Wrench (or “standard”) chuck handpieces have their perks and can be beneficial in your dental practice as they have a lower cost and can be more reliable as they have fewer moving parts. They are also simpler to maintain as you can free up a stuck chuck using a ¼” open-end wrench.
Back in Practice Tip #63, we discussed the different chucking mechanisms used on high-speed handpieces. This month, we’ll outline the precise technique to use a common hand tool to free up a stuck wrench ("standard") chuck.
First, if having trouble changing a bur, make sure your bur wrench is functioning properly. The central shaft of the wrench should be solid and not rotate independently of the handle. You can check your wrench using a pliers.
Just grasp the central shaft with a pliers and attempt to spin the handle. If you can spin the handle while holding the central shaft, the wrench is stripped (worn) and should be discarded. Replace with a new wrench. Generally, if the wrench is stripped, you’ll also be able to tell; the wrench will spin freely when engaged in the handpiece, but the bur will not loosen.
If the shaft is solid and you are still unable to open the chuck, the chuck is likely jammed and/or just stuck. In order to open it, you’ll just need more leverage. You can get more leverage by using a ¼” open-end wrench on the handle of the bur wrench. Just place the wrench over the handle as illustrated below:
Are you still having problems opening the chuck? You’ll need to use a second wrench to hold the spindle steady, while opening the chuck. It will be necessary to steady your handpiece by resting it on a table or counter top and holding the handpiece and wrench with one hand, while turning the wrench on the handle with your other hand.
During use, debris can get lodged in the chuck causing it to get stuck, or the bur can get jammed in if the handpiece is dropped, bumped, or jarred. Using the techniques illustrated above, you can still free up your handpiece and restore it to proper function quickly and easily.