just to settle an old argument

[hareng]

Always used quality keyless chucks except on current mill. Its worn when tighten up normally drill or whatever visably spins eccentric with around 2mm runout, nip the other two up and usually pretty central, may have to go round all three twice.

Keyless totally different to keyed chucks they work on a taper to centralise. http://www.jacobschuck.com/keyless-precision-chuck-repair-guide

New 3 or 6 jaw chucks its not a problem and can see the point in nipping all three up on a 3 jaw self centring but rarely do it.

 

[WorkshopChris]

Are the 3 holes so that one is always at the front/top, think about a chuck in a lathe tail-stock or geared drill, would be a pain if the only hole ended up at the back and you had to reach round to tighten it.
Definitely need to tighten a worm chuck & key from more than one point.

 

[MattF]

I use all three progressively.

I do the same.

 

[bletchmonster]

I use one hole as standard, 3 if i need extra tight for 'shiny' bits, main thing for me is when tightening push the lever of the key up towards the chuck teeth to encourage as much mesh as poss

 

[brightspark]

well ive learnt something new test on tightening chucks up . a Jacobs chuck on the drill I put the torque wrench on 1st hole and tightened a drill up till the click stop activated .went to the second one and it further tightened till click stop the 3rd also tightened till click stop went back to 1st and just a click . the 3 jaw scroll chuck on lathe. tightened the 1st till click stop the second hole turned then click stop but the 3rd just clicked and was tightened enough . well better go do something more constructive

 

[brightspark]

even with the results il still only tighten them up the once as ive never had stuff slip

 

[Sarto]

Tighten on all three even across the sea.