Rule #1 leads us to Full Form Check at MMC / 2-Point Check at MMC for RFS and MMC controls; it also tells us to do Full Form Check at LMC / 2-Point Check at MMC whenever the feature control tolerance or datum reference is made at LMC / LMB. Most people aren't aware of that second part as it...
I haven't heard from Dave since I left S.Ont 5 years ago. I know he'd been talking about retirement for a long while before that. He was quite hale & hearty last time I saw him, and he left our coffee-shop meeting to go roller blading with his wife.
Jim Sykes, P.Eng, GDTP-S
Profile Services...
I'm not sure if members of this forum have heard, but Don Day (Prof Don) passed away last month after a lengthy fight with brain cancer.
Don was a friend and mentor to me for the last 15 years. He provided the first useful training in GD&T that I received, and was a resource to me and many on...
Please add a cross-section of the members to your drawing, then re-post.
Jim Sykes, P.Eng, GDTP-S
Profile Services www.profileservices.ca
TecEase, Inc. www.tec-ease.com
Likely bad practice, BUT ... Is it a GD&T drawing? If it is a Y14.5 drawing and the dimensions all can be chained back to the datums using basic dimensions, then it's technically ok if still bad drafting practice.
Jim Sykes, P.Eng, GDTP-S
Profile Services www.profileservices.ca
TecEase, Inc...
Pmarc,
I understand your example, and again it is a good one. I like that you challenge me because it makes me rethink things and improve my communication. I was never taught to use a no-go gauge as a blind tool though; part of hard-gauging is still the visual aspect, so if any gap extends...
My apologies, gents, and thank you for the graphic, pmarc. I think that my mental gaff there comes from my mental bias towards using CMMs for verifying profiles, which is stupid because I teach people how to check profile in open-setup. CMMs still don't address datum shift in a profile callout...
Pmarc,
I'm fuzzy minded lately from helping kids with high school exams ... seemed a lot easier when I did the material first time around! IF you had a no-go gauge for the outer boundary of a profile control, wouldn't that work? I.e. the gage element cannot fit in the slot or else the slot is...
From a design perspective, Dave, slots are generally clearance features (i.e. the center of the slot isn't the critical aspect). So, controlling the surfaces (as with a Surface Profile) makes more sense. Position at MMC gives you a single goundary for the slots, but profile will give you both...
Simultaneously, as they are a pattern based on the quantity callout.
Jim Sykes, P.Eng, GDTP-S
Profile Services www.profileservices.ca
TecEase, Inc. www.tec-ease.com
If I ever saw data come across my desk as you propose, I would reject the lot, and probably cancel the contract. I have delisted and back-charged suppliers for invalid inspection. That is NOT what the callout means. If you elect to inspect it using an RAME pin, then your numbers are invalid...
The MMC modifier (not MMB because this is a pre '94 drawing based on the datum feature identifier symbols used) on the Datum-B reference in the profile control is of no value here. Profile is a surface control. While the standard doesn't say that the MMC modifier is illegal in this case, it...
I'm not sure what you're really looking for. Unilateral profile tolerance? If that's the case, then '09 has the Circle-U modifier available. For '94, you need to use offset chain lines to show which side the tolerance zone applies wrt the basic geometry.
Jim Sykes, P.Eng, GDTP-S
Profile...
The Web Course is a timed availability agreement, and you access the training through the internet. The Software is a copy that you keep permanently and is licensed to one computer only, so it will not run on another system once uploaded to the first computer. You can, of course, have other...
J-P,
I can see both of those reasons being true. The second one, as I'm sure it does to you, saddens me. It is something of a false sense of security. When I saw the difference in BOK and was able to tell the certification level of people during a technical conversation, I knew the path for...
