engine which isn't
highly stressed (1.5 hp at 700 rpm with a 3" bore) so it's probably
going to be more forgiving than modern engines. What do people think?

Any suggestions would be much appreciated.

Many thanks,

Chris


The thin ring is only a spacing ring to convert the wider original
ring to the more modern width. The thin ring is fitted above the oil
control ring in the groove.

Tom


That could be true in this instance. It all depends on how it fits the bore.
If it's the largest in diameter, it very well could be a wiper. With the
typical 4 piece sets, the thin rings are the wipers, and are made of heat
treated steel, not cast iron. You've likely seen them.

Harold


  #7   Report Post  
Tom
 
Posts: n/a
Default

Harold and Susan Vordos wrote:

"Tom" wrote in message
...
Christopher Tidy wrote:

Hi,

As everyone was so helpful with my last question about piston rings, I'd
like to ask another. I unwrapped the new rings for my Wolseley engine
this afternoon ready for fitting. Surprisingly there were four rings in
the pack, whereas there are three on the piston. The first two rings on
the piston are identical plain cast iron rings a little over 1/8" thick.
The third ring is a slotted cast iron oil control ring about 1/4" thick
(the bore is 3"). In the packet I have two identical rings which fit the
first two grooves fine. Then I have a slotted oil control ring which is
narrower that the original (perhaps by 1/16"), and a very thin ring
which is about 1/16" thick. When placed together these two rings are the
same thickness as the original oil control ring, and fit neatly into the
groove.

So it would appear that I am intended to replace the original oil
control ring with two rings. Is this common practice when the correct
ring is unavailable? I bought the rings a few years back and now I have
a vague recollection of some discussion about this, but I can't remember
the details. I just need to decide whether it's okay to fit these rings.
I should point out that this is a big, chugging engine which isn't
highly stressed (1.5 hp at 700 rpm with a 3" bore) so it's probably
going to be more forgiving than modern engines. What do people think?

Any suggestions would be much appreciated.

Many thanks,

Chris


The thin ring is only a spacing ring to convert the wider original
ring to the more modern width. The thin ring is fitted above the oil
control ring in the groove.

Tom


That could be true in this instance. It all depends on how it fits the bore.
If it's the largest in diameter, it very well could be a wiper. With the
typical 4 piece sets, the thin rings are the wipers, and are made of heat
treated steel, not cast iron. You've likely seen them.

Harold


Steel ring inserts for either adapting narrow rings to wider grooves
and enabling worn grooves to be turned out to fit standard width rings
are commonplace. Using a steel wiper in conjunction with a cast iron
oil control ring, well, that is singular indeed. Spacing rings seat on
the bottom of the groove and do not protrude past the ring land.

Harold, what's this I hear you're reluctant to put Colchester bearings
in your Graziano? :-) Graziano thought they were good enough..

Tom
  #8   Report Post  
Harold and Susan Vordos
 
Posts: n/a
Default


"Tom" wrote in message
...
snip----

Harold, what's this I hear you're reluctant to put Colchester bearings
in your Graziano? :-) Graziano thought they were good enough..

Tom


Chuckle! Not really reluctant. Just too poor. Mind you, I have no
quarrel with Gamet bearings (which is what Colchester used). This old
retired dude is looking for something more affordable, but I wouldn't
hesitate to buy the Gamet variety if all else fails. The original
bearings served me well----and owe me nothing. They're still very
serviceable, but I'd like to eliminate the .0002" runout that I didn't used
to have. Many think it's no big deal, and I can't argue with them, but
when you know it can be better, it's hard to ignore.

The number of jobs I ran with only a couple tenths tolerance are hard to
forget. I've always considered myself a good lathe hand, but not good
enough to work without a tolerance! :-)

Larry Jaques suggested I'd have a hard time putting anything on Mars with
that much runout. If I can't trust Larry, who can I trust? g

Harold


  #9   Report Post  
Tom
 
Posts: n/a
Default

Harold and Susan Vordos wrote:

"Tom" wrote in message
...
snip----

Harold, what's this I hear you're reluctant to put Colchester bearings
in your Graziano? :-) Graziano thought they were good enough..

Tom


Chuckle! Not really reluctant. Just too poor. Mind you, I have no
quarrel with Gamet bearings (which is what Colchester used). This old
retired dude is looking for something more affordable, but I wouldn't
hesitate to buy the Gamet variety if all else fails. The original
bearings served me well----and owe me nothing. They're still very
serviceable, but I'd like to eliminate the .0002" runout that I didn't used
to have. Many think it's no big deal, and I can't argue with them, but
when you know it can be better, it's hard to ignore.

