I was looking for a center offset marking gauge, but could not find a suitable one locally where I live. I saw that Rockler had exactly what I needed (https://www.rockler.com/rockler-center-offset-marking-tool), but alas they don't ship to South Africa it was cost-prohibitive to get the part shipped to me (US$10 vs US$10 plus US$40 shipping!). So I designed and printed a similar one! Total cost of approx. US$0.45 in filament, 1 day design time and 3.5 hours printing time :-)
There is already a similar type on TV by @tanialimacosta (https://www.thingiverse.com/thing:3570401), but I wanted the metric markings as well as the pencil holder clamp-fit similar to the original - I also wanted the pencil hole tapered to accept a wide range of pencils I use in my shop.
Further, I had a few spare rare earth magnets, so incorporated them into the design - they are 6mm wide by 3mm deep; glue them into the provided spaces with some contact adhesive.
So this is the result. Designed this morning, printed the prototype parts this afternoon, made some adjustments to the mm markings (as they were too small for a 0.4mm nozzle to cope with) and printed the final version this afternoon.
I split the printing into 2 parts, to avoid any supports, brims, etc - just print both parts, align the correct way (flat part to flat part, noting the correct orientation of the gauge markings which only fit correctly one way) and glue together with superglue or contact adhesive - clamp until fully dry.
Depending how accurate your printer is, as well as the first layer squish severity, you may have to file the gauge marking points slightly, however this tool is pretty much print, glue and use!
As I always work in millimetres, I've made the tool dimensions with the following gauge markings:
1.5mm, 2.5mm, 3mm, 4mm, 5mm, 6mm, 8mm, 10mm
The original Rockler is imperial with different gauge markings in inches - the SKP file is included, so feel free to convert and adjust the marker points if you want imperial measurements.
The pencil hole is made to take the standard and most common Faber-Castell, Staedtler or similar types (8mm diameter or less).
The tool's final printed size is 80mm (L) x 40mm (H) x 45mm (W). The space between the columns allows for use on wood up to 45mm thickness.
I've added quite a few pictures so you can get an idea of the 2 parts and the completed part, versus the original tool from Rockler. The only thing I didn't add was the holes for the pencil holder - I don't require this, but if you need it, please remix and post.
I hope others who are unable to buy this tool in their country find this thing useful, so enjoy and please like/comment/post a make if you download and make :)