Carbide masonry drill bit sizes: the ANSI B212.15 hole tolerance for each size, SDS-plus and SDS-max shanks, and the bit size for each concrete anchor.
A masonry bit is a twist drill with a carbide tip brazed across its point, made to drill concrete, brick and block in a hammer drill. Its size is the diameter across the tip, which is slightly wider than the body. The shank must match the drill: a straight round shank for a chuck, or SDS-plus, SDS-max or spline for a rotary hammer.
| Nominal bit | D min | D max |
|---|---|---|
| 3/16″ | .198 | .206 |
| 1/4″ | .260 | .268 |
| 5/16″ | .327 | .335 |
| 3/8″ | .390 | .398 |
| 7/16″ | .458 | .468 |
| 1/2″ | .520 | .530 |
| 9/16″ | .582 | .592 |
| 5/8″ | .650 | .660 |
| 11/16″ | .713 | .723 |
| 3/4″ | .775 | .787 |
| 7/8″ | .905 | .917 |
| 1″ | 1.030 | 1.042 |
| 1-1/8″ | 1.160 | 1.175 |
| 1-1/4″ | 1.285 | 1.300 |
| 1-3/8″ | 1.410 | 1.425 |
| 1-1/2″ | 1.535 | 1.550 |
| Shank | Shank diameter |
|---|---|
| SDS-plus | 10 mm |
| SDS-max | 18 mm |
| Bit | Anchor | Anchor size |
|---|---|---|
| 5/32″ | Concrete screw | 3/16″ |
| 3/16″ | Concrete screw | 1/4″ |
| 1/4″ | Wedge anchor | 1/4″ |
| Sleeve anchor | 1/4″ | |
| 5/16″ | Sleeve anchor | 5/16″ |
| Calk-in anchor | #8 | |
| 3/8″ | Wedge anchor | 3/8″ |
| Sleeve anchor | 3/8″ | |
| Drop-in anchor | 1/4″ | |
| Calk-in anchor | #10 | |
| 1/2″ | Wedge anchor | 1/2″ |
| Sleeve anchor | 1/2″ | |
| Drop-in anchor | 3/8″ | |
| Lag shield | 1/4″ (long or short) | |
| Lag shield | 5/16″ (long or short) | |
| Calk-in anchor | 1/4″ | |
| Double expansion shield | 1/4″ | |
| Single expansion shield | 1/4″ | |
| 5/8″ | Wedge anchor | 5/8″ |
| Sleeve anchor | 5/8″ | |
| Drop-in anchor | 1/2″ | |
| Lag shield | 3/8″ (long or short) | |
| Calk-in anchor | 5/16″ | |
| Double expansion shield | 5/16″ | |
| Single expansion shield | 5/16″ | |
| 3/4″ | Wedge anchor | 3/4″ |
| Sleeve anchor | 3/4″ | |
| Lag shield | 1/2″ (long or short) | |
| Calk-in anchor | 3/8″ | |
| Double expansion shield | 3/8″ | |
| 7/8″ | Wedge anchor | 7/8″ |
| Drop-in anchor | 5/8″ | |
| Lag shield | 5/8″ (long or short) | |
| Calk-in anchor | 1/2″ | |
| Double expansion shield | 1/2″ | |
| Single expansion shield | 1/2″ | |
| 1″ | Wedge anchor | 1″ |
| Drop-in anchor | 3/4″ | |
| Lag shield | 3/4″ (short) | |
| Double expansion shield | 5/8″ | |
| Single expansion shield | 5/8″ | |
| 1-1/4″ | Wedge anchor | 1-1/4″ |
| Double expansion shield | 3/4″ |
Good to know
Use a bit made to ANSI B212.15 for anchors. Anchor makers call for it: the standard holds the hole a few thousandths over the nominal size, the hole their anchors are tested in. A worn or out-of-tolerance bit can cut an anchor’s holding power.
SDS-plus and SDS-max are not interchangeable. Each shank fits only its own chuck, whatever the bit size — match the shank to the rotary hammer.
Quick answers
- What size masonry bit for a 1/2 inch wedge anchor?
- A 1/2″ carbide masonry bit — a wedge anchor takes a bit the same size as the anchor.
- What size bit for a 3/8 drop-in anchor?
- A 1/2″ bit: a drop-in is named by its inside thread, and the hole is bigger than the thread.
- What size bit for a 1/4 inch concrete screw?
- A 3/16″ bit, per our concrete anchor chart.
- How big a hole does a 1/2 inch masonry bit drill?
- ANSI B212.15 holds a 1/2″ carbide-tipped masonry bit to .520″ – .530″ across the tip, a little over its size, so anchors fit the hole they were tested in.
- What is the shank size of SDS-plus and SDS-max bits?
- SDS-plus: 10 mm. SDS-max: 18 mm. The two are not interchangeable.