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Exodus Advanced Communications Best in Class RF Amplifier SSPAs


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United Screw and Bolt Corporation Clutch Head Screws
October 1946 Radio News

October 1946 Radio News

October 1946 Radio & Television News Cover - RF Cafe[Table of Contents]

Wax nostalgic about and learn from the history of early electronics. See articles from Radio & Television News, published 1919-1959. All copyrights hereby acknowledged.

I have always wondered why hex (Allen) or clutch type heads for everyday wood, metal, and plastic screws and machine screws (aka small bolts) was not the norm rather than Phillips heads. Phillips heads are fine when the screws are not hard to get out, but when they are really difficult to break loose, a lot of force toward the screw is often required whilst turning. Unless you have a prefect fit between the driver and the screw head, the driver tends to ride up out of the cross slot. A straight slot screwdriver does not usually have that issue, but it has the disadvantage of slipping out of the screw slot and damaging the item it is holding (or your hand). Hex head (Allen), Torx head, clutch head, and other types with vertical walls also do not require a lot of inward force when really cranking on them. Maybe it's just me. This 1946 Radio News magazine promotion by the United Screw and Bolt Company extolls the virtues of their clutch head design. The point about restoring the damaged end of clutch head driver back to its original condition by putting it to a grinder is true of the hex and Torx driver ends, but is not useful for Phillips tips.

United Screw and Bolt Corporation Clutch Head Screws Ad

United Screw and Bolt Corporation Clutch Head Screws, October 1946 Radio News Article - RF CafeHere It Is, showing what goes on inside the Clutch recess, and why ... why users testify so freely that Clutch Head has features not matched by any other screw on the market for safety, speed, and savings.

Visibility a Speed Factor. The wide, roomy Clutch invites operator confidence. Saves "breaking-in " period. Presents an easy-to-hit target for stepped up production.

No Driver Canting to chew up heads and create a skid hazard. The Center Pivot Column on the Type "A" Bit guides the driver into the mating recess formation. Deep dead-center entry and straight-driving become automatic.

Safe, Effortless Drive-Home. Note straight sides of the driver matching straight walls of the Clutch recess. Contact is all-square on a broad pressure area for positive torque grip and non-tapered driving.

No Ride-Out to Combat. This feature disposes of "kick-out" as set up by tapered driving ... the commonest cause of driver slippage. The screw rides home easily without the application of fatiguing end pressure.

Lock-On Breaks "Bottlenecks". A reverse turn of the bit in the recess unites screw and driver as a unit for easy one-handed reaching to hard-to-get-at spots. Normal driving of the screw releases the Lock-On.

"Outlasts Other Bits 5 to 1"

The rugged structure of this Type "A" Bit logically explains this testimony. Also, a 60-second application of the end surface to a grinding wheel repeatedly restores it to original efficiency.

No expense. No delay.

Simplifies Field Service

This is the only modern Screw basically designed to operate with an ordinary screwdriver. With a Type "A" hand driver, the Lock-On feature permits the withdrawing of screws undamaged and held safely for re-use.

United Screw and Bolt Corporation

Cleveland 2

Chicago 8

New York 7



Posted May 6, 2022

Exodus Advanced Communications Best in Class RF Amplifier SSPAs

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Copyright: 1996 - 2024


    Kirt Blattenberger,


RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while tying up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

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