# What are 1 2 3 blocks?



## Brian Rupnow (Dec 14, 2008)

I see the term 1 2 3 blocks referred to in this site and on the machinists website, and I don't know what they are. Can someone please explain to me?---Brian


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## Mike N (Dec 14, 2008)

Precision ground block of steel 1" x 2" x 3"


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## jack404 (Dec 14, 2008)

Brian they are as described 

precisely ground blocks of steel

they are used like parralells to get a job square
some have threaded holes in them for mounting

i have a larger set that i used when cutting rails to get a perfect parralell cut 

2 such blocks held to a plate with bolts can be used like a large Vee block to hold pipe inline and parralell

i also mount them to hold a Vee block to work a right angle one angle through the hole in the 123 block the other rest in the Vee on the Vee block this way i know both angles are perfect

thay have a lot of uses but basically its a tool to ensure you get the right angle, or right angle if you get what i'm saying

very handy to have 

cheers

jack


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## tel (Dec 14, 2008)

_very handy to have _

.... that was gonna be my answer - they have a multitude of uses once you get aholt of a pair.


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## Brian Rupnow (Dec 14, 2008)

Thanks guys. One more thing that I have learned about this machining business.


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## Tin Falcon (Dec 14, 2008)

Brian do not feel bad. I know what 1-2-3 blocks are but up until a couple of years ago I had not really used them .Keep in mind I have been trained and have worked as a machinist. I asked on another board what are the various uses for the 1-2-3 blocks the answer I got from one guy was you may as well ask what a spoon is used for . 
I did not think it was a stupid question but he did I will not mention names because this guy is a respected published author and very experience machinist. 
Since then i just started using them for whatever seemed right and got creative. I use them a lot for machining the edge of a plate 3 inches wide or so just put one on either side of the work piece to stiffen the setup. 
The big brother twins are 2-4- 6 blocks same thing but scaled up. 
Tin


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## artrans (Dec 14, 2008)

Every day is a school day


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## rake60 (Dec 14, 2008)

We had a training session at work a few years back.
The older gentleman who was the teacher of that training session got a bit
off topic there one day.
He was a retired engineer / shop owner / machinist / hobby machinist / teacher.

He wanted to make his own 1 2 3 blocks and a small set of V blocks so he 
made the plan for them and machined them to + 1/4"
Then he heated the up to cherry red and threw them outside behind the shop.
After 3 weeks, he brought them back in and machined them to + 1/8" on
all surfaces. Heated them up again and threw them outside to stabilize.
A month later he brought them back in and machined them the the final specs.
This time he was pretty sure the internal stresses on the material had been 
given away. He was right.

He had made them 30 years before meeting us.
30 years later the 1 2 3 blocks and V Blocks measured *NO* indicated run out
on the most sensitive of measuring devices. 

I wouldn't have the patience to spend 2 years making 1 2 3 blocks when you can 
buy them for $20.
Knowing a man who did have that patience...
Well, I don't know how to put those feelings into words...

Rick


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## shred (Dec 14, 2008)

1-2-3 blocks are one of those things "everybody" said "you should get" when I was starting out not too long ago, so I bought a cheap set and rarely even looked at them for the first 6 months. Now I find myself using them quite a bit-- bolt them together to get a 90-degree angle that can move; rough-square up a machinists vice with a table by slapping one alongside; use them as tall parallels in the lathe chuck for short work; use them to support thin stock above the vice; hold one on the lathe chuck or work to quick-square a parting tool; etc; etc.


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## kvom (Dec 15, 2008)

The first use I was taught at school this year: Assume your lathe has no DRO and you want to turn off a precise length of stock, but it's greater then the 1" a dial indicator on a mag base can measure. Hold the block against the carriage to add 1, 2 or 3 inches of reach to the DI.

Making a pair 1-2-3 blocks is a project at my vo-tech school for those learning heat-treating and surface grinding.


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## mklotz (Dec 15, 2008)

I have an interesting use for 1-2-3 blocks. Say you want to measure the taper of a tool or workpiece.