The number of jobs I ran with only a couple tenths tolerance are hard to
forget. I've always considered myself a good lathe hand, but not good
enough to work without a tolerance! :-)

Larry Jaques suggested I'd have a hard time putting anything on Mars with
that much runout. If I can't trust Larry, who can I trust? g

Harold


It's like owning a Ferrari, generic parts don't exist,
so one has to suck up the damage to one's wallet. :-(
BTW, Colchester use Gamet bearings because they own them.
They don't come cheap for Colchesters either.

Tom
  #10   Report Post  
Harold and Susan Vordos
 
Posts: n/a
Default


"Tom" wrote in message
...
Harold and Susan Vordos wrote:

"Tom" wrote in message
...
snip----

Harold, what's this I hear you're reluctant to put Colchester bearings
in your Graziano? :-) Graziano thought they were good enough..

Tom


Chuckle! Not really reluctant. Just too poor. Mind you, I have no
quarrel with Gamet bearings (which is what Colchester used). This

old
retired dude is looking for something more affordable, but I wouldn't
hesitate to buy the Gamet variety if all else fails. The original
bearings served me well----and owe me nothing. They're still very
serviceable, but I'd like to eliminate the .0002" runout that I didn't

used
to have. Many think it's no big deal, and I can't argue with them, but
when you know it can be better, it's hard to ignore.

The number of jobs I ran with only a couple tenths tolerance are hard to
forget. I've always considered myself a good lathe hand, but not good
enough to work without a tolerance! :-)

Larry Jaques suggested I'd have a hard time putting anything on Mars

with
that much runout. If I can't trust Larry, who can I trust? g

Harold


It's like owning a Ferrari, generic parts don't exist,
so one has to suck up the damage to one's wallet. :-(
BTW, Colchester use Gamet bearings because they own them.
They don't come cheap for Colchesters either.

Tom


Yeah, I was surprised to find they weren't French owned. The name is a
real sleeper.
I learned it's a good idea to shop----the latest contact was considerably
lower in price than I had been quoted before. Gunner really came through.

The supplier is checking to see if there are any substitutes, but I'm not
holding my breath. The thought was to get away from the high speed bearings.
My machine runs at only 29% of the speed ratings of the Gamet bearings.
Could be I could use an angular contact bearing in place of the originals.
Could be I'd be asking for trouble, too. Any thoughts on that idea?

Harold




  #11   Report Post  
Tom
 
Posts: n/a
Default

Harold and Susan Vordos wrote:

"Tom" wrote in message
...
Harold and Susan Vordos wrote:

"Tom" wrote in message
...
snip----

Harold, what's this I hear you're reluctant to put Colchester bearings
in your Graziano? :-) Graziano thought they were good enough..

Tom

Chuckle! Not really reluctant. Just too poor. Mind you, I have no
quarrel with Gamet bearings (which is what Colchester used). This

old
retired dude is looking for something more affordable, but I wouldn't
hesitate to buy the Gamet variety if all else fails. The original
bearings served me well----and owe me nothing. They're still very
serviceable, but I'd like to eliminate the .0002" runout that I didn't

used
to have. Many think it's no big deal, and I can't argue with them, but
when you know it can be better, it's hard to ignore.

The number of jobs I ran with only a couple tenths tolerance are hard to
forget. I've always considered myself a good lathe hand, but not good
enough to work without a tolerance! :-)

Larry Jaques suggested I'd have a hard time putting anything on Mars

with
that much runout. If I can't trust Larry, who can I trust? g

Harold


It's like owning a Ferrari, generic parts don't exist,
so one has to suck up the damage to one's wallet. :-(
BTW, Colchester use Gamet bearings because they own them.
They don't come cheap for Colchesters either.

Tom


Yeah, I was surprised to find they weren't French owned. The name is a
real sleeper.
I learned it's a good idea to shop----the latest contact was considerably
lower in price than I had been quoted before. Gunner really came through.

The supplier is checking to see if there are any substitutes, but I'm not
holding my breath. The thought was to get away from the high speed bearings.
My machine runs at only 29% of the speed ratings of the Gamet bearings.
Could be I could use an angular contact bearing in place of the originals.
Could be I'd be asking for trouble, too. Any thoughts on that idea?

