SEMS(TAPPING) SCREW:

SEMS combines two normally seperate parts-typically a screw and a washer- into one permanently pre-assembled cost saving component. Washers are hel in place under the screw head by the rolled threads; they will not fall off and are free to rotate.

ADVANTAGES:

*SPEEDS: PRODUCTION BY ELIMINATING HARND ASSEMBLY AT THE WORK STATION

*PERMANENT : CAPTURING OF WASHER INSURES THAT IT WILL NEVER COME OFF OR BE LEFT OFF YOUR ASSEMBLY

*ADAPTS EASILY TO AUTOMATED FEEDING DEVICES AND DRIVING TOOLS

*AVAILABE IN ANY COMBINATION OF SCREW TYPE, HEAD STYLE, WASHER AND THREAD CONFIGURATION

*PRODUCTION RANGE : M2.5 ( #2) ~ M 12 ~ (1/2" . LENGTH : 4mm (5/32" ) ~ 160mm (6")

*ISO 9001 CERTIFICATED MANUFACTURER & EXPORTER*

 

 
Screw and washer assemblies-SEMS, DIN6900
Included in these specifications are SEMS comprised of the following types of screws and washers:
(a) Helical Spring Lock Washers.
(b) Tooth Lock Washers
(c) Conical Spring Washers]
(d) Plain Washers
(e) By the purchaser’s drawing or standard

Screw and washer assemblies

Coarse threaded Screws with captive plain washer

DIN6900

Examples of screw and washer assemblies



Figure 1. Assembly with screw threaded approximately up to the head.


Figure 2. Assembly with screw unthreaded portion of shank.



Screw and washer assemblies

Coarse threaded Screws with captive curved spring lock washer

DIN6900

Examples of screw and washer assemblies
Figure 1. Assembly with screw threaded approximately up to the head. Figure 2. Assembly with screw unthreaded portion of shank.


Screw and washer assemblies

Coarse threaded Screws with captive curved spring lock washer

DIN6900

Examples of screw and washer assemblies

Table 1. DIMENSIONS
Figure 1. Assembly with screw threaded approximately up to the head. Figure 2. Assembly with screw unthreaded portion of shank.

Thread size

(d)

 a / 2"

Washer dimensions

DIN 6907 washer

Type C

(7)
h d2
max min »  
M2.5 0.9 4 1.2 5.5
M3 1 4 1.2 6
(M3.5) 1.2 6 1.5 7
M4 1.4 6 1.5 8
M5 1.6 6 1.8 9
M6 2 8 2.1 11
M8 2.5 10 2.4 14
M10 3 12 2.7 18

Use of the size give in brackets should be avoided where possible.

1) / 2min is the smallest effective screw length manufacturable.

See relevant product standards for specifications for /.

Screw and washer assemblies

Coarse threaded Screws with captive curved spring lock washer

DIN6900

Examples of screw and washer assemblies

Table 1. DIMENSIONS


Figure 1. Assembly with screw threaded approximately up to the head.

Figure 2. Assembly with screw unthreaded portion of shank.


Thread size

(d)

 a / 2"

Washer dimensions

DIN 6907 washer

Type C

(9)
h d2
max min max  
M2.5 0.9 4 0.72 6
M3 1 4 0.85 7
(M3.5) 1.2 6 1.06 8
M4 1.4 6 1.3 9
M5 1.6 6 1.55 11
M6 2 8 2 14
M8 2.5 10 2.6 18
M10 3 12 3.2 23
M12 3.5 14 3.95 29

Use of the size give in brackets should be avoided where possible.

1) / 2min is the smallest effective screw length manufacturable .

See relevant product standards for specifications for /.

Tapping screw and washer assemblies

DIN6901

Type C (with cone point)

Type F (with blunt end)

Table 1. Dimensions


Figure 1. Assembly with screw threaded approximately up to the head.

Figure 2. Assembly with screw unthreaded portion of shank.


Thread size / 1 " a

Washer dimensions

DIN 6903 curved spring lock washer
Type A(1) Type B(2)
min max h d2 h d2
ST2.9 5.5 1.1 1 7 1 9
ST3.5 8.5 1.3 1 8 1 11
(ST3.9) 8.5 1.3 1 9 1 12
ST4.2 8.5 1.4 1 9 1 12
ST4.8 11.4 1.6 1 10 1.6 15
ST5.5 11.4 1.8 1.6 12 1.6 15
ST6.3 11.4 1.8 1.6 14 1.6 18
(ST8) 14 2.1 1.6 16 2 24

1) / 2min is the smallest effective screw length manufacturable.

Use of the size give in brackets should be avoided where possible.