MIL-F-18327 Filters; High Pass, Low Pass, Band Pass, Band Suppression, And Dual Functioning, General Specification ForThis specification covers the general requirements for passive frequency-selective networks, such as dual functioning, band suppression, band pass, low pass, and high pass \(or any combination thereof\) electric-wave filters, including those employing electromechanical and piezoelectric elements, for use over the frequency range of 0 to 500 megahertz. Filters covered by this specification are intended for use where operation under various environmental conditions is required. This specification covers filters weighing not more than 50 pounds and requiring root-mean-square test voltage ratings not greater than 5,000 volts.

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MIL-F-18327F

3. REQUIREMENTS

3.1 Procurement document. The individual part requirements shall be as specified herein and in accordance with

the applicable procurement document or drawing. In the event of any conflict between requirements of this

specification and the procurement document or drawing, the latter shall govern.

3.2 First article. When specified (see 6.2 and 6.3), a sample shall be subjected to first article inspection in

accordance with 4.5.

3.3 Material. The material shall be as specified herein. When a definite material is not specified, a material shall

be used which will enable the filters to meet the performance requirements of this specification. Acceptance or

approval of any constituent material shall not be construed as a guaranty of the acceptance of the finished product.

3.3.1 Pure tin prohibition. The use of pure tin as an underplate or final finish, is prohibited both internally and

externally. Tin content of components and solder shall not exceed 97 percent, by mass. Tin shall be alloyed with a

minimum of 3 percent lead, by mass (see 6.6).

3.3.2 Flammable materials. So far as practicable, materials used in the construction of filters shall be

nonflammable and nonexplosive.

3.3.3 Corrosive materials. Corrosive materials used in any of the manufacturing processes shall be removed or

neutralized so that no corrosion will result from such use. So far as practicable, materials used in the construction of

filters shall be noncorrosive.

3.4 Design and construction.

3.4.1 Mounting and terminal screws and nuts. Screw threads shall be class 2A or 2B, as applicable, in accordance

with FED-STD-H28. After receiving a finish, screw threads, class 2A fit, shall be capable of accepting a nut of class

2B with maximum installation torque in accordance with the following:

Maximum

torque

Screw size

(pounds-inches)

.112-40 - - - - -

.138-32 - - - - -

.164-32 - - - - -

.190-32 - - - - -

.250-20 - - - - -

.3125-18 - - - -

Nuts shall run down to within two threads of mounting surface. All mounting and terminal screws, nuts, and washers

shall be corrosion-resistant material or shall be protected against corrosion.

3.4.2 Terminals.

3.4.2.1 Solder terminals. Solder terminals may be of any shape, and shall be capable of being readily soldered.

The height of the solder terminals shall be considered as the maximum distance from the terminal mounting surface

to the highest point, including the additional height obtained if semi-flexible terminals are straightened. (It is not

intended that the "hook" in the "button-hook" type terminal should be straightened from its normal hooked position).

The type of terminal and the maximum size of round wire which the terminal will accept externally shall be as

specified (see 3.1).