Lathe Spindle Bearings

[Jud96]

How do you guys check spindle bearings and how much movement do you see in them?

I put an indicator on a turned piece 1” in front of my chuck then pushed up on the chuck with a 2’ piece of pipe and saw .002 lift.

Thanks

 

[jackieschmidt]

What kind of bearings?
.002 seems a little excessive.
If it has plain bearings, you can possibly remove any shims that might be present. If it is opposed roller bearings, some lathes have an adjustment nut inside the headstock so you can take up on the bearings.
It might be that simple.

 

[Jud96]

I believe they’re tapered roller bearings, but I’ll have to confirm that

 

[Sniperhandle]

I believe they’re tapered roller bearings, but I’ll have to confirm that

In your manual there is a section on bearing adjustment, Yes you use an indicator to find out how much clearance you have. There are 2 large round nuts on the gear train end of the spindle on Asian lathes that you use a spanner wrench to loosen/tighten, One set the clearance, The other is a jam nut to keep it set. I have changed out spindle bearings and adjusted them, It's not that hard to do, You just need some very large snap ring pliers.

 

[Sniperhandle]

Go to page 20 of this manual and there are instructions on how to do it.

This is for an 80's Grizzly, But should be close enough for your machine.

I couldn't get the manual to load, So I took some screenshots.

 

[Sniperhandle]

The bearings fit so tight on the spindle it can be a little tricky getting the feel for it sometimes, But you will figure it out. The main stuff you need is on the second screenshot.

 

[Sniperhandle]

That manual says to adjust the preload on the bearings every two years, There is extreme pressure on these bearings when you are taking a heavy cut, That's why I can't understand people cheaping out and using some generic Hydraulic oil in their headstock when the proper oils have ep additives.

Also people have ruined the bearings on their lathes by using the wrong oils, These Asian lathes have a splash lubrication system and call for 10 to 20wt oils depending on their specs, People have put 90 wt gear oil in these and no oil gets to the top cover and runs down to the bearings causing premature failures of the bearings.

Some of the older American Iron did use 90 wt gear oil, But not the machines most guys on here are running. I try to bring this up every now and then to save someone the trouble.

 

[WSnyder]

Some of the older American Iron did use 90 wt gear oil, But not the machines most guys on here are running. I try to bring this up every now and then to save someone the trouble.

My old Rockwell spindle bearings use grease

 

[Fuj]

My Victor I use the most, has a shim pack of 2 steel and one paper.
Paper one was oil glued in place and did not disturb it. The steel ones
were .020" and .009". I pulled the .009" And it was too tight. Put that
one back in, and replaced the .020" with a .015". It's been running happy.
Note.....My Victor uses an oil pump for the head stock bearings. The cross
over oil used in the original paper work was Valvoline 50wt. or Shell 46.
It was nasty, and pump screen 50% plugged. Do your bearings, and do
your oiler also while at it.

 

[ORjeff]

Before you do anything redo that test after you have warmed up those bearings. They expand as they warm up, if you set them to zero backlash when cold you risk damaging them during use and that's gonna be an expensive fix. It's also a good idea to warm them up before you do anything that needs max precision. Warm them up by letting it run for a while, at a minimum, but turning on some scrap to really load those bearings would be best.

 

[Jud96]

Okay, so I took the chuck off and put an indicator in the spindle taper. I put a pry bar in the outboard end of the spindle and pried up. The indicator never moved. So I mounted my inboard spider on the spindle and pried up on it and saw .0001 of movement. I believe I was seeing flex in the chuck, not the bearings. So that’s a major relief

 

[ELR LVR]

Okay, so I took the chuck off and put an indicator in the spindle taper. I put a pry bar in the outboard end of the spindle and pried up. The indicator never moved. So I mounted my inboard spider on the spindle and pried up on it and saw .0001 of movement. I believe I was seeing flex in the chuck, not the bearings. So that’s a major relief

Take the chuck off then measure runout...
...Good tip!
------------------------------------------------
But ummmm
now what do you do about chuck wander/the flex you're talking about
..... under load while you're turnin and burnin?

 

[Jud96]

Take the chuck off then measure runout...
...Good tip!
------------------------------------------------
But ummmm
now what do you do about chuck wander/the flex you're talking about
..... under load while you're turnin and burnin?

I’m not going to use that 4 jaw chuck for chambering, I’ll use my spider that had .0001 of movement

 

[Sniperhandle]

There's an old saying, "If it broke don't fix it"

I know a guy who went to all of the trouble of changing his spindle bearings because he thought they were making a noise, Still making the same noise, Japanese spindle bearings aren't cheap.

 

[Jud96]

There's an old saying, "If it broke don't fix it"

I know a guy who went to all of the trouble of changing his spindle bearings because he thought they were making a noise, Still making the same noise, Japanese spindle bearings aren't cheap.

Yeah I pulled the end cover off and looked at the bearings in the rear of the spindle and they were marked “Japan NSK” on them. So they’re good bearings and I’m happy to find that they’re not shot