Lay the 1-2-3 blocks on a surface plate with the 1" dimension vertical. Put the tapered item between them so the axis of the taper is vertical. Lay your calipers flat on the upper surface of the blocks and measure the diameter of the tapered item. Call this dimension d1.

Now repeat this process with the 2" dimension of the blocks vertical. Call the measured dimension d2.

You now have two part diameters measured exactly one inch apart. The half-angle of the taper can be found from:

angle = arcsin [(d2-d1)/2]

Double this angle to find the included taper angle.

Since the blocks provide a nice flat support for the calipers, it's easy to get accurate diameters spaced a known amount.

Since I make mostly smaller models, I've made myself a set of half-size blocks - 0.5-1-1.5 inches. They're as handy, at least to me, as the full-size blocks.


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## Philjoe5 (Dec 15, 2008)

Marv, Kvom,
Thanks a lot for those suggestions. Those are things I'm always trying to figure out. I never thought about using the 1-2-3 blocks that way :bow: :bow:. These applications remind me of something a student of mine once said - "I can't wait to graduate so I don't have to learn anything else". Poor kid missed the whole point :'(

Cheers,
Phil


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## shred (Dec 21, 2008)

I snapped a swarfy pic of a 1-2-3 block in action as a vice stop. Lots of ways to skin this particular cat, but this one is quick and easy.


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## Stilldrillin (Dec 22, 2008)

Hmmmm........
I learned of 1 2 3 blocks, on here, last week.

That`s after 40+ years as a production miller in rock drilling manufacture! ??? :

But I *did* have a large selection of assorted parallels.....


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## BobWarfield (Dec 22, 2008)

Stilldrillin  said:
			
		

> Hmmmm........
> I learned of 1 2 3 blocks, on here, last week.
> 
> That`s after 40+ years as a production miller in rock drilling manufacture! ??? :
> ...



Yep, I'd imagine that being in the UK a 25.4-50.8-76.2 block just wouldn't be very memorable!

Cheers,

BW


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## Kludge (Dec 22, 2008)

BobWarfield  said:
			
		

> Yep, I'd imagine that being in the UK a 25.4-50.8-76.2 block just wouldn't be very memorable!



True dat. It would make too much sense. 

Actually, the base dimension should be some fraction of the width of Queen Elizabeth's foot (the original QE, not this one) measured in wheat grains during her coronation precisely at the moment they plopped the crown on her royal head. Eventually, that measure would become so ingrained in the Imperial system of measure that no one would notice that, like the inch, foot, cubit and mile, there is no reasonable way to get from one unit to another without fudging a bit. That fudging was done along the way to make things work out more or less consistantly despite the somewhat odd multiples required to get from one to another.

Oddly enough, this system is still favored in some more or less civilized corners of the world and is deeply loved by those who use it, so much so that England recently was successful in telling the EU to stick it rather than become all metric. You go, England!

Best regards,

Kludge, the Historian. ;D


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## Stilldrillin (Dec 23, 2008)

BobWarfield  said:
			
		

> Yep, I'd imagine that being in the UK a 25.4-50.8-76.2 block just wouldn't be very memorable!
> 
> Cheers,
> 
> BW



Nice one, Bob!

Hmmmm..... I have *just* remembered......
Long ago, I made a pair of screwjack blocks, drilled & tapped for 5/8 whit capheads.
Still got `em, somewhere.....

The blocks measured 1.75" x 2" x 2.25".

Guess they`ll be 44.45 x 50.8 x 57.15 blocks? 

*Kludge.*

I spent the last 20yrs or so making rock drilling components on a (metric) Takisawa machining centre.....

*All* components were in Imperial measure & tolerance, apart from the button bit insert holes, which were metric, & graded in microns. :

Engineering`s a funny old game....


