For sliding steel parts that need to have good resistance to jamming after being "dropped in the dirt" what magnitude of clearances are generally considered better, tighter (.001 -.003") or looser (.015-.020")?
My application would be similar to a rifle design where only so much can be done to...
I haved a large assy file (NX8 and Teamcenter)and after about 3 weeks of work it developed an error that says something like "null pointer....". Or inhouse guru said it was probably because I have a Lightweight PMI Section view and those are known to generate errors.
Do others here agree with...
Is there a setting for accuracy that can be dialed down a bit? How do you do it? I'm finding that slight imperfections in part models I have keep constraints from being applied in ways that work on perfect parts, so hoping this might help.
I need to have custom jam nuts made as the mating parts have an extra fine J thd and these need to match and no common std parts of suitable quality exist. Need 50 each of these, .3125-32 UNJEF thd, .50 across flats, about .28 thick made of A286 STA. Program rules require parts list to call out...
I used this one recently but it did not behave as expected. I "bonded" a nut and washer to a bolt which was constrained to a hole in another component. When I changed arrangements the bolt moved with the part to which it was constrained but the nut and washer stayed in original position. The...
We always throw around the well worn phrase that tighter tolerances increase costs. I can understand that in many respects but what about the cost of inspection fixtures, like shown in the link, that have to be an order of magnitude more accurate than the part itself? On a low quantity purchase...
I have a large contoured part made of uniform thk material which will have 70 countersunk holes. (picture a 1960's era car fender made of thick material) All three datums (A,B,C) will be established by target points and few if any holes will be normal to any datum but all holes need the...
Anyone aware of an industry spec that defines a mold in place seal similar to a Parker gask-o-seal? I have an application where O-rings are an installation risk and would like a seal molded into Alum parts. Program requirements do not allow calling out supplier trade name materials and...
I have another cone shaped part in work and cannot find a set of features that make clear practical datums. Can't even get a set of points on this curvey thing that I think will be repeatable with good accuracy. I'm thinking of adding three small bosses and a hole to function as datum features...
I was hoping to have someone sanity check my calculation. I just need a decent ballpark estimate of how much air will flow thru a 2 inch dia opening in a large irregular shaped volume. Air at 7 psig inside and 0 psig outside. I got 60 scfm? Is that close?
For those who have to inspect and approve parts with illegal or impractical GD&T, how do you deal with it? I regularly see designs with illegal GD&T and yet we have parts made, delivered, accepted by our QC and put into use. I asked our inhouse Mfg advisor about this and he is convinced that...
I'm working on a set of curvey parts that do not have the easy orthogonal surfaces to pick as datum features. There are flat surfaces that are functional but they are at skewed angles to each other. If I pick one for A and one for B does that lock up all degress of freedom? Also, how do you...
Is there a way to make different faces of a solid different colors in different saved views? I want the solid to have a single color in all views but then add a view called COATINGS that will show the four final colors of the various faces. Is this possible in NX 6?
Hi all,
I'm the stuckee for the design of a conical shaped part and out of my league for determining suitable datums and tolerances. I attached a simplified pic that covers the main points for now. We work to 1994 ASME std and use Model Based Definition (MBD) which means means that you query...
I'm using the above terms in a dimensioning scheme but not sure I am doing it correctly. We use 1994 std. Can't post a pic due to proprietary rules but will try to describe. Assume A/B/C on perpendicular faces of a rectangular part. Say I have a pattern of 4 each .250 dia holes and this pattern...
I am working on a design that when finished looks like a circular plate with T shaped stiffeners (like wheel spokes) 30 degrees apart. All the T stiffeners are oriented to run thru the center of the circle plate. The top (flange) of the Tees are 3 inches above the plate. This part to be...
I used to have a Associated Spring design guide that would advise these things but the online references I have found do not include a way to get these specifics. I am looking at a compression spring (square ground ends) .240 dia, .018 wire, 2.0 free ht that will apply load to a locking pin...
Years ago there was the idea that most machined parts tend to be produced closer to MMC, the supporting reason that machinists worked that way to avoid rejects due to excessive material removed. I'm evaluating some fits of spherical bearings into bores that were not optimally sized and...
Looking thru a couple of supplier catalogs, the bearing OD to installation hole fit was recommended by some to be .0002" min clearance while another says min interference of .0003". We will purchase these bearings from MS part no., so don't know what supplier, could be multiple ones and the...
In attached sketch, I want to have the two .752 holes located +/- .004 dia to each other and perpendicular to datum A .001 dia. Then these two holes become datum B to locate the .252 dia hole. (We use model based definition where CAD file is queried to get dimensions that's why no dim are shown...
