I'm THinking of a project where I need to route a nearly square recess

[LCHIEN]

The recess will be about 3" x 3" square and 3/16" deep.

I'm thinking about a oversized template and using a hand router and a 1/2" spiral straight bit.
That will leave corners that are 1/4" R round. I'd like to get some 1/16" radius round corners and not have to chop the corners with a corner chisel and chisel out the rest.
If I use a smaller bit of 1/8" diameter it will take forever ( at least 16x as long since it has 1/16th the area) and probably not be so smooth on the bottom.

So I'm thinking make the template 1/8" oversize (1/4" overall) using a 3/4" OD bushing and 1/2" dia bit , to do the bulk of the removal
Then switch to a 3/8" bushing and a 1/8" bit. To do the corners, without moving the template. Just have to clean up a little in each corner.
Since the difference in Bushing OD to Bit OD is .125" in both cases the small diameter bit should fit the corner and finish it with a nice small radius.


My template would need to be 3-1/4" square to make a 3" square recess with 1/16" radius corners.

See Anything wrong with this approach?

[capncarl]

Not quite sure the purpose of the recess, but the corners could easily be cut with an oscillating saw and cleaned up with chisels. I’ve even had surprising success sanding corners with the dorky looking oscillating saw triangle sanding attachment. It might be just the trick for cleaning up the bottom or your recess.

[LCHIEN]

Oscillating tools have a large radius, can't get into corners without leaving a lot of collateral damage.

[LCHIEN]

I just wanted squarish corners with a small but nice looking small radius.
Reason is complex and immaterial.

Using a half inch router bit will leave corners like the left . Much bigger than I wanted. 1/8" router bit on the right.

[jacobs]

Using your plan, starting with a 1/2" bit and then switching to a 1/8" bit with a smaller bushing to clean the corners makes sense and should save time while keeping the radius tight; for tools or related guidance, check how to contact qvc, can help with ordering, product info, and support, offering quick access to live reps and useful advice for supplies.

[capncarl]

Have you tried using an Oscillating saw to plunge a square hole?

[LCHIEN]

as noted a square hole is not what I was looking for. I am looking for a recess with small radiused corners. Anyway, an oscillating tool is OK for a square hole in sheet material but not a 3-D cavity. It can't form the inside corners well.

[dbhost]

Would require more skill than I own, but what about a corner chisel?

[cwsmith]

Hi Loring,

Not sure what you are building, and as you say, it probably doesn't matter. I'm picturing a solid piece of of woodstock, with a recess of whatever depth, in the shape that you have illustrated. Sort of like you could store something in that recess. (Probably way off your objective )

I'd start with the the larger 1/2-inch bit and route your shape, as you propose.

Then I'd use a 1/16 inch drill bit or smaller to drill just inside the four corners, followed by your 1/8 inch router bit. That would sharpen your corner, and the minor peak left betweek the drilled corner and the 1/8 diameter, would be so small that it probably wouldn't be worth the effort to slice clean.

Here is an illustration showing one corner:

CWS

[capncarl]

Lchien, you are probably finished with your project, this is what I meant by using an oscillating saw. Then chisel out the remaining material

https://youtube.com/shorts/DcDCCluBq...UvrjDYZdRdvzm1

[LCHIEN]

Lchien, you are probably finished with your project, this is what I meant by using an oscillating saw. Then chisel out the remaining material

https://youtube.com/shorts/DcDCCluBq...UvrjDYZdRdvzm1

Well, I did specify I wanted radiused corners, a small tight radius but not square.

And I wanted a recess, not a cutout.

But thanks, anyway.