At Tanner Bolt & Nut, we field a lot of calls from customers trying to find the right bit or screw type.
To help, we prepared this guide to screw head types and drives.
It requires to be able to remove at least one of the screws, if they are reachable it is possible to undo them with pliers. Drill a hole into a piece of steel that fits the screw (drop in). Now use a copper nail or thick piece of copper wire and heat it up to glowing temp. Let it cool down - this softens the metal. Slot screw drives have a single horizontal indentation (the slot) in the fastener head and is driven by a 'common blade' or flat-bladed screwdriver.This form was the first type of screw drive to be developed, and for centuries, it was the simplest and cheapest to make. Screws and Anchors (2663 items found) Sort by Filters Sort By Recommended. Screws and Anchors. Sheet Metal Screws.
- These are also commonly referred to as Micro Screws, Camera Screws, and Eyeglass Screws NBK offers a broad line of miniature, precision screws designed by years of extensive R&D. The size range for these screws are S0.6 to M2.6; with options to choose for steel, stainless steel and plastic.
- Doing the job right takes both a Joint File that cuts only on the edges and won't widen the slot as it deepens, and an Equalling File to clean up the slot sides and square the bottom. Available in matched, same-size pairs, 1 Joint and 1 Equalling. Plus, there's the Master Screw Slot.
Click on the image that looks most like the top of the screw head to see the bit you need.
Always use the right driver for the screw head you are working on. I know some of these look the same (can you tell the difference between a Pozidriv and a Phillips from 10 feet away?) but they are not – and you risk damaging the screw and ending up taking a lot of time to extract it if it gets damaged.
Slotted
This is the original screw drive. You find these everywhere, though the practice of using screws with slotted drives is on the decline because the screwdriver slips out of the slot, particularly when you are applying heavy torque to really tighten down (or loosen, for that matter) these types of screws.
Phillips
This screw drive type is very popular – and again, you find them in a very wide range of applications. Common sizes are Phillips #1, #2 and #3. The most common Phillips size is #2.
See our available Phillips bits
Phillips Tamper-resistant
Not very common, but when you need one, you need one. Same shape and sizing as Phillips, but the screw includes a tamper-resistant pin in the middle. This screw is not used in high torque applications as the design is not very strong and the bits cannot be manufactured to high strength specifications.
Quadrex
A combined Phillips and square recess drive.
Pozidriv®
Y Slot Screw Head
This screw head isn’t seen very often in the U.S.A., though it is very common in Europe. It looks a lot like a Phillips screw head, but it includes 4 more contact points. Common sizes are Pozidriv #1, #2 and #3.
Square Recess
Square recess is being used more and more as they are very resistant to cam-out, which is a fancy way of saying the tip of the tool does not slip out and mar the screw head very easily. Commonly found in two sizes: Square #2 and #3.
See our available square recess bits
Square Recess Tamper-resistant
Same design and sizing as square recess, but includes a centered tamper-resistant pin.
TORX®
TORX, the funny looking screw drive. Well, you see them in a lot of electronics here in the US, and they are gaining ground in a variety of their applications. They range in size from T5 through T55 in 1/4″ insert bits and power drive bits.
Tamper-resistant TORX
Tamper-resistant TORX has a small post in the middle of the drive that prevents a regular TORX driver from working.
See our available Torx tamper resistant bits
TORX Plus
TORX Plus is an enhanced TORX design that allows more contact area between the driver and the screw head allowing more torque to be applied, even at high driving speeds. This is a fairly new design.
Tamper-resistant TORX Plus
Tamper-resistant TORX Plus is a licensed design, only available after the purchaser has completed paperwork indicating their authorization to purchase these bits. This design is used extensively in correctional facilities and in other high-security applications. It is different than the usual TORX Plus because it uses only a FIVE lobe design, with a center pin.
Tamper-resistant Hex
The tools to access tamper-resistant hex are limited from general distribution in order to protect equipment from access by end-users. Similar to tamper-resistant TORX, there is a small metal post in the middle of the screw head that prevents a normal hex driver from engaging. Tamper-resistant hex come commonly in the following fractional sizes: 1/8,3/32, 3/16,1/4 and 5/16
Mont Blanc T Slot Screws
See our available hex tamper resistant bits
Tri-Wing®
This unusual three-leg design of the Tri-Wing comes in 3 sizes: #1, #2, #3. We don’t see these too often, though they are available as part of our Master Security Bit Kit.
See our available Tri-Wing bits
Spanner
Sometimes also known as “snake eyes” and “notched.” Though our diagram shows two holes in the top of the screw, these sometimes also look like a screw with two notches cut into the edge on opposing sides of the screw. A commonly used screw head to avoid tampering, we’ve seen these used in everything from electronics to bathroom stall doors in public restrooms! Comes in 6 common sizes: #4, #6, #8, #10, #12 and #14.
See our available spanner bits
One Way removal tool
This is a specialized application for sure. A one-way screw is installed using a slotted bit – but since the edges of the slot are ramped in the opposite direction, a slotted bit will not engage to remove the screw. This one of a kind removal bits can be adjusted to fit one-way screws and back them out.
See our available one-way screw removal tool
We offer all of the drives described in a variety of formats – 1/4 inch insert bits, power bits, and as complete screwdrivers. Some drives are not listed in our catalog, please call us at 1.800.456-2658 or drop us an email at via our contact us form to order any of these drives individually.
Like nails, screws are (usually) small pieces of hardware used to hold materials together. One of the main differences is that screws are designed to be able to be removed and replaced easily without damage to the screw itself or the material it connects. Most screws are made from some type of metal, and many are covered in a rustproof coating. Aside from material, screws differ in head shape, head type, threading and purpose.
T Slot Screws
Machine screws are designed to hold pieces of machinery together. Most machine screws require that the hole already be drilled and threaded, although there are a few types of machine screws capable of tapping their own holes. Like other screws, machine screws are available in a variety of shapes and sizes. Pan head machine screws are machine screws with heads that are flat on top and rounded on the sides. They're similar to oval head machine screws, which also have rounded sides; the difference is that oval head screws have a rounded top, too, as opposed to a flat top, and they have tapered bases. Both are commonly used for metal applications. Pan head machine screws can also be differentiated from flat head screws, which have flat tops, as well. However, flat head screws are tapered on the underside of the head so they can lie flush with the material they're driven into. Meanwhile, round head screws have flat bottoms with rounded heads, much like half a sphere. Round head screws can't sit flush with the material they're driven into; instead, their heads poke out like little bumps.
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Pan head machine screws can be designed with a variety of head types, too. A slotted pan head machine screw has a single cut in the head for use with a straight screwdriver. Philips pan head machine screws have a cross cut into the top for use with a Philips screwdriver.