Press-in Inserts

EFZ – Expansion Fin Zerts

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3D CAD Models available. Contact a PENCOM Account Representative to request.

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  • Simple press–in installation for most thermoplastics.
  • Mating screw resistant to loosening after installation.
  • High pull–out and torque–out resistance.
efz-features
efz-expansion-fin-zerts-tech

General

Inch

Insert Thread Insert Thread Code Boss D Insert Diameter
B Hole Dia. +.004 -.000 W Wall Thickness Min.
2-56 256 .126 .063 .146
4-40 440 .157 .079 .177
6-32 632 .189 .094 .209
8-32 832 .220 .110 .242
10-24 1024 .252 .126 .272
10-32 1032 .252 .126 .272
1/4-20 2520 .315 .157 .335
1/4-28 2528 .315 .157 .335
5/16-18 3118 .378 .189 .398
5/16-24 3124 .378 .189 .398

(1) All dimensions are in inches and reference unless toleranced.

Metric

Insert Thread Insert Thread Code Boss D Insert Diameter
B Hole Dia. +0.10 -0.00 W Wall Thickness Min.
M2 x 0.4 M2 3.20 1.60 3.70
M2.5 x 0.45 M2.5 4.00 2.00 4.50
M3 x 0.5 M3 4.00 2.00 4.50
M3.5 x 0.6 M3.5 4.80 2.40 5.30
M4 x 0.7 M4 5.60 2.80 6.20
M5 x 0.8 M5 6.40 3.20 6.90
M6 x 1.0 M6 8.00 4.00 8.50
M8 x 1.25 M8 9.60 4.80 10.10

(1) All dimensions are in millimeters and reference unless toleranced.

Stud Length

Inch

Insert Thread L Insert Length Insert Length Code
2-56 .1572 157
4-40 .157 157
4-40 .2282 228
6-32 .157 157
6-32 .2832 283
8-32 .228 228
8-32 .3232 323
10-24 10-32 .228 228
10-24 10-32 .322 322
10-24 10-32 .3742 374
1/4-20 1/4-28 .283 283
1/4-20 1/4-28 .374 374
1/4-20 1/4-28 .5002 500
5/16-18 5/16-24 .5002 500

(1) All dimensions are in inches and reference unless toleranced.
(2) Preferred length.
(3) Custom insert lengths available by request.

Metric

Insert Thread L Insert Length Insert Length Code
M2 x 0.4 4.002 4.00
M2.5 x 0.45 4.00 4.00
M2.5 x 0.45 5.802 5.80
M3 x 0.5 4.00 4.00
M3 x 0.5 5.802 5.80
M3.5 x 0.6 4.00 4.00
M3.5 x 0.6 7.202 7.20
M4 x 0.7 5.80 5.80
M4 x 0.7 8.202 8.20
M5 x 0.8 5.80 5.80
M5 x 0.8 8.20 8.20
M5 x 0.8 9.502 9.50
M6 x 1.0 7.20 7.20
M6 x 1.0 9.50 9.50
M6 x 1.0 12.702 12.70
M8 x 1.25 12.702 12.70

(1) All dimensions are in millimeters and reference unless toleranced.
(2) Preferred length. Custom insert lengths available by request.
(3) Custom insert lengths available by request.


Boss Design Recommendation

The EFZ Expansion Fin Zert is designed to be installed into a straight hole with a 1° inclusive taper. The top of the hole should not be countersunk or counterbored as this will decrease the insert’s performance. The recommended hole size applies at the point reached by the bottom of the insert. Molded holes should be used wherever possible as drilled holes may result in diminished performance. Minimum boss wall thicknesses shown are for reference and may vary depending on the type of plastic.

efz design

Installation

Press the insert into the boss using a squeezing action – never a hammer blow. Ensure that the insert maintains axial alignment during installation to prevent tilting which will induce side loads on the boss. Oversize boss holes weaken the insert’s self-aligning characteristics causing side loads which may lead to possible boss cracking. Install fixing screw from the knurled end with sufficient length to fully penetrate the insert and achieve maximum fin expansion prior to applying full clamping load.

Performance

efz-performance
(1) Performance data shown is for preferred insert lengths and reference only. Variations in application, boss material type and size, and installation method will affect the loads. PENCOM strongly encourages testing in the application.