Dieter Schmid's Fine Tools
Auger Bits INCH

Auger Bits in Inch Measurements for Machine and Hand Drilling

Up until now we could not offer the ideal bits to cut the round mortises for our Veritas Tenon Cutters, and could only offer Forstner bits in inch measurements. Auger bits have a number of advantages over Forstner bits in that case, as one can cut slowly, or even use hand braces and the center threaded spur can be carefully controlled for accurate results especially when starting the hole. So we are happy to be able to offer these auger bits in very exact inch measurements from a very reputable Japanese toolmaker, STAR-M, for precisely fit and strong joints. These are excellent bits and easily as good as the metric auger bits we have long offered. As always, we think there is no sense in experimenting with cheap tools, especially for applications like round mortises.

For clean, tearout-free holes, whether you use a power tool or a hand brace, these STAR-M bits are a fine choice. Japan can look back on many many centuries of tradition in woodworking and timberframing at the very highest levels of the art, and with it the same quality of toolmaking to provide those working today with the best tools modern technology can provide. So we can also enjoy the fruits of this marriage of tradition, modernity and outstanding quality in products like these auger bits.

These bits have a pronounced spur on the leading edge of the bit for a clean cut, even at slow speeds with a hand brace. The main cutter is shaped like a chisel, and turns around the threaded center spur, cutting up the wood freed by the circular cutting action of the edge spur. The center screw point pulls the bit into the wood so that little or no pressure is needed when boring. The screw point features a smaller thread than those bits designed for hand brace use only. See Comparison! This is because the hand brace bits would be pulled into the wood much too quickly if used in a drill press. Be careful, especially when starting the hole, not to tilt the drill and to keep it straight and true, otherwise the point can break off and render the bit useless.

These auger bits are designed for use with all kinds of softwoods and European hardwoods like beech and oak. They do not work well with the various kinds of very hard tropical woods. Use either a correctly-sized hand brace or a an electric drill. When using an electric drill, one must be careful not to overheat the bit and to frequently "air" the bit and free the threads of any shavings by turning the machine in reverse and pulling it out of the work piece. Pulling the bit out with the center screw still holding in the wood can damage or break the point! Use only light pressure with these bits! Do not use a drill press!

STAR-M Auger Bits in Inch Measurements STAR-M Auger Bits in Inch Measurements
1 main cutter
1 spur cutter
Center lead screw
Six-sided shaft end on bits Code 312350 to 312363 with different shaft sizes, see the table.
The two big bits, Code 312364 (1-3/4 inch) and Code 312365 (2 inch) have a round 12 mm shaft, that is slightly flattened on three sides, to allow them to be used in a drill press with a three fingered chuck without having the extra torque of the big bits turn the bit fixed in the chuck in use.
Bit Code 312350 (1/4 inch) can only drill shorter holes, as the shaft is thicker than the bit diameter. Here is a photo of the 2-inch augerbit.
Enlargements and instructions how to use

Total Length
Total Length
Bore Depth
1/4 6.35 hex 6.35 6-1/2 160 95
Code 312350CartPrice € 5.90
3/8 9.52 hex 6.35 7-1/2 190 155
Code 312351CartPrice € 5.90
1/2 12.7 hex 6.35 7-1/2 190 155
Code 312352CartPrice € 5.90
5/8 15.85 hex 9 7-3/4 200 155
Code 312353CartPrice € 6.90
11/16 17.38 hex 9 7-3/4 200 150
Code 312354CartPrice € 8.90
3/4 19.05 hex 9 7-3/4 200 150
Code 312355CartPrice € 8.90
13/16 20.54 hex 9 8-1/8 210 150
Code 312356CartPrice € 9.90
Diameter Diameter Shaft Total Total Length Bore Depth CodePrice
7/8 22.19 hex 9 8-1/8 210 150
Code 312357CartPrice € 9.90
15/16 23.7 hex 9 8-1/8 210 150
Code 312358CartPrice € 13.90
1 25.4 hex 9 8-1/8 210 150
Code 312359CartPrice € 13.90
1-1/8 28.57 hex 9 8-1/8 210 150
Code 312360CartPrice € 14.90
1-1/4 31.75 hex 11 8-1/8 210 150
Code 312361CartPrice € 16.90
1-3/8 34.91 hex 11 8-1/8 210 150
Code 312362CartPrice € 24.90
1-1/2 38.1 hex 11 8-1/8 210 150
Code 312363CartPrice € 32.90
Diameter Diameter Shaft Total Total Length Bore Depth CodePrice
1-3/4 44.45 round 12 8-1/8 210 150
Code 312364CartPrice € 109.90
2 50.08 round 12 8-1/8 210 150
Code 312365CartPrice € 129.00
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