how many millimeters is this thread?

[scotty38]

I mix and match all the time. Plenty of times I'll measure something and say it's 150mm by 31/2 inches....

[Ratlet]

1/4 in unc I think.

[Guest]

2 hours ago, 900SL said:

When I worked in the Caribbean all the house designs were in feet and inches. It was a nightmare to start with, but I eventually got my head round working in Autocad to base 12  

As long as it is 16 on center you are good to go lol 

[Kimboman]

Hi I use a one quarter  British standard Whitworth bolt on my Celestron mount to  secure it to other tripods if you can’t find one pm me and I will send you one 

there is 2and a half 1 and 3quarters 1 and a quarter 

[saac]

2 hours ago, Mike Q said:

Here is the brutal honesty about metric in the US.  We see it..... A LOT.  I see it everyday at work.  Its in anything manufactured.... Cars, appliances, you name it.  Its on our speedometers right along with mph.  We just prefer not to use it.  Our tool sets, you guessed it will have SAE and metric in them.  So we are ready for what happens to come along.  The one place you dont see it much... Road signs.  Its been years since i have seen a roadsign that says how many km to wherever you are going 

Mike, that's basically how it works here (UK) too. Ask most folk their height or weight and they will respond in feet and inches or in stones and pounds. As for road distances and measurements of alcoholic beverages well we too stick to imperial here so miles, miles per hour for speed limits and I could see a revolution happen if pubs were forced to sell beer in anything other than pints.  Petrol is priced in litres now but I think most folk still think about fuel in gallons and miles per gallon  - km per litres just sounds so wrong.  I still go into a sweet shop and ask for a quarter (8 oz) of loose sweets and not 4 oz. Industry however by and large uses SI except for one or two niche areas. 

Jim

Edited May 5, 2023 by saac

[Guest]

1 minute ago, saac said:

Mike, that's basically how it works here (UK) to. Ask most folk their height or weight and they will respond in feet and inches or in stones and pounds. As for road distances and measurements of alcoholic beverages well we too stick to imperial here so miles, miles per hour for speed limits and I could see a revolution happen if pubs were forced to sell beer in anything other than pints.  Petrol is priced in litres now but I think most folk still think about fuel in gallons and miles per gallon  - km per litres just sounds so wrong.  I still go into a sweet shop and ask for a quarter (8 oz) of loose sweets and not 4 oz. Industry however by and large uses SI except for one or two niche areas. 

Jim

That stone thing.... Yeah i am giving that a hard pass LOL.  

[saac]

Just now, Mike Q said:

That stone thing.... Yeah i am giving that a hard pass LOL.  

14 lbs.  I know my weight in stones and lbs without much thought but never think of the kg equivalent. Don't know why just habit, the conversion is easy enough.  

[Guest]

1 minute ago, saac said:

14 lbs.  I know my weight in stones and lbs without much thought but never think of the kg equivalent. Don't know why just habit, the conversion is easy enough.  

Our stones are bigger.  I weigh one stone.  Which is 203 pounds LOL.  We have a couple old school measurements left over as well.  Rods is the one that always comes to mind. Nobody measures in that anymore, at least not in the normal daily run of the mill stuff.  

[saac]

2 hours ago, Louis D said:

Having grown up in the 70s/80s in the US, we were constantly told to be ready for the inevitable switch to the metric (SI more properly?) system.  It never happened.  The US kind of stalled out part way there.  Engineering uses SI units for the most part.  Day to day living uses customary units.  I've got to admit, talking about how tall someone is in feet and inches seems much more intuitive than in meters, decimeters, and/or centimeters.  Pounds/kilograms, inches/centimeters, miles/kilometers are each close enough by themselves that I could make the switch eventually.  The mix of units for everyday nuts and bolts is a bit of a pain.  Of course, wire and nails have their own systems of units that are neither customary nor SI.

I'm still waiting for the SI version of time keeping with 10 hours per day, 10 decihours per hour, 100 centihours per hour, etc.  I'd love to see how they shoehorn 100 or 1000 days per year against the solar calendar.

