Lines and swirl marks on Hardwood

[drodda]

I am surface planing some hardwoods like cherry,oak and walnut. Using a 1/4" downspiral and it is leaving swirl marks and lines patterns in the top of the material. This is taking some time to remove by hand sanding. The marks seem to be getting more frequent and I am thinking I may need to fix something. Chatter on the edge of the cuts is also very much a problem. I have a prt alpha 120 x 60 with a 12inch Z. I am using a PC router also.

Any help would be appreciated on this.

-D

[billp]

Dave,
I guess one of the obvious questions here might be why are you using such a small bit to plane with? Is the wood very thin, or narrow?
Also the bit geometry on some down cut spirals might be self defeating as the tips of the flutes might protrude past the center of the bit's bottom, and that would accentuate the "swirl"patterns you're trying to sand out.
Another issue is that a 1/4"bit will flex (unless you have a very short shanked bit). Your 12"Z is not much help, and the PC router only aggravates all of these issues...
There are a number of "mortising bits", "bottom clean out bits","surface planing bits", etc. all with flat bottoms that might work better. Just about any bit catalog will have a variety.

[drodda]

Bill,

I have tried to use a 1.25" Surface Planing bit from Magnate and it just leaves burn marks everywhere. These are harder to sand out than the swirls and lines. After I surface the top I also cut the sides to the proper width and I have always used the 1/4 inch downspiral for that. I cut in .25 inch passes then come back and clean up the last .03 in a single pass. I am glueing in inlay material of different spieces and then I clean up the last .05 to flush everything up. I leave the inlay proud a bit and the surfacing takes it all down level. The reason I have been using the .25 bit is to try and take out any tolerance in my Z axis not being perfectly square to the table. Thinking that a larger bit would show lines even more? Maybe I need to rethink this a bit?

-D

[cnc_works]

One of the things I was most surprised about was that I got a much better surface with an upcut spiral instead of downcut or straight.

If you are getting burning, I suspect your are either running your feed too slow or your bit too fast. I once used a 2" straight bit to rough plane some oak...my memory says about 9000rpm at 90ipm.

Donn

[drodda]

I had the bit spinning at 13 to 15,000 rpm. I adjusted the feed from 1.2 IPS to 2.4 IPS and still had the burning. I can't go any lower than 10,000 rpm with my Pc router. Will give the lower RPM a try. I do this task almost daily so I have plenty of chances to try new settings.

[burchbot]

Dave
I have been using a .750 straight bit for planing with very good results, Looking at your 1.25 planer bit the cutting edge runs the entire bottom of your cutter.( I looked up your cutter on their website.) I think the cutter rubs on your just planed surface causing the burns. Where as my bit has very little contact with the surface. Only the two cutting edges.
Dan

[rhfurniture]

I like this one.
http://www.datapowertools.co.uk/acatalog/Surface_planers__r3_5512_1_2_.html
Bit of an upcut shere.
Cheap tips
Comes from Australia.