Questions re Plain Headstock Bearings and Way wear

[Vicroamer]

I'm new to all this so have a couple of real newbie questions
How does one determine bearing wear with plain headstock bearings and how can worn bearings be put right. Recently I was talking to a machinist with a preference for taper roller bearings saying plain bearings were no good(not trying to upset anyone here), but I think plain bearings would be more common, so can worn plain bearings be put right and how does one go about it.
Also how does one determine if way wear is excessive he said wear can be determined by feeling the difference between lightly and frequently used sections but how much is to much and how to put it right. I've heard about scraping but have no idea how to go about it or even if a tyro shoud attempt it.
First post BTW I'm thinking of having a bash at model engineering, my preference is a classic lathe in good nick rather than new chinese.

[tanii51]

firstly welcome to our forum. just a few words on my background with lathes, my first one was a 1955 hercus c model lathe plain bearing no power feed just screw cutting with maual change gears. I measured head play etc with a dial test indicator, removed a couple of spacer shims to tighten it up a little ( it got too hot then) so i put them back didnt know how to check bed wear whats that ??. my first go at turning a piece of steel that was a garden stake turned out like a round file lines evry where... what have i done.... this is a piece of junk the handles are all sloppy ( back lash )ah i learnt if you tighten the apron lock till it will just move then slide it full lenght that will tell you howmuch bed wear
now i have 3 lathes of my own c model A model ( both plain bearing) an 260 arm ( roller bearing) almost new.. and 4 boarders Hercus DGMLH precision metal lathe- long bed-hardened so ive got a few to compare with each other
results almost evry failure has been operator error
type of material used
wrong speed and feed rates
poor tool sharpening or shape
finally have a read of this http://http://www.mermac.com/advicenew.html
some will say a plain bearing gives superior finish to roller bearing headstock
hope this helps
JOHN
ps i still have that first peice of steel and it still machines like a gramaphone record even on a good used machine

[cba_melbourne]

I'm new to all this so have a couple of real newbie questions
How does one determine bearing wear with plain headstock bearings and how can worn bearings be put right. Recently I was talking to a machinist with a preference for taper roller bearings saying plain bearings were no good(not trying to upset anyone here), but I think plain bearings would be more common, so can worn plain bearings be put right and how does one go about it.
Also how does one determine if way wear is excessive he said wear can be determined by feeling the difference between lightly and frequently used sections but how much is to much and how to put it right. I've heard about scraping but have no idea how to go about it or even if a tyro shoud attempt it.
First post BTW I'm thinking of having a bash at model engineering, my preference is a classic lathe in good nick rather than new chinese.

Plain bearings are famous for producing the very best surface finishes on turned items, especially on lathes using flat belts. On the down side, plain bearings have limited top speeds and need constant attention (oiling). With plain bearings, the spindle center line is very slightly lower when the spindle is not rotating, because when the spindle rotates it rides up on a thin oil film. Scraping is used with split babbit bearings (a cast white zinc alloy) and with tapered bronze bearings (Myford). Some older lathes like the Myford ml10 even had the spindle running directly in the cast iron headstock (max 1000rpm). Oher lathes use thin walled bronze bushings that can be exchanged easily.

Way wear is always close to the chuck, where most smallish turning is done. It does not affect the precision of the lathe too much until wear is well advanced, but it depends much on how the saddle is designed (some saddles are held down by gibs on their front, and these will become sloppy towards the headstiock or bind towards the tailstock when the bedways are worn). Hardened bedways must be re-ground. Scraping is only an option for unhardened (soft) bedways. Check with a file. Chris

[Vicroamer]

OK thanks for replys looks like plain bearings will be fine probably better seeing they can give a better finish, can one tell if wear is excessive by lifting the chuck maybe, to feel for wear if it has been run without proper lubrication or just worn out, a seller's not going volunteer much. They can be dumb like a fox if need be.
Can a bit of wear be corrected by removing shims as suggested.

[nadroj]

Some older lathes like the Myford ml10 even had the spindle running directly in the cast iron headstock (max 1000rpm).

Hercus too had the spindle running directly in the headstock casting. That might be a problem after a couple of centuries of regular use.

Jordan

[nadroj]

Can a bit of wear be corrected by removing shims as suggested.

