Jump to content

- - - - -

bumpkeys work one some locks

  • Please log in to reply
2 replies to this topic

#1 bump_it85


    Junior Member

  • Members
  • Pip
  • 1 posts

Posted 02 June 2007 - 09:34 AM

Im from germany, and my english is not so very good, but i hope it is
understandable. I`ve got 1 Problem with the bumpkeys I made: they work
sometimes only on 1 site of the lock. But on this site then sometimes VERY good.
(my record is 6 times opened with 6 bumps). but on the other site i must
bump 30 times ore more to open the lock. (sometimes more....) on other locks with
the same key it works sometimes also ok, (10 - 15 bumps). I don`t know how
this can be. I think, maybe the tolerance in some locks are different what makes the
bumpkey to work or work not.... is it that? when yes, how can i fix the problem?

#2 theopratr


    The Wise One

  • Members
  • 454 posts

Posted 02 June 2007 - 11:04 PM

The tolerances on locks that use the same key can vary greatly. Turning the key one way in a lock can produce very different results... this is due to the slight differences in the way the pins are aligned. I include a picture to help you understand.

Posted Image
(Grün = Einfach, Rot = Schwierig) [Green = Easy, Red = Difficult]

If the very slight differences in the position of the holes in the plug lend themselves to the smaller pins coming last in relation to the way you are turning the key, then there is a greater chance that those pins will not get stuck at the shearline, as they are crossing it later than the top pins from the larger bottom pins. They all experience the same force, and all go the same approximate speed.

If the top pins which have further to travel go must cross the shearline first, this is difficult, and they often get stuck. Thus, it is common that a lock be easy to open in one direction, and difficult in the other.

(Ob Sie mehr fragen haben, fragen Sie mir bei PM.)

#3 MrLocks


    Senior Member

  • Members
  • 100 posts

Posted 25 March 2011 - 12:20 AM

Very interesting and self-explanatory. With the help of you post its really easy to understand the whole topic. Thanks