Bit slips inside chuck when drilling, what am I doing wrong?

Red Squirrel · 12-22-2010, 05:45 PM

When I'm drilling into cement with my Dewalt hammer drill, often the bit will end up slipping inside the chuck, and getting grinded in the process. This is both bad for the drill and the bit itself. I end up getting the job done by continuously tightening it, but no matter how tight I put it in, it will always happen.

Is this normal, or could I be doing something wrong?

If it matters, I occasionally spray water on the bit to keep it cool.

Bud Cline · 12-22-2010, 06:43 PM

Not familiar with that particular tool - what type of chuck does it have?

Is it SDS?

Mr Chips · 12-22-2010, 06:58 PM

It's pretty normal on these keyless chucks, especially if you are really pushing on the drill. If it was an old school Jabobs chuck with a key (or an SDS) you wouldn't have this issue.

I have two suggestions that should help:
1: look for drill bits that are manufacured with "flats" on the shank end. This will help a lot
2: If you find yourself really bearing down on the drill, DON'T! when you push down in rotohammer mode you really make the tool less effective. Let the machine do the work, you should just be holding it straight

EDIT: a third suggestion is to pull the bit up out of the hole a little more often. this will help with dust removal, which will keep the bit from binding ( and ultimately slipping). The water may actually be making it worse, as it may be causing the dust to cake up in the flutes of the bit, making it harder for the bit to get the dust out of the hole

Mr Chips · 12-22-2010, 06:59 PM

Quote:

Originally Posted by Bud Cline

Not familiar with that particular tool - what type of chuck does it have?

Is it SDS?

from his description I'm willing to bet its a standard keyless chuck, not SDS

Tom Struble · 12-22-2010, 07:50 PM

and the dewalt keyless chucks are known to be a problem

hvaclover · 12-22-2010, 09:08 PM

The chuck won't tighten well on some of the older De Walt stuff. I had to use two adjustable pliers to tighten my De Walt hammer drill so the masonry bits would not slip.
When I switch to my newer Milwaukee hammer drill I have no problem.
The chucks are better than the ones the De Walt uses.

Red Squirrel · 12-23-2010, 10:03 AM

It's a key chuck, but the end of the bit and the way it goes in, is basically the same as keyless. There's not much as far as something for it to really grab on to and hold the bit steady.

del schisler · 12-23-2010, 02:19 PM

Quote:

Originally Posted by Red Squirrel

It's a key chuck, but the end of the bit and the way it goes in, is basically the same as keyless. There's not much as far as something for it to really grab on to and hold the bit steady.

If it were me i would take and grind it flat on both sides. And when you put in in the chuck put the pointed part's of the bit in the open parts of the chuck and tighten. I bet it won't slip now. I do that to some drill bit's i use in my dewalt keyless chuck.

Red Squirrel · 12-26-2010, 11:03 PM

hmm not a bad idea, I'll have to try this.

12-22-2010, 05:45 PM	#1
Red Squirrel Wire Chewer Join Date: Jun 2009 Location: Ontario, Canada Posts: 2,975	Bit slips inside chuck when drilling, what am I doing wrong? When I'm drilling into cement with my Dewalt hammer drill, often the bit will end up slipping inside the chuck, and getting grinded in the process. This is both bad for the drill and the bit itself. I end up getting the job done by continuously tightening it, but no matter how tight I put it in, it will always happen. Is this normal, or could I be doing something wrong? If it matters, I occasionally spray water on the bit to keep it cool.

12-22-2010, 06:43 PM	#2
Bud Cline Tileguy Join Date: Mar 2006 Posts: 9,104	Bit slips inside chuck when drilling, what am I doing wrong? Not familiar with that particular tool - what type of chuck does it have? Is it SDS?

12-22-2010, 06:58 PM	#3
Mr Chips DIY Hack Join Date: Mar 2008 Location: Location, Location Posts: 1,296	Bit slips inside chuck when drilling, what am I doing wrong? It's pretty normal on these keyless chucks, especially if you are really pushing on the drill. If it was an old school Jabobs chuck with a key (or an SDS) you wouldn't have this issue. I have two suggestions that should help: 1: look for drill bits that are manufacured with "flats" on the shank end. This will help a lot 2: If you find yourself really bearing down on the drill, DON'T! when you push down in rotohammer mode you really make the tool less effective. Let the machine do the work, you should just be holding it straight EDIT: a third suggestion is to pull the bit up out of the hole a little more often. this will help with dust removal, which will keep the bit from binding ( and ultimately slipping). The water may actually be making it worse, as it may be causing the dust to cake up in the flutes of the bit, making it harder for the bit to get the dust out of the hole __________________ Those who can, do... Those who can't criticize on the internet Last edited by Mr Chips; 12-22-2010 at 07:03 PM.

12-22-2010, 07:50 PM	#5
Tom Struble Member Join Date: Dec 2008 Location: west milford n.j. Posts: 2,692	Bit slips inside chuck when drilling, what am I doing wrong? and the dewalt keyless chucks are known to be a problem

12-22-2010, 09:08 PM	#6
hvaclover Member Join Date: Oct 2008 Location: Suburbs of Detroit Mi Posts: 3,702	Bit slips inside chuck when drilling, what am I doing wrong? The chuck won't tighten well on some of the older De Walt stuff. I had to use two adjustable pliers to tighten my De Walt hammer drill so the masonry bits would not slip. When I switch to my newer Milwaukee hammer drill I have no problem. The chucks are better than the ones the De Walt uses. __________________ Just slow, not stupid.

Bit slips inside chuck when drilling, what am I doing wrong?