+/+ tolerances? 1

[MikeHalloran]

Bearing seat dimension is nominally 4.7244" diameter. The model is constructed that way. Now I'm tolerancing the drawing.

I want to show limit dimensions as 4.7251/4.7245.

SW was having none of it. When I put a negative value in the (-) deviation, SW seemed to take the absolute value. Sorry, I'm used to another package that interprets a negative value for a minus deviation to mean plus.

I was able to force what I want by giving SW an override primary value of 4.7245 (which it insisted on displaying as 4.725 within its dialog box), and specifying deviations of -0/+.0006.

Is there a better way to get SW to deal with press fits?



Mike Halloran
Pembroke Pines, FL, USA

 

[ctopher]

I have always used +/+, -/- and +/- tolerances on dwgs. Inspection, machinist and the customer need to know what the part is made to.

Chris
SolidWorks 07 4.0/PDMWorks 07
AutoCAD 06
ctopher's home (updated 04-21-07)

 

[dogarila]

Check Machinery's Handbook for Allowances and Tolerances.

I met machinists who couldn't understand +/+ and -/- tolerances. They didn't last long.

 

[drawoh]

MikeHalloran,

I model at the nominal and apply tolerances. I use the SolidWorks bilateral tolerances on my drawings. When I finalize them, usyally, I change them to limit dimensions. Sometimes, I forget.

I have not had a phone call from the shop about this. I have had people in-house discuss how to convert them to "correct" dimensions. This can get dangerous.

JHG