SPAX length and head types, which one to use (for joining to horizontal beams)?

threesixright

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Joined
Aug 17, 2017
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Hi!

I'm lost in the SPAX screws(heads) :-[.

I need to join to 2 timber beans, one 120x200 mm (w*h) and on top goes a 80x140 mm (w*h) (the length is ~ 3 meters). So total height is ~ 340 (metric).

I was looking at SPAX screws and see different head types, but to understand which one to use is getting academic  [scared]. I hope someone can get me some advice which screws to use. I was thinking of 200 or 220 length  :-\

Headtypes:
- cylindrical
- washer
- countersunk
https://www.spax.com/uk/products/construction/cid-8/

Much obliged,

--
Rog.
 
What is that going to be used for?

Rule of thumb is, if you want the two pieces of timber being pulled to each other, you use a partial threaded screw. The length is determined by the thickness of the piece you want to be pulled to the other. So the determining factor is the length of the unthreaded part = thickness of the piece getting pulled to the other.

For maximum pulling force you go washer head. Counter sink if you need the heads to be sunk/flat. Cylindrical is more or less special application.

Check sizes/diameter, the German page is more specific than the english one you linked. It misses that not all the screw types are available in all diameters ... For example those counter sink head screws are available in 8, 10 and 12mm diameter only.

Kind regards,
Oliver
 
The flat countersunk head is the most common type used with wood because it allows you to sink the screw into the wood so nothing sticks out.

With the other types the head always sticks out, and sometimes you want that, depends on what you're making.

The washer head is for when you want to fasten materials that can break more easily, the extra size of the head distributes the clamping force.

The cylindrical head is more for when you want to use metal plates. Same as the "bolkopschroef", sorry, don't know the english name for that.
 
For heavy duty structural applications, I prefer the washer head style. It distributes the load more evenly. So for connecting 2 timber beams, I'd initially go that route.

HOWEVER...not knowing your exact application you may be wanting to secure the beams without having to see the large washer head, obviously the countersunk version is easier on the eyes and if you really want to hide the head, countersink it deeper and add a timber plug.
 
Alex said:
The cylindrical head is more for when you want to use metal plates. Same as the "bolkopschroef", sorry, don't know the english name for that.

In this very instance, no. The cylindrical head type screws linked above are: Spax-Iso (for insulation) and In.Force for wood construction. They are not for fixing metal plates to anything.

Kind regards,
Oliver

 
Cheese said:
For heavy duty structural applications, I prefer the washer head style. It distributes the load more evenly. So for connecting 2 timber beams, I'd initially go that route.

HOWEVER...not knowing your exact application you may be wanting to secure the beams without having to see the large washer head, obviously the countersunk version is easier on the eyes and if you really want to hide the head, countersink it deeper and add a timber plug.

You can buy pre fabricated plugs in common diameters as well for hiding the washer head type screws. It's done all the time. ;)

->https://shop.layer-grosshandel.de/_...olltext=&s_group_id=020012007&newvariants=yes

Kind regards,
Oliver

Kind regards,
Oliver
 
six-point socket II said:
You can buy pre fabricated plugs in common diameters as well for hiding the washer head type screws. It's done all the time. ;)

Interesting Oliver...never knew those existed...from 15-40 mm.  [smile] 

I've always made my own.

[attachimg=1]
 

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I do love me some Spax.  Is there a way to get them in larger quantities than what is usually available at HD?
 
That's regular quantities, at least around here. Up to 1000 screws/box.

Then you can have a "Master box" which - in many instances - consists of 10 boxes.

And then you can have a pallet.

Short but informative example:

Flat countersunk head, T-STAR plus

3.5x12mm box = 1.000, master box = 10.000, pallet = 1.120.000
4.0x50mm box = 500, master box = 5.000, pallet = 140.000

Kind regards,
Oliver
 
Oliver,

Are screws like Spax approved for framing in Germany?  That is the issue here,  they advertise them implying they are for framing, but in the end, they are not code approved.  If you contact spax, they basically dodge the issue.

They are great, but they are expensive, and come in just small boxes. 
 
To the best of my knowledge:

Regular/universal type Spax screws for the longest time have not been approved to be used on/for load bearing timber construction. They are also not to be used on wood/timber connectors. To the best of my knowledge, that has not changed.

