Installation Guide

The BumpStop

advanced cylinder technology is standard equipment in all Grade 2 lock

products. Because of the cylinder design, it cannot be offered as an option in the Grade

3 products.

One primary component of BumpStop

technology is a special stainless steel driver pin

shown at the right. Only one of these special pins is required in a cylinder to make it

bump resistant, but in some cylinders we actually place two to eliminate the potential for

someone to develop a systematic method of defeating the BumpStop

technology.

Cylinders that are compatible with the BumpStop

pin have been specially manufactured

to exacting speciﬁcations, and consequently, our BumpStop

pins may not be used

effectively to prevent a bump attack in other cylinders. In fact, our BumpStop

pins may

not be used in retroﬁt door hardware cylinders that were supplied by us prior to July 2008,

or in other manufacturers’ cylinders.

The current proposed ASTM standard for bump resistance has a highest grade level of 6, and to qualify for that level of

resistance a number of cylinders must each successfully withstand 60 bump impacts without operating. Master Lock

routinely subjects our test cylinders to 240 impacts without losing any of the bump resistance.

The location of the BumpStop

pin within the cylinder is a critical factor for the bump resistance. The last column of the

table on the next page indicates which depths of cut must be associated with the location of the BumpStop

pin in the

cylinder.

Cylinders keyed at our factory have the bible marked to indicate the month and year they were produced and a number

indicating which chamber contains the BumpStop

pin(s). When rekeying, consult the table and relocate the BumpStop

in the appropriate pin chamber for your new combination.

Master Lock uses ITL key machines to produce door hardware keys to original manufacturer speciﬁcations. We also can

take your existing bittings from a MK system and regenerate your entire system including all designed expansion. A copy

of that expanded bitting list in both places allows you to select the exact keys you desire and be assured that they will be

produced as you want them.

Because there may not be a constant cut of the correct depth for the speciﬁc brand, some MK system locks for existing

systems cannot be BumpStop

compatible.

Master Lock also sells these cylinders Zero Bitted if you prefer to do your own keying. In those cases you can use the part

number map on page 16 to determine the correct part number for the keyway you desire.

The BumpStop

pin will always be located in the 5th pin chamber in Zero Bitted locks for your convenience. Simply relocate

the pin to the appropriate pin chamber for a compatible depth of cut as shown in the table on page 3. Zero Bitted cylinders

will not have markings on the bible for the BumpStop

pin location.

BumpStop

ADVANCED CYLINDER TECHNOLOGY