Page 694 - Mastik®

Overview of locking effectiveness Securely fastened joints
levels

The following elements are designed to nut). The effectiveness levels are based its own tests to check the suitability of
prevent loosening, rotations loosening on typical industrial applications. Condi- the locking element in his/her applica-
and loss (complete separation of bolt and tions may vary so the user should make tion.

Locking against:
Locking feature / Locking element Loosening up to Rotational loosening up to Loss Notes:
div. 5.6 8.8 10.9 div. 5.6 8.8 10.9
Screws and nuts w/corrugated bearing area Increased breakaway torque, because
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(VERBUS RIPP ) 0 1 of corrugated bearing area
Screws and nuts with serrated bearing area Serrated bearing area prevents
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(VERBUS TENSILOCK ) 1 rotational loosening
Screw with integrated spring washer Increased breakaway torque,
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(eco-fix ) 3 3 because of concave flange
Locking adhesives Locking adhesive eliminate play between
1 1 1 1 1
mating threads – no oscillating
Screws with nylon patch Locking against separating of bolt and nut –
1
max. temp. 120°
Thread forming screws No play between mating thread –
3 3 3
no oscillating
Plastics thread forming screws No play between mating thread –
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Type: PT and Delta PT screws 3 1 1 no oscillating
Prevailing torque lock nuts, rivets nuts with Locking against separating of bolt and nut –
1
locking feature (w/nylon insert) max. temp. 120°
Prevailing torque lock nuts (all-metal type) Locking against separating of bolt and nut
1
Sealing lock nuts (Seal-Lok ) Locking against separating of bolt and nut
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1
(plus sealing)
Hexagon lock nuts (Serpress ) Locks only when tightened against the
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3 0
clamped parts
Castle nuts Cotter pin limits unwinding; some rotational
3 3 3 1
loosening is possible
Hexagon nuts with attached spring washer Attached lock washer compensates for seating
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Comby -S 3 3
Hexagon nuts with attached tooth lock washer Attached lock washer increases breakaway torque
0
(Comby-S, Keps etc.)
Flange nuts / flange screws Increased bearing area reduces surface pressure,
0 0
increased effective diameter reduces rotational loosening
Split lock washers Slight increase of breakaway torque
3 0
through its spring action
Tooth and serrated lock washers Increased breakaway torque on «soft» surfaces
3
Lock washers (Rip-Lock ) «Springy» one sided ribbed universal lock washer,
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3 0 3 0
One-sided ribbed increases breakaway torque on unhardened material
Ribbed lock washers Springy doubled sided ribbed lock washer, increases
0 1 3
Doubled-sided ribbed breakaway torque on unhardened material
Conical spring lock washers High clampdown force with appropriate
1 3
spring force
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NORD-LOCK washers The NORD-LOCK bolt securing system uses ge-
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Bolt securing system ometry to safely lock bolted joints in the most critical
3 3 1 1
applications. Resists loosening caused by vibration
and dynamic loads.
Locking effect: 1 very good 3 good 0 fair
Screws which should be locked
Loading
Grip length Lk
static dynamic
Thread Ø d
in the direction of the axis transverse to the axis in the direction of the axis transverse to the axis
short
none Clarify locking effect Clarify locking effect Locking required
Lk < 2 d
medium Depends on the conditions
none none Locking required
5 d > Lk ≥ 2 d clarify locking effect
long Depends on the conditions
none none none
Lk ≥ 5 d clarify locking effect