Why was 10 chosen as the base?  Base 12 makes a lot more sense.  It's divisible by 1,2,3,4,6, and 12.  10 is only divisible by 1,5, and 10.  Being a computer engineer, I've grown quite adept at base 16 or hexadecimal arithmetic, so it should be doable to work in base 12.

I do often prefer the use of customary units' fractions to decimals for day to day functions as opposed to engineering usage for taking a swag at a measurement.

Apparently the French messed about with decimal time for a while, didn't catch on though.

https://en.wikipedia.org/wiki/Decimal_time

Jim

[Mandy D]

19 minutes ago, saac said:

Petrol is priced in litres now but I think most folk still think about fuel in gallons and miles per gallon  - km per litres just sounds so wrong. 

Jim

The metric unit for fuel consumption used by car manufacturers is actually litres per 100 km! So, even crazier than you'd think! In SI, it would be metres per kg, m kg^-1

😂

[Mandy D]

4 minutes ago, saac said:

Apparently the French messed about with decimal time for a while, didn't catch on though.

https://en.wikipedia.org/wiki/Decimal_time

Jim

Yes, I recall this! Personally, I think we should move over to base 8 (octal). It would make life so much easier, all numbers would convert properly and easily to binary. I used to enter octal code into a Honeywell 516 mainframe at college and it was so easy to check against the binary. It would also make the 8 times table, which is the most complained about one, much simpler!

[Mandy D]

2 hours ago, scotty38 said:

I mix and match all the time. Plenty of times I'll measure something and say it's 150mm by 31/2 inches....

You'll like this can of paint from Canada, then! Check the various ways the quantity is listed. None have sensible values.

[Mr Spock]

All the roads here and cars use miles. It would cost £ billions to change all the road signs to Km. I think of room sizes in feet as I can't visualise metres, but use metric for everything else. I like my pint to be in a pint glass, but I measure for cooking in Litres and grammes. I like gallons of petrol in my car so I know what my mpg is.

You could say I'm ambi-physics...

[Mr Spock]

2 minutes ago, Mandy D said:

You'll like this can of paint from Canada, then! Check the various ways the quantity is listed. None have sensible values.

At work we order paint from a particular company. We order in litres and they measure in Kg... I do the accounts and we have something called Goods Received Not Invoiced. We order 10lt and they deliver 9.77ltr - that leaves a cash balance in GRNI which I have to journal out! Does my head in.

[fozzybear]

30 minutes ago, Mr Spock said:

At work we order paint from a particular company. We order in litres and they measure in Kg... I do the accounts and we have something called Goods Received Not Invoiced. We order 10lt and they deliver 9.77ltr - that leaves a cash balance in GRNI which I have to journal out! Does my head in.

same over the river here our supplier supplies in either 25kg or 30kg tins. depends on the viscosity of the paint used

[Stephenstargazer]

In day to day life like many my age I still think of distances in feet, yards, miles but am more polylingual when it comes to volumes and weights, happily swapping metric and imperial. My engineering degree was done in SI units however at work both imperial and technical metric (German habit) persisted for years after. The worst being for a renowned American petrochemical contractor who would only accept calculations in USA Imperial. including kips (1000 lbs) and short Tonnes - we had to rewrite some software to produce them.

I think of chains when I listen to cricket, and remember surveying with actual chains which were by then 20m long. 😁

Now back to that thread - if it is 1/4" UNC  aka National Coarse aka 20 tpi then that is still the defacto standard photo thread that you will find on the base of your latest mega pixel digital super camera. Some people think it is a Whitworth thread but they disappeared, along with BSF, when UK and USA agreed Unified threads after WW2.

(I am the proud owner of two substantial boxes of taps and dies with thread gauges - when in doubt measure!)

[saac]

38 minutes ago, Mr Spock said:

At work we order paint from a particular company. We order in litres and they measure in Kg... I do the accounts and we have something called Goods Received Not Invoiced. We order 10lt and they deliver 9.77ltr - that leaves a cash balance in GRNI which I have to journal out! Does my head in.

