Thread: Model 260 spindle question

I took the headstock apart today. I am a little puzzled. This 260 has less than 100 hours running time, it was in storage the past 17 years, and was barely ever used before. I can tell, because all ways still show the original machining marks, and most parts still have the original conservation grease. So, I do not think anyone ever took it apart before.

But... I found no felt wicks in the headstock oilers. The oil goes straight from the oilers to the taper roller bearings. I thought that the US made Southbends all has felt wicks to filter the oil and keep any harmful chips/dust out. The Hercus 260 spare part manual also shows no felt wicks.

So what is the experience from you other 260 owners, felt wicks or no felt wicks? Did someone add them afterwards to his machine? Or does it maybe not matter that much for home use?

Chris

PS: by the way, the left bearing is a Timken 11162, the right bearing is a Timken 18690. Nothing fancy, just ordinary ABEC7 "boat trailer wheel" bearings (as these are described in the Timken manual). According to the 1988 price list, precision spindle bearings would have cost $350 extra (option 05 han, along with the half error alignment). I assume these would then have been ABEC3 class bearings. I do not dare to look up how much these would cost today, I guess around $1000.... But the bearings I have look like new and unused and are probably quiet enough for me and what I do.

I've never had mine apart. But, I've not seen felt wicks used for ball or roller bearings on any machine. Rather they seem to be used to get oil to the working surfaces of plain bearings. With rolling bearings, it's easy to arrange proper lubrication - just have the oil level high enough so that the rollers or ball just dip into the oil bath. I'd assumed that's how it is on the 260, and R models 9 inch Hercus.

Jordan

As stated previously,they dont have wicks,just oil in the elbow.
The purpose of the wicks in the 9" plain bearing models is just that,to wick the oil.

Makes sense, thanks
Chris

Hi Chris,
Just to confirm pipeclays reply, after having had several apart there are no wicks in the 260 headstock that I have seen.
Mal

Tank for all replies. I found this document very helpful in understanding the way the Hercus 260 headstock is designed and supposed to work:

Timken® Super Precision Bearings for Machine Tool Applications

www.timken.com/en-us/products/Documents/5918_09-09-29.pdf

The pictures in the manual look exactly like the Hercus 260 Headstock. Only a small quantity of oil is at the bottom of the outer race. This is to keep the bearing cool, if it was submerged in an oil bath the bearing would heat up just by friction with the oil.

I now feel quite safe the 260 spindle should be good for some 3500rpm top speed. That is what the stock 3-phase 4-pole motor will drive the spindle at when fitted with a variable speed inverter at a top 100Hz (or twice the normal line frequency). The limiting factor is not the bearings, its actually the chucks. The Burnerd 150mm 4-jaw chuck I have has apparently a maximum safe speed of 3,000 rpm.

My Hercus is not fitted with super precision bearings like a toolroom lathe. But the above Timken booklet is - despite its title - still valid for plain automotive bearings when used in a spindle application. The bearings I have are still the originals and look like new, no rust or marks. The reason I took the spindle apart was to make sure the bearings are still fine after 20 years of no use storage, and of course to get some surface rust off the sides of the cone pulley and backgear.

I did paint the cabinet today, with Wattyl Killrust epoxy gloss enamel. As others found out before, the color "Colorbond Wilderness" is the best match to Hercus green there is commercially available, just a tad lighter. It's an extremely slow drying paint though....

Chris

Hello Chris,

It's surprising that Hercus would have fitted, as standard, less than precision bearings on the 260 spindle. My '69 ARL has Timken Class 3 (inch system) bearings that, when assemled, had a maximum radial runout of .0003".

If you could justify the expense, the runout could be reduced by fitting Class 0 (.00015") or Class 00 (.000075") bearings. These figures are stated in the 1987 "Shop Manual for Timken Roller Bearings".

Maybe that's what the extra $350 was for, halving the runout of an already precise bearing. The price list does state "high precision".