Yes.

Jordan

[morrisman]

hello I jumped off the cliff and bought a lathe without knowing anything at all . It turned out to be a roller bearing headstock Sheraton , made in Melbourne . I like the roller bearings in terms of maintenance and strength . When you think of the enormous loads and stresses that truck wheel bearings have to withstand, and they last and last for years, tapered rollers get my vote. As for a better finish, it comes down to speeds and tooling really . The differences in finish are tiny , we are talking microns , not thou and for hobby stuff it isn't relevant I feel. MIKE

[Vicroamer]

I've noticed a Sheraton up for sale at the moment, I have more interest in the Hercus mainly because there looks to be more Hercus parts around if needed but I'm sure the sheraton is a fine machine and would do just as good a job for what I need.

[nadroj]

Nice thing about ball or roller bearings in standard sizes is that they can be obtained and replaced with less hassle than bushes, which need line-reaming etc, even if you can find or make them. Decades after they were made, machines with bushes can be a bit of a liability.
Running direct in the headstock casting seems ideal, if like Hercus (ie South Bend) a shim adjustment is designed in. It's not foolproof though, as running it dry (as I've seen evidence of) damages the bearing surfaces. Then what?

Jordan

[morrisman]

I've noticed a Sheraton up for sale at the moment, I have more interest in the Hercus mainly because there looks to be more Hercus parts around if needed but I'm sure the sheraton is a fine machine and would do just as good a job for what I need.

Yes I spotted it as well on EVILBAY ..it's the same as mine with tapered bearing headstock , I bet it's from a school. The Sheraton 9" is about 90% the same as a Hercus ...both are clones of the South Bend 9" . I found parts are easy ..I got a new cross feednut from Hercus in Adelaide and its been fine . Most bits for a Hercus 9 will fit the Sherarton 9 , no worries .MIKE

[Vicroamer]

Thanks Mike

[Vicroamer]

Nice thing about ball or roller bearings in standard sizes is that they can be obtained and replaced with less hassle than bushes, which need line-reaming etc, even if you can find or make them. Decades after they were made, machines with bushes can be a bit of a liability.
Running direct in the headstock casting seems ideal, if like Hercus (ie South Bend) a shim adjustment is designed in. It's not foolproof though, as running it dry (as I've seen evidence of) damages the bearing surfaces. Then what?

This is my concern being damaged by misuse which is more likely to happen as machines fall into inexperienced hands, thanks for taking the time to respond.

[Steamwhisperer]

Can a bit of wear be corrected by removing shims as suggested.

I have removed shims from an old vanguard lathe which dates back to the late 1800s to early 1900s. In the old days they used to use what was called 'Leads' pronounced leds. They were actually made out of lead wire of a known diameter. You would take the top cap off the headstock bearings and lay the lead on the spindle then tighten the top cap back on. Remove the top cap and measure the width of the now flattened lead. Nowadays, they are made of a plastic type of material which you hold against a chart to tell whether you have
1, 2, 3 etc. thou clearance. That way you can remove or replace shims to get the required clearance and ensure oil will make it to where it has got to go
It's not as hard as it sounds to maintain plain bearings.

Phil

[Abratool]

I have removed shims from an old vanguard lathe which dates back to the late 1800s to early 1900s. In the old days they used to use what was called 'Leads' pronounced leds. They were actually made out of lead wire of a known diameter. You would take the top cap off the headstock bearings and lay the lead on the spindle then tighten the top cap back on. Remove the top cap and measure the width of the now flattened lead. Nowadays, they are made of a plastic type of material which you hold against a chart to tell whether you have
1, 2, 3 etc. thou clearance. That way you can remove or replace shims to get the required clearance and ensure oil will make it to where it has got to go
It's not as hard as it sounds to maintain plain bearings.

Phil

Phil
Thanks for the info on the measuring lead wire for bearings.
I have only heard about these but never used them.
The plastic stuff sounds interesting. Any ideas where that can be obtained ?
regards
Bruce

[Steamwhisperer]

The plastic stuff sounds interesting. Any ideas where that can be obtained ?
regards
Bruce

Hi Bruce
I think we got them at either Blackwoods or one of the bearing suppliers. I am back at work on Monday so will take a photo and find out where so you know what to look for.

Phil