I just got done having that same problem. Needed to make a t-square. Its not any easy thing finding a tool that makes an accurate 90 degree angle. You need to use a good square or you need to make a pattern and cut it out of wood.

Not sure if I can explain this well but I will try. Draw a line 3 units long (or multiples such as 6,9,12,etc). Label one end "A". Label the other end "B". Place a compass on point "A" and scribe an arc 4 units long (or multiples such as 8,12,16,etc). Now place the compass on point "B" and scribe an arc 5 units long (or multiples such as 10,15,20,etc). Draw lines from the intersection of the arcs to the points "A" and "B". You now have a 90 degree angle.

You can make it any size you want by using multiples of 3,4 and 5. A triangle with sides of 3 and 4 (or multiples) will always have a hypotenuse or 5 (or multiples).

You can draw this on plywood and then cut it out and then plane or sand the edges smooth. And yes, you can use this pattern with a router using a pattern bit. Or you can draw it out and then use a straightedge to follow it with a router.

I'm sure others will tell other methods.

 

I don't think Pythagoras's theorem will really help solve the problem here. There is still too much room for error with regard to measuring, marking etc. - it works great for laying out fencing and such, but we need precision here. I reckon the best approach is to follow a template of some kind. It shouldn't be too difficult to find something around the home or garage which is an accurate right angle, then use that as a guide for a pattern bit. Even a store bought sheet of MDF or melamine coated particle board should be quite accurate.

 

Welcome to the forums Billy.

 

Welcome to the forum Billy, the usual way to make a drawer front would be on the table saw. It's difficult to give specific advice when a new member fails to complete his/her profile, which should include woodworking experience and a list of the main tools available.

 

how can i make a 90 degree corner using my router. i am trying to cut 3/4 plywood . i am want to use the plywood as the front of a dresser , the drawer front will sit even with the front of the dresser so everything is even. just not sure if i can use the router to cut thru the plywood . if so what bit? do i make a jig what do i need to follow the jig? how to i cut perfect right angles?

So is your question "how do you make 90 degree angles?" or is your question "the router bit leaves radiussed corners so how do you make the radiussed corners into straight corners?"

 

Hi Billy,
If you are asking how to square out the very corner where the router cannot reach, then I use a 3/4 or 1" SHARP chisel to clean out the corner that the router does not reach. Place the back side of the chisel against the cut made by the router and slice to the corner, removing the excess material. Do this from both sides. If you are careful, you can make a beautiful square corner. If you get too anxious or too strong, you can ruin the corner, so be careful. I do not use a hammer, all of the work is done manipulating the chisel by hand. Take small cuts and carefully control the chisel for best results.
If you are trying to just make a router cut that changes 90 degrees from the previous cut, then you will need to make sure that your guides for the router cuts are precise before making the cuts.
I hope that this helps.

 

Hi

The short is you can't they do make a bit to cut out holes in plywood it's call and panel bit, you can make your drawer box and then just round them over so they go in the hole just right...
They make in the 1/4" and the 3/8' cutter size, the smaller OD in your case would be best I think.

Panel Pilot Bits-Sommerfeld's Tools For Wood

Note they need a block of wood clamp or screwed /glued in place for the bit to ride on but that's a easy one to setup.
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