Probably this is quite challenging task to get appropriate font for technical drawings? After quick search it looks like a set of ISO standards or for the USA ASME standard is used most widely:
http://en.wikipedia.org/wiki/Engineerin ... mbiguation
In service of the goal of unambiguous communication, engineering drawings are often made professionally and expected to follow certain national and international standards, such as ASME Y14.5 and Y14.5M (most recently revised in 2009) or a group of ISO standards with similar content.
For ASME i found:
http://www.cad-notes.com/2012/10/what-i ... -and-type/
And an actual font that it looks like we would be able to use it in FreeCAD:
When it comes to ISO standards i know it's quite easy to find basic set of rules (size, line thickness...) but ready made fonts:
http://en.wikipedia.org/wiki/Engineerin ... _lettering
Technical lettering is the process of forming letters, numerals, and other characters in technical drawing. It is used to describe, or provide detailed specifications for, an object. With the goals of legibility and uniformity, styles are standardized and lettering ability has little relationship to normal writing ability. Engineering drawings use a Gothic sans-serif script, formed by a series of short strokes. Lower case letters are rare in most drawings of machines. ISO Lettering templates, designed for use with technical pens and pencils, and to suit ISO paper sizes, produce lettering characters to an international standard. The stroke thickness is related to the character height (for example, 2.5mm high characters would have a stroke thickness - pen nib size - of 0.25mm, 3.5 would use a 0.35mm pen and so forth). The ISO character set (font) has a seriffed one, a barred seven, an open four, six, and nine, and a round topped three, that improves legibility when, for example, an A0 drawing has been reduced to A1 or even A3 (and perhaps enlarged back or reproduced/faxed/ microfilmed &c). When CAD drawings became more popular, especially using US American software, such as AutoCAD, the nearest font to this ISO standard font was Romantic Simplex (Roman) - a proprietary shx font) with a manually adjusted width factor (over ride) to make it look as near to the ISO lettering for the drawing board. However, with the closed four, and arced six and nine, romans.shx typeface could be difficult to read in reductions. In more recent revisions of software packages, the TrueType font ISOCPEUR reliably reproduces the original drawing board lettering stencil style, however, many drawings have switched to the ubiquitous Arial.ttf.
It looks like the path of least resistance leads to Microsoft fonts... This is not that appealing in my opinion to rely on this fonts and i investigated a bit further and found ISO 3098 and actual font that might fit perfectly inside FreeCAD:
In some european countries, CAD projects must have font which conform to IS0 3O98 specification. Comercial CADs has this font, but free CADs not. There is no available free font yet, so this project will fix this. This font will be created completely from the scratch. Font is created with free tools like FontForge, Inkscape, Gimp. Font is distributed under GNU GPL licence version 3 with GPL font exception.
This two fonts probably could address majority of use cases and for users wanting to use something else like Arial or Sans Sherif... It's their choice indeed isn't it!