Regards Bob.

Just a thought: The only place some NSK precision bearings are marked is on the box it came in. I know a guy who uses NSK balls in a precision application and he has run into problems with users of older 20 year plus spindles who have "Rebuilt" his spindles by replacing the bearings with the same part number. They get a bit irate when it doesn't work as well as the new bearing is not the same precision or clearance as the original.

A lot of older precision stuff has the extra spec marked with an electric pencil separate from the base markings too.

Maybe the Hercus parts have a similar situation with their Timkens and are precision but lacking the extra markings.

Bob, I must admit I have ZERO experience with imperial taper roller bearings. And the 260 lathe happens to use imperial sizes. That said....

In the metric world, standard bearings used to be ISO P0 precision. In the past 10 years or so, all bearings made by a reputable maker (like Timken) are in fact P6 precision even if the suffix P6 is not stamped on the bearing. In the smaller sizes these bearings are also called automotive, or sometimes simply "boat trailer" bearings.
Bexause that is obviously where most of these bearings are used.

Now the next precision class up is P5. These already cost 2 to 3 times more than standard bearings. The inner and outer races of each bearing are matched, and stamped with a unique serial number so they do not get mixed up during installation.
Next up are P4 and P2 bearings (of course also with serial numbers on the races). P4 is what one would expect to find in an industrial "toolroom" lathe or mill spindle. P4 would cost about 10x the price of a standard bearing. It is interesting to note, that all these bearings are made on the same production line, at the same time. The one and only difference is, that P5 and better bearings are measured and sorted and matched and picked and tested and stamped with serial number by hand - that is what the extra price covers.

In the inch world of bearings, things are slightly different. The ISO precision class is replaced by the American ABEC class. It works the other way around as ISO. ABEC 3 is an ordinary automotive bearing comparable to ISO P6, whilst ABEC 7 is a high precision spindle bearing comparable to ISO P4 and ABEC 9 is the equivalent of ISO P1.

Anyway, my understanding is that if a taper roller bearing has no matching serial numbers on inner and outer race, it cannot be anything better than an ordinary car wheel bearing.

Not that it matters a lot for a lathe like the Hercus 260. The difference is just a few micrometers in runout. Compare this with a 3-jaw chuck, a brand new and unused Pratt Burnerd may clamp to 20 micrometers accuracy, but a slightly used 3-jaw chuck can be as far out as 100 micrometers. By the way, in bearing maker terminology, runout and bearing noise is the same thing. In a lathe, it is what affects the surface finish of turned parts (among many other things).

The $350 05HAN Hercus option reads "Lathe supplied to high precision limited: High precision spindle bearings, half error alignment abd accurate". That would include something like ABEC 7 bearings. The halving of the alignment error has to be done by matching components and scraping (things like the cross slide angle, or the tailstock height, which have ofset tolerances, can in practice only be bettered by selecting the best components from a production run). A 260 lathe fitted with this option has a suffix "N" stamped after its serial number. For example, my lathe would be a ATMN instead of only an ATM.

I a no bearing expert, so maybe my conclusions are wrong. But my lathes spindle bearings have no suffix and no serial numbers on the races, making it very likely these are plain standard car wheel type bearings. Chris

Chris,

There is a footnote on one of the pages in the '87 manual that states -

' NOTE: Class #3 cones and cups are dimensionally interchangeable and are shipped as individual parts.

'' NOTE Class #0 and Class#00 parts are matched assemblies and are shipped as complete bearings.

Further reading suggests that the matched assemblies were serial numbered.
This explains why the numbers on my bearings don't match but are all marked with the suffix *3.

Back then, Timken used an alphabetical system for classing metric roller bearings, KNCBA with A being the most precise.

Regards Bob.

> #00 parts are matched assemblies and are shipped as complete bearings.
>
> Further reading suggests that the matched assemblies were serial numbered.
> This explains why the numbers on my bearings don't match but are all marked
> with the suffix *3.

