[Yurtman]

I have recently been using Southeast tool SUD448 1/4" compression cutters. I have followed the recommended chip load for the tool of 0.012", but I am left with tool marks on the edges, pic attached, this is a new cutter and it's particularly noticeable cutting birch ply. Prior to this, I was using downcut spirals and not experiencing thes marks. I'm very happy with the lack of break out that the compression cutters give, but the edge marks are a problem. I have adjusted fee/speed ratio's but there's little improvement. I have noticed as the tool edges dull, the marks are less noticeable, but then the birch ply edges fluff. Any ideas?

[ger21]

.012 sounds like a rather large chipload for a 1/4" tool in baltic birch. Chipload can vary based on tool diameter and the material your cutting. What feedrate and rpm are you using?

Your probably getting tool deflection, but it could also be caused by runout, or a lack of machine rigidity.
Have you tried using a finish pass to remove maybe .01 and see if it's better?
Personally, I'd try to use a larger diameter tool if possible.

[Yurtman]

Thanks Gerry, my chipload is 0.0078", not 0.012". I'm cutting at 236IMP at 15000rpm. I cut with other 1/4" downcuts with no visible tool marks. Do you think the regularity of the marks could be deflection? When I have seen pics that people have posted with suspected deflection, the edges don't seem to be marked in such a regular way.

[ger21]

Do you cut in one pass with the downcut bits?

I've never used a 1/4" compression bit, but I've seen the same marks when cutting at higher feedrates than you're using, even on big industrial machinery.

[Yurtman]

I've seen the same marks when cutting at higher feedrates than you're using, even on big industrial machinery.

That's interesting Gerry, may be my feedrate is too high for this tool. I have the 8mm version which I will test cut, and may point to deflection in the 1/4". With the 1/4" cutter I have been cutting in 3 passes at 6.25mm, G wizard had a red warning for deflection with passes any deeper.