One sets a saw blade. The other checks whether anything is actually square.
Verdict
A digital angle gauge sets a blade to a bevel in seconds and reads to a tenth of a degree, which is far quicker and more accurate than a protractor. A good combination square is the reference against which everything else is checked, including the gauge. Buy the square first, because without a known-square reference nothing else can be trusted; add the gauge for bevel setting.
~$80
Check PEC Tools 12 in Machinist Combination Square Price| PEC Tools 12 in Machinist Combination Square | Wixey Digital Angle Gauge | |
|---|---|---|
| Checks 90 degrees | Yes, it is the reference | Yes, to 0.1 degree |
| Sets a saw bevel | Slowly | In seconds |
| Needs batteries | No | Yes |
| Needs calibration | No, if accurate | Zero it each use |
| Marks and scribes | Yes | No |
| Best for | Layout and checking | Machine setup |
You need to know whether your fence, blade, table and joints are actually square. A cheap square that is not square is worse than useless, since it propagates its error into everything. Check any square with the flip test against a straight edge before trusting it.
Check PEC Tools 12 in Machinist Combination Square on Amazon
You cut bevels and want to stop fiddling with the saw's own scale, which is usually approximate. Zero the gauge on the table, then set it on the blade, and mind that a tooth set can throw the reading if you rest it on the teeth rather than the plate.
Check Wixey Digital Angle Gauge on Amazon
Scribe a line against it from a known straight edge, flip the square over, and scribe again from the same point. Any gap between the two lines is double the error.
Usually the blade is not parallel to the mitre slot, or the fence is not parallel to the blade. Both are adjustable and both matter more than the blade itself for cut quality.
You need one accurate reference. A quality combination square doubles as a marking tool, depth gauge and straight edge, which is why it is the usual choice.
Comparison based on published manufacturer specifications and the general consensus of owner reports. We have not tested these units side by side. Confirm current prices and specifications before buying. As an Amazon Associate we earn from qualifying purchases, at no extra cost to you.