sliding mitre saws with trenching/grovving setup

[mooretoolsplease]

Evening all,
I'm after a reasonably priced mitre saw to setup for a joint I need to do on the window frames I make. The company I make them for is introducing a standard size of windows and as they are standard sizes, is wanting them cheaper than the bespoke ones. Which is fair enough.
I've attached a photo of the joint and how I want to do it, basically it is a masons mitre.


I normally do the bespoke frames on the 4 head tenoner, and then run them through the spindle after.
I can make quite a big saving by buying in the material pre moulded, and then do the masons mitre for the joints.
I'll need to set up 3 of them to do the various operations, with a spacer for the material to sit on depending on whether it is the cill section @ 69 thick or the heads and jambs at 57 thick.
I've just picked up the 8 1/4" metabo slider but it isnt big enough, and the depth stop for trenching is micky mouse.
what saws does the forum have which have a good trenching facility, and reasonably priced?
Thanks

[lynx]

if you have a tenoner, why not create a block that will scribe the rails into the heads and cills? if it's going to be standard then your sorted

[mooretoolsplease]

Thats how I have done it so far, but I think that with this method I will be able to speed up the mortice and tenons by not having to do the moulding afterwards, I could make up formers for the sections and still use the tenoner, but I;ve tried it and it hasnt been as successful as I had hoped

[trousers]

I agree with Lynx. Wrong tool esp. as it looks to be a mitre and not just a trench. Don't think you'll find a SCMS, except poss the Kapex, will do the accuracy. My Makita 1012/3? (£500 new?) has too much flex in the frame to be any use for trenching or similar. Better ways.

[engineerone]

surely that is the kind of thing that you do on a spindle moulder or a router?

i too cannot see how you can set up any of the available scms to accurately cut that simply and quickly. not least because at the intersection of the mitre and the masons, you are surely going to get an undercut?

paul