Home
- What's New: home page and list of updates to this site.
- Site Index: a list of all of the page on this site.

Vim Scripts
- TagHighlight: highlighting of typedefs, #defines, enumerated names etc in Vim.
- EasyColour: colour schemes made easy!
- Bandit Colour Scheme: a colour scheme for Vim.

Metalwork
- Introduction: an introduction to the metalworking pages on my website.
- My Workshop: some information about my metalworking workshop.
- Mini-Lathe: improvements and tooling for my mini-lathe.
- SX3 Milling Machine: improvements and tooling for my milling machine.
- Harrison M250: improvements and tooling for my Harrison M250.
- Grinder: improvements and tooling for my bench grinder.
- Bandsaw: improvements and tooling for my bandsaw.
- Welding: projects related to welding.
- Miscellaneous: metalworking-related stuff that doesn't fit elsewhere.
- Metalwork Calculators: a selection of on-line calculators related to metalworking.
- Metalwork Data: some useful data for metalworking projects.

Woodwork
- Introduction: an introduction to the woodworking pages on my website.
- My Workshop: some information about my woodworking workshop.
- Hand Tools: hand tools and accessories that I've made.
- Power Tool Accessories: power tool accessories that I've made.
- Benches: benches that I've made.
- Furniture: furniture that I've made.
- Boxes: boxes that I've made.
- Outdoor Projects: outdoor projects I've done.
- Other Projects: woodwork projects that don't fit into the other categories.

3D Printing

Software
- ARPCalc: a powerful reverse polish calculator.
- Digraph: a simple tool to make symbol entry easier when typing.

Useful Tools and Notes
- Google Maps to GPX: a tool to create route plans for your GPS with Google Maps.
- GEMF Format: a format for efficiently storing map tiles for use off-line on smart phones with FAT32 or similar file systems.
- Ebay Seller Blacklist: a browser plug-in to allow you to blacklist bad ebay sellers.

Tap Drill Sizes

The general rule of thumb for tap drill sizes (with 75% thread engagement) is to take the diameter (e.g. 10 mm) and subtract the pitch (e.g. 1.5 mm), giving the tap drill size (e.g. 8.5 mm). However, in some cases it is useful to either reduce the thread engagement (for example when tapping in hard materials) or increase it (for example when tapping thin materials).

This calculator allows you to adjust the thread engagement percentage and see the corresponding tap drill sizes for thread cutting and thread forming taps.

Thread Engagement (%):
Custom Thread Diameter (millimetres):
Custom Pitch (millimetres):
Show Only Coarse Threads:

Thread Cutting Taps:

Thread Forming Taps:

This website is free, but costs me money to run. If you'd like to support this site, please consider making a small donation or sending me a message to let me know what you liked or found useful.