Thread: Noisy Spindle - Hercus Model O

Dont get to carried away with trying to fill it with oil,as it will flow out.
A couple of squirts should be sufficent.

I was wondering what that screw was for. I topped 'er up today.

As noted in an earlier post, my cone pulley had no oil screw fitted to it. So there was no way of retaining oil in the pulley, even oil had been used! What I am not sure of therefore, is what the screw looked like. Has anybody got details of this screw?

I have seen a picture posted by PeteF on the forum which shows his cone pulley with a screw having a slot in it. It looks like it is set up for instalation and removal by screwdriver. I also found that the thread at least for the oil nipple in the bull gear is 1/4 inch UNF. Is the oil screw also 1/4 inch UNF? I don't have my cone pulley with me. It is at the machinist so I can't check the thread just now.

Greg

I will measure the screw and report back tonight Greg.

BT

Originally Posted by gdonald

As noted in an earlier post, my cone pulley had no oil screw fitted to it. So there was no way of retaining oil in the pulley, even oil had been used! What I am not sure of therefore, is what the screw looked like. Has anybody got details of this screw?

I have seen a picture posted by PeteF on the forum which shows his cone pulley with a screw having a slot in it. It looks like it is set up for instalation and removal by screwdriver. I also found that the thread at least for the oil nipple in the bull gear is 1/4 inch UNF. Is the oil screw also 1/4 inch UNF? I don't have my cone pulley with me. It is at the machinist so I can't check the thread just now.

Greg

Your question prompted me to check out my Hercus 260 lathe which appears to have the same Cast Iron cone pulley as the Model O Mill.
The screw in the pulley is a Grub Screw .250 " dia (Quarter inch Dia) threaded BSW 20 threads per inch.
I take it out using a magnetised screwdriver .187" wide (Three sixteenths)
The screw is quarter inch long.
Squirt some oil in & carefully replace the screw.
It would be very easy to drop & lose this small screw & I guess that is what has happened in your instance.
Now getting back to the Hercus Model O Mill. My mill has the same grub screw & configuration as the lathe EXCEPT it has on the left hand side alongside the backgear an oil nipple that looks like a grease nipple. All of the other lube points on this mill have the same nipple fitted. The only thing is you must use oil, not grease.
There is the same grub screw fitted in the cone pulley as noted above in the lathe, however its my guess this is a carry over from the lathe & in fact lubrication is by the nipple.
I use a push pull oiler I think they are called "Pom Poms"
Now if you have a look at the diagram on page 5 of the Hercus mill Operational booklet it nominates the oiling spots but no mention of the grub screw. So with this in mind when you get your pulley back I would be inclined to fit a grub screw & leave it there to retain the oil & use the nipple for oiling. I hope this makes sense, & if I am wrong I stand to be corrected.
Secondly I have been using the Mill recently in the horizontal spindle configuration, & have been getting some annoying chatter from cutters, maybe Bob can assist me with this problem. I think the bearings could be adjusted up a little, & will look forward to advice,
regards
Bruce

Thanks for doing the homework on the screw Bruce. A dab of Loctite Screw lock on the thread might be a prudent move.

I replaced the arbor end support bronze bush on my mill. There was some play in the original. Could that be a source of chatter in your's? The spindle bearings were preloaded in accordance with the Hercus instructions. They are a light mill and too ambitious a feed normally courts disaster, as we both know.

BT

Originally Posted by Anorak Bob

Thanks for doing the homework on the screw Bruce. A dab of Loctite Screw lock on the thread might be a prudent move.

I replaced the arbor end support bronze bush on my mill. There was some play in the original. Could that be a source of chatter in your's? The spindle bearings were preloaded in accordance with the Hercus instructions. They are a light mill and too ambitious a feed normally courts disaster, as we both know.

