Bolt hole sizes 1

[rakes]

Is there a standard to be used when specifying bolt holes for metric screw threads? For example do I specify a hole dia of 6.3mm, 6.4mm or 6.5mm for assembling M6 coarse thread bolts? Does anybody know where I can get this information?

 

[israelkk]

You should use the smallest holes that allow assembly at all the tolerance variations. There is no standard for such issue. The hole dimensions depends on the geometric and positional tolerances of the assembled parts.

 

[tdalke]

http://www.csgnetwork.com/screwmetmachtable.html

 

[CoryPad]

Yes, there is a standard: ISO 273 Fasteners -- Clearance holes for bolts and screws

available at:

http://www.iso.ch

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[Cockroach]

Machinist Handbook calls this out.

Metric follows exactly the same principle as imperial, tolerances depend on the classification by fit: close, medium or loose.

Most drafting textbooks discuss this also.

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada