How to cut a 45 on an 8” Maple board

[wdphillips]

I am put a 16’x 8” Maple cap in the shape of an “L”on top of a stair well wall. The long side is about 12’, the short side 4’

I need some advice on the best blade and technique to cut the 45 such that the two pieces mate properly at the corner of the “L”. I will be using a Dewalt chop saw.

Any help would be greatly appreciated.

[JPG]

[quote="wdphillips"]I am put a 16&#8217]
Under cut it slightly so you can easily 'sand' it to fit. Undercut as in slight bevel. If the dewalt doesn't do compound cuts, . . . get the angle(s) correct.

P.S. Not sure I completely understand the task here. Are the boards wrapping a corner with the wide face vertical, or wide face horizontal????

[wdphillips]

Wide face horizontally! The board is capping two half walls in the shape of an "L". The thickness of the wall is 6" so the 8" maple board sits on top of the two half walls.

[JPG]

The kicker is what is the wall angles(s). Rarely is 90° the answer.

If you can, I would temporarily lay the boards in position and determine(mark) where you want the 'joint' end to be on both sides of both boards. Then cut from 'mark to mark' on each. Try sneaking up to the angle in the cutoff area of each board prior to final cut.

I would think a hollow ground blade is advisable here.

[charlese]

[quote="wdphillips"]I am put a 16&#8217]

It would be a daunting task to match bevel two boards 16' 8" long. Even with the best set-up, there is likely to be slight waves in the cut that will show after joining. I'm also thinking of the joining process of those two boards. Another daunting task!:eek:

Let me recommend making a long but joint. You could even use screws and glue. To hide screws you can cut plugs.
If you would be concerned with the joint showing, you can mill a small "V" or bead at the joint.

[michaeltoc]

The kicker is what is the wall angles(s). Rarely is 90° the answer.

If you can, I would temporarily lay the boards in position and determine(mark) where you want the 'joint' end to be on both sides of both boards. Then cut from 'mark to mark' on each. Try sneaking up to the angle in the cutoff area of each board prior to final cut.

I would think a hollow ground blade is advisable here.

I agree - walls are never plumb or square. This is really the best way. As an alternate you cut a square of a contrasting wood for the corner (similar to how a rosette is used on a door frame), then you have plain straight cuts (trim the square to fit).

[h-bomb]

The kicker is what is the wall angles(s). Rarely is 90° the answer.

If you can, I would temporarily lay the boards in position and determine(mark) where you want the 'joint' end to be on both sides of both boards. Then cut from 'mark to mark' on each. Try sneaking up to the angle in the cutoff area of each board prior to final cut.

I would think a hollow ground blade is advisable here.

There is a possible slight refinement on the above method.

Do as above, but only cut the angle on the long board.

We are assuming the wall is level horizontally and the cut is vertical.

Using a piece of hardboard or thin plywood, make a template of the shorter board. It needs to be full width, but does not need to be full length 2 - 3 ft should be fine.

Place long board in position slide template underneath mark and cut. Offcuts of template material should be temporarly placed under long board ensuring it is level.
This should allow you to obtain perfect angle for shorter piece.

If not you can refine the template by repeating above method until you are satisfied.

[anmius]

There is an old carpenter's trick to cut miters like this on long boards. Put the boards in place overlapping at the miter. Clamp in place, mark a miter cut (half way) between the two boards (approximately 45 degrees). Then cut both boards in place at the same time. If there is no room to cut them in place, move both of them to a new location and re-align them by your previous marks. Then cut them both together. The key to a perfect fitting miter is to cut both boards together at the same time. It doesn't have to be exactly 45 degrees, just close. But if they are both cut together, they will fit perfectly.

[wdphillips]

A picture is worth 1000 words. Here is the job at hand...

[wdphillips]

There is an old carpenter's trick to cut miters like this on long boards. Put the boards in place overlapping at the miter. Clamp in place, mark a miter cut (half way) between the two boards (approximately 45 degrees). Then cut both boards in place at the same time. If there is no room to cut them in place, move both of them to a new location and re-align them by your previous marks. Then cut them both together. The key to a perfect fitting miter is to cut both boards together at the same time. It doesn't have to be exactly 45 degrees, just close. But if they are both cut together, they will fit perfectly.

To that end... the two ends of the "L", 12' and 4' will be cut out of the same 16' board. If I cut the 45, turn over one board to create a 90, will I have a good fit?