Use a 1/2" upcut 2 flute spiral. Also, measure the tool runout and make sure it's not excessive. I cut solid surface with these, with very good results. http://www.vortextool.com/index.cfm?fuseaction=category.display&category_id=13

Paul,

I am cutting .5" solid surface material.  I am using a .25" Solid Carbide UpCut Spiral O Flute Onsrud 63-775 bit.  I am cutting .125" with each pass at 90 degrees to the surface of material.  I am using a Milwaukee 5625 router in my machine and it has a standard .25" collet.  The bit has a CEL of .75" and only the cutters are showing out of the collet.  The router is set at 14,000.  The machine is a MechMate.

I think I understand and have answered all your questions. 

Thanks for you help.

Cruiser,

I am cutting with a bit that recommended by Onsrud for solid surface material.  I need to use .25" bit for details.

The little piece missing is from a tab that broke off.

You are running that very near the top end of it's recommended chip load, which will not always work well.  Also, what I see in the picture is not what I would call "chatter", but rather indications of an over-loaded tool - you're feeding too fast, and the tool is flexing.  Either reduce feed, or increase RPM, and I bet it works fine.  I'd bet going to a stiffer tool (1/2", for example) would also help, as it would increase your SFPM, and allow a heavier chipload, albeit with more spindle power and higher feed force required.

Regards,
Ray L.

YEP I am in agreement with Ray on this one > Looks like the chip load is too high for conditions and the cutter is being pushed over when the flutes get loaded up and can no longer cut. THen the chips clear out and start cutting again. Either UP the spindle speed, slow the feedspeed or go to a 2 flute high helix cutter.

Hope that helps, (;-)TP