Say you have two pieces of plywood.

the goal is:

  1. to assemble the two pieces at a 90 degree angle (where 3/4 inch edges are touching)
  2. create an angled edge sit the edges sit flush against each other

How can a 45 degree edge be created spanning the height or width of the plywood?

EDIT: assume edge requiring the 45 degree angle = 6ft

  • 5
    It's hard to cut a 45 on the edge that long, and typically a simple butt joint would be used for that corner. Is there a reason you need the miter joint? – JPhi1618 Jan 29 at 19:31
  • 3
    "How can a 45 degree edge be created spanning the height or width of the plywood?" What is the height or width of the plywood? This would dictate whether you can use a table saw or a circular saw with a straight edge. How are you securing this joint ? – Alaska Man Jan 29 at 19:43
  • 2
    A rail saw can do this - and my son has done several during his build for planks 3 or 4 metres long, just need to secure the wood so it stays straight. – Solar Mike Jan 29 at 19:49
  • 1
    sounds like a job for a table saw, unless you're a lot better at using hand tools than I am. – dandavis Jan 29 at 19:59
  • 2
    table saw is obviously best. How do you intend to fasten the joint? When I've done long mitered joints like that I've used biscuits to help with alignment. But then you need a plate joiner (biscuit joiner). short dowels can also work, you just need the template and a drill. JPi asked why a butt joint would not do, good question. If for appearance, you could make the butt joint slightly shy to leave room for a glue on or iron on wood trim strip to cover the end of the plywood. – George Anderson Jan 29 at 20:15

If you do not have a table saw and the run out table big enough for this job and you do not have a track saw you can use a straight edge and clamps.

The straight edge (hear after referred to as SE ) needs to be rigid so it will not flex in the middle, a long level works, but some times it so thick that the motor of the saw may not pass over it, and the clamps can also interfere. Testing is required with your saw.

I have a long SE that is not as rigid as i would like so i have to cut a 2x4 the correct length and clamp it so it reaches the middle of the SE from the side to keep the saw from flexing the SE.

I created a block of wood that is as wide as the distance from the edge of the saw fence to the blade so i can place one side of the block on my mark and the SE up against the block. Then i know that with the fence against the SE the blade will hit the mark.

For 45 deg cut with circular saw a sharp blade is needed with as many teeth as you can afford.

Because of the rotation of the blade you want the finished surface or your plywood to be on the bottom. I.E. the finshed side of the wood will be underneath and saw will be on top, this will keep the finished side from getting tear out. ( this is the opposite of a table saw )

Go slow and keep the saw fence against the SE. Do some test cuts on scrap wood.

| improve this answer | |

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.