Expressly the screws linked above (by [member=65767]threesixright[/member] ), are approved for use on load bearing timber construction. Thus framing. Especially Hi.Force and In.Force screws - as well as the so called threaded rods. Speaking only for Germany/ probably Europe.

Besides that, there is a fairly new approval (ETA) document available (7/2020) ->https://downloads.spax.com/index.php?open=f61be045f56481f0a45a184bed20c79f

I have no idea, how American/ state bulding codes treat Hi.Force/In.Force and the threaded rods made by Spax.

I did a quick search, and the screws linked above are sold in the US under the name: PowerLags Structural Wood to Wood Screws for Framing. (https://spax.us/products/powerlags ) Doing another quick search, this document comes up:https://spax.us/uploads/resources/ICC-ES_Report_ESR-1782.pdf

Which to me is an indicator that these would be approved for framing. Might be

Again, these are different type screws made by Spax. This is not the "famous"/ often referred to standard "Spax universal screws".

Hope this helps. :)

Kind regards,
Oliver
 
Hi All, [member=61712]six-point socket II[/member] and [member=5277]Alex[/member], thanks!

Olivier, you asked for a better description. I made a little sketch what I plan to do, hope it helps  [big grin]

The beam on top (140 mm heigh) needs to be screwed to the bottom beam (200mm). Now the later is load baring, the top I'm not sure. Its for sure not only decorative, but the function is limited. I tried the SPAX (project) tool, but tbh didn't get much wiser from that.

The green  rectangular (with red border) are the "spax" screws (staggered), joining the beams.

On the right you see: floor board, insulation, floor-heating (Schlüter), cement, finished floor.

Since the beams will be visible (want to oil them of some sort), its important it looks good [big grin] and needs to be strong  [blink]

 

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When I start reading beam connections, my first thought is brackets...

ss-cc88px-column-cap.jpeg
 
Are you going to see the top of that beam that this sitting on the other?

I'd use the washer head (Hi.Force). Start by drilling with a Forstner bit so you can cover the heads/ get a smooth look.

If you don't get results with the tool, run it by Spax via E-mail. They are very helpful.

Kind regards,
Oliver
 
six-point socket II said:
Are you going to see the top of that beam that this sitting on the other?

Yes, indeed visible. Thanks! 

The tool wasn’t particularly clear about this type of joining.

Sent from my iPad using Tapatalk
 
Peter_C said:
When I start reading beam connections, my first thought is brackets...

ss-cc88px-column-cap.jpeg
Yeah.  But these are 2 beams horizontal. I looked at some angle brackets. Just for a bit of lateral strength.

Sent from my iPad using Tapatalk
 
threesixright said:
Yeah.  But these are 2 beams horizontal. I looked at some angle brackets. Just for a bit of lateral strength.
I will admit I am not fully understanding your drawing or needs.

Did you pull building permits? Was this engineered? Building codes should come into play. Here in the USA California we have earthquakes so everything is beefy, with brackets and tie downs required. Mortising in some form adds strength.
 
Didn’t want to write that I didn’t understand either. 
(Just decided my brain not working properly…  If so, please bear with me…  [embarassed])

Looks like most of the given measurements might be one decimal place out.
(I get it that the floor could be 21mm.)
For example:
Is the top ‘load bearing’ measurement (horizontally) 80mm or 800mm?

As I read the drawing, the ‘beams’ are vertical – not horizontal. 

I’m not even clear why you need to join the beams at all. 
Are they ‘stand-alone’, or, to be fixed to the ‘load-bearing’ material itself?
(For sure – that seems a really, really stupid question; but that’s indicative of how massively & thoroughly I’m not understanding) 

Enough – can you help me out – or am I doomed?  [scared]

Richard (UK)
 
[member=50292]Peter_C[/member]  [member=9980]fuzzy logic[/member]

The drawing is a profile, the lower beam is (load baring, calculated by an engineer) 200(h)x120(w), the one on top of that (non load barring) 140(h)x80(w) (not calculated). All in millimeters.

The beams are ~ 3300 mm (3.3 meter) long.

I added 3D view for better understanding. What your are looking at is the side of the staircase.
 

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