Sgian Dubh
Established Member
Well, in the image you placed in one of your earlier messages, repeated below, I think you can see it's just a case of cutting one piece first, marrying the cut end to the other piece, and cutting that to match. However, in your case, unlike in the image here, you have restricted access at both ends away from the corner where the parts are to meet. Given that, your best bet would be to make a template out of some 3 or 6 mm MDF, or even a piece of stout card. Your template would be two pieces that exactly match the full length, i.e., they both go right into the corner, and width of the window boards, and where they fit. Also mark on your template the width of your proposed front moulding, and let's say, for the purpose of discussion, that width is 12 mm.
Next, using the image below as the example to follow, put the template piece running left to right (horizontal) in place, and call it piece A. Then lay the up/down piece, piece B (vertical in the image) over the top and pencil a thin line along the front edge of B across the top face of A where they meet in the corner. As long as you make sure your two templates fit tight against the window frame, this drawn line gives the appropriate intersection of the two pieces in the corner, whether that's 90º, or a bit less, or a bit more. Take the pieces out of the opening. Mark a 135º line from the front edge of piece A at the point where your pencil line from B intersects it. This line should extend to just beyond the width of the 12 mm wide moulding and should therefore be (according to a bit triangular trig, i.e., the square root of A²+B² = hypotenuse) approximately 17 - 18 mm long. Then mark from the end of the hypotenuse a line parallel with the pencil line you got from the front edge of piece B. Cut this.
Next put piece B back in place into the corner, and put piece A in place also and over the top of B. Scribe the cut you did on piece A onto piece B using a sharp pencil and/or a sharp knife. Cut piece B and test fit your template. If all is good, you can use these templates to mark and cut your window boards.
How you cut the thicker window boards depends on what equipment you have. The relatively easy bit is piece A because it's mostly cross cutting with a saw (either by hand or with a machine) which is fairly straightforward. Piece B is a bit trickier because, as well as the mitre which can be sawn easily enough, you have to do a rip cut which might require using a hand held panel saw and cleaning up with a chisel or bullnose plane. Alternatively, if you have a router you could use that and a clamped straight edge to cut the set back from the front edge of the rest of the board.
Anyway, if everything goes well, it's just a case of fitting your boards in place, which might mean a bit of trimming is required at the far ends away from the mason's mitred corner to allow you wriggle the parts into place, and then plastering over any gaps. Slainte.
Next, using the image below as the example to follow, put the template piece running left to right (horizontal) in place, and call it piece A. Then lay the up/down piece, piece B (vertical in the image) over the top and pencil a thin line along the front edge of B across the top face of A where they meet in the corner. As long as you make sure your two templates fit tight against the window frame, this drawn line gives the appropriate intersection of the two pieces in the corner, whether that's 90º, or a bit less, or a bit more. Take the pieces out of the opening. Mark a 135º line from the front edge of piece A at the point where your pencil line from B intersects it. This line should extend to just beyond the width of the 12 mm wide moulding and should therefore be (according to a bit triangular trig, i.e., the square root of A²+B² = hypotenuse) approximately 17 - 18 mm long. Then mark from the end of the hypotenuse a line parallel with the pencil line you got from the front edge of piece B. Cut this.
Next put piece B back in place into the corner, and put piece A in place also and over the top of B. Scribe the cut you did on piece A onto piece B using a sharp pencil and/or a sharp knife. Cut piece B and test fit your template. If all is good, you can use these templates to mark and cut your window boards.
How you cut the thicker window boards depends on what equipment you have. The relatively easy bit is piece A because it's mostly cross cutting with a saw (either by hand or with a machine) which is fairly straightforward. Piece B is a bit trickier because, as well as the mitre which can be sawn easily enough, you have to do a rip cut which might require using a hand held panel saw and cleaning up with a chisel or bullnose plane. Alternatively, if you have a router you could use that and a clamped straight edge to cut the set back from the front edge of the rest of the board.
Anyway, if everything goes well, it's just a case of fitting your boards in place, which might mean a bit of trimming is required at the far ends away from the mason's mitred corner to allow you wriggle the parts into place, and then plastering over any gaps. Slainte.