Harold


I'd be very surprised if you'd get angular contact bearings that
would fit the Gamet bearing dimensions and still compare load rating
wise. How are yours preloaded?

Tom
  #12   Report Post  
Harold and Susan Vordos
 
Posts: n/a
Default


"Tom" wrote in message
...
Harold and Susan Vordos wrote:

"Tom" wrote in message
...
Harold and Susan Vordos wrote:

"Tom" wrote in message
...
snip----

Harold, what's this I hear you're reluctant to put Colchester

bearings
in your Graziano? :-) Graziano thought they were good enough..

Tom

Chuckle! Not really reluctant. Just too poor. Mind you, I have

no
quarrel with Gamet bearings (which is what Colchester used).

This
old
retired dude is looking for something more affordable, but I

wouldn't
hesitate to buy the Gamet variety if all else fails. The

original
bearings served me well----and owe me nothing. They're still very
serviceable, but I'd like to eliminate the .0002" runout that I

didn't
used
to have. Many think it's no big deal, and I can't argue with them,

but
when you know it can be better, it's hard to ignore.

The number of jobs I ran with only a couple tenths tolerance are

hard to
forget. I've always considered myself a good lathe hand, but not

good
enough to work without a tolerance! :-)

Larry Jaques suggested I'd have a hard time putting anything on Mars

with
that much runout. If I can't trust Larry, who can I trust? g

Harold

It's like owning a Ferrari, generic parts don't exist,
so one has to suck up the damage to one's wallet. :-(
BTW, Colchester use Gamet bearings because they own them.
They don't come cheap for Colchesters either.

Tom


Yeah, I was surprised to find they weren't French owned. The name is a
real sleeper.
I learned it's a good idea to shop----the latest contact was

considerably
lower in price than I had been quoted before. Gunner really came

through.

The supplier is checking to see if there are any substitutes, but I'm

not
holding my breath. The thought was to get away from the high speed

bearings.
My machine runs at only 29% of the speed ratings of the Gamet bearings.
Could be I could use an angular contact bearing in place of the

originals.
Could be I'd be asking for trouble, too. Any thoughts on that idea?

Harold


I'd be very surprised if you'd get angular contact bearings that
would fit the Gamet bearing dimensions and still compare load rating
wise. How are yours preloaded?

Tom


I've never had the headstock apart, but from indications, there's a threaded
collar that establishes preload. Problem is, the manual doesn't address
assembly, just shows the exploded view, and so far I've found nothing that
indicates preload values of any kind. The main bearing is a double row
opposed roller type, with split inner races. I can't help but think that
going to a ball type would sacrifice load capacity. One of the things
I've given some thought to is adjusting the bearing ever so slightly, with
the idea that it might have worn enough to be slack. Question is, how much?
If that worked, I'd have no need to change out the bearings. I'd like
that!

Maybe I should touch base with someone that has been there, done that. I
hate to run blind on something of this nature. Ignorance can get real
expensive.

Harold


  #13   Report Post  
Christopher Tidy
 
Posts: n/a
Default



Tom wrote:
Christopher Tidy wrote:

Hi,

As everyone was so helpful with my last question about piston rings, I'd
like to ask another. I unwrapped the new rings for my Wolseley engine
this afternoon ready for fitting. Surprisingly there were four rings in
the pack, whereas there are three on the piston. The first two rings on
the piston are identical plain cast iron rings a little over 1/8" thick.
The third ring is a slotted cast iron oil control ring about 1/4" thick
(the bore is 3"). In the packet I have two identical rings which fit the
first two grooves fine. Then I have a slotted oil control ring which is
narrower that the original (perhaps by 1/16"), and a very thin ring
which is about 1/16" thick. When placed together these two rings are the
same thickness as the original oil control ring, and fit neatly into the
groove.

So it would appear that I am intended to replace the original oil
control ring with two rings. Is this common practice when the correct
ring is unavailable? I bought the rings a few years back and now I have
a vague recollection of some discussion about this, but I can't remember
the details. I just need to decide whether it's okay to fit these rings.
I should point out that this is a big, chugging engine which isn't
highly stressed (1.5 hp at 700 rpm with a 3" bore) so it's probably
going to be more forgiving than modern engines. What do people think?

Any suggestions would be much appreciated.

Many thanks,

Chris



The thin ring is only a spacing ring to convert the wider original
ring to the more modern width. The thin ring is fitted above the oil
control ring in the groove.


