Screws

Who doesn't have flathead screwdriver, so they are common, cheap, and you can torque them using the entire head of the screw...

https://www.reddit.com/r/AskEngineers/comments/3exfcg/why_are_flat_head_screws_still_made/

With slotted (minus) screws, the driver can slide out. Phillips (plus) screws were invented to allow fast assembly and had the advantage of self centering. Phillips screws have the disadvantage of being easy to strip, especially old corroded screws.

My favorite is the star type you can get now. You can put it on the bit and zip it in with your drill without worrying about it slipping off or stripping.

I prefer the 6 point Torx head for anything that does or may require any degree of force to tighten or remove.

I hate using flathead and phillips are almost as bad being there are so many sub variants of the design that never match the drivers well enough to get a proper bite on them plus both need to have the driver near perfectly aligned straight on and usually with considerable pressure whereas the Torx don't.

Yep. A slotted - screw is only an emergency solution.

Phillips + are OK for dry wall.

Those are the only ones I use any more.

Common slot and phillips screws are junk.

Your array does not include the Robertson type. A Canadian invention and my most preferred as you can actually put the screw on the screw driver and it stays there so you don't have to hold the screw driver and the screw.

I was fortunate enough to visit the factory in Milton, Ontario to watch them being made. I have found that they are not common at all in the U.S.. I have had several requests from some of my U.S. friends for the actual screw drivers as they also seem to be very uncommon in the U.S. as well. They come in 4 sizes of drive and the screw drivers are usually color coded for each size. When I need a screw driver and have some one helping, I just ask for a "red Robbi"(#2 size) or the other colors, yellow(#0), green(#1) or black(#3).

Robertson is the inventor who tried to sell his invention to Henry Ford (see #22). I use his screws on my decks and have had great success with them.

Robertson was not successful in selling his invention to Ford, so, thanks to Henry Ford we have the Phillips head invented at Ford.

If you like "How it's Made", check out
"How it's Unmade".

http://mentalfloss.com/article/55595/unmaking-oreo-cookies

I agree with this. When screws and screwdrivers were first hammered into shape, they were fine.

"The slotted screw drive simply has a single slot in the head of the fastener and is driven by a flat-bladed screwdriver. The slotted screw drive was the first to be developed and was for centuries the most common, simplest and cheapest drive to make. It works well when hand driven, but is not often used with power tools as the screw driver can easily slip out of the slot and damage the surrounding material."

From the article Most Common Types of Screw Drives (no longer available)

For an interesting look back at the beginning, watch: Building Muskets

Agreed, gunsmiths have been using screwdrivers like these for years. Many years ago I purchased a set of bits from a gunsmith supplier. Never had a problem getting a screw out with these bits.

Lately I've been using machine screws that have a head that combines the slotted head with a phillips head. They work well in a power or ratchet screwdriver with a phillips head, but can also be tightened or loosened using a flat blade screwdriver.

Slotted screws are everywhere because they're everywhere. (Sometimes recursion is the simplest approach.) When a minimal amount of torque is needed to install a threaded fastener the low cost slotted screw head has become the knee jerk, de facto, standard answer.

In one "How it's Made" episode, an assembly worker was driving slotted head screws with a "push" type screw driver. Screw drivers come in sizes to suit slotted head screws, but most people don't have a complete set of flat tip screw drivers and will use whatever screw driver is handy. I still have a ton of slotted head screws left over from my boat building days. I don't use them anymore, preferring socket head machine screws. If I need a wood screw, I will use Robertson, square drive screws. I still don't understand why industry still sticks with slotted head screws.

"I still have a ton of slotted head screws left over from my boat building days."

Could be part of the answer as to why slotted screws are still used today.

Where I used to work, the screws were selected for auto drivers. Phillips was the choice, with bits matched.

The drivers were pneumatic controlled with torque adjustment and also depth monitoring.

Next screw was "auto loaded" from a vibration feeding bowl to assure correct orientation. Reload time for the driver was les than the time it took for the operator to reposition the driver for the next location. (Around 8,000 per day.)

We used to use 6BA slotted cheese head (brass) screws for trailer harness connectors. These were tipped into a slotted tray so that heads were "up" and operator picked them up with a tube gripper that shrouded the driver bit. (Split tube with a rubber band) We could pick the supplier by the number of sheared heads. 2,000 assemblies per day with 7 screws per assembly.

So slotted or phillips are both suited for auto driving.

One of the biggest factors of what type of screw is used/available is when the screw was made and what was it being used for. Slotted were among the first because they were easy to hand make and required little or no fancy work to make them. This is also why rivets were used in some applications, heat it up- slam it with a hammer- your done. Many slotted have been used in powered screwdrivers prior to phillips becoming popular. It can be done if the right pressure, tip, etc. are used.

Phillips came along because the slots on slotted ones were stripping and becoming impossible to back out. Ever try to use an easy-out to remove a #10 wood screw? Hint- use a left hand drill. If used properly, pressure, size tip (extremely important), angle, material of construction, etc. a phillips can easily outperform the slotted.