BT

Bob
Sometimes I wonder about myself.
One can live with a problem for a long time & overlook the blinking obvious !
I just went & checked the Arbor & it measured .623 " dia
The bore of the bronze bush measured .631" dia.
So a clearance of .008" ..... way, way, too much, & I am sure this has been a contributor to the chatter problem.
The next step is to machine up a Phosphor Bronze replacement bush with a .624" bore which should help fix things.
One never stops learning on this forum its an excellent source of info.
Thanks again !
Bruce

Bruce, thanks for your research on the screw. I am impessed! It. makes sense that under normal operation, it. stays put and you oil the spindle via the oil nipple near the bull gear. Also Bob's suggestion of some Loctite on the screw will avoid the potential loss of the screw in future.
Greg

Originally Posted by Abratool

Bob
Sometimes I wonder about myself.
One can live with a problem for a long time & overlook the blinking obvious !
I just went & checked the Arbor & it measured .623 " dia
The bore of the bronze bush measured .631" dia.
So a clearance of .008" ..... way, way, too much, & I am sure this has been a contributor to the chatter problem.
The next step is to machine up a Phosphor Bronze replacement bush with a .624" bore which should help fix things.
One never stops learning on this forum its an excellent source of info.
Thanks again !
Bruce

Thanks Bob for the hint on the outrigger arbor bearing, on the horizontal spindle.
This afternoon I machined up a new bronze bearing with about a thou operating clearance max. & evaluated it cutting with a half inch wide side & face cutter & its heaps better.
In the morning a check will be made on the preload of the main spindle bearings.
The other aspect I have noticed is that the screw & nut on the table longitudinal feed has a bit of backlash. I would like to tighten that up.Perhaps I need a new nut to reduce endplay?
regards
Bruce

Bruce,

There is a lot of backlash in mine, maybe 30 thou. Always made me fearful when returning a cutter under power. Plenty of times I would turn off the machine and traverse the cutter back to the start to avoid some accidental and usually disastrous, climb milling. My mill is old, the serial no is OL-8. There is wear. I dare say, without too much effort that wear could be compensated for with some careful scraping and some thread cutting. Maybe down the track.

BT

Originally Posted by Anorak Bob

Bruce,

There is a lot of backlash in mine, maybe 30 thou. Always made me fearful when returning a cutter under power. Plenty of times I would turn off the machine and traverse the cutter back to the start to avoid some accidental and usually disastrous, climb milling. My mill is old, the serial no is OL-8. There is wear. I dare say, without too much effort that wear could be compensated for with some careful scraping and some thread cutting. Maybe down the track.

BT

Bob
I just checked my Mill & its serial no is OLM-261
Do you have any info on its actual age, & the age of your Mill ?
The main bearings seem all OK but the backlash in the longitudinal table is 20 thou
& the cross slide 6 thou.
The cross slide still has scraping marks on it & is acceptable however I would like to restore the longitudinal table as it seems to have the most wear. Perhaps I can get into it, by hand scraping which would not be a big job.The feed screw seems to be a square thread form & maybe a new bronze nut might fix it. I do not know if Hercus S.A might have one, but will check it out.
My Mill is Metric & I would prefer Imperial as I have never really got comfortable to using metric in smaller measurements.
I manually feed & like youself switch off the machine when reversing the table after the cut, because climb milling can be a disaster.
regards
Bruce











regards
Bruce
.

I reckon the No.O was introduced in 1972 based on my recollection of conversations I have had with Steve Durden at FW Hercus. The 3 slotter made it's debut around 1986.

The mill handbook makes reference to the SFM/RPM table 4 on page 21 of the Text Book of Turning. I have the 1970 second edition and the table appears on that page. If table 4 doesn't appear on page 21 of the '64 first edition, it would suggest that the mill was not introduced earlier than 1970.

The vertical head on the earliest model was not offset. My version of the slotting head utilizes the old straight casting. The early spindle had to be modified to accommodate the new head. The modification was the drilling and tapping of the 1/4" holes used to secure the drive gear. Hercus produced a drawing for this modification in 1977 but this can't really be used to determine the date of the new vertical head intoduction simply because it was only an upgrade of existing spindles.

There may be some manual arts teachers out there who might remember when the schools first installed No.Os.

Below is an Ebay seller's photo of an early mill.

BT

The information on manufacture date of Hercus Model Os is interesting Bob. Since mine is a 3 slotter (OLM 670), I now know that it is at least post 1986.

I am still waiting on the machinist to finish the bushing of the cone pulley. I will post photos of the work he has done when complete.

Finally, I notice that SurfinNev has raised the issue of the cost and availability of a new spindle in another thread. I have actuallly asked the same question of Mal at Australian Metalworking Hobbyist. A new spindle would be a good solution for me but looks like it would be expensive!

Greg

I found out today that my mill was purchased by James Nash State High School in Gympie in 1993. I assume it was new at this time. As noted before it is OLM 670.

Greg