A little help surfacing a large project - Bit Size

Good afternoon,

I have a large 44" (dia) cross cut poplar epoxy pour project that I want to surface (about 1/8" on each side) - the piece is 4" thick. I have a Journeyman X50 (so I will have to do this in two carves) but the question is what size bit can I use.
I am also considering just doing this with a router sled and a full size router - but want to see if I could do it on the CNC (I am relatively new to CNC). Second question - should I do it on the CNC?

I have a 1" Whiteside surfacing bit but wanted to see if I can go bigger and if so what should/could I use.

If I use the 1" bit, what feeds and speeds should I use.

Would love to hear some thoughts.
Thanks for the help

Hey Eric,

Are you using the Makita trim router? If so, you’d probably kill the router before you finished the project. Anything over 1/4" is risky. Do a search on Makita in this forum and you’ll see several articles.

Welcome to the forum; it’ll become essential to your success. The CNC process is complex and there is a bit of a learning curve. However, always search the forum before you ask. The smart folks here (and I consider myself a student) will answer questions but sometimes get a little tired of answering the same things over and over.

Hi Eric - welcome to the forums.

I have the Whiteside 1" bit and the much more expensive Amanda flycutter (RC-2265) that claims to be 1.5". I say “claim” because the cutters are closer to 1" apart than 1.5".

Generally the Amana bit is far superior in nearly every way except price. But, buy once, cry once. The primary advantage are the replaceable cutters, which means as long at the shank and the cutting head are in good shape, you can use it forever just by replacing the cutters. Each cutter has 4 sides, so that “quadruples” the cutter life. I recently rotated mine and it made a huge difference on my router sled.

On the flip side, my Whiteside bit is basically destroyed after 3-4 uses and should be replaced.

It really comes down to how often you are flattening large surfaces – for me I do a fair amount of slab work and epoxy, so investing the Amana made sense (and I don’t regret it).

As for feeds and speeds, I’d say 0.05" (~1mm) for DOC and 100-200 ipm. You can certainly push the machine a lot harder than that, but I’ve found epoxy chips easily so keeping the DOC small helps prevent that. Alternatively, you can do a 0.1-0.2 DOC and slow down to 40-50ipm.

On my router sled, I usually use 1/16" DOC and push very conservatively (no clue what the IPM would be). When I get tired or impatient, I pay with massive epoxy chip out every time. The last slab I did manually took about 4-6 hours of milling (over 2 days); it was 60"x32" and I did 3 or 4 passes per side to get it flat.

I have accidentially cut well over 0.25" DOC at 100ipm and the machine handled it. But I would not recommend it :wink:

Hope this helps.




Good morning, thanks for the note and help.

I did search the forum and found a little bit of info - but I might need search a little harder

Have a great day
Best regards

Good morning, thanks for the detailed response.
It really helped.
I have a larger bit for my big router, with the replaceable cutters which after your post, has me leaning to using the router sled which may be a little safer…
Have a great day
Best regards

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