richards
09-03-2004, 01:20 PM
It took a lot of tests, but I think that I've finally found a workable combination for cutting baltic birch plywood on my Alpha 120-60.
Since I'm running a Porter-Cable 7518, feed speeds are slow.
Cutter = Whiteside, single-flute, 3/8-inch
RPM = 19,000
Direction = Conventional
First Pass:
Speed = 3 ips
Depth = 0.660 inches
Run this pass 0.035 inches oversize
Second Pass:
Speed = 8-10 ips
Depth = 0.680 inches
Run this pass at desired dimension
The finish is nearly perfect with tool marks hardly visible.
The choice of a Whiteside single-flute cutter was made because using a $50-$60 spiral cutter gave me almost exactly the same results, but at 3-1/4 ips instead of 3 ips. In my opinion, the Porter-Cable is marginal when relatively heavy cuts are made.
The depth of cut, at 0.680 inches, leaves 0.030 inch of material (this batch of baltic birch is running 0.710 inches thick (18.03 mm). With a Fein vacuum and Shopbot's 4-zone vacuum grid, 0.030 inch holds vacuum and still trims away with a quick pass with a 1/4-inch bearning guided laminate trimmer router bit.
Mike
Since I'm running a Porter-Cable 7518, feed speeds are slow.
Cutter = Whiteside, single-flute, 3/8-inch
RPM = 19,000
Direction = Conventional
First Pass:
Speed = 3 ips
Depth = 0.660 inches
Run this pass 0.035 inches oversize
Second Pass:
Speed = 8-10 ips
Depth = 0.680 inches
Run this pass at desired dimension
The finish is nearly perfect with tool marks hardly visible.
The choice of a Whiteside single-flute cutter was made because using a $50-$60 spiral cutter gave me almost exactly the same results, but at 3-1/4 ips instead of 3 ips. In my opinion, the Porter-Cable is marginal when relatively heavy cuts are made.
The depth of cut, at 0.680 inches, leaves 0.030 inch of material (this batch of baltic birch is running 0.710 inches thick (18.03 mm). With a Fein vacuum and Shopbot's 4-zone vacuum grid, 0.030 inch holds vacuum and still trims away with a quick pass with a 1/4-inch bearning guided laminate trimmer router bit.
Mike