As usual, click any photo to bring up a larger version.
NOTE: there is a second video at the bottom of this web page.
PLEASE NOTE: this is a "first impressions" comparison. It is NOT a detailed in-depth review which would involve thousands of screw operations in many many different situations.
Not too long ago, I released a video on the subject of lousy screws, and how I thought Robertson screws were far superior. (You can see that video at the bottom of this web page.)
That was just a fun little joke video where I vented some of my frustrations with lousy screws. However, I received a number of fairly serious comments and a number of people challenged me to check out Torx screws.
So that is what this article (and video) are all about. I'm testing out Torx screws to see how they compare.
I have virtually no experience with Torx screws. I have encountered them when disassembling computer hard drives, and I have seen other woodworkers using them (on youtube), but I've never used them myself in woodworking.
Let me be totall up front with my biases and background: I have been using Robertson bits since I was a little kid. They are everywhere here in Canada. I know that they are not as common in the USA. In fact, I wonder if my non-Canadian viewers really appreciate just how deeply entrenched the Robertson screw is in Canada. So I snuck my camera into the local big box home store to show you the fastener aisle.
If you look at that photo, just understand that pretty much everthing at the close end of the aisle is Robertson screws. On the left there are three bays of screws -- indicated by the red arrows. This includes countersunk wood screws, pan-head wood screws, machine screws, metal screws, metric thread machine screws, brass screws.... they are practically all Robertson Screws.
On the right side there are two more bays, containing two different kinds of deck screws, floorings screws, and general construction screws. ALL of them are robertson.
(the third bay on the right are drywall screws, which are phillips. We're not going to talk about them...)
Here at the far end of the aisle there is a small display (indicated by the blue arrows) of GRK Torx screws. That's it for torx in the entire big box store.
I picked up two boxes of GRK torx bits to try out. One box was T15 Pan-head screws, the other box was T25 countersunk bits. Both boxes were 1-3/4" long screws. Both boxes also contained a Torx head bit for a driver -- I would guess they know that few of us here in Canada would already have one. I also picked up a seperate bit designed for an impact driver.
As an aside... In preparation for this article I read up on Torx bits and I discovered that the official name for these bits is hexalobular. I think I'll stick with calling them torx bits. (From the Wikipedia page: ISO 10664: hexalobular internal) There are also something like 25 different sizes ranging from .8mm to 22mm in size. For woodworking it appears that two or three sizes are what you'll usually encounter.
For completeness, let me also write a bit here about Robertson screwdrivers and screws.
One neat thing about Robertson screwdrivers is that they are all colour-coded by size. I don't even tend to remember the names of the different sizes, as I usually call them out by colour: "I need a red-handled robertson!"
So, All green-handled Robertson screwdrivers are the same size - #1 size Robertson. These are frequently used by electricians, as a lot of the internals of electrical boxes (switch contacts, etc) are sized for these screws.
All black-handled Robertson screwdrivers are the same size - #3 Robertson.
And of course, all red-handled Robertson are also the same size - #2 Robertson. The "Red Robbie", as it is commonly known, is probably the most common size that you would encounter in woodworking. The Red Robertson is used to drive #8 and #10 sized screws.
There are a few more sizes than that. You can read about them on the wikipedia page. But these three are the main ones for woodworkers.
Why do Robertson screws "stick" on the screwdriver?
Despite the fact that Robertson are often referred to as "Square Drive" in the USA, they are NOT cube shaped...
... A proper Robertons screwdriver actually has a wedge-shaped tip on it, as you can see in the close-up photo here of one of my "Red Robbies".
The recess in the screw has a matching taper, so they sit very snugly on the bit. As well, if you give them a bit of a push, you can usually wedge them onto the screwdriver so that they will stay on even better, as shown in the original video (at the bottom of the page.)
I pulled out a section of 4x4 softwood and proceeded to screw in a bunch of torx and robertson screws. For all my tests I made sure to do the same thing for each type of screw. I first drove in 10 torx screws without pre-drilling. I then did the same for 10 Robertson. Then I pre-drilled 20 holes and repeated this with 10 torx and 10 robertson.
I also tried out some screws in hardwood, end grain, and some other random things. The results were the same for all of them.
So, here it is: My first impression was that the torx bits were every bit as good as the Robertson
Both work well. Neither one cammed out. Neither one jumped out of the bit. Both seated firmly in the screw and performed well.
The Torx are actually fractionally quicker to seat on the screw. This make sense when you consider that there are six points on a torx, versus four on a robertson. So there are more positions where the torx screwdriver will just slip into place. I had two or three times when I had to slightly twist the Robertson drive to get it seated into position before I could proceed to screw it home. This is a small difference, but I'm trying to be completely fair and open.
The Robertson stays on the bit better, due to that wedging action noted above. The torx screws will fall off if you tip the driver. This is actually a rather important fact.
These GRK Torx bits cut very fast into the wood. I believe that a lot of that had to do with the thread design. These bits are advertised as self-tapping and that they don't need pre-drilling. (Not true, they needed it in hardwood, but I believe that these are marketed more toward the building trade so hardwood is not expected.)
If you look at the close-up photo you can see the wedge at the tip of the screw which aids in cutting. As well the first four-five turns of the threads are also a bit saw-toothed, which aids in drilling into the wood.
I would really like to find some robertson screws that have bits like that. I was just using ordinary Robertson screws for my testing. I should go back and check out the Robertson flooring or construction screws and I could probably find some.
So am I going to throw out my Robertson screws and switch? No. The Robertson are still the overwhelming majority of screws on the market here, and I'll keep using them. And the way they stay on the bit cannot be minimized. But I will keep these torx in mind and I'll have no qualms using them.
So to repeat, my first impressions are that these Torx screws are essentially just as good as the Robertson. This is NOT a huge scientific study. That would take thousands upon thousands of screws to really fairly evaluatte. This is strictly my first impressions.
Either one is FAR superior to the straight or phillips screws!
Here is the video that started this whole screw evaluation business. Yes, this is primarily a joke video, but my low opinion of the slotted and Phillips screwdrivers is quite serious.
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