Milling machine spindle

I have just discovered that my Dore-Westbury milling machine spindle, has acquired a lot of end play . Thankfully, it is just the large retaining nut over the top of the upper bearing which has loosened. I shall lock it in place with a thread locking adhesive. My question is, how do I tell when it is tight enough? I don't want to over-tighten it.

Thanks for any guidance

Regards Maurice

When all the endplay has gone?

Tony

I changed mine to tapered roller bearings as I was not happy with the angular contact ones have been fine for past few years.

Bob

Hi gents; thanks Tony, but when is that? Do you have to pre-load the bearings? I feel sure that if I just did the nut up until I could feel no movement, then the spindle might still move when under load. As to changing the bearings to roller bearings, this is made a bit difficult as the lower one is hard up against a collar with nothing to "grab" to pull or push it off. Being angular contact bearings, the outer race and the balls just pull off, leaving the inner race on the spindle.

Maurice

You could use a DTI to establish when all the end float has gone & then perhaps pre load slightly, that should be acceptable.

Tony

The inner half of the race should not present too much trouble to get off, I've done loads in the past on car front wheel bearings. You'd have to remove it if you were replacing the bearings which is where I started and decided as there was a tapered roller bearings with the same dimension as the angular contact ones it was no contest.

Bob

Maurice,

The build instructions for the Mk2 state re setting the pre-load

"Tighten the nut until rotation of the spindle is just resisted" "then tighten the socket screw" - this is fitted through the side of the nut to lock it in place.

This is of course done on assembly so the spindle can be held in a vice during the procedure, but it should not be different on an assembled machine.

Thanks for the feedback gents. Sorry for the delay in answering, I,m not at home at the moment, and my laptop has just turned into a plastic box! Had to borrow one for this.

Maurice

I haven't had to touch mine so far and it's still on angular contact and came with a spare set.

I haven't seen the nut arrangement and the drawings are tucked away. I would have thought that it should be possible to lock it. If you thread lock it any future adjustment is going to be a bit tricky. If you greased the bearings you will probably find that they need adjusting after it's been used for a while, even a short period.

Mine is a MK1. No spring return on the quill - I'm glad to say. I've yet to hear of any one who is dissatisfied with a DW other than the person I bought it off - end milling with a blunt slot drill in a totally inadequate vice with the slides set way too loose.

Boxford use an interesting method of locking the nut on their spindle bearing adjustment. 2 drilled and tapped holes with grub screws in them. These press on some disks of soft metal against the spindle thread. Might well be white metal but I managed to loose one so replaced it with soft solder. I just drilled a suitable sized hole in some mdf and cast the disc in it then flattened the end and fitted it. The nice thing about this way is that the nut doesn't move when it's locked in position. It can with a split nut depending on the thread clearance when it's adjusted.

If you need to know what should be there I could dig out the drawings and photo the bits for you if needed. Just ask. It would have to be tomorrow.

John

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Edited By John W1 on 16/10/2015 20:31:19