How Big
How Big
(OP)
Hi Guys,
I'm designing some basic things but I need some clarification regarding the gap that I should leave. If I have a cutout and then into that cutout I insert another part of the same shape, how big a gap should I use? If you add paint, the part that I'll be inserting will become larger, also, CNC machines aren't exactly perfectly precise so this needs to be taken into consideration also, any helpful hints, ideas or links to sites that talk about this?
Thanks.
I'm designing some basic things but I need some clarification regarding the gap that I should leave. If I have a cutout and then into that cutout I insert another part of the same shape, how big a gap should I use? If you add paint, the part that I'll be inserting will become larger, also, CNC machines aren't exactly perfectly precise so this needs to be taken into consideration also, any helpful hints, ideas or links to sites that talk about this?
Thanks.





RE: How Big
RE: How Big
RE: How Big
RE: How Big
What is the tolerance on the CNC parts?
If any of the frame parts are welded, then what is that tolerance?
What happens if you have a gap? Do you worry about water intrusion or not? How much of a gap is too much?
"Art without engineering is dreaming; Engineering without art is calculating."
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RE: How Big
You also need to understand if there are any functional constraints beyond simple fit.
When dimensioing take into account not just the impact of nominal size but also how variance in angle etc. can play into it - use of surface profile potentially simplifies this but not clear you're familiar enough with dimensioning & tolerancing yet to take advantage of that.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: How Big
Preparing dinner
How much time in the oven
Salad is on fire
All in good fun.
RE: How Big
What do you want to accomplish?
The Machinery's Handbook has a section on ANSI limits and fits, which I use extensively. How accurately do you need to locate stuff? Are you trying to seal something?
--
JHG
RE: How Big
Nescius,
That haiku was awesome.
John Acosta, GDTP Senior Level
Manufacturing Engineering Tech
RE: How Big
Microns, thousandths, mm's, hectares......take your pick.
What's the cost of being wrong, anyway?
Proud Member of the Reality-Based Community..
To the Toolmaker, your nice little cartoon drawing of your glass looks cool, but your solid model sucks. Do you want me to fix it, or are you going to take all week to get it back to me so I can get some work done?
RE: How Big
Thoughts?
John Acosta, GDTP Senior Level
Manufacturing Engineering Tech
RE: How Big
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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.
RE: How Big
RE: How Big
Berlanger - there's a nice TED talk on being wrong. The presenter asks some people in the audience what it feels like to be wrong and they answer that it feels unpleasant. Then the presenter says that's what it feels like when you find out; that just being wrong can feel just like being right.
https://www.ted.com/talks/kathryn_schulz_on_being_...
This should have been taught in school.
RE: How Big
That's why I love this forum so much. Thank you.
John Acosta, GDTP Senior Level
Manufacturing Engineering Tech
RE: How Big
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
RE: How Big
Fortunately, since I do thousands of things every day, the chances that I will get one of the really risky things wrong is pretty small.
STF
RE: How Big
No, not trying to seal anything, not welding anything, not designing any punch presses and nothing to do with liquids. Just designing both static parts and dynamic parts and would be nice to have something other than a guess to estimate gaps.
Just general design work i.e looking for info that will serve me in a wide variety of design problems.
MadMango - Not sure what type of paint at this stage, most likely automotive. But as I mentioned, not talking about clearances just for paint coatings.
KENAT - sumed it up nicely.
drawoh - Machinery's Handbook - had a quick look at it, have realised that a quick look is not enough :), will look into it some more thanks for the suggestion.
RE: How Big
You literally just defined every part in the world. They're all either "static or dynamic" so yea... your answers will usually only be as good as the question.
RE: How Big
Diego
RE: How Big
Fair comment, I guess I was asking for pointers on where to read up on tolerances in general. Got a couple of leads so got the answer I was looking for.
RE: How Big
Now there is a question folks can seriously respond to.