Mini Mill woes

[Roger ClarkParticipant @rogerclark]

Otherwise known as was it me or the tool?

[Roger ClarkParticipant @rogerclark]

I bought this X2 type mill 2 or 3 years ago and have never really been happy or comfortable with it. It is my first mill so a steep learning curve was the case so when I got bad finishes and chattering etc. and it's always been noisy in the area of the spindle but was told it was probably the gears left in there from the belt conversion so I put it down to me.

Anyway the last couple of months it has got worse, also the spindle movement was getting rough.

So, start of the new year complete with 'women flu' (she gave it to me and hers is always worse than mine ) I stripped out the spindle without too many issues and as the spindle came down out of the housing ball bearings started to drop out! Anyway the bottom angular bearing came out leaving the outer race in the housing, the source of my noise and issues

So I've decided to go with taper roller bearings, I'll get my friend to mill out a mm from the top housing which will keep everything as is positional wise.

Roger

[old martParticipant @oldmart]

When you put it back together with a small amount of lithium grease (not moly grease) there needs to be the tiniest bit of preload. The only way to check that the preload is not too high is to run the machine and check the temperature of the area near the bottom bearing. If it gets more than luke warm with the fingers after ten minutes, then reduce the preload a tiny bit and retest. At maximum speed it should run all day without getting hot.

There should be some sort of shield to stop swarf jumping up into the bottom bearing.

[Roger ClarkParticipant @rogerclark]

Hi Old Mart, yes I've got some JCB Lithium Blue that I'll use. I plan to look at what other mods I can incorporate while it's apart to give it the best chance of having a continuing presence in my workshop, my mini lathe also decided to strip the teeth off the drive pulley as well, I was cutting off some rather tough metal to make a toolpost nut for my big lathe, had to use the bandsaw to finish and belt sander to clean. , at least my big lathe is useable now finally, at long last yay

Roger

[Howard LewisParticipant @howardlewis46836]

Any chance that you could turn the nut just finger tight and then fit a DTI.?

If this is possible, you could zero the clock and apply preload by a measured amount.

Taper rollers don't like excessive end load, preferring to run with zero to minute end float, but this is not possible in machine tool applications; hence the need not to overdo things.

Howard

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