Quill bearing temperature

[Michael GilliganParticipant @michaelgilligan61133]

Posted by John Haine on 27/12/2016 10:54:28:

Here is a C/S of the spindle from the manual. …

And maybe the main source of friction could be the seal? So I'll carry on using and keep an eye on the temperature rise (which is easy now I have the IR gadget).

.

Thanks for posting the picture, John

Regular monitoring sounds a good idea

Apart from that; I think Mark has summed-up nicely.

MichaelG.

[AjohnwParticipant @ajohnw51620]

There are no assumptions at all about the behaviour of the older style boxford spindle Michael. Other similar arrangements are likely to behave in a similar fashion for very simple reasons.

I've probably mentioned on here that twin bearings on the front of a spindle can be better also the reason for many lathe having long head stocks compared with spindle size. Also the same aspect in relationship to plain bearings. The reasons are similar after a fashion.

I could also mention that some lathes with twin bearing arrangements at the front also tighten up when warmed up. Again there is no surmise about that what so ever.

As to the rest we have all been exposed to different things and different expertise in our life times. Some more so that others and in totally different areas.

Twerp – well if some one chooses to be rude to me I am likely to do so back in a more obvious fashion. Especially when they are entirely wrong.

John

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[Mark CParticipant @markc]

Ah well, so much for sensible debate. If only I had been born with the ability to insert a digit into the end of a machine spindle and be able to sense not only the operating temperature of the bearings, but more importantly understand the thermal behaviour of the entire assembly…. and all without making any assumptions at all!

As a mere mortal, I have to make do with measurements of prototypes and thermal numeric modeling (which I would contract out as it is way past my basic skill level).

Mark

[AjohnwParticipant @ajohnw51620]

Perhaps there is something wrong with your nervous system.

John

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[Mark CParticipant @markc]

John, Instead of being childish, could we not manage a sensible discussion just for once? You are keen to inform everyone about your wide and varied work experience in R&D.

Mark

[AjohnwParticipant @ajohnw51620]

There is no R in my work Mark. Unfortunately. Things generally must work when finished.

Anyway some years ago I wanted some specific information on bearings and came across a pdf by MIT as usual it is in no way complete and refers to various standards that most people will have problems getting their hands on. It does mention why bearings tend to tighten when they warm up which they must do in realistic machine tools except probably certain grinders etc that use spring derived preload. There are also the strange aspect of plain bearing that have been known to not wear out. An area that is much more clearly understood now. That goes back a very long time.

I still have it about. An extract.

It's still about and I would add if only some of it could be so simple. Some will probably disagree on that. A google link unfortunately.

**LINK**

John

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[David George 1Participant @davidgeorge1]

Hi John.

Having seen the correct drawing for the spindle it is very similar to the one on the mill with the heating seal, the contact point of the seal had worn a flat and increased the contact area thus increase in temperature. just thought it is cheaper to investigate the seal to see if it is increasing in temperature at the contact point. can you get the thermometer on to the seal in that area.

Good look

David

[John HaineParticipant @johnhaine32865]

Good suggestion David, I'll see if I can do that.

Otherwise, as this discussion is in danger of getting a little "heated" I think we might declare "this correspondence is now closed"?

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