Thanks for all the helpful responses. It seems like these rings are
fine. But I'm not sure whether to fit the thin ring above or below the
oil control ring; there seems to be some disagreement here. If it helps
the thin ring is approximately 1/16" thick and rectangular in
cross-section, with a very small rectangle removed from one of the
outside corners.

Chris


  #14   Report Post  
Chas
 
Posts: n/a
Default


"Christopher Tidy" wrote in message
...


Tom wrote:
Christopher Tidy wrote:

Hi,

As everyone was so helpful with my last question about piston rings, I'd
like to ask another. I unwrapped the new rings for my Wolseley engine
this afternoon ready for fitting. Surprisingly there were four rings in
the pack, whereas there are three on the piston. The first two rings on
the piston are identical plain cast iron rings a little over 1/8" thick.
The third ring is a slotted cast iron oil control ring about 1/4" thick
(the bore is 3"). In the packet I have two identical rings which fit the
first two grooves fine. Then I have a slotted oil control ring which is
narrower that the original (perhaps by 1/16"), and a very thin ring
which is about 1/16" thick. When placed together these two rings are the
same thickness as the original oil control ring, and fit neatly into the
groove.

So it would appear that I am intended to replace the original oil
control ring with two rings. Is this common practice when the correct
ring is unavailable? I bought the rings a few years back and now I have
a vague recollection of some discussion about this, but I can't remember
the details. I just need to decide whether it's okay to fit these rings.
I should point out that this is a big, chugging engine which isn't
highly stressed (1.5 hp at 700 rpm with a 3" bore) so it's probably
going to be more forgiving than modern engines. What do people think?

Any suggestions would be much appreciated.

Many thanks,

Chris



The thin ring is only a spacing ring to convert the wider original
ring to the more modern width. The thin ring is fitted above the oil
control ring in the groove.


Thanks for all the helpful responses. It seems like these rings are
fine. But I'm not sure whether to fit the thin ring above or below the
oil control ring; there seems to be some disagreement here. If it helps
the thin ring is approximately 1/16" thick and rectangular in
cross-section, with a very small rectangle removed from one of the
outside corners.

Chris


That would indicate a scraper ring which should be placed above the slotted
oil ring with the rectangular groove next to the slotted ring, ie facing
down. You should also check to see if the slotted ring is symmetrical or
has a reduced diameter on one side. If so, this side should face upwards to
the scraper ring. Most rings in non-symmetrical ring sets have the upper
face marked in some way.
--
Regards, Chas.


To Email, replace 'xxx' with tango papa golf.




  #15   Report Post  
Christopher Tidy
 
Posts: n/a
Default

Chas wrote:
"Christopher Tidy" wrote in message
...


Tom wrote:

Christopher Tidy wrote:


Hi,

As everyone was so helpful with my last question about piston rings, I'd
like to ask another. I unwrapped the new rings for my Wolseley engine
this afternoon ready for fitting. Surprisingly there were four rings in
the pack, whereas there are three on the piston. The first two rings on
the piston are identical plain cast iron rings a little over 1/8" thick.
The third ring is a slotted cast iron oil control ring about 1/4" thick
(the bore is 3"). In the packet I have two identical rings which fit the
first two grooves fine. Then I have a slotted oil control ring which is
narrower that the original (perhaps by 1/16"), and a very thin ring
which is about 1/16" thick. When placed together these two rings are the
same thickness as the original oil control ring, and fit neatly into the
groove.

So it would appear that I am intended to replace the original oil
control ring with two rings. Is this common practice when the correct
ring is unavailable? I bought the rings a few years back and now I have
a vague recollection of some discussion about this, but I can't remember
the details. I just need to decide whether it's okay to fit these rings.
I should point out that this is a big, chugging engine which isn't
highly stressed (1.5 hp at 700 rpm with a 3" bore) so it's probably
going to be more forgiving than modern engines. What do people think?

Any suggestions would be much appreciated.

Many thanks,

Chris


The thin ring is only a spacing ring to convert the wider original
ring to the more modern width. The thin ring is fitted above the oil
control ring in the groove.


Thanks for all the helpful responses. It seems like these rings are
fine. But I'm not sure whether to fit the thin ring above or below the
oil control ring; there seems to be some disagreement here. If it helps
the thin ring is approximately 1/16" thick and rectangular in
cross-section, with a very small rectangle removed from one of the
outside corners.

