Hohner B Bass Professional IV truss rod size?

[lownote]

Anyone know what the right size Allen key is? 5mm is too loose and 5.5mm won't go in. Just spent a fiver on Imperial keys and none of them fit either, either far too loose or too big. The socket doesn't [u]look [/u]rounded...

[MoonBassAlpha]

If I recall correctly it is metric. 5mm sounds right. You could try putting a layer of pvc tape over the end of the loose hex key, might give it enough grip.

[lownote]

many thanks