Myford Oiling

[John PurdyParticipant @johnpurdy78347]

Justin

If you decide to remove the spindle the check the wick here is the perhaps the definitive way to set the front bearing clearance when re-assembling it. I have used this procedure a couple of times and it works well.

It was previously posted on this Forum, but I cannot find the post: apologies to the original poster(s).

John

 

The Gospel according to Malcolm (The original Myford works procedure)

1. Power Down

2. Remove all belt tension.

3. Remove Chuck

4. Rotate RH collar one complete turn. (top towards you).

5. Rotate LH collar one complete turn. (top towards you).

Spindle should be completely free of front bush.

6.Loosen allen screw on collar at end of spindle.

7. Using the Allen key tighten collar as tight at it will go by hand.

Inner tapered roller races are now locked together with correct pre-load.

8. Back off LH collar one complete turn + a bit (top away from you)

9. Rocking the spindle by holding the spindle nose tighten the RH collar by hand (top away from you).

10. When you feel resistance to movement stop.

11. Collar should be just tight enough that spindle can just be moved by hand holding the nose.

12. Do up the LH collar by hand (top towards you).

You should still feel resistance when turning the spindle by the nose.

13. With the crescent wrench on the LH collar tap the end smartly with a 12oz hammer.

The spindle should move forwards by a couple of tenths and be completely free running.

14. With the lathe running slowly (lowest direct speed) put the oil gun in the front oil cup and pump until oil issues from the front bearing.

15. All should be sweetness and light with great rejoicing in heaven and on the earth.

 

[noel shelleyParticipant @noelshelley55608]

Bearing in mind the wick/capillary type oiling of the front bearing item 14 sounds more like an instruction for an ML7 ? Noel.

[John PurdyParticipant @johnpurdy78347]

Noel

I’m not quite sure why you think it “sounds more like an instruction for an ML7”. The ML7 has drip feed oilers on top of the bearing whereas the S7 has a “front oil cup”. Those times I have used this procedure to set the front bearing clearance I haven’t bothered with step “14”, just filled up the front oil cup.

I used my lathe 4 days ago for about an hour and had filled up the front oil cup before turning it on. I just checked it and it was empty. It took 4 pumps from the oil can to fill it up to the top. Close inspection of the joint between the spindle and the front of the bronze bearing shows a very small meniscus of oil.

John

[noel shelleyParticipant @noelshelley55608]

Hi John The proceedure you listed was only for the setting of the spindle. I had possiblly wrongly thought that the need for this would be after removing the spindle to check the front bearing, in which case one would lube it up as it was assembled and simply fill the cup.The time taken for the oil to wick through would be tiresome, so just fill the cup and leave it, refill as needed ? I am well aquainted with both the ML7 and S7,has your S7 got roller bearings on the rear ? Normally they should be a pair of angular contact ball races ! Noel.

[John PurdyParticipant @johnpurdy78347]

Noel

Yes, the procedure I listed is only for setting the front bearing clearance, either after the spindle has been removed and replaced (say for a belt change) or after a period of use to compensate for wear. I’m not really sure why “step 14” is there, as you say I think it would take forever for oil to wick up the felt and show at the front of the bearing. I have always just filled up the cup and left it, re-filling as necessary.

Yes my S7B, of 1976 vintage, has 2 annular contact ball bearings (listed in the Myford manual as “Hoffmann 125 AC”, SKF equivalent is 7205B, not cheap! ) back to back at the rear of the spindle. They are preloaded by tightening the collar on the left hand end of the spindle (step 7), then the whole assembly (spindle, bearings and collar ) is moved forward or back in the headstock casting to set the front bearing clearance by adjusting the two rings either side of the bearings with a “C” spanner. (steps 8 – 13).

John

[Justin Thyme]

On Justin Thyme Said:

Many thanks for all the replies – lots to think about.

But first things first, how do I establish if the wick is working ?
I have filled the cup up to brim full with a 32 hydraulic oil,  and after two days it is still brim full.  I have run the lathe for a few minutes and the level does not change.

Don’t want to run the lathe for half an hour to see if that alters the level, and bugger the bearing because the wick is not working.

 

Whilst this does not establish the condition of the wick you can ensure that there is a free passage of oil to the front bearing in the following way. Put the oil gun into the headstock oil reservoir and with the lathe running pump until oil issues from either the front or the rear of the bronze front bearing.

Once you have established that it does you can be assured that the oil way is not blocked by someone filling the system with grease and you will have supplied an oil film to the front bearing and that the wick is full of oil.

You can now confidently run the lathe keeping a check on the temperature of the front bearing and an eye on the level in the reservoir. If the bearing doesn’t get excessively hot (stop if it does) and the reservoir level drops over time then you can be reasonably confident the lubrication system is functional.

Personally if I was in doubt about the condition of the headstock I would whip the spindle out and fit a new wick giving me an opportunity to inspect the front bearing, change the rear bearings and set the whole thing up to my satisfaction. It’s not that difficult and you end up knowing for sure things are OK.

ps The oil gun in the reservoir trick is a good thing to do after a spindle removal or bearing adjustment anyway. It was Myfords protocol after such work.

regards Martin

[Nigel Graham 2Participant @nigelgraham2]

Re Screw-cutting Gearboxes….

I don’t know if the 7 and the Super 7 differ much in this regard but the earlier gearboxes at least were supplied with a single-chain banjo to link them to the spindle tumbler-reverse output pinion.

To change between slow self-acting feed and screw-cutting you reverse the centre gear-pair on its stud.

The disadvantage is that the design only gives inch-based threads because you cannot change the gears from the headstock around. Later gearboxes (or perhaps early ones with an option?) have a slotted banjo allowing change-wheels for Metric, BA and non-standard threads.

So if swapping gearboxes between machines it’s worth a little research first, if you want to be able to cut different standards of threads.

Also the early gearboxes needed shortened lead-screws, but mindful of possibly future reversion to full change-wheel setting when I installed a second-hand gearbox, I bought a length of lead-screw material (from HP Gears) for the new one and kept the original lead-screw and other parts intact.

Having just run into this problem when I wanted to screw-cut some studs, I am tempted to revert the lathe to original, on the basis that the fiddly task of manipulating the wheels and banjo is compensated for by the greater range of threads available – including the common Metric pitches – with the standard change-wheel set.

….

As for lubricating, my ML7 has plain oil-cups with turn-caps on its main bearings, and I lubricate everything else by liberally oiling the appropriate surfaces, nooks and crannies. Those ball-bearing oiling-points are a right pain, but at least ensure I am oiled as well as the exterior of the lathe.

Despite what the manual says, there is no oiling-point on the spindle pulley and it’s not clear how you do oil it. Nor is there a spindle lock. These must be Super Seven features.

…….

Incidentally, Hemingway Kits used to offer a kit for a Myford-compatible screw-cutting gearbox. I don’t know if it still does, or how it compares to the Myford product. It uses standard Myford change-wheels.

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