2022-08-30
What size drill bit do I need for a 1/4-20 bolt?
What size drill bit do I need for a 1/4-20 bolt?
| Screw Size-TPI | Recommended Hole Diameter | Drill Bit Size |
|---|---|---|
| 1/4-20 | 0.2280″ | #1 |
| 5/16-18 | 0.2900″ | L |
| 3/8-16 | 0.3580″ | T |
| 1/2-13 | 0.4531″ | 29/64″ |
What size drill bit do I use for a 1 4?
US Tap and Drill Bit Size Table
| Tap | Fractional Drill Bit | Number Drill Bit |
|---|---|---|
| #12-24 | 11/64″ | 16 |
| 1/4″-20 | 13/64″ | 7 |
| 1/4″-28 | 7/32″ | 3 |
| 5/16″-18 | 17/64″ | – |
What is the diameter of 1/4-20 hole?
Tap and Clearance Drill Sizes
| Screw | O.D. | |
|---|---|---|
| 1/4-20 | 0.2500 | 0.2010 |
| 1/4-28 | 0.2500 | 0.2130 |
| 5/16-18 | 0.3125 | 0.2570 |
| 3/8-16 | 0.3750 | 0.3125 |
What does a 1/4-20 tap mean?
Example: 1/4 – 20NC The 1/4 represents the diameter of the thread in inches. The 20 represents the number of threads per inch or TPI. Standard taps are either standard coarse series threads NC (1/4-20), fine series threads NF (1/4-28) or extra fine series NEF (1/4-32).
What size pilot hole should I drill for a 1/4 lag screw?
Drilling Lag Screw Pilot Holes
| Pilot Hole Size for Softwood | Lag Screw Diameter | Pilot Hole Size for Hardwood |
|---|---|---|
| 3/32″ | 1/4″ | 3/16″ |
| 9/64″ | 5/16″ | 7/32″ |
| 11/64″ | 3/8″ | 1/4″ |
| 1/4″ | 1/2″ | 11/32″ |
How Big Should you pre drill a hole?
As a general rule, a pilot hole should be the same diameter as the neck of the screw. A common mistake woodworkers make is drilling the pilot hole too small, thinking that the screw will hold better in a tighter space.