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## scoop (Dec 23, 2008)

wishful thinking Kludge.Imperial units of measurement are fading fast.I have had the experience of starting out in engineering in inches and slowly converting to metric.During this time I realised that metric is by far the best system of measurement.As an Englishman I know I should go and wash my mouth out with soap,but its true.No more fractions to deal with,ie not having to add 1-31/64" to 3-7/16" just to arrive at 4-59/64",which you cannot measure with a micrometer or a vernier,then having to convert to 4.9219" only then to find that if I was working in metric is only a few tenths of a thou' over 125mm,which if I was working to a tolerance of +/- 0.010" I could have measured with a steel rule.Sorry about all the confusion but it is a fact of life that working in tens is a doddle compared with twelves,sixteenths etc etc.More confusing is having engineering drawings that are dimensioned in metric but still retain all the thread detail in imperial so that just when you think its safe to throw all your old imperial stuff out,somebody draws a 10-32 thread on his latest creation instead of keeping to metric forcing you to search the skip outside for the correct gauges.Hope I have not wound anybody up with my pro metric ramble,any body else got an opinion.Maybe a vote on it is required.

 best regards  Steve C.


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## Kludge (Dec 23, 2008)

scoop  said:
			
		

> wishful thinking Kludge.Imperial units of measurement are fading fast.



Can you still buy a pint in your local friendly pub? 



> No more fractions to deal with,ie not having to add 1-31/64" to 3-7/16" just to arrive at 4-59/64",which you cannot measure with a micrometer or a vernier,then having to convert to 4.9219"



So why not start with decimal inches? Our lathes, mills et al don't have fractions on them - or none that I've seen do - so why dimension in fractions to begin with? That's something I've never quite understood. The only time I used fractions on drawings was when I was in classes. The rest of the time, it was all decimal for precisely the reason you state. Fractions are almost as evil as I am. 



> More confusing is having engineering drawings that are dimensioned in metric but still retain all the thread detail in imperial so that just when you think its safe to throw all your old imperial stuff out,somebody draws a 10-32 thread on his latest creation instead of keeping to metric forcing you to search the skip outside for the correct gauges.


Okay, you asked for it. Soon as I have my tool kit to a reasonable point, I shall build something using as many different thread systems as I can. :big: :big: :big:



> any body else got an opinion.Maybe a vote on it is required.



Oh, boy. ASking for an opinion here is dangerous. 1992 members (at this writing) will yield 2500 opinions at least. ;D

Oh. What are we voting on because mine's for pizza.

BEst regards,

Kludge

PS: If you read the body of my message, you'll note that I was having some fun. Honest!


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## Brian Rupnow (Dec 23, 2008)

When I started in engineering in 1965 everything was in British Imperial.--inches, feet, miles, and pounds (weight). Then, our blind and stupid government leaders, decided that we in Canada would go totally metric to be in line with our foreign trading partners. Somehow they overlooked that country with which we share our longest common border, just south of us who account for 85% of our foreign trade, has 100 times our population, and was NOT going metric!!! Then ensued a long and very painfull 5 year period when all engineers and designers were forced to learn and work in the Metric system. Educators quit teaching feet and inches in the public schools, high schools, and colleges, and proceeded to teach all the kids to work in metric. However, all of the machinists and mechanics who had a ton of money invested in tools that measured in British Imperial basically said "Screw this!!", and as soon as a metric blueprint hit the shop floor, it was converted to British Imperial by the people who had to work from it.---with many numbers being "rounded off". All of our steel mills shrugged their shoulders and went on rolling structural steel shapes based on feet, inches, and pounds, as they always had. After about 10 years of this nonsense, many of the smaller machine shops quietly said "Enough of this damn foolishness" and went back to using British Imperial. However, the big companies with trade ties to Europe stayed working in Metric. Now we have the damdest mish mash of measurements styles, preferences, and confusion that the world has ever seen. Any engineer or designer must be prepared to work in either British Imperial or Metric, depending on who the customers is. And the kids somehow have all managed to graduate and move into the workplace, not being certain of the difference in a foot, inch, millimeter or cubit!!!


