Getting rid of toolmarks

[wardsa]

I have a PRT Alpha w/ a PC router. When pocketing into solid wood; Cherry, Maple and Oak,
I am getting alot of tool marks. I'm using a .25 endmill @ 240imp, 16000rpm. My cuts are only .05 deep. I had alot of backash in my Z and I removed as much as I could, seems pretty tight now. Am I going to fast/slow? Also looking for good options for sanding. I've tried everything I could find, flap sander, star sander..... I've got drawers full of sanding heads. Thanks for any help.
Terry

[woodworx]

reduce your step over, and speed up your feed rate will help. Also you could pocket .49" and then run over it once at.5" deep. Tool marks on the sides of your cut can be fixed by running a profile pass after you are finished pocketing. Your bit might have a little to do with it, but most likely it sounds like your bit is deflecting as it cuts causing a bit of flex. When the bit is flexing you will get angled lines on the bottom of your cut. Reducing the amount of material it is cutting at once will reduce the amount of flex on your bit.

[wardsa]

My stepover is at 40% or .1 . Do you still think I should reduce it? What would you speed it up to? I was freaking out at 240 ips! I can go alot faster then that?
Terry

[ljdm]

Could they be from the Z not perpendicular to the table? If it's off a little, it will show with an endmill. Cutting across the grain makes the marks worse. I saw a thread recently here about very slightly rounding the outer edge of the endmill to reduce marks. I noticed it the most when my Z was only a few thousandths off perpendicular, when pocketing hardwood.

[harryball]

Check that your Z is square to the table.
Reduce your step over to about 20 to 25%
Increase your speed to 5 ips or so (300 ipm)
Try a different bit
If you are pocketing in offset (going around and around) try rastering in the direction that looks the smoothest.

/RB

[knight_toolworks]

also pocket with the grain when possible for cleaner cuts.

[beacon14]

Router or Spindle? I noticed a significant decrease in tool marks when I upgraded from a router to a spindle.

[wardsa]

OK, the raster with the grain has seemed to take care of alot of the tool marks, but I'm still getting a "swirl" mark from the start and stop of each line. Would that have anything to do with ramping??? I realy don't know anything about it and have never checked or changed the settings since I bought the machine (used). Right now I'm using a Centurion, downspiral bit and it seems to be the "points" on the bottom of the bit that is leaving the marks. I'm going to Lowe's to see if I can find flat bottom bit to try just to see if that makes a difference.
Terry

[ljdm]

If you are getting marks from the "points" of the bit, I assume you mean the outside edges of the endmill? That could point to the spindle/router not being perpendicular to the table in the x or y axis. Very slightly rounding the edges of the bit would help that, but not fix the cause. Have you checked your Z for plumb both x and y? Could save a lot of time searching for the reason you are getting marks, if you eliminate this possible cause. Even a flat bottom bit will do the same thing, if the Z is off a little. My 2 cents.

[wardsa]

My Z is plumb. I checked that already. The swirl marks are a perfect O , where the bit stops to change direction. I actually was fileing down the edges of a bit, but I couldn't tell if I was taking anything off. I wish I could find a "dish bit", .25 diameter. It has to be .25 . Anyone know of a source?

[kencraft]

I have a Whiteside solid carbide core box bit 1/4" shank 1/4" diameter. I can mail it to you to save a trip. -Tracy