I've got an old Bosch corded hammer drill, model PSB 500. It's not the "RE" (reversible) model. The chuck is a traditional one with the jaws and the key to loosen and tighten the bits.

Since this model is not a reversible one, the chuck has not the central screw to remove. There is only a sort of flat head, it seems like a pin, and a really small hole on a side of this flat head. I can't understand if the hole has something to do with the removal process.

I followed the procedure I found here and on YouTube to unscrew the chuck: - lock a big Allen key in the chuck - hit it with a hammer in counterclockwise but: 1) the drill model doesn't have a lock button to avoid the rotation of the entire engine group; 2) the chuck shaft doesn't have a wrench friendly grip (the notches you see in the picture are at 120 degrees so useless for a normal wrench); 3) I tried to lock the shaft with a pliers but the chuck doesn't loosen the same.

Is there a way to remove this kind of chuck?

Bosch PSB 500 chuck

EDIT Inside the chuck

  • I removed the chuck from a similar but different Bosch model using a thin spanner on the flats between the chuck and the body, then turning the chuck with mole grips.
    – Chenmunka
    Commented Mar 27, 2019 at 18:44
  • 1
    @Chenmunka, answers go down there.
    – isherwood
    Commented Mar 28, 2019 at 14:47

2 Answers 2


The last time I removed a chuck like that, I had to open the jaws and remove the screw that was down inside the chuck...

And, sadly, they are usually "munched" due to the drill bits that have turned in the past....

  • I added a picture to show you what's inside the chuck. Is it possible that thing was a screw? Just in case what's the sense of the little hole you can see?
    – epikarma
    Commented Mar 31, 2019 at 5:57

If this diagram represents your drill:
Exploded diagram Then it looks like you:

  1. Chuck up an allan wrench.
  2. Use a thin wrench that fits the flats on the shaft in the first picture.
  3. Turn the allan key against the wrench to remove the chuck. Most chucks have a right hand thread - lefty loosy.

It may be that there is an allan screw in the small hole inside the chuck (your second picture above has a small hole inside the chuck where an allan screw may be hiding). The diagram does not show an allan screw - but I'm not completely sure the diagram below is your drill.

On this page is a search feature that will bring up an exploded diagram of your drill if you enter the right product number or model number.
A product number uses a ten digit number like "3601B18110" to identify the drill. A model number looks like "1191VSRK".

What you are looking for in the exploded diagram is a screw or allan screw that holds the chuck on. In the drawing above the chuck - part 63 - is simply threaded on to the shaft - 62.
If you find a screw or allan screw in the diagram for your drill then you would remove the screw and then follow the steps above.

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