3-ply timber lintels

[PeterW]

That’s a concrete screw. You need wafer head timber screws. 

[SillyBilly]

Thanks.  I thought the construction adjective was implying not a wood screw. 

TIMco Wafer Head Index Screws 6.7mm x 75mm or ??

Edited June 17, 2021 by SillyBilly

[Nickfromwales]

@SillyBilly

These

[SillyBilly]

Thanks, but these range from 160mm to 360mm while I need about 90mm.  I will look around at similar ones

[Mr Punter]

https://www.screwfix.com/p/turbocoach-coach-screws-yellow-zinc-plated-8-x-120mm-50-pack/52740

 

You can sink the heads in 10mm with a spade bit.  3 ply 45mm = 135mm.  Your 90mm will not have any embedment in the 3rd timber.

[SillyBilly]

On 16/06/2021 at 09:24, Nickfromwales said:

I prefer resin glued and construction screws just short of the width of 2 timbers / layers. Fix 2 together, flying and clamping and working from one end to the other so you can manipulate the timbers with additional clamps as you work along the length, then add the 3rd timber repeating the same method. The construction screws allow the timbers to be pulled together incredibly tightly, thus ejecting the excess of the resin glue, plus, combined with the info below, you should be able to marry the timbers to pull each other back to a straight pair, if so necessary. 

I was picking up Nick's suggestion which is a good one because of the part threaded screw

[Nickfromwales]

5 minutes ago, SillyBilly said:

I was picking up Nick's suggestion which is a good one because of the part threaded screw

That's the intention with the design of those screws, to pull the two pieces of timber together and for the head of the screw to not countersink itself, hence the large flange type screw head. The type of metal used also resists snapping, like you get with long woodscrews. I used 6.0 x 150mm Velocity screws to secure the ridge beam of my gazebo down, and most of them have snapped where the blank shank meets the start of the threaded section. I changed to hex drive timber-lock screws and they're way better. Heads are too small on both for what you're doing, hence the need to jump to construction screws. 

[SillyBilly]

Excellent, so it just the length I have to sort

[Nickfromwales]

2 hours ago, SillyBilly said:

Excellent, so it just the length I have to sort

Remember to not use a single screw in the middle of the timber, instead go 1/3 down and 1/3 up with 2 screws per position so the timber gets uniformly pulled together and the glue fully ejected / displaced.