Hi,
Background:
We have bushings and "extremely fine" (M3 x 0.2 mm pitch) adjuster-set screws used in kinematic mirror mounts for some of or optical systems. The bushings are made of brass and the adjuster screws are made of 303 stainless steel. We have some design concerns and one of them is...
Hi,
I'm investigating the difference in precision between standard lathes and standard CNC milling machines, with respect to diametrical size tolerances and coaxial tolerances.
What are, typically, the tightest tolerances for each?
I'm an opto-mechanical designer and I'm currently designing...
As I understand it, the ISO 1101 Geometric Tolerancing standards do not recodnize Rule #1. How doe this approach work? I'ts hard for me understand since Rule #1 is such an important concept when using the ASME standard.
There is no such thing as perfect form at MMC?
All envelopes are to be...
As I understand it, a FOS must satisfy all of the following:
Contains opposing elements or surfaces (regular or irregular shapes).
Can be used to establish an axis, median plane, or a center point.
Is associated with a size dimension.
Then you hear about the "Caliper Rule", where you should...
Why was the ability to override Rule #1, with straighness on a FOS dimension, created in the first place?
I'm curious to hear other people's opinions.
Thanks,
Sean
In most cases, that I've seen, when referencing datums for a hole (for example), typically the datum perpendicular to the hole is the first datum referenced in the FCF, then the subsequent datums. Is there a particular reason or benefit in doing this?
Thanks,
Sean
A couple of questions on Runout,
1) It is my understanding that Runout surfaces are not defined with basic dimensions, rather, Runout is simply a surface call-out with tolerances withing the limits of size of the indicated surface. Is that correct? This is somewhat confusing since Runout is not...
Hi,
I'm designing a small flexure made of 440C. Is there a particular heat treatment used to maximize the spring-back characteristics?
Thanks,
Thanks,
Sean
Say you start with a square plate with 2 holes. The surface of the plate is identified as datum A, 1 hole is datum B and the other hole is datum C. Then lets say datum features B & C are not parallel (horizontal or vertical) to the edge of the plate.
Q: Since datums B & C are both axis, would...
How do you call-out Parallelism over multiple surfaces that are controlled within 1 common tolerance zone.
Can you simply call-out "x surfaces" under a Parallelism FCF and it's understood that all indicating surfaces are controlled simultaneously (similar to Flatness of multiple surfaces...
Hi,
I’m having a discussion about using the ‘BOUNDARY’ condition on a slot, and I am having trouble figuring out its benefit. I’ve read this section ('94), SEVERAL times and still don’t fully understand if one theoretical boundary is better than the other, particularly between;
(a) In Terms of...
Hi,
I'm looking for a good combination of stainless to stainless threaded materials that that will hold up well against wear and galling (Martensitic against Austenitic).
-High RPM's is not a factor.
-Lubrication is not allowed.
-Nitronic 60 has been considered for one element (Austenitic)...
I'm hoping to be able to use Nitronic 60 for a bushing to solve a wearing issue we're having with the current bushing made of brass.
Nitronic 60 seems ideal to prevent wearing and galling.
However, the thread size is M3x0.20 "extremely fine pitch". This thread is made by the manufacturer on a...
Can you use GD&T to establish and/or inspect a light source relative to datums of the physical part?
At my company, we detail external interfaces of lens assy's (lens housing with optical lenses internally), and we have vendors that develop the internal Optical Axis (OA). An OA is established...
Wondering if there is a general rule of thumb for max milling depth? I'm designing a fiber optics cover that is about 4" inches tall. Due to design requirements it’s going to be machined aluminum. I'm debating on whether it should be designed in 2 pieces, each 2" tall and assembled, or 1 piece...
Is "MAJOR DIA" placed under a position FCF, for threaded holes, something that should be done? Initially I was taught to do this from my first GD&T mentor. But I do not regularly see this and I can't find documentation to support this.
Thanks,
Sean
Are the segments of a multi-segment FCF to be written from top down (& not bottom up)
And if so
Does the lower segment of a multi-segment FCF have to be a refinement of the preceding segments (like a composite FCF)?
Thanks,
Sean
Is there a difference between the following call-outs?
A double segment FCF that states, for example:
Top segment: Perpendicular tolerance of .02 relative to datum -A-
Bottom segment: Parallel tolerance of .02 relative to datum -B-
and
A single segment FCF, for example:
Profile tolerance of...
