# GRK verses SPAX construction screws



## Merkava_4 (Nov 22, 2012)

I've been doing some extensive testing of both brands. I've been comparing GRK R4 screws to SPAX T-STAR PLUS Flat Head Multi-Material Construction Screws. The sizes I've been comparing are GRK #9 x 3-1/8'' to SPAX #9 x 3-1/4''. The material I've been driving them into have been Douglas Fir 2 x 4's. Both brands are supposed to be self countersinking and neither require pre-drilling. GRK are Torx drive while the SPAX require you to use their own proprietary driver bit which is similar to a Torx but with an added recess at the center. 

The only problem I've had with the GRK screws are that some of them in the box are bent which causes them to wobble when driving them in. Some of them are so badly bent that it can be difficult to hold the bit on center with the head because of all the out-of-round movement when driving them in. That's my only complaint about the GRK screws.

The problem I've had with the SPAX screws are that they spin out every so often when fastening two 2 x 4's together at an intersecting right angle. I'm going across the grain through one board and then into the end-grain on the other board. The screw will stop biting and just start spinning around without countersinking itself. That's a deal breaker for me as I can't be having that. It's a shame because they're such excellent screws otherwise. 

They are both great screws and they both have their positives and negatives. Here's what I've discovered:

*GRK R4 Construction Screws:*
Positives:
1. Easy to start and never spin out (always bite)
2. Drives very easily into the lumber
3. Head countersinks very well with zero tear-out
4. Driver bit never cams out of the head

Negatives:
1. Some of them are less than straight (bent)


*SPAX Multi-Purpose Construction Screws*
Positives:
1. Great pulling power
2. T-Star Plus bit fits very good
3. All seem to be straight

Negatives:
1. Spins out when going into end-grain (stops biting)
2. Bit will cam out of the head sometimes
3. Difficult to start sometimes (blunt tip)
4. Tears the surface up while countersinking


----------



## rrich (Jun 24, 2009)

Two comments.

Bent screws are probably used and put back into the box. (Get another supplier)

Screws tend to not hold very well when driven into end grain. That is one of the reasons that houses are built with nails and green lumber. The moisture in the wood sort of causes the nail to stick in between the end grain better.


----------



## Merkava_4 (Nov 22, 2012)

^ Thank you sir for commenting. I was hoping at least one person would comment. :smile:

Yes I know that the end grain is not the ideal environment to hold a screw; however, the GRK screws do very well at holding in end grain. I'm not sure why the SPAX screws don't hold in the end grain. Maybe it's the long unthreaded portion under the head, but I'm not even close to being sure of the reason. The SPAX screws still hold very well going into cross grain though. And also, the SPAX screws will pull the boards together very well as long as you're going into cross grain.


----------



## Chaincarver Steve (Jul 30, 2011)

I too am a fan of these screws (both brands). I discovered the Spax screws first and _loved_ them. All of the ones I've used are phillips head. But they do sell other drive types (square, Torx, others). The special Torx bits you're referring to are - I believe - just your "standard" _security_ torx bit (sometimes called "tamper resistant"), NOT a proprietary item.

The only real problem I had with Spax are that they are over priced. At $1 per screw for a medium-sized screw the price got hard to justify. That was when I discovered the GRK screws. And boy are they great. I've been assembling my gazebo with the GRK 9 x 3-1/8" "R4" screws. These babies drive easily and hold rock solid. The Spax hold extremely firmly as well but seem to require slightly higher driving torque. But the GRK are priced much more fairly. They still aren't dirt cheap. But they are well worth the price.

And you are correct about bent screws. I've been buying the GRK's in the 240ct buckets. And there's been approximately 2 bent screws per bucket. Why? Who knows. The defect rate (bent screws) seems pretty consistent and seems higher than with any other brand I've used. But I don't mind 2-3 bad screws per 240 when the non-bent ones perform so beautifully.

*rrich*, in the case of the crooked GRK's, it's not used screws tossed back into the hopper. It's just a flaw in the QA process at the GRK factory.


----------



## Merkava_4 (Nov 22, 2012)

Chaincarver Steve said:


> The special Torx bits you're referring to are - I believe - just your "standard" _security_ torx bit (sometimes called "tamper resistant"), NOT a proprietary item.


They are not tamper proof Torx. They are a special proprietary bit that looks similar 
to a Torx but with an added extension on the tip as seen in this Home Depot image: 










The added extension goes into a recess at the center of the screw head. The added 
extension locks the bit on center and prevents the bit from wobbling side to side.

Nonetheless, I still appreciate your comment sir. :smile:


----------



## Chaincarver Steve (Jul 30, 2011)

Merkava_4 said:


> They are not tamper proof Torx. They are a special proprietary bit that looks similar
> to a Torx but with an added extension on the tip as seen in this Home Depot image:
> 
> 
> ...


Huh, interesting. You're right, that's definitely not a security Torx bit. Thanks for enlightening me.


----------



## ACP (Jan 24, 2009)

Love me some Spax screws. The boxes I've got have all included a new bit with them too, so I don't really worry about them. I've got plenty floating around. I don't recall using GRK so I can't comment. The Spax have never failed me.


----------



## Chaincarver Steve (Jul 30, 2011)

I should correct my statement to say that my first experience with Spax was some 1/4 hex head lag bolts (if my memory isn't tricking me now). I was attaching hand holds to our pressure treated dock pilings. I was impressed by how easily they drove in without need for pre-drilling.


----------



## WarnerConstInc. (Nov 25, 2008)

I have been using grk's for 5 years, best damn screws made.


----------



## chopnhack (Dec 16, 2007)

Meh.. each to their own. :smile:

House brand type 17 tip, square drive head seems to be one of my favorites. Especially when hanging cabinets, the no slip, no drop square head makes it easy to fasten one handed over your head :sweatdrop:


----------



## overenthused (Dec 28, 2017)

Howdy! You look like just the folks to answer a question I've been grappling with. I'm doing some framing work which involves repair to the rafters, joists and collar ties in my attic, and I scored a fantastic deal on a whole bunch of GRK #9 R4 3 1/8. So, should I consider them equivalent to 10d? 16d? 8d? None of the above? I asked the GRK Corp, and they referred me to their certification test (which read like gibberish to me), and told me to ask my local code officials. The thing is, I DON'T CARE about my local officials, because my work is essentially invisible and there is no way that I will be inspected. However, I will have to live with the results, and I DO CARE about safety and durability. Thanks for any insights you can provide!!!


----------



## Toolman50 (Mar 22, 2015)

I’ve never used Spax but I’ve been really impressed with the GRK screws and I’ve never got a bent one.


----------



## Selftaught Simple (Mar 25, 2018)

Our first house dated to the 1920's, with attic post wiring. However, the worst upgrade was by an owner/concrete contractor who didn't believe in ground wires apparently, nor boxes when a tape splice sandwiched between drywall layers seemed okay to him. I had to re-do 2/3 of the wiring because he used modern 2+grnd romex and 3-plug outlets - he just clipped every ground wire inside every box and never connected any inside the main box. Willfully ignorant.
Codes are not a liberal conspiracy to rip off patriotic homeowners. Many grades of structural fasteners exist for a purpose, such as the Simpson nails and screws that are accepted for use in plates, hurricane straps, etc. They meet both strength, shear, corrosion, and brittleness criteria that unknown fasteners might, but easily might not meet. If you do your own work, whether or not you get a permit or inspection, you could be considered criminally liable should your work fail and cause harm.
You, but more important, those who come after you will either live, or not, by your lack of concern over proper structural soundness, and I would hardly brag about willful ignorance. Should your place be fully inspected during a sale, full disclosure will either make you out as a liar, or result in a broken contract. But hey, so what if your roof blows off, or collapses under snow, etc?


----------

