Hex key sizes

[Gary WoodingParticipant @garywooding25363]

I need to undo a hex socket screw but cannot find a hex key that fits. A 3mm key is slightly too big and a 7/64″ is too small. Are there any other sizes?

[Clive Brown 1Participant @clivebrown1]

I don’t know of any intermediate size. Can you “adjust” a 3mm key with, perhaps, a diamond file or similar.

[bernard towersParticipant @bernardtowers37738]

Im with Clive but have you checked the socket for any damage?

[noel shelleyParticipant @noelshelley55608]

Check it is hex not torx and also 6 point not 5 point. Is the head damaged or been hammered ? Adjust the size of key with a grinder, or drive the key in by force, stillsons or Mole wrench on the head. Noel.

[Michael GilliganParticipant @michaelgilligan61133]

Have you physically measured that 3mm key, Gary ?

… or are you relying upon the marking ?

 

[ sorry, don’t mean to be rude … but it’s worth checking ]

MichaelG.

[Gary WoodingParticipant @garywooding25363]

The screw is at the bottom of, basically, a well. It’s actually a Master 6321 padlock. I managed to get a couple of photos with a rather cheap digital microscope.

I’ve tried two different makes of hex keys with the same result.

[Paul LParticipant @paull58212]

Maybe its a proprietory size for security reasons.

[Michael GilliganParticipant @michaelgilligan61133]

Looks like the diamond hone needs to be used on the the key then !

If there’s any way you can take a cast from the socket, that would give you an idea of how much needs to come off.

MichaelG.

[Gary Wooding]

On Gary Wooding Said:

That looks like Torx (or similar) to me – note the curved edges at the base of the of the “hex”

 

[JasonBModerator @jasonb]

Masterlocks site say to use a 7/64th key, is yours worn or undersize? Page 4

[Gary WoodingParticipant @garywooding25363]

Well… It looks like I’ve been on a wild-goose-chase. It seems that my 7/64″ key was miss-sized. I should have realised that Master, being an American company, uses Imperial sizes. I spent a few minutes with a diamond file and converted an old 3mm key until it fitted. The lock is now ready for gutting.

Thank you for all your suggestions and interest, I’ll go and find the remainder of my humble pie.

[Author]

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