Advice on Cutting Oak

1

Long time listener, first time caller

I’m trying to create some picture frames out of oak, so I’m basically doing a lot of pocketing operations. I’m going to share what I’ve learned about cutting oak below (photos below!), and am looking for any advice on:

  1. What feeds/speeds/bits people have used to successfully cut oak
  2. How people handle inside corners at high feed rates

Bits & Chip Rate
I started my cutting with an ONSRUD 40-100 type 1/4" bit. According to this sheet I should be aiming for a chip rate of 0.005-0.07. For a 2-flute bit on a Dewalt 611 set at 1 (16,000 RPM) that implies a feedrate of 250 ipm! I’ve never heard of anyone running an X-carve at that rate so I went to 90.

I did my first cut at depth of pass 0.0625" (1/4 the width of the bit) and then did another one at 0.03" (all times I used 9 ipm for plunge rate). See the photo below, but both had lots of “fuzzies” that would require me to sand like mad.

I switched to an ONSRUD 52-240B 1/8" bit. According to the datasheet, it has a chip rate of 0.003-0.005 and by setting the feed rate at 90 ipm I can get to almost exactly 0.003. I did that and tried depths of pass of 0.0625", 0.03" and 0.02".

The first impact of the switch to the smaller bit was that the fuzzies went away. This leads me to my first question:

  1. Has anyone used a 1/4" bit to cut oak? What bit were you using? Has anyone tried the ONSRUD 12-00 series - according to the datasheet it looks like it has a chip load of 0.003-0.005 which means I could run it at 90ipm on the X-carve.

The second impact of the switch to the smaller bit was that, as I reduced the depth of pass, the fuzzies went away and by 0.02 I basically wouldn’t need to do any sanding. But, the inside corners aren’t even (see 2nd photo). I am trying to create a 0.125" radius using a 0.125" diameter bit. This leads me to my second question:

  1. Any advice on how to create inside corners like this? e.g., don’t try to create radii that are bigger than the radius of your bit? Any rules of thumb or advice here?

Photo 1 - Impact of different bits & depth of pass


comparison.jpg4032×3024 2 MB

Photo 2 - Unequal inside corners

close-up.jpg3024×3024 1.11 MB
2

Just for my own edification, were those slots done with upcut or downcut bits? I’ve been made to believe that if I was using downcut bits I wouldn’t see torn up material (fuzzies) on the top surface like that.

Steve

3

Upcut bits. Here are the ones I’ve used:

1/4"

1/8" was in this set

4

What type of oak? It looks like red, if you want oak, can you use white oak? It is more friendly to high speed bits. I haven’t used oak yet on my x-carve, so other than that I’ll listen to what others say.

As for the uneveness, I wonder if the you are using an upcut bit and easel thinks a downcut? Perhaps easel has the wrong one and it causes it to not be able to carve well and the bit bends?

5

Appreciate the advice. I’ll check out white oak.

Any idea how to tell Easel the correct bit?