What is the type of purpose of these particular screws?

I think they are for screwing landscape timbers together.

they look like grk screws and are high strength.and cost a lot of money and are worth every penny.if you got em for free,save em.i used to sell that brand.high quality.

its a truss head screw, used in cabinet building and other builds, large washer type head gives great grab and pressure, one sometims has to be careful if using power torque driver to not strip unit, quite a few come with the ddrill head to ease install

they look like grk screws and are high strength.and cost a lot of money and are worth every penny.if you got em for free,save em.i used to sell that brand.high quality.

- pottz

Click to expand...

I concur and used similar to these recently. Torx heads don't cam out when using an impact driver.

Look like GRK Brand. Structural rated.

Hmm, just a tad long for pocketholes on 19mm stock.

... and cost a lot of money and are worth every penny.if you got em for free,save em.i used to sell that brand.high quality.

- pottz

Used to sell them pottzy... what s the story, abandoned quality Yankee stuff and now selling Chinese crap?

- LittleBlackDuck

Click to expand...

switched to a similar brand thats just as good but about 30% cheaper. most of our customers it's all about pruce sadly.

+1 GRK RSS Rugged Structural Screws.
The secondary spiral just above the threads make id easy.
Typically used with pressure treated lumber on outdoor projects due the corrosion resistant coating.

The Contractor would have likely remembered to pack those screws back on the truck as he paid for them. Employees can get in a hurry and fail to walk the jobsite one final time to check for items missed. Ask me how I know. I go to jobsites and find boxes of wire, step ladders and other items left behind. Probably buy 10 Kline 10 in one screwdrivers a year for employees' that already have them. Got to the office at 8:00 AM and the van was idling in the lot I turned it off. Employee didn't leave until 8:40, oh I might add that I am wearing short sleeves today.

Assuming the deck is connected to the house, these were most likely used to attach the deck ledger board to the house rim joist.

Yes, structural screws and expensive. A quick browse through your local big box "borg" center would show you all kinds of fancy screws. Worth the time as you can find out all things that are not obvious.

Assuming the deck is connected to the house, these were most likely used to attach the deck ledger board to the house rim joist.

- JohnDon

Click to expand...

I don't do decks anymore but they used to be bolt thru into rim joist. Current code here is for deck to be free standing and not attached to house

Those big GRK screws are 2 for a dollar in bulk. That's a USA dollar, not one a dem more slender dollars.

...and they're still made in you know where.

Those big GRK screws are 2 for a dollar in bulk. That s a USA dollar, not one a dem more slender dollars.

...and they re still made in you know where.

- Ocelot

Click to expand...

german engineered owned by a canadian company and made in taiwan !

I think he was saying the contractor was dumb to leave the screws behind.

- Ocelot

Click to expand...

+1