Thread: Is there a right way to tighten a drill chuck?

Bob

My Dad told be the same thing and, like you, I have tended to follow it. The idea of distributing pressure around the circle makes sense to me - like tightening wheel nuts a little at a time and going around and around before nipping them up tight.

I suspect that it doesn't make much of a difference, but, like chicken soup, it can't hurt and it might help, so I will continue to follow your and my Dad's advice.

PS do you use the chuck key only to tighten , or do you spin the chuck by hand to get a first "grip" on the drill and then use the key? I do the latter, which I find both quicker and to give an nice centred grip which doesn't let go easily...

Although any hole will "activate" all three jaws to get the tightest grip tightening at all three sites will work best.

Bob, I usually tighten a chuck with use of the three holes and the key, but dont know if it is absolutely necessary. A lot of hand drills now have the newer keyless chuck which is tightened by hand to about 10mil size, a great idea. Unless the metal ring distorts badly and it is only measurable with a vernier caliper I do not see a problem. Might be splitting hairs with this idea.

Regards Mike.

As someone who used to regularly drill 12mm up through to 32mm holes in 12mm up through to 25mm thick steel, I can say with great confidence that tightening the chuck via the 3 holes does make a huge difference.

Originally Posted by Bob38S

When working on the drill press recently I was seen to do this tightening procedure and was laughed at as being pedantic, was a waste of time and did absolutely nothing with regards evening the pressure as it could just as easily be achieved by only tightening 1 of the key holes.

Regards,
Bob

That bit is factual.
The 3 holes are there simply for convenience.

Having thought about this a bit further the greater tightness when using all three holes probably relates to removing the key and replacing in a position that allows greater mechanical advantage. You may get the same benefit by removing the key and replacing in the same hole and retightening.

Like those above taught to tighten x3 still do on many occassion's
But the reasons behind it chucks back then were not self centering as we have had for many years now it is till god practice as wearing one hole and the teeth begets frustration later on.

Meh, I've never done it this way and never had a problem. I have a feeling this all comes down to history but I have no proof. What's the bet that in the old days the fingers were not all connected on a nice wheel which when moved tighted *all* the fingers. Instead you had to individually do it per finger. Like anything old habits die hard I guess.

I don't waste my time. I just tighten one and it works fine. The fact that they are all linked basically seems to me like it's just a myth that you need to tighten all 3. Three are there to make it easy to undo the bit rather than having to spin it around until you find the one hole.

I see it as the same principle as the keyless chuck. You don't go around the chuck applying pressure with your hand to all points. There is no need.

I wonder if this 'tightening every hole' theory came from the old 4-jaw lathe chucks etc that had each of the 4 jaws moving independently?

IANAME (I am not a mechanical engineer) but, having followed the three hole procedure and also being slack I have only tightened via one chuck hole, and I really can not see much difference.

...But, I can honestly say that "I have never been sorry when I have exercised an extra bit of caution, but I have frequently been sorry when I didn't."


...how's that for an old phart, non-commital rant?

You could always try what the rest of the world has since discovered...key-less chucks.

It saves time and is more effective at securing the bit. Only been around for 20 years...

Well I hand tighten to center the bit then tighten at least two holes. If it is a reduced shank 14mm and above I will tighten all three, I can learn thru experience

why would you not tighten all 3? i've always been taught to do all 3.

Thanks for the replies, I do spin where possible [on a hand drill but not on the DP] and tighten by hand first, then the 3 holes - I do have keyless chucks but not many.

As my "teacher" was not a mechanical engineer I can't comment on some of the above but can say that if there were 3 holes to tighten, I used them. Can't really imagine that 1 was for tightening and the other 2 were spares but I'm willing to be re-educated by a convincing argument.

Many thanks,
Bob