Cutting veneered plywood without chipping the delicate top or bottom layers is a notoriously difficult task. Today, I’m testing the Amana Tool solid carbide spiral compression bit to see if it delivers chip-free edges on both faces.
What is a Compression Bit?
A compression bit combines both up-cut and down-cut flutes. The bottom portion of the bit pulls chips upward, while the top portion pushes chips downward. When the bit is plunged into a sheet of plywood, it “compresses” the top and bottom fibers inward toward the middle of the sheet, preventing tearout on both faces.
Specs and Manufacturer Claims
- Shank: 1/2 inch
- Cutting Diameter: 1/2 inch
- Cutting Length: 1-1/4 inches
- Material: Solid micro-grain carbide
- Brand: Amana Tool
Amana claims this bit provides flawless cuts on double-sided laminates and plywood, with long tool life and minimum runout. Let’s see how it holds up on the bench.
Bench Testing: How We Tested
I mounted the Amana compression bit in my CNC machine and cut 150 linear feet of cabinet carcasses in 3/4-inch pre-finished birch plywood at a feed rate of 120 inches per minute and 16,000 RPM. I inspected the edges of both the top and bottom veneers for tearout.
| Test Specimen | Top Face Tearout | Bottom Face Tearout |
|---|---|---|
| First 50 Feet | Zero (Flawless) | Zero (Flawless) |
| 100 Feet | Microscopic fuzzing | Zero |
| 150 Feet | Minimal fuzzing | Zero |
The Bottom Line
The Amana Solid Carbide Spiral Compression Bit is a must-have for cabinetmakers using sheet goods. It is an expensive bit, but it saves hours of sanding and prevents wasted material.
Derek’s Verdict: 9.8 / 10 (Gold Standard)
For more basic router bit concepts, check Router Bits: A Working Woodworker’s Guide. To learn about carbide materials, read The Complete Guide to Carbide Woodworking Tools.
Buy this compression bit at our trusted partner Woodcraft Supply.
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