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View Full Version : Anyone working their CNC to 2/10 of a Thousanth of an Inch



magicniner
29-07-2018, 11:46 AM
I do some lathe work in that region but nothing I make on the CNC mill requires that level of precision, anyone here doing that kind of work and other than Nuclear and Aerospace what requires it?

spluppit
29-07-2018, 03:09 PM
I just knew this thread was coming ...... it was a matter of when. :biggrin:

Well its is possible but as you know very expensive and in a grade we do not use in the Uk.... Youtube Engineering strikes again! It's very rare unless its in the tooling world or something extreme we need these kind of tolerances. In ally welllll thermal expansion will take core of that tolerance. Walk it out the room and its done.

We really need a guide post on here for drawing, general engineering knowledge and realism.

routercnc
29-07-2018, 03:15 PM
I assumed it was a typo and was 2 thou (undersized). That would be a fair tolerance for a press fit ball bearing in aluminium.

spluppit
29-07-2018, 03:18 PM
I personally didn't read it as a typo due to the rest of the text in the post....but its a fair point and you may well be right.

jamesgates1000
29-07-2018, 08:10 PM
I guess magicniner is referring to the latest RFQ that has been posted which calls for that tolerance. I have seen tolerances that tight on turned components but only rarely on milled components for the silicone chip industry. Seemed silly to me to have such tight tolerances in aluminium parts and always assumed it was due to an over zealous designer rather than a real need. Not to say we wouldn't achieve it but we would just price accordingly.

m_c
29-07-2018, 09:42 PM
I remember chatting to someone who had a repeat job producing pins with a tenth tolerances. After producing several thousand, he finally asked what they were for, that they required such a tight tolerance. Turned out they were for a nylon pulley, and the designer had mistakenly done the drawing using the template with the standard specs for their hydraulic components. The tolerance should of been a couple thou.

magicniner
29-07-2018, 10:13 PM
I remember chatting to someone who had a repeat job producing pins with a tenth tolerances. After producing several thousand, he finally asked what they were for, that they required such a tight tolerance. Turned out they were for a nylon pulley, and the designer had mistakenly done the drawing using the template with the standard specs for their hydraulic components. The tolerance should of been a couple thou.

:D Nice one!
I hope he was charging for "Tenths Tolerances" ;-)