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## scoop (Dec 23, 2008)

looks like I may have poked a wasps nest here.No offense to anybody or any measurement system was meant or implied but having worked with both over a long time I just prefer metric.I agree that fractional sizes are a pain and when using imperial we would be better off going decimal,but when you go to buy some brass bar or similar you have to use fractions again so you are back to square one.Yes pints of beer are still readily available in English pubs but then again my local will sell me a yard of ale if I ask for it,its madness I tell you.I swear that if metric units of measurement were used along with decimal currency(still pounds,shillings and pence then) when I was at school I could have saved myself 2 years of learning time.I dont really mind what sizes I use at home now especially on small engineering projects as its just a trip down memory lane when using inches.The drawings supplied with stuart kits are fun though the fractional sizes are quite cute in places.I sympathise with Brian who has had similar problems in Canada with the switch,however when visiting Canada a few years ago my biggest problem was working with two languages!Never have got on too well with French,even though most of my work now involves French based electrical drawings.
 I did notice a slightly humorous tone to your reply Kludge,I did think my earlier post was a bit opinionated.All I wanted to do really was to test the water and see what people really think about the different systems and find out how members of this group get on with using both.Do Americans really hate the metric system?

    best regards to all Steve C.


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## cfellows (Dec 23, 2008)

scoop  said:
			
		

> All I wanted to do really was to test the water and see what people really think about the different systems and find out how members of this group get on with using both.Do Americans really hate the metric system?
> 
> best regards to all Steve C.



I don't think Americans hate the metric system. It's just unfamiliar. When you've used inches and feet all your life, it's hard to look at a part or a piece of stock and estimate it's size in millimeters or centimeters. It's kind of like trying to describe something in a second language that you haven't used very much... requires to much mental conversion. And, our machine tools are all designed to work in inches and decimals.

Chuck


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## scoop (Dec 23, 2008)

Bit of a slip there using the word hate,what I really meant to say was "do Americans dislike using metric".I appreciate the problems with equipment made for inches,that can make it a lot more awkward.

 best regards Steve C.


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## mklotz (Dec 23, 2008)

In the USA, the metric system is used widely in the military and aerospace industry and almost exclusively in the scientific and medical communities. Folks who have to deal frequently with units conversions or need to minimize the risks of using disparate units recognize and embrace its superiority.

The man in the street who does no technical work sees no need for change and so resists it vehemently. He'll go so far as to argue that ACU (American Customary Units) are superior - this despite the fact that most of these proponents don't understand ACU themselves. The very concept of a measurement *system* (as opposed to a hodge-podge collection of units of convenience) is lost on him.


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## Stilldrillin (Dec 23, 2008)

Through all those years in engineering.

Imperial, metric, then back to imperial, then (now) a modern day mixture....... No problem! 

Until a schoolkid uses _centimeters_....... What size is that, then? :


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## Kludge (Dec 23, 2008)

scoop  said:
			
		

> looks like I may have poked a wasps nest here.



Nah, but I was seriously concerned my somewhat odd sense of humor was slipping. They kind of tolerate me here despite being an escapee from the Home for the Terminally Weird. When people say I'm crazy, I can show them papers from the VA that say I really am. Not too bad a deal, is it. 



> No offense to anybody or any measurement system was meant or implied but having worked with both over a long time I just prefer metric.



I'm one of those odd Americans who can bounce from one to the other pretty comfortably since I've run into one situation where being comfortable in metric was needed plus talking with people who had no understanding of Imperial. 



> I agree that fractional sizes are a pain and when using imperial we would be better off going decimal,but when you go to buy some brass bar or similar you have to use fractions



Yep, yep. Yet there's a company that makes wall partition material in decimal inch and in metric, both of which buck the norm. That is sufficiently cool in itself that it's a moral imperative for me to make something like a machine tool bed from the framing stock. 



> Yes pints of beer are still readily available in English pubs but then again my local will sell me a yard of ale if I ask for it, its madness I tell you.



Hmmm ... over on this side of the pond, combining any alcoholic beverage and "yard" usually means you're in a neighbor's yard stealing garden ornaments. Or doing something unsavory with them, at least.



> I did notice a slightly humorous tone to your reply Kludge,I did think my earlier post was a bit opinionated.



No harm, no foul. And no offense taken. 



> Do Americans really hate the metric system?



