Brotherhood of the Green Koolaid... I need your help... Plywood cutouts

[LTD]

I'm a Novice when it comes to my Festool Router.  I would like some help on a future project.  Would anyone help advise me on how to do cutouts with a radius in plywood like those in the attached pictures...?

Thank you for any advice..

David

 

[nclemmons]

Make a pattern and use a collet or a bearing guided bit in the router to follow the pattern with the bit plunging below.  Pattern in your case would be a hole slightly larger than your cutout and route to the inside.  You can use double stick tape to adhere the pattern if it is too far from the edge to clamp.  Alternatively you could use a pin nailer.

You can cut the pattern with a saw and use a drum sander to round the corners.

 

[Holmz]

Or one can attach 4 straight pieces onto the template and use a guide the fits onto the router.
Then the template gets routed out with a bit the radius of the finish piece.

Then that template can be mounted on the backside (with nails if you like)..
Then a router bit with a bearing to ride on the template, which will be on the bottom.

But Neil's method also works.

 

[Michael Kellough]

Depends on the specific radius. You could simply make a square frame and run a round base radius inside the frame, depending on the specific radius.

If you have the ability to make a specific radius sub-base for a router and install it concentric with the bit then you can use any router.

That's all wrong. See tomp's reply below for why etc.

 

[tomp]

Whether you use a bearing guided bit or guide bushing and straight bit, using a template with inside square corners (or four strips attached to the surface) will give you a cutout with a corner radius that's one half of the bit diameter - 1/2" bit, 1/4" radius - and you will get the same corner radius if the OD of the router base is located on the inside of the template, makes no difference what the diameter is, only how much offset you have to build in to the template. To get a specific corner radius in your cutout, you need a template opening to the finished size and with the required corner radius, if you're using a piloted bit. Using a guide bushing, the inside dimensions of the template, as well as the corner radius, will have to be adjusted based on the combination of guide bushing and bit being used.

 

[Michael Kellough]

Whether you use a bearing guided bit or guide bushing and straight bit, using a template with inside square corners (or four strips attached to the surface) will give you a cutout with a corner radius that's one half of the bit diameter - 1/2" bit, 1/4" radius - and you will get the same corner radius if the OD of the router base is located on the inside of the template, makes no difference what the diameter is, only how much offset you have to build in to the template. To get a specific corner radius in your cutout, you need a template opening to the finished size and with the required corner radius, if you're using a piloted bit. Using a guide bushing, the inside dimensions of the template, as well as the corner radius, will have to be adjusted based on the combination of guide bushing and bit being used.

Doh!  tomp is right, I'm wrong.

 

[LTD]

Thanks for the help.  [wink] Now it's time to go practice on some scrap plywood.

David