Chris



That would indicate a scraper ring which should be placed above the slotted
oil ring with the rectangular groove next to the slotted ring, ie facing
down. You should also check to see if the slotted ring is symmetrical or
has a reduced diameter on one side. If so, this side should face upwards to
the scraper ring. Most rings in non-symmetrical ring sets have the upper
face marked in some way.


Thanks very much for the clarification.

Chris



  #16   Report Post  
Gunner
 
Posts: n/a
Default

On Thu, 19 May 2005 21:37:22 -0700, "Harold and Susan Vordos"
wrote:


"Tom" wrote in message
...
Harold and Susan Vordos wrote:

"Tom" wrote in message
...
Harold and Susan Vordos wrote:

"Tom" wrote in message
...
snip----

Harold, what's this I hear you're reluctant to put Colchester

bearings
in your Graziano? :-) Graziano thought they were good enough..

Tom

Chuckle! Not really reluctant. Just too poor. Mind you, I have

no
quarrel with Gamet bearings (which is what Colchester used).

This
old
retired dude is looking for something more affordable, but I

wouldn't
hesitate to buy the Gamet variety if all else fails. The

original
bearings served me well----and owe me nothing. They're still very
serviceable, but I'd like to eliminate the .0002" runout that I

didn't
used
to have. Many think it's no big deal, and I can't argue with them,

but
when you know it can be better, it's hard to ignore.

The number of jobs I ran with only a couple tenths tolerance are

hard to
forget. I've always considered myself a good lathe hand, but not

good
enough to work without a tolerance! :-)

Larry Jaques suggested I'd have a hard time putting anything on Mars
with
that much runout. If I can't trust Larry, who can I trust? g

Harold

It's like owning a Ferrari, generic parts don't exist,
so one has to suck up the damage to one's wallet. :-(
BTW, Colchester use Gamet bearings because they own them.
They don't come cheap for Colchesters either.

Tom

Yeah, I was surprised to find they weren't French owned. The name is a
real sleeper.
I learned it's a good idea to shop----the latest contact was

considerably
lower in price than I had been quoted before. Gunner really came

through.

The supplier is checking to see if there are any substitutes, but I'm

not
holding my breath. The thought was to get away from the high speed

bearings.
My machine runs at only 29% of the speed ratings of the Gamet bearings.
Could be I could use an angular contact bearing in place of the

originals.
Could be I'd be asking for trouble, too. Any thoughts on that idea?

Harold


I'd be very surprised if you'd get angular contact bearings that
would fit the Gamet bearing dimensions and still compare load rating
wise. How are yours preloaded?

Tom


I've never had the headstock apart, but from indications, there's a threaded
collar that establishes preload. Problem is, the manual doesn't address
assembly, just shows the exploded view, and so far I've found nothing that
indicates preload values of any kind. The main bearing is a double row
opposed roller type, with split inner races. I can't help but think that
going to a ball type would sacrifice load capacity. One of the things
I've given some thought to is adjusting the bearing ever so slightly, with
the idea that it might have worn enough to be slack. Question is, how much?
If that worked, I'd have no need to change out the bearings. I'd like
that!

Maybe I should touch base with someone that has been there, done that. I
hate to run blind on something of this nature. Ignorance can get real
expensive.

Harold


You can adjust preload? Then by all means do so. Put a dial
indicator on the side of the spindle and with a 2' bar in the spindle
bore, apply a bit of side to side pressure and tighten up the preload
collor a tinsey bit until the indicator shows minimal movement In BOTH
directions. And I mean tiny wheenit itsybitsy tightening each time.

Run the spindle at 2000 rpm for 30 minutes and see if there is any
unusual heating of the headstock over the bearing location (check
temps now before doing this as a reference.

But personally..I think you are guilding the lilly at .0002 backlash.
Btw..is that TIR? .0001 each way, or .0002 each way?

Also..did you measure the backlash cold, or warm? Makes a huge
difference.

Gunner

"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.

Think of it as having your older brother knock the **** out of you
for torturing the cat." Gunner
  #17   Report Post  
Larry Jaques
 
Posts: n/a
Default

On Thu, 19 May 2005 19:54:27 -0700, the inscrutable "Harold and Susan
Vordos" spake:

--snip--
serviceable, but I'd like to eliminate the .0002" runout that I didn't used
to have. Many think it's no big deal, and I can't argue with them, but
when you know it can be better, it's hard to ignore.

--snip--

Larry Jaques suggested I'd have a hard time putting anything on Mars with
that much runout. If I can't trust Larry, who can I trust? g


bseg


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