Quick and dirty way of creating nut thread for bolt with some clearance?

I am not creating an actual bolt CAD file, just drawing something and wish to show where in it the nut/bolt array go., but just for appearances sake, rather than just boolean difference the nut hole out of a closed surface nut with the bolt, If I clone the bolt and offsetsrf then Boolean Difference with the nut that should suffice for appearance, wondering what ‘approx’ clearance to apply and does it vary per thread diameter in the real world or is it same clearance for a range of shaft/thread diameters ?
bolt thread/shaft diameter is 0.375inch

BOLT clearance on nut.3dm (2.0 MB)



The Bolton plugin for Rhino generates nuts or threaded holes with the correct clearance.

Although that only covers mainstream bolts, not much use if you are modelling an archaic thread.

Edit: Duh, speelcheckers: Bolton should be Boltgen

Whitworth was the standard in the UK and still one can buy Whitworth. Does it deal with Whitworth as my subject matter being 80 yrs ago is Imperial fasteners Whitworth etc.


Hi @Steve1,

Boltgen creates imperial bolts to the UTS (i.e American) standard: i.e. UNC, UNF & UNEF). I believe UNC and Whitworth have the same thread pitch, but the thread profiles are slightly different. Also the AF dimension of a UNC bolt of a specific diameter falls between the “Pre-war” BS 190 Whitworth size and the smaller BS 1083 size introduced during the war to save metal.

For example a 1" UNC bolt requires, I think, a 1.5" AF spanner, A BS 190 Whitworth needs a 1.67" AF and a BS 1083 Whitworth needs a 1.46" AF spanner. Depending on the accuracy you need the UNC might be close enough.

(thanks Wikipedia.org)