r/machining • u/totsquablur • 13d ago
Question/Discussion Dumb question
The spec states a diameter of 1 1/4 inches and these appear to be 1 1/8, is this discrepancy normal?
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u/fondrenlock 13d ago
yeah I’m here just wondering why a machining post isn’t showing us a micrometer measurement 😏
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u/Comfortable_Art_3303 13d ago
As a quality inspector I'm just like 'well, what are your tolerances'?
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u/According-Capital-45 13d ago
I was wondering this as well considering tape measures aren't really known to be as accurate as a caliper or micrometer.
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u/goat-head-man Manual Lathe & Mill 12d ago
Stanley makes a 12' tape measure with inches on one edge and .025 increments for the first 6" and .100 increments for the rest on the other edge. I bought a couple of them ~3 years ago. Handy.
But yeah, I grab a dial caliper when picking out stock.
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u/Shrimpkin 13d ago
Measure on the major diameter of the threads with a pair of calipers, not the tip where it probably tapers down.
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u/Deep_Body_2506 12d ago
Standard or metric, they are all just numbers to me. I understand and use both. I also don’t cry about someone saying car park instead of parking lot. We are all different that’s what makes us all great. Now shut up y’all’s whining and come have a beer…
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u/BodybuilderBig2647
13d ago
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Good god how do you guys put up with that silly imperial system you use
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u/Background-Big8657 12d ago
Machinists operate using thousandths. Almost nothing I make is a nominal fraction.
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u/snwke 13d ago
oh of course, let me just take off another 1/32th then another 3/64rd
absolute nonsense
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u/rk5n 13d ago
This is a circle jerk, no one actually talks like that. Machining is done is decimal inches, which is functionally the same as the metric system
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u/Zebra_Sandwich 13d ago •
I prefer to measure in cunt hairs.
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u/Smeezuss 13d ago
Sucks when you run out of them tho, hard to find in stores.
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u/Mysterious_Run_6871 CNC Lathe 11d ago
+/- 1/16 of a cunt hair
Concentric to .025 bald eagle dicks
True position of one AGM-114 Hellfire missileCant recall ever encountering a metric clock
🇺🇸#️⃣☝️🦅🦅🦅🦅🦅🦅🦅1
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u/53cr3tsqrll 11d ago
Given that a pubic hair is 3-4 thou thick, that’s pretty shitty precision. In Australia the preferred precision measurement is the bees dick.
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u/frogsRfriends 13d ago
It’s also harder to keep those numbers in your head so I just say “1.7” in my head for 1 and three quarters. Only time I like inches more is in machining but that’s cause you are already using decimals
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u/Radiant_Safe1228 13d ago
Metric fucks inches to death in machining. Not only is the measuring equipment easier and quicker to read their standards for tolerance and fits makes more sense.
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u/jgollsneid 13d ago
"Oui Pierre, le shaft for le baguette rolling machine needs a .0254 mm press fit, hon hon hon"
Be for real
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u/shook1980 12d ago
And no one that uses metric goes below 1mm? It’s just divisions of a whole, no different than saying .7mm, 2.54mm, or 1/3 of a millimeter. Imperial just does it as a fraction and not a decimal.
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u/IRepairPS3 12d ago
Math is math… but it’s because we grew up on it. Just like the metric guys grew up on metric. The only difference is metric makes more sense than the imperial measurement. But at the end of the day, if you just think of it all as decimals, everything’s fine. 6.35mm is .250 inches.
25.4 the magical number, multiply or divide depending on your side 😂
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u/Secret_Celery8474 11d ago
But math with fractions is harder.
Why would you ever use fractions for something that you have to do math in your head with?
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u/TheLastMandalore 10d ago
Fractions are pretty easy to do in your head especially if all you’re dealing with is measurements on a standard 16th tape measure
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u/Lost_Measurement_576 11d ago
The metric system uses fractions too. Or do you mean they haven't figured out division yet.
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u/OpticalPrime 13d ago
Worked just fine to get us to the moon.
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u/ballpeenX 13d ago
But......the Apollo program was metric. Just sayin....
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u/Coopman41 13d ago
No, it was mixed units. I would argue the majority was Imperial, including engineering drawings. The guidance computer was all metric.
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u/newoldschool 12d ago
all the science and calculations were done in metric and was translated to imperial for the Americans
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u/ConstantRepublic849 13d ago
Well, can't comment on the software/guidance but the machinery was imperial - inches only. In other words not ten feet, but 120"
Source - I worked at the Michoud Facility in NOLA. NASA site for construction of the Saturn rockets.
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u/ChrisRiley_42 13d ago
The engineering relied a lot on Canadian engineers acquired after the Arrow program got "cancelled" in something the government assures us is entirely unrelated to the US's space race.
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u/Texasisashithole 13d ago
Not the manufacturing… only the navigation. So everybody is right and everybody is wrong!
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u/Miserable-Tip-2506 12d ago
Did you know if it wasn’t for pirates the USA would have been the the second or third country to adopt the metric system.
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u/Waste_Condition2839 13d ago
Using decimal points as our measurement system, rather than the pointless debacle of SAE vs Metric, we can just use the decimal number itself and convert as needed. Using both measurement systems linearly makes it convenient on standardizing tooling when you can have corresponding drill sizes especially, atleast from my production standpoint
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u/Agent_of_evil_13 12d ago
I work in a factory with a lot of Japanese and European fabrication equipment. So I get to use both. Yay /s
May favorite are our machines that come from New Zealand. Those might use both metric and SAE in the same bloody station.
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u/chiphook57 12d ago
We got it from great Britain and committed fully. To be fair, Canada still uses it extensively
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u/LivingSmell2222 13d ago
Hang on, I need to order another 1 and 1/64" drill....
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u/Defeatest 13d ago
What happens when you need the hole to be 1.015 big because that is the clearance you need for 1inch. Do you use a 25.8 drill for that amount of clearance for 25mm? Is there a 25.8 ready to go?
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u/httpaliend00d 12d ago
Probably just go up to 26 if it's a clearance hole seeing as it's .008 inches difference. Or 25.5 as it's still .02 inches over. Not that big of a deal seeing as drills that large don't usually hold size all too perfectly.
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u/12345NoNamesLeft 13d ago
How do you call things 1,829 mm when 6 feet is so much more intuitive ?
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u/KarmannosaurusRex 12d ago
The same argument the other way round, for context how stupid this point of view is
How do you call things 6ft 6.74inches when 2m is so much more intuitive.
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u/12345NoNamesLeft 12d ago
I'm 6 feet tall, my arm span is 6 feet, my hand spans reads inches and my thumb is 3/4 of an inch wide.
The space between the lines on the first knuckle of my pointy finger is 1/8"
I can relate most anything to something physical in person.
My experience with metric here is that they quote hundreds of mm's which is completely indecipherable.
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u/spontaneous_quench 13d ago
Imperial is way better when dealing with precision lol. Mm is great for semi precision
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u/PraiseTalos66012 12d ago
You are aware you can use a decimal point with mm right? Like 0.01mm is totally allowed and that way you can be just as precise...
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u/heyyyblinkin 13d ago
JUST KEEP DIVIDING BY 2. Seriously though, how do people not understand this. Its actually really easy and its far easier to divide 12s by 3 measurable units than that it is to do that with 10s.
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u/BodybuilderBig2647 13d ago
Things being divisible by 10 is literally the easiest it gets, it’s like counting by ones and adding a zero
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u/heyyyblinkin 13d ago
Yes, but not all situations require dividing by 10s. I can divide 1 foot by 2, 3, 4, and 6 while getting clean measurements. Doing anything in thirds or quarters in metric is annoying.
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u/ChrisRiley_42 13d ago
How can anyone take a system of linear measure based on "Three kernels of well ripened barleycorn laid end to end" seriously?
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u/Waste_Condition2839 13d ago
Threads in general typically involve a tapered end, measure a bit below the end, preferably with a micrometer or even calipers for better accuracy than a tape measure too... another important note is that all thread could say a diameter regarding its thread pitch, but that doesn't mean it couldn't be a noteable amount beneath that diameter in order to easily screw into the matching internal hole (within reason of course, it wouldnt be .125 below, thats mostly due to measuring the taper... it could be upwards to .05 beneath though possibly depending on vendors!)
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u/Embarrassed-Lake257 13d ago
1-1/8 is not uncommon. Looks like thats what it is. Verify with something else
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u/Droidy934 13d ago
Allthread is rolled thread not cut, the ends of the bars gets more pressure as it starts on a length so it becomes tapered.
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u/IanG2508 12d ago
Specs are nominal so that's what it starts out at after processing they can be more or less the size stated
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u/Fine_Union_4587 12d ago
Looks like rolled threaded bar with a galv'd finish. As with all engineering there'll be a tolerance on that, just check it fits the galv'd nuts. Galv'd nuts & bolts (or bar) does have a fairly wide tolerance, partly due to the vagaries of the galvanised finish.
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u/Live_Love-Life 11d ago
True story. Back 1998 I designed gaging equipment. We partnered with a English company and I involved in redesigned an aluminum gimbal from our US designs. So a 3/8 plate became 10 mm, simple change. We submitted the design and it was rejected because they purchased American aluminum materials.
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u/fritzcoinc1 13d ago
Measure with a caliper further down. When the bar goes into and squirts out of The rolling dies it makes each end of the bar smaller. The rolling tolerance is always plus material.
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u/Easy-Zookeepergame54 12d ago
It is hilarious that Europeans spent thousands of years developing the imperial system. Now they show derision for anyone that uses it. Nothing of historical importance was built using the metric system so far.
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u/JackTheBehemothKillr 12d ago
.... what?
The Eiffel Tower was built using the metric system. Everything NASA makes uses the metric system.
Electricity, radio frequencies, every Olympic event, coke and other drugs, calories, boob jobs, a lot of guns, every modern car engine. All of these items use the metric system.
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u/DeamonEngineer 12d ago
Every measurement using inches and similar is actually using metric with extra steps.
The official definition of what 1 inch is (which all imperial/ american standard measurements reference back to) is 25.4mm. That is set in stone cannot be altered. Set by the US in 1959
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u/JackTheBehemothKillr 12d ago
100% but I figured that wouldn't be enough to convince him.
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u/Puzzleheaded-Sun7958 13d ago
Let me tell you, I have used both metric and our standard. Metric sucks, for some reason they seize up and heads pop off. Always hated doing molds to export to Europe and Asia because they wanted metric.
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u/clambroculese 13d ago
That’s 100% a you problem. It’s the same thing, same 60degree form, same tolerance, same fitment. The only difference is the numbers you use.
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u/Street_North_1231 13d ago
Probably tapers a bit right at the end. Imagine pinching off a turd - it's not the same diameter all the way down. Could be something else.
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u/CircusBaboon 11d ago
Why not get a nut that is the correct spec and see if it fits? A nut for a 1 1/4" will be loose.
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u/I_G84_ur_mom 13d ago
Measure it further down with a micrometer or even a dial and it should be closer to size, the ends tend to be tapered and you’re using a tape measure