Hardware Size Selector
Pick the right drill bit, nail or wood screw size for the material and job, with metric and imperial sizes.
About this tool
Hardware Size Selector
Pick the right drill bit, nail or wood screw size for the material and job, with metric and imperial sizes.
Pick the hardware and the job and get a size that holds without splitting the material. This page brings together 3 separate hardware size selector pages (Drill bit, Nail, Wood screw) so you can compare them without hunting for the right one.
How to use Hardware Size Selector
- 1
Open Hardware Size Selector on AltFTool — it loads instantly in your browser.
- 2
Choose your hardware at the top: Drill bit, Nail, Wood screw. On a phone it is a drop-down list.
- 3
Fill in the hardware size selector for that hardware; each of the 3 options keeps its own rules, data and defaults.
- 4
Read the result, then switch hardware to compare. The page link keeps your hardware (?v=drill-bit), so you can bookmark or share it.
Why use Hardware Size Selector
All 3 in one place
Drill bit, Nail, Wood screw and the rest sit behind one picker, so switching hardware takes a tap instead of a new search.
Built for each option
Every hardware keeps its own rules, numbers and defaults rather than one generic template.
Shareable view
The link remembers the hardware you picked, so a bookmark or a shared link opens straight on it.
Common use cases
- Fixing a hardwood shelf without splitting the batten or shearing the screw head off
- Sizing nails to fix 19 mm boarding to a stud without splitting it or under-driving it
- Fixing an 18 mm plywood shelf through into a 44 mm softwood upright and needing the exact gauge, length and pilot drill
Frequently asked questions
Which hardware options does this tool cover?
3: Drill bit, Nail, Wood screw. Pick one at the top of the tool; the page link updates (for example ?v=drill-bit) so you can bookmark or share that exact view.
What size pilot hole do I need for a screw?
About 60% of the screw's outer thread diameter in softwood and 75% in hardwood. A 4.2 mm screw therefore takes roughly a 2.5 mm pilot in pine and a 3.2 mm pilot in oak. The denser the timber the closer the pilot must be to the screw's root diameter, because dense fibres split instead of compressing around the thread.
How long is a 16d nail?
3.5 inches, which is 89 mm, on an 8-gauge shank measuring 0.162 inches. Between 2d and 10d the length in inches works out as (d + 2) ÷ 4, so a 6d is 2 inches and an 8d is 2.5, but above 10d the series stops following that formula and the tabulated lengths take over.
How long should a wood screw be?
Long enough to bury about twice the thickness of the board it passes through, so roughly three times that thickness in total — an 18 mm board wants around 50 mm of screw. On a blind joint the tip should still stop at least 3 mm short of the far face, so a thin base board caps the length.