Tailstock fittigs

[Mark Hancock]

Hi Mark

That is what I was referring to, when you bore into the work the drill encounters resistance which tries to stop it turning - this resistance, (reaction), is transmitted to the chuck body, the sleeve is still being driven by the lathe which will tend to loosen the jaws.

This I couldn't get to happen regardless of whatever load or resistance I applied to the item held by the chuck :?:

You can simulate this by holding the chuck body still whilst rotating the lathe, (by hand), in it's normal direction of rotation - the jaws will open. Was this what you observed?

Regards Mick

Yes I could do this.

 

[Mark Hancock]

Wow, interesting points raised by a misunderstanding. When I mentioned fitting a Jacobs chuck in the headstock, that is what I meant. The Jacobs chuck on, in my case a MT2 into the headstock spindle. Had I thought of something being mounted and held in a scroll chuck That is the wording I would choosen.
I would have thought that the seasoned turners here would have credited me with some intelligence NOT to recommend trying to grip a taper fitting in a parallel jaw. (To the MOD's Sorry I started this. Keith)

Keith, it's all about passing on the knowledge that we have acquired, especially to those that are learning.

Sometimes I am surprised that something that I think is common knowledge, isn't, & conversely, when I read something by someone who has overcome a problem that I have perhaps not solved, or solved differently, I get that 'doh' moment when it crosses my mind that I should have thought of that particular solution.

Exactly Robbo. Still learning after 25 years

 

[Spindle]

Hi Mark

I think you can now see what I was referring to - if the drill is clamped in the chuck using the chuck key you will not be able to loosen the chuck purely by hand pressure, however the tendency for it to become undone due to the lathe gripping the sleeve is demonstrated by you holding the empty chuck body whilst rotating the lathe and observing the chuck jaws loosening. Under power, loosening could be initiated by vibration or shock loading.

Regards Mick

 

[Mark Hancock]

Hi Mark

I think you can now see what I was referring to - if the drill is clamped in the chuck using the chuck key you will not be able to loosen the chuck purely by hand pressure, however the tendency for it to become undone due to the lathe gripping the sleeve is demonstrated by you holding the empty chuck body whilst rotating the lathe and observing the chuck jaws loosening. Under power, loosening could be initiated by vibration or shock loading.

Regards Mick

Yes Mick I understand that but it's the last bit that I couldn't get to happen ..".Under power, loosening could be initiated by vibration or shock loading." Maybe I've just been fortunate? I'll continue to use this way of holding a Jacobs chuck as I find it very useful but I'll certainly be more aware in the future of what may happen.