Screw head

[chuckster57]

Anybody know what type of driver:

Old hydro flame furnace on an Avion

[Dhuhn]

Im just guessing could it be a pop rivet?

[chuckster57]

Nope. I just found out it’s called a “clutch head”.

Learn something new every day.

[Javi]

One way security screw, you can tighten it with a flat head screwdriver but can't back it out without the clutch bit.

Used to see a lot of them.

[wiredgeorge]

An obscure explanation plus a miracle tool to remove the things...
https://www.fastenright.com/security...oval-tool/cl08

[chuckster57]

I may just have to get a set of drivers…just because. Seems like I’m seeing a LOT of older stuff these days.

[JRTJH]

The "first RV's used 1/4" hex head screws. That changed to Clutch head screws in the 70's and early 80's which then changed to Robertson "square drive" screws... The clutch head bits are different sizes, just like Phillips screwdrivers are #0, 1, 2, 3, etc. Most I remember on RV's were 1/8 and 3/16". I don't know for sure, but I don't think a "one way security driver" will fit properly in a clutch head screw. The security screwheads have a sloped side in the head, the "true clutch head" is 90 degrees on all sides of the drive slot. You can see the difference in the security screw and the clutch head screw in these photos.

Wait till you find a #6 torqueset or a #8 torqueset screw. At first glance, it looks just like a phillips, but a phillips won't fit the slots.....

[chuckster57]

Bottom pic is what I used to install security screen door on my last house.

[Javi]

Chevy used Clutch Head Screws from the 40's until about '69 for a lot of fasteners especially the door hinges


I've still got almost a full set of drivers in my junk tool chest.

[wiredgeorge]

Japanese motorcycles and electronic equipment use Japanese Industrial Standard hardware. The pan screw heads look like Phillips but have a different conformation and using a Phillips screw driver is a sure way to strip them. The #3 JIS and #3 Phillips heads are pretty much interchangeable and a hand impact driver using a #3 Phillips bit won't strip the JIS stuff but most is #2 and on electronics even smaller (#1 or smaller) and JIS screwdrivers are a must.

[wesaysoracing]

Holley Liked to use the clutch head screws on their metering plates in their carburetors

[LHaven]

Originally Posted by chuckster57

I may just have to get a set of drivers…just because. Seems like I’m seeing a LOT of older stuff these days.

For something used so seldom, a bit set is probably good economics. (Link) I thought these bits were included in HF's $10 security bit set, but apparently not.

[Lee]

Originally Posted by wesaysoracing

Holley Liked to use the clutch head screws on their metering plates in their carburetors

You beat me to it!!!

Another term for the clutch head's was "Dog Bone" screws. Somewhere I have a driver when I was rebuilding those old Carbs.

[Gord]

Looks like it might be a CLUTCH HEAD https://www.protoolreviews.com/speci...at-bit-called/These bits were very popular on vintage motorhomes. If you own one or are thinking about buying one to restore, chances are you’ll need a set of clutch bits.

[larryflew]

Clutch heads used on mobile homes for MANY years. Gord's link shows almost every bit I have seen.

[retiredusps69]

They use the screws in the bottom picture on alot of rest room divider walls, Son is grammer school maintainence . how the students back them out and remove is a good one!!!! but they do it .