Keyed drill chuck...why?

[jordec66]

Hi and happy new year all,

I am looking to replace my aged Makita SDS , and had the idea of buying a core drill which could double as an everthing drill. I have seen a reasonably priced Sparky in Screwfix which will cut 152mm cores but has a keyed chuck. Anyone know why core drills have to be keyed? I've googled a few and they all have keys.

Thanks
Declan.

 

[jasonB]

less likely to come loose

 

[Steve Maskery]

I think it is likely that the forces on a core bit are considerably larger than a drill, due to the greater circumference. I suspect that a keyless chuck cannot tighten as firmly as a keyed one.
S

 

[WoodMangler]

I have a modern Makita drill with a 1/2" keyless chuck, and an ancient Black & Decker with a 3/8" keyed Jacobs chuck. I find that the B&D will often hold onto a drill which slips in the Makita, especially when breaking out at the end of drilling a hole in metal.

 

[jordec66]

Thanks for the replies; that must be the reason then. I'm hoping that I can put a keyless chuck in this:

http://www.ebay.co.uk/itm/DeWalt-D2...Home_Garden_PowerTools_SM&hash=item4ab181cbe1

then just use the keyed chuck for coring.