Some advice on creating these joints.

[Risky Duckfeet]

Your Bosch is a scms - sliding compound mitre saw

That's embarrasing, you would have thought that with a tool like that I'd know the abreviations. I might have gone for DBMS

 

[mtt.tr]

Bench gouges?

 

[jasonB]

Given thats the tools you have then I would cut the big notches with teh saw using the trench function on the 2mm recesses with a simple jig and the router.

Jason

PS how are you intending to cut the T&G?

 

[mtt.tr]

Now i see it would off thought router the beads

the line the the lengths up with the end grain inline the notch it with a router

 

[Jacob]

2mm recess is a bit tiny for these structural components. Your error is likely to be greater (timber movement etc). I'd either omit it or make it deeper say 6mm.
If you don't want to get any extra kit you could just use your saw and then knock out the waste with a big chisel and mallet. I'd make sure that the cut-outs avoided knots, if possible.

 

[Risky Duckfeet]

Given thats the tools you have then I would cut the big notches with teh saw using the trench function on the 2mm recesses with a simple jig and the router.

Jason

PS how are you intending to cut the T&G?

Buying the timbers pre grooved and crosscut to the various lengths but the supplier that I've found will not do the notches.

 

[myturn]

You mentioned dado cutters at the start, why do you not think you could use these?
As long as they will fit your saw they sound like a good solution to me.

 

[Risky Duckfeet]

You mentioned dado cutters at the start, why do you not think you could use these?
As long as they will fit your saw they sound like a good solution to me.

I'd not heard of them before, I've been looking into them a bit today. If they do fit the saw, a) would I have to take the guard off? and b) do they come in 305mm or would I have to raise the base of the saw? With a 305mm blade the saw only just goes beneath the bed if the base.
I'd certainly use these if they are a valid option. It was just that the bloke on the other forum said that... well, you've read the quote

 

[jasonB]

No you can't fit them in a SCMS

Not aware of 12" ones

Yes you would need wider gaurds if they could be fitted

Like me he was possibly confused by your term "Sliding saw" as they can be fitted to a radial arm saw and certain table saws but at the lengths you are looking at it would need a tablesaw with a large outrigger on the sliding table.

 

[Jacob]

Dado cutter (on a TS with sliding table) IS the way to do this as I posted near the start of this thread. If you are doing 400 it could be worth buying a machine for the job. You could sell it on afterwards.
The other options, where feasible, are all inferior, unless you go for very expensive industrial machinery.

 

[devonwoody]

Your locale is shown as High Wycombe, perhaps there is a machine shop that can cut the joints for you?

 

[Mcluma]

I think you should buy a radial arm saw, with a dado head cutter

That is to most ideal solution

Do not put a dado in a SCMS ( I have never heard off or seen it)

Google radial arm saw, they are on google quite a lot, make sure it will take a dado, make a nice bench for it and off you go

Once you have set up the tabel and the saw (with end stops), then its very quickly done.

Then afterwards you can sell the Raidal arm saw

If you make your table wide enough, you can cut probably 10 in a time, roll them over, do the otherside

That is what i would do

 

[Risky Duckfeet]

Thanks to everyone who has commented and made suggestions. I didn't expect quite as much interest. I've just had another read through and wanted to point out that I wasn't ignoring anyone, especially Jacob and JasonB, I was just listening to all the suggestions.
I'm going to look for a radial arm saw but think that it's unlikely that I'll be getting one as this all has to be done outdoors on the base that the cabin is to be built on so everything needs to be portable.
I think that the most likely method is going to be the mitre saw and router with guides.
One way or another I'm sure that I'll make a few mistakes and then work it out. Look forward to showing you the results and thanks very much everyone.

 

[Erasmus]

I think you should buy a radial arm saw, with a dado head cutter

That is to most ideal solution

Do not put a dado in a SCMS ( I have never heard off or seen it)

Google radial arm saw, they are on google quite a lot, make sure it will take a dado, make a nice bench for it and off you go

Once you have set up the tabel and the saw (with end stops), then its very quickly done.

Then afterwards you can sell the Raidal arm saw

If you make your table wide enough, you can cut probably 10 in a time, roll them over, do the otherside

That is what i would do

So would I. This is by far the best way to cut this joint. Given that the OP has now stated that this is all to be done on site, a decent dimension saw with sliding table is not really feasible anyway.

I would use a radial arm crosscut saw with a dado cutter and build level benches 4m long either side of the saw and gang up the individual pieces for cutting. Just make sure that the saw stays square to the fence. I've quite often taken a radial arm to site and set it up like this on similar projects. As long as you can store it securely and protect it from the elements it's the quickest and easiest way. I've even used those camping gazebos to keep the rain off while I'm working outside