I don't know if hate is so true as don't understand it. It has been taught in terms of conversions rather than as a system of its own which, to me, is terribly confusing. There used to be an ad for a soft drink where a teacher asks the class how much 2 liters is. The "local punk" holds up a 2L bottle of the drink and says "This is 2 liters," while the "bright kid" gives the conversion from quarts. The teacher praised the latter when the former was right. That one ad pointed out the weakness of how the metric system is being taught here.

By the way, I noticed from your message count that you're one of our recent victims ... er, joined recently. Welcome aboard. We've got a bunch of really cool people here with a knowledge well that seems bottomless. Ask, and you'll have a bunch impart wisdom, both on and off topic. 

Best regards,

Kludge


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## rleete (Dec 23, 2008)

Kludge  said:
			
		

> I'm one of those odd Americans



Took the words right out of my mouth!  :big:




			
				Kludge  said:
			
		

> I don't know if hate is so true as don't understand it.



Too true. Back when I was working for a company that did everything in metric, I'd talk to my machinist friend about what I was working on. I'd say something was 6mm, and he'd give me a blank look. When I said about 1/4", he'd understand. He just couldn't "see" it in metric the way he could in inches. If you aren't around it all the time, it's hard to grasp.

Personally, I have worked in both, and I do find metric easier in terms of fewer decimals. The real confusion and pain-in-the-butt comes from mixing systems, where you get odd conversions. In my current job, where most of the lens specifications come from Europe - and hence in metric - we use them, but specify the tooling (made over here) in decimal. I tend to use round numbers - .300 for instance - instead of the fractional equivalent like .3125 because it's just as easy for the shop using DRO and CNC to hit, and it makes the numbers neater.


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## Kludge (Dec 23, 2008)

rleete  said:
			
		

> Took the words right out of my mouth! :big:



Would you like them back? ;D



> Personally, I have worked in both, and I do find metric easier in terms of fewer decimals. The real confusion and pain-in-the-butt comes from mixing systems, where you get odd conversions.



Here's a good one for you. American watch sizes run from 0s (1-5/30") in both directions to 18s and 8/0s (might be smaller, I can't remember right off) ... in steps of 1/30". I have no clue why or where that system originated. The Swiss Ligne system isn't any better, just in metric. Going between the Swiss and American systems is a real "treat". On the other hand, watchmaker's lathes on both sides of the pond are metric machines and I have yet to find anything threaded from either side of the ocean that wasn't metric. 



> In my current job, where most of the lens specifications come from Europe - and hence in metric - we use them, but specify the tooling (made over here) in decimal.



I'm a ham radio operator. Calculations involving frequency and wavelength work out much more neatly in metric so when I would doing something like designing a stripline or an antenna, I worked in metric whenever possible. However, PC boards, components etc are in fractional or decimal inches. As a result, I would lay out the striplines and/or antennas first then add anything else needed on the board to fit behind it. I don't play with microwave anymore but if I was, I'd be even more insane than I am now. Not that anyone would notice. ;D

In optics, I have several lenses with the diameter measured in decimal or fractional inches and the focal length in metric. 

Gotta love it!

BEst regards,

Kludge


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## Kludge (Dec 23, 2008)

BobWarfield  said:
			
		

> Yep, I'd imagine that being in the UK a 25.4-50.8-76.2 block just wouldn't be very memorable!



Reflective thought: 25 50 75mm blocks would be quite handy ... or 20 40 60mm or 10 20 30mm for small projects. Actually, I'd love a set that size. 

Side question: The blocks I've seen are sold in pairs. If one purchases two pairs from the same company, would the individual blocks be interchangable?

BEst regards,

Kludge


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## rleete (Dec 23, 2008)

Kludge  said:
			
		

> Side question: The blocks I've seen are sold in pairs. If one purchases two pairs from the same company, would the individual blocks be interchangable?



Not necessarily. We use blocks to set up the seamlines on large optical panels. In order to get them matched, you have to get sets. More expensive, because all have to be within some miniscule number of each other (+/- 1 millionth?). Pairs are matched, but may not match each other.

For what we do, they're probably close enough.

