Is this threaded hole perpendicular?

[rbraithwaite]

Good morning,

Please be advised my knowledge is very limited as I am not a trained engineer. I have had some aluminium parts milled that include a threaded hole as per the attached image (drawing.jpg) taken from the drawing.


However, when I thread a rod into the holes it appears visually not to sit perpendicular to the surface. I have tried checking the 'squareness' by using a square and measuring with a protractor; you can see from the second image (protractor.jpg) that the angle is a few degrees from 90.


The issue I have is that I do not know what tolerance is acceptable and whether I should reject the part or have to accept it; this is because I do not have the skills to imterpret the symbols on the drawing. I told the supplier I think they are out of square and they say they are fine.


Can anyone please advise? E.g. does perpendicular mean perpendicular, or is there astandard acceptable tolerance, e.g. +/- 1 or 2 degrees? Also, how can I accurately measure the perpendicularity of the threaded hole, or is there a company that I can send the parts to to be analysed or a specific instrument that should be employed?


Many thanks for your time.

[rbraithwaite]

have also just seen the attached that states +/- 2 degrees. Does that mean hole doesn't ahve to be spot on 90 degrees but anywhere between 88 and 92 is okay?
notes.jpg

[Kelly_Bramble]

There's so much to unpack here for you - I'll try..

The geometric tolerance specified on the engineering drawing is the final requirement and supersedes the title block. The title block tolerances are when there is no other tolerance is specified for a feature or features.

The tolerance specified for that thread only applies to the thread feature within the material - not any feature or part that projecting out of the part.

The method you show is not how that thread is to be measured - the axis of the thread as derived from the pitch cylinder is where the
position a tolerance of dia. 0,2 is measured to relative to datums A, B, and C.

You need a dimensional metrologist (Inspection professional) to inspect / measure this for you using either a CMM or even open setups with dial indicators or micro-height.

You appear to way out of element here - you really-really should read up or get training on ASME Y14.5-2018 and/or ISO 1101.

This engineering forum is not where you should attempt to train your self in GD&T or G&T.

Good luck..