# What are SD screws?



## dbrode1 (Apr 22, 2011)

And why would I want to use them. Somebody here was referring to them. Are they Strong Drive screws. I googled it but didn't come up with much.

Thanks!


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## TwoSkies57 (Feb 23, 2009)

here ya go Doug..

Strong-Drive® SD Structural-Connector Screw


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## bobj3 (Jan 17, 2006)

Hi

I use the ones I have on hand for screwing items down to concrete without the need of any anchors , they are that strong ,they are just about always have a blue green tint coating telling that you are using a .75 cent screw on the long ones. ( 2 1/2" )
They are not cheap 

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## amaonline (Jan 1, 2011)

Engineered fasteners for engineered connectors. They are designed and approved specifically for Simpson connectors... joist hangers for example. Liability will be assumed for the "system" only if used in its entirety. (if you use the hanger use the fastner made for it as well). Most of my experience with Simpson strong-tie systems is good and its seems that that they make a "system" for almost everything.


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## Cherryville Chuck (Sep 28, 2010)

If the contributor was Canadian it may have referred to Robertson square drive screws. Invented in 1907, if I remember correctly, it is the world's best screw. They came up with "posi-drive" a few years ago which is a combination phillips and square.


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## bobj3 (Jan 17, 2006)

Hi 

All the ones I have are hex or phil. drive heads..not one with the sq.drive head.

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Cherryville Chuck said:


> If the contributor was Canadian it may have referred to Robertson square drive screws. Invented in 1907, if I remember correctly, it is the world's best screw. They came up with "posi-drive" a few years ago which is a combination phillips and square.


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## harrysin (Jan 15, 2007)

Downunder we know SD screws as "square drive"

Product Details


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## Cherryville Chuck (Sep 28, 2010)

*Square drive*



bobj3 said:


> Hi
> 
> All the ones I have are hex or phil. drive heads..not one with the sq.drive head.
> 
> ======


They aren't available in the states. If they were they would put a few screw manufacturers out of business. I saw Norn Abrams use them on one episode of the NYW (and raved about them) and never saw him use them again. Maybe he got a hand slap. I first found out about them in about '73 when I first got to Canada. It was the first screw I had ever seen that I cut put enough torque on the driver to snap the heads off without stripping the head out. PM me with your address and I'll try to smuggle you a few with a driver to try out. Then you can try and figure out why they never made it to the states in 104 years.


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## bobj3 (Jan 17, 2006)

Hi

Thanks, I have many screws that are the sq.drive and I have been using them for years..the ones I like the best are the deck stainless steel screws..about 3 1/4" long..
But all the SD screws are Hex washers heads..

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## Cherryville Chuck (Sep 28, 2010)

*Square drive*



bobj3 said:


> Hi
> 
> Thanks, I have many screws that are the sq.drive and I have been using them for years..the ones I like the best are the deck stainless steel screws..about 3 1/4" long..
> But all the SD screws are Hex washers heads..
> ...


Not sure if you are on track there Bob as that is the wrong picture for what I am talking about. I went online and looked up the history of the Robertson square drive and found out that you can thank Henry Ford for not having the Robertson and having the Phillips instead. I was going to call it the second best screw but I don't think it's that good. Have a look at this link. Robertson Screws


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## BrianS (Nov 7, 2004)

Charles, the SD screws are not "Square Drive" in this case, but "Strong Drive". 

And, I agree with you, Robertson Screws are great.


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## Cherryville Chuck (Sep 28, 2010)

BrianS said:


> Charles, the SD screws are not "Square Drive" in this case, but "Strong Drive".
> 
> And, I agree with you, Robertson Screws are great.


You could be right. I was only offering a different opinion and promoting the world's best screw, 104 years old this year and Canada's best kept secret.


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## jw2170 (Jan 24, 2008)

Cherryville Chuck said:


> You could be right. I was only offering a different opinion and promoting the world's best screw, 104 years old this year and Canada's best kept secret.


All the Kreg screws are square drive, aren't they?


Ia Australia: http://sachys-robertson.com.au/index.html


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## The Warthog (Nov 29, 2010)

It's a pity Mr. Robertson wasn't a better businessman, then his screws manufactured by others would be called Robertson instead of square drive. I've never neard of Strong Drive. The screws I use for concrete answer the description of Strong Drive, but go by the brand name Tapcon. They are great.


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## bobj3 (Jan 17, 2006)

Hi


The Blue Green screws would be a better name for them they are the same as the SD screws..the green must be for the high bucks they cost. 

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The Warthog said:


> It's a pity Mr. Robertson wasn't a better businessman, then his screws manufactured by others would be called Robertson instead of square drive. I've never neard of Strong Drive. The screws I use for concrete answer the description of Strong Drive, but go by the brand name Tapcon. They are great.


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## Cherryville Chuck (Sep 28, 2010)

James,
I don't have a Kreg so I had to check Lee Valley's catalog and yes they are square drive.
Roger,
I used the Tapcons too and they are good. I haven't heard of Strong Drive either. Maybe they are only in the states and Tapcon only in Canada.


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## Ralph Barker (Dec 15, 2008)

Cherryville Chuck said:


> Not sure if you are on track there Bob as that is the wrong picture for what I am talking about. I went online and looked up the history of the Robertson square drive and found out that you can thank Henry Ford for not having the Robertson and having the Phillips instead. I was going to call it the second best screw but I don't think it's that good. Have a look at this link. Robertson Screws


If you substitute Gary Kildall (CP/M operating system) for Robinson, Bill Gates for Phillips, and IBM for Ford, you have another case of an inferior product becoming market dominant as a result of making the right deal with the right company. 

The Robinson screw (square drive) rocks. But, alas, I have thousands of (free) slotted and phillips screws that I inherited from my dad. Going square means I have to buy new ones.


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## tdublyou (Jan 8, 2010)

Cherryville Chuck said:


> James,
> I don't have a Kreg so I had to check Lee Valley's catalog and yes they are square drive.
> Roger,
> I used the Tapcons too and they are good. I haven't heard of Strong Drive either. Maybe they are only in the states and Tapcon only in Canada.


Tapcon et al, and Strong Drive are 2 completely different screws, designed for entirely different purposes.

Tapcon, which is a brand name, (there are several other competing versions), are designed for fastening directly to concrete and other masonry substrates without the need for any additional anchors, sleeves etc. They cut their own threads right into the substrate.

Strong Drive screws are made by Simpson Strong Tie, (the joist hanger people) see the second reply in this thread from TwoSkies57 for a link. These are made specifically for use with their joist hangers and other metal fastening aids and are engineered solely for that purpose. 

Neither is a substitute for the other. Think the right tool for the right job.


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## bobj3 (Jan 17, 2006)

Hi Tim

I know the SD screws are not for concrete but I use them for that job also, I drill a small hole 1st. than just put them in place just like the Tapcon, no need for a concrete anchor that way.. 


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tdublyou said:


> Tapcon et al, and Strong Drive are 2 completely different screws, designed for entirely different purposes.
> 
> Tapcon, which is a brand name, (there are several other competing versions), are designed for fastening directly to concrete and other masonry substrates without the need for any additional anchors, sleeves etc. They cut their own threads right into the substrate.
> 
> ...


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