Interesting fact: We make lenses (mostly Fresnel style) at work. Take a piece of metal, what to the naked eye is perfectly smooth and defect free. Heck, check it under magnification, it still looks good. Now, compression mold a piece of plastic on that, and hold it up to the light. Your eye can now see every minor imperfection in that metal. That's why the seamlines have to be perfect, and we spend big bucks for very precise 1-2-3 blocks.


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## jack404 (Dec 23, 2008)

Kludge  said:
			
		

> Reflective thought: 25 50 75mm blocks would be quite handy ... or 20 40 60mm or 10 20 30mm for small projects. Actually, I'd love a set that size.
> 
> Side question: The blocks I've seen are sold in pairs. If one purchases two pairs from the same company, would the individual blocks be interchangable?
> 
> ...



Kludgy,

contact anchultz in Chech land ( the gunsmithing tool works factory)

they have just what your dreaming about, small and large "stepped" blocks too, not cheap but very handy

i got mine as part of a kit 

no web site i know of 

i looked em up through a dealer here and phoned em, they sent me a catalogue

the rest is expencive history.. tools.. oh the dollars we spend..

you know i bought a mechanical flint knapper? $200 right there..

precision angle set $189

Vee Blocks with clamps $139

but 123 blocks are cheap , ($35-$65 in OZ half that in the US)
handy, in sooo many ways
accurate enough for what we want (ok ok theres some of you who want nanometer stuff)

blocks for the most part are not matched unless stated "matched set" and then i'd be dubious unless a known brand was involved

but my non matched pair are close enough to perfect on the marked thin edges , maybe i am lucky but most blocks can be "paired" with another along at least one edge.

cheers

jack


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## Kludge (Dec 23, 2008)

If you could send me the contact info, I'd appreciate it.

BTW: the "good" tap and die set that I have my eyes on is from Brownells, also a gunsmithing supply house. They are supporting my new "love affair" with 40 tpi which may or may not be a good thing. 

Best regards,

Kludge


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## BobWarfield (Dec 23, 2008)

Personally, I think measurement systems are like languages. They can separate us, but those who take the time to learn more than one are better for it. I'm happy to convert between metric and Imperial for all the common measurements I ever encounter. I am better at eyeballing Imperial, but that's okay, I just do the conversion. I am better at Base 10, so metric can seem better, but as a Computer Scientist by trade, I have to deal in binary, octal (Base 8), and Hexadecimal (Base 16) as well, so some familiarity with conversion is called for.

I had to learn both measurement systems as well as the different numbering systems as part of my schooling and it has stuck with me without too much trouble. That's not to say I instantly convert everything, but it doesn't take much longer as I have my Excel open most all the time as a calculator. 

Where it gets ticklish is the odd measurements that I use far less often. Stepper motor torque, for example.

In any event, i should think the metric world has its own equivalent of 1-2-3 blocks. And while we're on that latter more on-topic subject, 2-4-6 blocks are extremely handy as well. Watch for a pair to be on sale, they come up every so often.

Cheers,

BW


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## Hilmar (Dec 23, 2008)

How about big numbers?

 Mega  1 Million   =  Number with  6 zero
 Giga  1 Milliards   =  Number with  9 zeros
 Tera  1 billion    =  Number with  12 zeros
 Peta  1 billiard    =  Number with  15 zeros
 Exa   1 Trillion    =  Number with  18 zeros

Well how do you write a Billion or Trillion in English ??


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## jack404 (Dec 24, 2008)

no wonder we got so many billionaires

a billion here (Oz) is 1,000,000,000

if i read the above right the US billion is 1,000,000,000,000

hmmm 

jack


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## Kludge (Dec 24, 2008)

jack404  said:
			
		

> a billion here (Oz) is 1,000,000,000



Same in the US. I thought Milliard came before Million ... but, being an American, what do I know?

