Safety concern: beware of cordless drills with brakes

[ToddF]

I was looking for the right spot to post this, and was surprised not to find a safety forum.

I have seen a bunch of videos on youtube of people running shooter wheels with drills. We tried this last night with a fairly new Dewalt cordless drill. It incorporates a brake which is intended to slow down the chuck when the trigger is released. This brake kicks in as soon as pressure to the trigger is lessened and the speed begins to reduce. Since we were driving a shooting wheel with fairly high momentum, the wheel tried to keep coasting. This interacted very badly with something in the chuck brake mechanism, and caused the brake to instantaneously lock. The momentum of the spinning wheel caused the drill to kick violently, and nearly ripped the drill out of the hands of the student using it.

I have never seen a drill behave this way, and wanted to warn the community before someone gets hurt. We switched over to driving the wheel with a plug-in drill, with no chuck brake, and had no more problems. I don't know if this is a characteristic of all drills with chuck brakes, or just this particular Dewalt model. But, if you choose to run your prototype shooter with a drill, be on your guard.

[SenorZ]

Thanks for the head's up!

[Brandon Holley]

Originally Posted by ToddF

I was looking for the right spot to post this, and was surprised not to find a safety forum.

I have seen a bunch of videos on youtube of people running shooter wheels with drills. We tried this last night with a fairly new Dewalt cordless drill. It incorporates a brake which is intended to slow down the chuck when the trigger is released. This brake kicks in as soon as pressure to the trigger is lessened and the speed begins to reduce. Since we were driving a shooting wheel with fairly high momentum, the wheel tried to keep coasting. This interacted very badly with something in the chuck brake mechanism, and caused the brake to instantaneously lock. The momentum of the spinning wheel caused the drill to kick violently, and nearly ripped the drill out of the hands of the student using it.

I have never seen a drill behave this way, and wanted to warn the community before someone gets hurt. We switched over to driving the wheel with a plug-in drill, with no chuck brake, and had no more problems. I don't know if this is a characteristic of all drills with chuck brakes, or just this particular Dewalt model. But, if you choose to run your prototype shooter with a drill, be on your guard.

If you do use a cordless drill, putting the chuck setting on one of the slip settings will probably avoid this issue. The clutch would slip instead of trying to exert the intertia of the spinning wheel into the drill and therefore the drill handle.

Just take your time getting it up to speed and it shouldnt slip on the way up.

-Brando

[Teched3]

Originally Posted by Brandon Holley

If you do use a cordless drill, putting the chuck setting on one of the slip settings will probably avoid this issue. The clutch would slip instead of trying to exert the intertia of the spinning wheel into the drill and therefore the drill handle.

Just take your time getting it up to speed and it shouldnt slip on the way up.

-Brando

If you use a drill with a chuck that requires two hands to tighten or loosen, that won't happen. Drills with a one hand chuck employ this type of mechanism to lock the arbor when tightening/loosening the chuck, elimination of the need for the 2nd hand. You can also take the drill apart if this route is not available and remove the locking pins/springs and rods of the locking mechanism. However, a previous post to reduce the clutch mechanism setting might work, but might release before the wheel spins up to speed. .

[tlivingd]

Originally Posted by Teched3

If you use a drill with a chuck that requires two hands to tighten or loosen, that won't happen. Drills with a one hand chuck employ this type of mechanism to lock the arbor when tightening/loosening the chuck, elimination of the need for the 2nd hand. You can also take the drill apart if this route is not available and remove the locking pins/springs and rods of the locking mechanism. However, a previous post to reduce the clutch mechanism setting might work, but might release before the wheel spins up to speed. .

I can second the above statement. They are fairly easy to remove but you won't be able to get the chuck locked w/o sticking something into the motor.

This was actually necessary back when we used cordless drills for the main drive motors for FIRST.