Eliminating Hand Sanding in Pocket CNC Routs

The right tool, ramping in, and a light finish pass can eliminate most tool scratches in decorative routs. October 3, 2007

I am currently working on a Weeke Venture 3l and am wondering if there is a way to get a clean pocket route without all of the tooling marks. I have used up spirals, down spirals, and mortise compression bits, all with same results. Do they make a buffer/sander bit that could be used to eliminate them? We are trying to create a decorative post. How would the CNC world do it?

Forum Responses
(CNC Forum)
From contributor B:
What material are you routing? Can you describe the tooling marks?

From the original questioner:
Solid wood, alder, maple, etc. The marks are the size of the tool used and are little spirals. We have only used standard CNC router bits. Would an insert tool cure this problem? They can be sanded out by hand, but we are looking for a faster, more efficient way to do it.

From contributor B:
Onsrud makes a "dish carving" bit that may work for you. It appears that it is designed to finish cut on the bottom. I don't have anyone else's catalog handy, but this is the type of bit I would look for. I would suggest that you call your bit supplier and ask them if they have a bit that is designed to give you a good pocket finish.

From contributor D:
Sounds to me like you are doing the cut in one pass and getting chatter marks as a result. Try re-programming with a couple thousandths cleanup pass. If that doesn't do it, I would look at the tool - use new, not re-sharpened.

From contributor T:
Any chance you could post a picture of the pocket? Make sure your tooling doesn't pause too long after plunging in.

From contributor R:
I think that you will always have some hand cleanup on decorative surfaces, but if your last cleanup pass takes about .06" or less in depth (high rpm and sharp) and runs in a linear pattern with the grain, you can take a sharp chisel and scrape the marks out fairly quickly.

From the original questioner:
Thanks for all of your inputs. I talked to our tool guy about the dish cutter and he is bringing samples tomorrow. Hopefully they will work. Also, I tried the linear direction with the grain and that did reduce the problem quite a bit.

From contributor G:
Onsrud 66 series has worked well for me. They are made for surface finishing. The part number for the 1/2 diameter cutter is 66-326.

From contributor E:
Some of the tools that are manufactured today do not have the correct clearances on the end grind. All of our [Courmatt's] tools have the correct angles, which eliminate teeth marks.

From contributor I:
Also, ramp in instead of plunging to avoid the pause that might show a circle at the start of the pocket.

From the original questioner:
Thanks for all of your responses. You have helped out more than you know. Our tool guy brought in the samples and they performed very well. Now all I have to do is make it ramp in instead of plunging, and I will be set with very little hand sanding.