Making a jig for cutting firring strips with a skil saw

Calahonda52

so yellow is two 4 by 2's, domino'd together with 14 mm dowels

Red is the cut I want to make

The finished piece needs to be c 200 to zero and then I will add on a 2 by 1 to give me 225 to 25 to give me a 5% slope

I need 28 so 14 cuts so want to make a jig, don't have table saw

I have a track for the skil saw and as the length is 1.9m, was thinking could cut a 200 wide by 1.9 slot in a half sheet of ply and screw the track across the diagonal and just slot it over the pair of 4 by 2's?

The next puzzle is how would you fix these to the joists underneath?

Am using 300 by 60 I joists

I have some 8 by 260 screws...

listermint

Not just cut the ply diagonally and use the ply as your longer tracksaw jig adding a thin bit of ply as your saw guide to it. ? Unless I've taken that up wrong.

Would assume pocket holes and glue would be the most suitable for fixing its strong and neat.

Calahonda52

https://www.boards.ie/discussion/comment/121487250#Comment_121487250

Hadn't thought about the pocket holes!

Thanks

kadman

Order tapered I Joists which saves loads of hassle. Either a complete full depth tapered i Joist, or a smaller filler tapered I Joist and attach it to a smaller normal size I Joist.

Calahonda52

https://www.boards.ie/discussion/comment/121735590#Comment_121735590

Have you a link, the only I joist I can get for this small job are the standard S45/60/90 flanges in 220 or 300 depth and 6.5 long

kadman

Why not make your own top firring I beam pieces to sit on a normal I beam joist. Simple.

You say you are using a slope of 5% so its easy to draw and get your angle for cutting the structural osb panels, groove the best strength graded material for the top and bottom bearers of any of your I beam, then stagger the joints of both the bearers and osb panels. Job done

kadman

All the design details for a tapered I Beam construction are here.

https://www.redbuilt.com/wp-content/uploads/2019/10/RedBuilt-Tapered-Red-I-Guide.pdf

Calahonda52

https://www.boards.ie/discussion/comment/121770221#Comment_121770221

Thanks for that, will explore this idea They are only 2m long so would not be any need to stagger joints

would also make it easier to fix them to the full I joists

kadman

Are the I beams only 2 metres long?

Calahonda52

https://www.boards.ie/discussion/comment/121770349#Comment_121770349

```no 4m with a shallow A roof finish to red squeeze in below the 4m apex rule

In passion g what glue would you use for the grooves

kadman

In your previous post you say they are 4m long, and now gone down to 2 metres???

Calahonda52

https://www.boards.ie/discussion/comment/121777318#Comment_121777318

shed span 4m small A roof makes the firring joists 2m😀