BEst regards,

Kludge


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## Peter Neill (Dec 24, 2008)

On the eternal debate of Metric vs Imperial, I thought that "Boris", who posts over on the PM forum managed to sum it up very well with this little gem:
*
"Seeing as I'm British, I'll give the run down of how a modern british engineering type person thinks

From 0 to 0.001" I use microns
From 0.025mm to 0.1mm I use imperial
From 0.04" to 1" I use metric
and anything above 25.4mm I use imperial

Boris"*

Peter


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## Kludge (Dec 24, 2008)

Peter Neill  said:
			
		

> On the eternal debate of Metric vs Imperial, I thought that "Boris", who posts over on the PM forum managed to sum it up very well with this little gem:



What? No Angstroms?

BEst regards,

Kludge


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## Tin Falcon (Dec 24, 2008)

Guys I am a little disappointed. I know the metric vs imperial thing touches a lot of thoughts and feelings. But I am sad that the discussion has derailed a potentially great thread on the uses of 1-2-3 block or there metric equivalent if there is one. 
There have been threads on the metric rant lets keep that stuff in the break room unless it really actuality applies to the topic.
Tin


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## John S (Dec 24, 2008)

Just my opinions on the 1-2-3 blocks.

I feel that they don't have an exact use in that someone could come up with an instruction sheet from 19 ought plonk and say this is what they are for.

They are for whatever use the owner has for them, a bit like screwdriver, Ok it turns screws but what length ?

A lot of peoples use of them is as precision packings or parallels but why do they have to be 1-2-3 ? Does anyone ever measure off them? I suppose some must do.

One thing I hate about parallels is the sizes, take the 1-2 -3 blocks for example. using the 1" side they can't support a 1" bar in a vise as the block will grips slighly before the bar because of the splay of the jaws and the fact that commercial bar is usually about a thou under.

Same applies to packing strip sets, I usually make my own up from Ground flat stock, cleaned up on the surface grinder to a few thou below nominal size to get by the trapping issue. They might not be to microns but neither is my work 

John_S


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## Kermit (Dec 24, 2008)

Hilmar  said:
			
		

> How about big numbers?
> 
> Mega  1 Million   =  Number with  6 zero
> Giga  1 Milliards   =  Number with  9 zeros
> ...



This has to be a joke of some kind. Please explain to the newbie...


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## Kludge (Dec 24, 2008)

John Stevenson  said:
			
		

> A lot of peoples use of them is as precision packings or parallels but why do they have to be 1-2-3 ? Does anyone ever measure off them? I suppose some must do.



I would imagine they are the minimum practical size someone lost to antiquity came up with to manage myriad tasks without having to have a special jig for each. The ones I've seen have had evenly spaced holes along each surface and some have a few holes of those holes that are tapped. If nothing else, this means you can set up something at right angles to something else with a minimum of fuss & bother. It wouldn't take a whole lot of magic to create T-slot adapters to lock them down to a milling deck or a cross slide that has T-slots in it.

I guess it comes down to them being whatever the you want them to be and this being a decent size to accomplish that task. 

Just my opinion, of course, which has a street value something less than dirt.

BEst regards,

Kludge


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## Hilmar (Dec 24, 2008)

Kermit, 

No joke,
 The ways things measured or counted in one country is not necessarily so in another country.
In the English language the billion has 9 zeros and the Trillion has 12 and in the German and I am pretty sure in other languages also the billion has 12 and the trillion has 18 zeros. 

Merry Christmas to all.
Hilmar


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## shred (Dec 25, 2008)

One of my favorite 1-2-3 uses is two bolted together at right angles to make a perpendicular that's more useful in many situations than an ordinary square. I confess I also rarely make use of the dimensional measurements.

Another good one is aligning lathe tools-- trap one between the chuck face and toolpost to square up the parting tool and the like.


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## rleete (Dec 25, 2008)

No one has mentioned it, but shred touched on it, so I'll tell you one thing I was taught to use them for.

Bolt 2 together, they form a nice right angle. Sort of a large V-block. Clamp a round piece to it, and indicate the height after zeroing on one of the faces. This gives you the diameter. You halve that, and can now scribe a line across the face of the round. Flip the whole thing over 90 degrees, and scribe another line. Volia, centerlines at right angles. Perfect for laying out a hole pattern.


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