Ah is where you round up all those 1/4, and 1/8th of a penny and put them all together at the end of the year for the staff party  

Jim 

[Mr Spock]

26 minutes ago, saac said:

Ah is where you round up all those 1/4, and 1/8th of a penny and put them all together at the end of the year for the staff party

I wish that were the case. I don't want to bore people with accounts, but the difference between the Purchase Order value and the Purchase Invoice value goes as a credit to stock otherwise the stock value of the paint is incorrect. Same if a difference appears in the price variance account - but now we are getting too complicated for an astronomy forum. Hopefully people can see accounts is just a bit more complicated than counting beans 

I've been doing it for over 40 years. It's about time I retired... 

[saac]

4 minutes ago, Mr Spock said:

I wish that were the case. I don't want to bore people with accounts, but the difference between the Purchase Order value and the Purchase Invoice value goes as a credit to stock otherwise the stock value of the paint is incorrect. Same if a difference appears in the price variance account - but now we are getting too complicated for an astronomy forum. Hopefully people can see accounts is just a bit more complicated than counting beans 

I've been doing it for over 40 years. It's about time I retired... 

I  think you have to have a head for it for sure Mike, I think the intricacies of accounting could give quantum mechanics a good showing in the difficulty stakes. I salute you for your dedication to the art. 

Jim 

[Mr Spock]

2 minutes ago, saac said:

I salute you for your dedication to the art.

If I had my time again I'd be elsewhere. The knowledge, accuracy and attention to detail required far outweigh that required by people who earn twice as much as me. When I look round the business I see no job I couldn't do, yet there isn't one of them who could do my job. Rant over 🤬🤬🤬

Time to get back on topic 

[StevieDvd]

In Yoda voice:

"Furlong time have I metric been using."

Give me an inch and I'll take 1.60934km 😁

[Louis D]

2 hours ago, Mandy D said:

Yes, I recall this! Personally, I think we should move over to base 8 (octal). It would make life so much easier, all numbers would convert properly and easily to binary. I used to enter octal code into a Honeywell 516 mainframe at college and it was so easy to check against the binary. It would also make the 8 times table, which is the most complained about one, much simpler!

Warning! Esoteric computer hardware discussion ahead:

The problem with octal versus hexadecimal is that you need only 3 bits to represent octal digits versus 4 bits for hexadecimal digits (hexits).  This leads to a problem when storing values in memory locations that tend to be in multiples of 8 bits (1 byte) in modern machines (they were multiples of 6 bits in older machines, so octal worked).  Hexadecimal packs nicely with 2 hexits per byte and no waste.  Octal packs as 2 octal digits per byte with 2 bits wasted.  Thus, the shift about 40 or 50 years ago from octal to hexadecimal digits along with the shift from memory words in multiples of 6 bit to multiples of 8 bits.  If the octal digits are allowed to spill across bytes for packing efficiency, it becomes difficult to read memory dumps aligned on byte boundaries.

[Louis D]

5 hours ago, Mike Q said:

The one place you dont see it much... Road signs.  Its been years since i have seen a roadsign that says how many km to wherever you are going 

Don't drive much in Canada, do you?  It always freaked me out driving from Michigan to New York by way of Ontario to see all road signage in km instead of miles.  Now, you need a passport to drive through Canada, so I just take the slightly longer way through Ohio (your stomping grounds) and Pennsylvania.  That, and the border security lines became unbearable over the last 40 years.

[Guest]

9 minutes ago, Louis D said:

Don't drive much in Canada, do you?  It always freaked me out driving from Michigan to New York by way of Ontario to see all road signage in km instead of miles.  Now, you need a passport to drive through Canada, so I just take the slightly longer way through Ohio (your stomping grounds) and Pennsylvania.  That, and the border security lines became unbearable over the last 40 years.

I have not been to Canada in decades.  No desire to.  Canada translated to English means its colder then hell here LOL 

[Cosmic Geoff]

To bring this back to topic:  It looked like the bolt I found that fitted the plate in the base of my SLT was either 1/4" BSW or 1/4" UNC. 

I had a thought last night and tried screwing a couple of camera tripods into the base of the SLT mount. Both fitted perfectly. 

Looking up the camera tripod thread, I find it is 1/4 20 UNC   So that answers the original poster's question.

Just to kill off the 11mm suggestion: 11mm is a lot bigger than 1/4".  My SLT also has a rectangular label stuck to the underside, but it has something completely different printed on it.