Then came the female hex head such as most set screws, socket head cap screws, etc. They are good for certain uses but bad for others. Ever have an allen wrench strip the flats on a set screw? Again, use a left-hand drill bit. Each type has its own purpose that it is better for than other types.

There are thousands of different screw/bolt heads available for many preferred uses but many of them will also work for other applications. Don't complain, use the right one. If you look in your stash/supply of screws, unless you had a benefactor (the supply at work), you probably have more slotted than anything else. Who knows when you will need that certain type in the future? Solution ----> hoard everything! Sound familiar? Don't save tamper-proof ones unless you are going to be installing stalls in a school rest room. They aren't much good for any other use.

Good Luck, Old Salt

Slotted screws do drive well with a parallel-ground screwdriver - unless they're countersunk (flat-head in USA) - in which case a full-width screwdriver blade will butcher the target object material, to the diameter of the head and the depth of the drive slot.

Phillips head drivers and PoziDriv screws are mismatched, so there needs to be supervision when purchasing and issuing drivers and screws.

Allen screws and hex drivers can be problematic at high torque when the driver is hex-ball or when the obvious inch/metric mismatch is overlooked. A 3/32" bit in a 2.5mm hex hole is asking for trouble, when an operator lacking vernier eyeballs steps up.

Gimme Torx. They're difficult to mis-drive and the multiple points discourage "neat freaks" from aligning adjacent heads by rotation (all pointing East-West or all pointing North-South) instead of by torque or by countersunk head depth. This behaviour is worst with slotted heads. The "neat freak" can try to over-tighten a slotted screw up to half a turn, Phillips up to a quarter turn.

I am really surprised that slotted screws are used with power tools. I worked over 46 years for a major electronics company, and never saw that. It was Phillips for many years and then star. Another bad part of slotted screws is that when you find a screwdriver the right width, it is too thick to fit in the slot, so you need to got one with less width than the screw! Real crap engineering.

Because screwing things up is still easier than screwing them down?

I have a little gizzie for driving slotted head screws. It's a sleeve over the od of the screwdriver that just clears the od of the screw head. The sleeve is spring loaded so that the screwdriver tip and the sleeve stay on the screw head until the screw head is at the work surface.

While working for a Japanese company I found out that Phillips head, JIS and DIN cross head screws have different shapes and that a Phillips head driver doesn't play nicely with JIS crosshead screws. On the other hand a JIS screw driver doesn't play nicely with Phillips head screws either. They just don't fit well and strip out the head at lower than expected torque.

As far as screw head types, if you believe in a screw head type hard enough, it will work for you. I subscribe to Fine Woodworking and a few years ago there was a vitriolic series of exchanges in the letters to the editor concerning wood screws and how everyone else was an idiot, because MY type of screw was obviously the best, particularly when lubricated with the finest tail oil of the albino ocelot, so there!

The form of the driver makes all the difference in how well a screw head performs. So to all my SSPCTH associates, SLOTTED HEADS MATTER.

When doing fine woodwork, and also in ship building, slotted bronze screws were often specified for exposed (non-plugged) work, as the slots were aligned in the same orientation, and looked great. The reason for leaving them exposed were for pieces that were easily worn, and /or needing occasionally to be replaced, therefore easy to remove.(Think teak stair treads, etc.) Ever see exposed brightwork on a fine wooden yacht with exposed philips or Torx head screws?

Here's my take on a screwy subject, the slotted screws are still popular because the flat tip screw driver is a multi-purpose tool. Ever try using a phillips or a torx driver as a chisel? They don't work. And the handle on the flat head screw driver also serves as a mallet to beat the living snot out of the screw you just stripped!

Here's an old trick we use in aviation. Before the screw head completely strips out, apply a dab of valve lapping compound to the head of the fastener then back it out. This works with most all types of fasteners. It's saved my butt quiet a few times and saved having to replace $1,000 access panels too.

Note, if you still have to drill out the fastener after trying the lapping compound, make sure you remove all traces of the compound, otherwise you'll smoke that $20.00 drill bit you just bought.

Ever try and use a slotted screwdriver as a center punch? Phillips works a lot faster as an ice pick than a slotted screwdriver. Ever try and use a magnetic tipped slotted screwdriver to hold a screw on that you are trying to screw in at the very end of your arm's reach? Ever try to get a slotted screw driver (square peg) in a phillips (round)hole? If you can get two hands on the screw as you are turning it but can't see it the phillips is easier to keep the screwdriver on the head than with a slotted head. When the phillips screwdriver slips and hits your hand it is less likely to cause a bad cut than that created with the slotted screwdriver. Phillips screwdriver handle can also be used as a mallet. It will even knock the livin' shXt out of you.

Also, if extracting a screw (no matter what type of head) out of either wood or metal make sure you use a left-handed drill bit. The rotation of the bit will tend to back it out and not drive it in further. Right-hand (cw) threads only. You may not even need the easy-out!

