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Certificate #10254
1000 Piece / $125 Minimum Order
Quality threaded inserts, made in America
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Tri-Star Industries, Inc. S Series Symmetrical Inserts

Symmetrical Threaded Inserts for PlasticsS Series: Symmetrical Threaded Inserts for Plastics

Say goodbye to expensive part orientation high-volume feeding mechanisms. Our symmetrical threaded inserts for plastic can be installed either end first for faster installation (using ultrasonic or thermal equipment) and lower costs.

By decreasing outward hoop stress, symmetrical threaded inserts decrease cycle times. Their proportionally engineered design ensures that the displaced material is encapsulated by knurls and undercuts. They are designed for straight hole applications and are ideal for thin-wall applications because little stress is applied to the walls of the part.

Recommended Hole Size – See chart below for installation hole size. Additional information can be found in our Design Guidelines.

Click here to download the catalog page for Tri-Star's symmetrical threaded inserts for plastics (75k PDF).

symettrical brass inserts
SYMMETRICAL THREADED INSERTS
INCH   METRIC   A
±.004
B
±.004
C
±.004
Hole H
+.003 -.000
Min.
Boss
Thread
Size
Part
Number
Thread
Size
Part
Number
2-56 256 x 115S† M2.0 x 0.4 M20 x 115S† .123 .115 .138 .126 .252
256 x 157S M2.0 x 0.4 M20 x 157S .123 .157 .138 .126 .252
4-40 440 x 226S M2.5 x 0.45 M25 x 226S .154 .226 .175 .157 .314
M3.0 x 0.5 M30 x 226S .154 .226 .175 .157 .314
6-32 632 x 281S M3.5 x 0.6 M35 x 281S .185 .281 .206 .188 .376
8-32 832 x 321S M4.0 x 0.7 M40 x 321S .218 .321 .239 .221 .442
10-24 1024 x 375S M5.0 x 0.8 M50 x 375S .249 .375 .270 .252 .504
10-32 1032 x 375S .249 .375 .270 .252 .504
1/4-20 2520 x 500S M6.0 x 1.0 M60 x 500S .312 .500 .333 .315 .630
1/4-28 2528 x 500S† .312 .500 .333 .315 .630
5/16-18 3118 x 500S M8.0 x 1.25 M80 x 500S .374 .500 .393 .377 .754
5/16-24 3124 x 500S† .374 .500 .393 .377 .754
3/8-16 3816 x 500S† M10.0 x 1.5 M100 x 500S† .465 .500 .484 .468 .936
3/8-24 3824 x 500S† .465 .500 .484 .468 .936

† Non-Stocking Item – Minimum Order May Apply

Stainless Steel Symettrical Inserts – Class 3A/4H screw must pass with finger torque, standard class go gage may stop on last thread. Part numbers for Stainless Steel Inserts are the same as listed in the chart, but ending with -SS.

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101 Massirio Dr., Berlin, CT 06037 :: Tel 860-828-7570 :: Fax 860-828-7475 ::
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