Mick,

If anyone can make better sense of your post than I can, I will have to wait and see what they say!

1. Spindles don't stall. Motors do. If you have variable speed, then do you mean the overload cuts in? Or are you literally talking stalled motor or belt slip?

2. You're not a beginner, so have you done the obvious and tested the ability of the spindle to turn by hand? If it is tight , then you have made the adjustment just that bit too good. Slacken your setting off just a tad.

3. Don't understand the "quarter inch" measurement.

Sorry, but I don't understand fully. It seems like you simply have a tight spindle or a new motor fault.

Dennis

Mick – I think you are probably doing it correctly (pages 24 and 25 of the manual?) but if you have removed the spindle – are you certain everything went back in the right place (and the right way around).

The spindle adjustment is quite sensitive and I've sometimes taken a few go's to get it right. The spindle only has to "stick" – not be completely "hard" locked on – then you back off the adjusting ring by 1/4" as you say – or 15 degree rotation if that is easier to understand. I don't think an over-tight adjustment would stall the lathe – I'd expect it to run hot before it did that…

Are you sure everything is well seated – were the back gears damaged in any way – I think I'd check both gears carefully (especially the lower one) – and do you know what caused the back gear to be "stuck" in the first place – because I don't recall ever having that problem myself..

Regards,

IanT

Sorry Mick – you spoke of adjusting the gears – so just to be clear – is the problem with back gear engaged or not?

Regards,

IanT

A long time since I had to worry about this area. This image from a post on here shows why it's a tricky thing to do

It's a two stage adjustment. The bearing position is set by the rings but bearing pre load is set by the nut on the end. So each time the bearing position is moved to pull the front cone in the nut on the end needs slackening off first. Bearing position adjusted and then the bearing pre load re applied. In this case preload mean zero of very low end float. Your not looking for zero clearance on the front cone just a very low number to suit the oil that is being used to lubricate it. Perhaps the best way to do that is to smear some oil on the spindle cone before assembling it. This is likely to be too much. Adjust and run the lathe and then adjust again. You will also probably have to adjust again later on as the oil film settles down over time – best done eventually after the lathe has been running for say 15min at a medium speed. Lathe bearings warm up due to friction which will also thin the oil. After adjustment check for problems at high speed.

Summary – the angular contact bearings can always give zero end float. They also have to position the cone so that it has a sensible oil film to run in when the lathe has warmed up. It wont be possible to do this quickly. People might also find that the cone is too tight really before the lathe has warmed up. It's a matter of compromise if that happens.

Personally on these lathes I think it is worth checking the condition of the angular contact bearings as the adjustment is so easy to mess up. They are designed to be used in pairs with each one the right way round and like all bearings shouldn't have any play when not loaded. Some probably doesn't hurt at all given the way Myford use them but any jitter / ripple when they are pressed home and rotated is bad news. The cone can wear in odd ways as well if the lathe has been used with the bearings incorrectly adjusted – too loose in other words and lubrication is very important.

John

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Mick – when the spindle "stalls" what happens to the drive belt and the motor?

If the belt slips, have you got it at a high enough tension?

If the motor stalls you could have a fault there.

You might well be chasing your own tail with the spindle bearings looking for a fault that isn't there but somewhere else.

You might find that using the tailstock to push the spindle home will help getting the rear bearings set correctly. If your sure that your tailstock is on centre but a centre on it and press it into the morse 2 on the headstock spindle. The cone on the centre needs to be bigger than the morse 2 hole though.

John

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You might find that using the tailstock to push the spindle home will help getting the rear bearings set correctly.

Works for the M series. Put some load on the thrust bearings, make sure the spindle spins freely under load, and adjust the cone bearing until it starts resisting, then ease off a bit

The aspect that needs thinking about when the rear end is adjusted to get the cone right is that all 3 nuts play a part. The end nut forces the spindle shoulder up against the bearings closing them up. The very rear ring positions the bearings. The other ring just fixes the stuff in place so can be left to last but each time an adjustment is made the other 2 need setting appropriately.

Using the tail stock helps because it's likely to thin any oil film other than probably the one in the cone and it will take up any play in the end ring's thread so it wont move when the other ring is tightened – we hope.

Ideally when the cone is positioned correctly there should be some drag. So after an adjustment with the tailstock applying pressure tighten the ring that keeps things in place, withdraw the tailstock and rotate by hand. If after getting this right the cut is still not adequate just make a very small marginal adjustment to the rear ring with the others loose and then tighten them up in the right order. This all assumes that the rear bearing pair are held tightly together otherwise it falls flat on it's face. Hopefully the tail stock pressure will take care of that. Oil films are measure in 1/10 thou, less in some cases. That should give an idea how much difference a turn of a ring can make.

If the cone bearing in the headstock has worn oval that will mess this up and probably mean that the set up needs to be run a little looser than ideal.

There is a fair chance after doing this that it will need doing again once things have settled down – tiny adjustments again. The viscosity of the oil drops a lot once a lathe is in use for a while and that will make a difference usually loosening bearings but on some with roller races etc they can actually tighten a little. The spindle expands due to heat.

John

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Edited By John W1 on 01/06/2015 23:07:54

Edited By John W1 on 01/06/2015 23:16:09

You say 0.4in cut – 0.8 off the dia ?? – rather a lot for a Myford really assuming free cutting mild steel. From memory the auto feed rate on a Myford is sometimes rather coarse so how much per rev?

To give you some idea big DSG 5hp motor, 3/8" cut, bad chip breaker that crunched up the swarf rather than just broke it up, 1/64" per rev but the swarf measured more like 1/16 due to the breaker, blue swarf, bar around 5in dia and the motor really sang. They do when working hard and make a very distinctive sound.

A photo of the tool tip you are using might help as well.

John

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Edited By John W1 on 22/06/2015 15:40:34

IMO you need to keep moving the spindle forwards with the thrust bearings, until the tailstock loading no longer slows the spindle down

Don't forget to release the tailstock loading between adjustments

Edited By Ady1 on 22/06/2015 16:13:52