Good Luck, Old Salt

I think we all agree that you should have left hand drill bits if your going to be screwing lot. I have a ton of #10's and #30's left twist drill bits!

But, if you use lapping compound before the fastener head is destroyed, chance's are you can extract it without having to drill it out.

It's a bit OT, but still about screws. As an inspector for one airline I worked for, there was a mechanic that came in one night bragging about his new Dewalt cordless drill he just bought. It was nice all shiny and new. But after about 2 weeks some of the aircraft started cycling back through and I started seeing discrepancy write ups about screws having to be drilled out. After the third plane with the same bitches, I went in to records pulled the maintenance logs to find out who was the last person who worked on them. As it turned out, it was the mechanic and his shiny new Dewalt. I tried his drill on the lowest setting (1) and it was over torquing by foot pounds on fastener's that required 10 inch pounds of torque. I very nicely told him to take his nice shiny drill home and I didn't want to see it on the floor again. And for the punishment, he was tasked with replacing all screws and blind nuts he screwed up. Funny after that, I didn't see anymore discrepancies of panel screws needing to be drilled out.

I am always very surprised how many people should know about using the left-handed drill bits but don't. That's why I repeat it so much. I also learned by experience until my father shared the "trick" with me.

This is similar to my posts about the direction of greatest power on impact hammers. Many believe the force is the same in both directions. Most of the average or better impact hammers have more force in the CCW direction than the CW direction. This is so that the loosening force (CCW, off direction) is greater and anything that the unit tightened will also be able to remove by the same impact hammer. Even some of the Harbor Freight ones have this. If 450-ft-lbs is required to tighten you are going to need more than that to remove it. A 450-ftlbs CW unit would probably have about 500-ftlbs in the CCW direction.

Good Luck, Old Salt

Your post reminds me of the time I broke a screwdriver while using it as a hammer. It was my own fault. I knew I should have used the crescent wrench.

For my own needs I solved that problem. I try to only buy screwdrivers that the shank, extends up to the top of the handle. That way I have a combination screwdriver, ice pick, scroll awl, cold chisel wood chisel among numerous things. Give me one of these and a hammer and I can chip enough ice to provide a lot of cold one, either cans or bottles. If the screw driver is a gigundo one I can even split fire wood with it.

Good Luck, Old Salt

In the early days, large users of screws (think Henry Ford), tried to get the biggest bang for their screw buck. Until that era, all screws were slotted. A Canadian inventor demonstrated to Mr. Ford, the savings he could realize by switching to a patented self centering square screw head. Ford ignored the patent and used the new invention. The debacle cost everyone a lot of money and Ford switched to resistance spot welding for most joints. Spot welding had also been patented by Thomson, but that didn't phase Ford who lost on appeal. The bottom line is that since those days, the legal status of fasteners and spot welders has been largely open to anyone who decides to invent a better widget.

Slotted head screws are great for wiring panels using a Screw Starter Screwdriver. I haven't found a screwdriver that works as well on Philips head screws.

Try some that have "Phillips head" as a description on them.

Is English your first language?

Nope! Easy to see in my post above! Must have been drunk but.

I used to own a frame house built around 85-90 years ago.

EVERY screw in the original construction was slotted. Those that might be exposed to weather were brass, interior ones steel.

Nary a Phillips, Torx or any other type throughout the place.

I cringe when I see or hear of someone using a tool for a purpose not intended for that tool. That includes using a screw driver for a chisel, ice pick or paint stirer. I was brought up to respect tools and to never abuse them. That is why machinists and other craftsmen never lend out their tools. I might make an exception if the tool is made in China and is junk right off the bat.

ronseto-

All the "alternate uses" for screwdrivers I listed were somewhat in jest. They are a few of the many abuses of this tool that I have seen for myself or reputably heard of. I too was brought up to respect tools and never abuse them. If the correct tool is not available you either didn't do the task or you used a suitable and safe alternative. Such an example could be an adjustable wrench instead of a socket, open-end or closed end. This certainly wouldn't work in every situation but they are better than a pair of pliers. During my lifetime I have chosen tools that will last longer than me and can be used safely for the same length of time or longer. My machinist tools are somewhat old but mostly Brown & Sharpe or Starrett. They can certainly do a better job than I can with them.

There are only a few people, like you, that I will lend too. Brother and two friends but I make them sign that I loaned the tool(s) to them. Besides not loosing them or them being damaged it also reduces embarrassment when I ask the wrong person to return it back to me.

Good Luck, Old Salt

ronseto, I haven't had the chance to get back to this thread until now. I was just joking about using a flat tip screwdriver as a chisel. But, if the tool has a broken tip and is of a decent quality tool steel, I will re-purpose it, whether it be a chisel, punch or a pick. I make it a point not to buy cheap crap, I've lost to much skin because of them. And, I too don't loan my tools out to others, they never come back and if they do, it's only because they broke it and need to borrow another one. Lawnmowers and wheelbarrows seem to have only a one-way ticket with no return trip back!

I wasn't joking about using the valve lapping compound, it works