The Shop > Tools
Any idea why this lathe is chattering? Spindle bearings?
bertie_bassett:
with a bit of bar about 6 inches or so hanging out my chuck I can read about 1 thou of deflection on the side of the chuck, if I pull fairly hard toward me. that's on a badly maintained viceroy tds
id second joining the denford forum, loads of info on the site. a member there called dazz did a full strip down of his a few years back including a vsd conversion. pics are still there I think
plus they have all the original drawings
loply:
Thanks for that Bertie. I'm getting about 2 thou in the same situation, just pushing hard with the fingers of one hand.
I presume you took the reading off the end of the chuck nearest the tailstock?
I might just go ahead and try some new bearings out of interest as much as anything. Seems about £45 for a pair.
As far as I can tell the bearings fitted aren't high precision or anything, just standard timkens as used on wheels and other things.
bertie_bassett:
sorry ment to add a pic of my set up but forgot
as you can hopefully see I was measuring between the headstock casting and the rear end of the chuck. pushing quite hard wit my hand I was getting 1 thou deflection either way.
things to note though: iv never adjusted the preload on this lathe, its got fairly thick grease in it and takes a little while to get up to speed when cold. the chuck jaws are definitely belled out, generally in need of an overhaul.
loply:
Success :wave:
Thanks for all the advice folks, think I've got this sorted.
I ordered some new spindle bearings which gave me the confidence to go to town on tightening the old ones. As I mentioned earlier, the rear bearing is a stupidly tight fit on the spindle - instead of a sliding fit like my other Viceroy, it's a tight press fit (presumably a factory error?).
I put a 2ft extension bar on the spanner and cranked down on the rear bearing nut... nothing for a while, then crack, it turned an eighth or so... Half expecting that I'd cracked the casting I checked it, ran it for a while, then tried again... Literally giving it all my muscle, in fear of knocking the lathe over if I slipped, it moved another eighth or so. I backed the nut off then snugged it back up hand tight.
End play disappeared completely, and play on the spindle nose came down to about 0.001mm (down by a factor of ten). The bearings are getting pretty hot but I can keep my hand on them (although not by much). The chuck is still deflecting though not quite as much (but it doesn't seem to matter).
On that exact same steel bar from the first video I can now take a 0.4mm deep cut without a single bit of chatter! Turning 100% parallel too... 0.00mm taper in 4 inches.
Couldn't be happier! The lathe is now performing exactly as I'd hoped. Thanks for all the advice everyone.
Video - this is at 1800rpm, 0.4mm DOC -
awemawson:
Excellent news :thumbup:
Always good to hear of a satisfactory conclusion to these things :wave:
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