What is the name of this type of screwdriver?


Old 07-21-03, 09:32 AM
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What is the name of this type of screwdriver?

I have a small electric transformer I need to fix. It has two screws that I need to remove. I need a specific screwdriver.

I will describe the screws.

They have a rounded smooth head, (no linear groove for a flat tip to enter nor a cross tip for a Phillip type screwdriver).

As a matter of fact, the top of the screw head is shaped like half of a ball, except for these indentions along the sides. There are six of these indentions.

Any idea of the name of screwdriver that is used for this type of screw?

Can these screwdrivers be found just about anywhere?


ps. I would use a plier but the screws are sunk into a circular space not accessible with my needlenose pliers.
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Old 07-21-03, 10:06 AM
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Can you post a picture of the screw?
Old 07-21-03, 02:36 PM
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I would like to post a picture of it but do not have the means to do so.

Let me describe it further. You know how a drop of water on a surface looks like a blob or globular - before it flattens out? That is exactly what the head looks like. No indentions or cut outs on the top, nothing to stick a TORX type screwdriver into, just a smooth top.

BUT, on the SIDES, it has these nicks/indentions that are vertical/up and down. There are six equally spaced indentions and it looks like this is where the screwdriver would grasp the screw.

Old 07-21-03, 04:23 PM
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could be inverted torx
Old 07-21-03, 04:43 PM
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Yes, it sounds like the fasteners could be removed with a torx socket - I've seen them in 6, 7, 8, 10, 12, 14, and 16 sizes that sell for about $25 a set or $4 to $5 each and I'm 99 percent sure that Proto, Westward or TorquePlus all make them.

BUT - there are lots of electrical screws that are "proprietary" or unique to the manufacturer to discourage repair or to prevent tampering or to stop unskilled repair attempts. Many electrical units come with proprietary screws that are patented and or copyrighted and require a tool produced only by that manufacturer. It would help to know the make and model of the unit you are attempting to open to determine if you need a proprietary tool.
Old 07-21-03, 05:17 PM
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I think we figured it out here... I think.

Yes, I would need a female torx socket to remove them. Yep, think it is an inverted torx.

But, it could be proprietary as well. The item is a RadioShack model number 273-1680. I looked it up at their site but one cannot see the picture.

I will throw it away IF what I see inside cannot be fixed by me.
Old 07-21-03, 06:55 PM
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I could be wrong, but I don't think Radio Shack products need any proprietary tools. I never had a customer ask for any, and I also never had to locate any special replacement fasteners.
Old 07-21-03, 07:05 PM
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I may have the screwdriver you need.

The shape of the socket end is dome shaped and has six spline like grooves on the outside.
At one time I used it to open up some types of microwaves and got it from an appliance parts depot.

An inverted torx looks kinda like a volcano with straight sides.

Looked again and I might have found it. It's called a Bristol Spline:
<img src="http://www.mgs4u.com/pictures/spline2.gif">


Does it look anything like it?
Old 07-22-03, 06:57 AM
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I checked my catalogs this AM and it's a gray area, but it appears to me that your screws MIGHT very possibly be #8Coarse TRH "Tamper Resistant Hex" which are shared by Motorola and Quasar (and others) products. If that is correct a TRH nut driver, or TRH 1/4" drive socket should do the trick; however I don't know what size you'll need (#8 TRH can have 3 different head sizes), and I personally have only seen TRH tools sold in 6 or 7 piece sets, but a Graingers store or an appliance parts store is a good start to find one.

Is there a serial or part number on your transformer with a prefix C or D? Some, not all, but some manufacturers use those letters to denote the item as "consumable" or "disposable" or a throw-away item because it is cheaper to replace it than to repair it, or because it's replacement cost is a minor percentage (less than 15%) of the total unit.
Old 07-25-03, 03:05 AM
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Have you considered slotting the heads of the screws with a dremel cutting wheel then use a standard slotted blade to remove?

Almost as good a repair as duct tape! -Josh
Old 07-26-03, 07:11 AM
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FYI and not an ad - just a tip for tool enthusiasts: A company with headquarters in Gothenberg Sweden will soon (Winter) be exporting a tool to the US and Canada called "The Clinch" for removing round, cap and button head screws that require special hard to find tools, or for removing those type of screws that are damaged. It comes in a kit, three sizes and they resemble nut drivers. You choose one of the three tools that has a socket end slightly smaller than the diameter of the screw head, place it over the screw, and then strike it with a hammer. The socket end of the tool is sererated and (if you hit it right) the tool tightly grabs the edge of the screw head. It's really not a new concept - we've been whacking and forcing 12 point sockets onto damaged screw heads for years, but The Clinch is a very nicely made (1 piece steel shaft and striking head) and packaged tool. A salesman gave me a sample tool and it worked ok, even on those one way screw heads. Keep an eye out for it, could come in handy.

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