Hang on... unlike with metric taper roller bearings, imperial taper roller bearings do have different part numbers for inner and outer race.

I am no good at this old inch stuff, but this appears to be so, because it is within reasonable limits possible to match different inner/outer races to fit a specific bore/shaft diameter requirement. For example, the left bearing on my Hercus 260 has an 11162 as inner race, and an 11300B as outer race (no idea what the B suffix means) . The only other markings are "TIMKEN SF MADE IN ENGLAND" stamped on both inner and outer race.

These are part numbers though, not serial numbers. Any bearing better than automotive precision class would necessarly need to have, additionally to the above part number, a unique serial number to match the inner/outer race???

> Back then, Timken used an alphabetical system for classing metric roller bearings,
> KNCBA with A being the most precise.

My 260 is only 1988 vintage, I thought the Americans did long use the ABEC classification by then? Or is this "class 3-0-00-000" maybe a British thing, seeng that its American Timken bearings but made in the UK? At this stage I am simply and uttely confused. Metric stuff is sooo much easier to understand.

Chris

Originally Posted by cba_melbourne

Not that it matters a lot for a lathe like the Hercus 260. The difference is just a few micrometers in runout. Compare this with a 3-jaw chuck, a brand new and unused Pratt Burnerd may clamp to 20 micrometers accuracy, but a slightly used 3-jaw chuck can be as far out as 100 micrometers. Chris

I don't see any useful comparison here. Who cares what the chuck's runout is? The spindle's truth will be no better or worse, whatever the chuck's condition. I think a Hercus lathe is doing well if it can get within a thousandth of an inch.

Jordan

Hello Chris,

I'll either scan or photograph the relevant pages in the Timken manual and let you have a go at working it out. Certain bearings were "tagged" with a strip that had coded numbers indicating deviation from nominal dimensions, runout etc. There are 13 pages.

Regards Bob

Originally Posted by cba_melbourne

> #00 parts are matched assemblies and are shipped as complete bearings.
>
> Further reading suggests that the matched assemblies were serial numbered.
> This explains why the numbers on my bearings don't match but are all marked
> with the suffix *3.

Hang on... unlike with metric taper roller bearings, imperial taper roller bearings do have different part numbers for inner and outer race.

I am no good at this old inch stuff, but this appears to be so, because it is within reasonable limits possible to match different inner/outer races to fit a specific bore/shaft diameter requirement. For example, the left bearing on my Hercus 260 has an 11162 as inner race, and an 11300B as outer race (no idea what the B suffix means) . The only other markings are "TIMKEN SF MADE IN ENGLAND" stamped on both inner and outer race.

These are part numbers though, not serial numbers. Any bearing better than automotive precision class would necessarly need to have, additionally to the above part number, a unique serial number to match the inner/outer race???

> Back then, Timken used an alphabetical system for classing metric roller bearings,
> KNCBA with A being the most precise.

My 260 is only 1988 vintage, I thought the Americans did long use the ABEC classification by then? Or is this "class 3-0-00-000" maybe a British thing, seeng that its American Timken bearings but made in the UK? At this stage I am simply and uttely confused. Metric stuff is sooo much easier to understand.

Chris

Hi Chris, after rebuilding a few 9" and 260 lathes how do you know yours is a AmericanHercus/Southbend I have heard plenty that Hercus had the Chinese made Hercus sent overseas but did they go to Canada or America as any paperwork would be appreciated as my serial numbers stop a1982 at 18066 do you have a updated page of the Hercus serial numbers or any thing about the 260 as having rebuilt one from scratch the castings which I believe were made in China and assembled in Australia then a supposed 2,000 lathes were exported overseas to either USA or Canada

all the best Derek
[email protected]

Chris,

What started out as a simple discussion about bearing classes has suddenly, and inexplicably, speared off in another direction. I will bow out of this.

I can scan the pages at work and send them to you in a private email if you are interested.

Regards Bob.