FASTENER-FIRST DRILLING PLAN
What should I drill for this screw or anchor?
Choose fastener, material, and bit set. Get every hole in order.
#8 wood screw · Softwood · Join two boardsDefault preview
3-hole plan
Pilot
7/64 in
2.78 mm · exact size is in your 29-piece fractional set
Published guide
Conventional flat-head wood screw · source-scoped straight-bit starting points
LIVE HOLE MAP
Steps 1–3
See where each size goes
1
Clearance
11/64 in
top board
2
Countersink
3/8 in
top face
3
Pilot
7/64 in
receiving board
Step 3 · Pilot · receiving board · 7/64 in. In your 29-piece fractional set.
Drill in this order
3 operations-
1
Clearancetop board11/64 in 4.37 mmDrill through the top board.Lets the screw shank pass so the head can pull the two pieces together.Your set has 11/64 in
-
2
Countersinktop face3/8 in 9.53 mmStop when the actual screw head sits flush.Opens the surface for a conventional flat head; cutter diameter is published, depth is fitted to the actual head.Your set has 3/8 in
-
3
Pilotreceiving board7/64 in 2.78 mmDrill to the intended threaded penetration.Creates room for the screw core while leaving material for thread engagement.Your set has 7/64 in
PRINTABLE REFERENCE
Wood screw & Tapcon bit size chart
Use the visual planner for one job. Use this source-scoped table to compare sizes or print a bench copy.
Print includes both units
Swipe → Pilot sizes by material
Conventional flat-head wood screws
13 supported gauges| Screw | ClearanceThrough top board | CountersinkTop face | Pilot · softwoodCurrent material | Pilot · hardwoodReceiving board | Use |
|---|---|---|---|---|---|
| #2 | 3/32 in2.38 mm | 1/4 in6.35 mm | 1/16 in1.59 mm | 1/16 in1.59 mm | |
| #3 | 7/64 in2.78 mm | 1/4 in6.35 mm | 1/16 in1.59 mm | 5/64 in1.98 mm | |
| #4 | 7/64 in2.78 mm | 1/4 in6.35 mm | 1/16 in1.59 mm | 5/64 in1.98 mm | |
| #5 | 1/8 in3.18 mm | 5/16 in7.94 mm | 5/64 in1.98 mm | 3/32 in2.38 mm | |
| #6 | 9/64 in3.57 mm | 5/16 in7.94 mm | 3/32 in2.38 mm | 7/64 in2.78 mm | |
| #7 | 5/32 in3.97 mm | 5/16 in7.94 mm | 3/32 in2.38 mm | 7/64 in2.78 mm | |
| #8Current plan | 11/64 in4.37 mm | 3/8 in9.53 mm | 7/64 in2.78 mm | 1/8 in3.18 mm | |
| #9 | 3/16 in4.76 mm | 3/8 in9.53 mm | 1/8 in3.18 mm | 9/64 in3.57 mm | |
| #10 | 13/64 in5.16 mm | 7/16 in11.11 mm | 1/8 in3.18 mm | 9/64 in3.57 mm | |
| #12 | 7/32 in5.56 mm | 7/16 in11.11 mm | 9/64 in3.57 mm | 5/32 in3.97 mm | |
| #14 | 1/4 in6.35 mm | 1/2 in12.7 mm | 5/32 in3.97 mm | 11/64 in4.37 mm | |
| #16 | 9/32 in7.14 mm | 9/16 in14.29 mm | 11/64 in4.37 mm | 3/16 in4.76 mm | |
| #18 | 5/16 in7.94 mm | 5/8 in15.88 mm | 13/64 in5.16 mm | 7/32 in5.56 mm |
Exact concrete-screw products
2 core records| Product | Required bit | Supported substrate | Rule | Use |
|---|---|---|---|---|
| 3/16 in Original Tapcon | 5/32 in3.97 mm | Concrete · Masonry block / solid brick | Exact manufacturer bit · no substitution | |
| 1/4 in Original Tapcon | 3/16 in4.76 mm | Concrete · Masonry block / solid brick | Exact manufacturer bit · no substitution |
Source scope
Wood shank/pilot values: McFeely's; countersinks: Bolt Depot; exact concrete-screw mappings: Tapcon. Exact product instructions override this chart.
Reviewed 2026-08-16 · next review by 2027-02-16