Metric measures

[DeformedTree]

But they generally learn to move on from cm because else where as has been mentioned by myself and others it's either inches or mm. Also living in country that is stuck with inches I know all too well the issues that come up with cm.  If you try to convince people of the value of the metric system, a centimeter is seen as just a different sized inch, it's different but doesn't help them any any way, it's just different. 

Nobody is moving on from cm. There are no issues with cm. Where do you get these ideas? Certainly not in places that actually use metric. Conversion between mm, cm and m is done all day without effort or confusion.

The scientific community made the SI system to avoid confusion because their high end applications required more clarity in cross-communication. But the scientific community is just a very small percentage of the world, and for the vast majority that are the rest it doesn't matter.

I think you are still missing the original point I brought up.  It's not that one can't convert between cm and mm easily, obviously that is extremely simple. It's when you make a mistake such as what happens with a tape measure.  If you are going to mark 1106mm , you look at the tape that you have pulled out past a meter and see "106" you mark it because it is what you are going for.  You're not thinking that you just marked 1060mm. You are now 54mm off, this isn't because you don't know a cm is 10mm.  Typical metric tapes don't have markings set up as you would expect. If they aren't going to just count from 0mm up to how many mm it goes to, you are expecting a repeat, such as ever meter, it counts from 0mm again and works back up to 999mm and then repeats after the next meter mark. The fastcap tape keeps counting up in 100mm increments, so 100mm, 500mm, 1300mm, etc.  Every 100mm the marks reset and count from zero up to the next 100mm.  It works like you would expect a tape to work.  If you need 923mm,  you see (900), and then advance to (20) go 3 more ticks, you find the mark the same way we speak number NineHundred, Twenty, Three.  On a cm tape you are going to 92 and then going 3 marks more. It's not natural, we don't say NinityTwo-Three to say 923.  A proper mm tape works the way we speak, which is key.  We say Eighteen, not  One-Eight.

 

[Michael Kellough]

I much prefer to work in millimetres and have no reason to include centimetres.
I’ve also noticed that when discussing measurements with clients, suppliers and architects, all is just fine until somebody introduces cm’s or mtrs into the conversation.
Usually lots of mumbling and placing of decimal points follow.

Yup, have had meetings where the one person uses cm and throws people off, especially if you are in a country that defaults to inches.  When you work on stuff that is always different and generally doesn't have a baseline to work from to have an idea how big the thing someone is talking about it, it gets very confusing.  If you work on the same stuff all the time, that is always more or less the same size, it's going to be less confusing.

Reminds me of my first encounter with CM.

Winter of ‘78-‘79, installing the premier exhibition of Cy Twombly’s suite of ten paintings titled “Fifty Days at Iliam”. Cy flew in to supervise from Rome, Italy (where he’d been living for the past twenty years) and was asking for the distance between the last two canvases. I told him “thirty two inches” (from memory) and he scowled and said “don’t give it to me in inches. Give it to me in sin timitters”. He grew up in Lexington, Virginia. About the paintings.

 

[demographic]

This Youtube vid is worth a watch regarding the metric system .

 

[DeformedTree]

I watched that now, wasn't expecting it to hit on so many things I have gone thru.  The stuff starting at 5min in on centimeters is spot on.  His stuff on rulers is spot on. This was from around 2014 it sounded, but he's right, I think the fastcap tape is the only mm tape you can find in the US.  Even to get my other cm tapes I had to find them online. He mentioned the Japanese company, I have bought stuff from them for the very reason.  I have bought some of their stuff in a local store.  I actually found some dual tapes (yes dual is terrible like he mentions) at a local shop that supports trades. I asked if they had any that were just metric, he said they don't but mentioned how people ask for them all the time. Which drives me mad, people ask for them all the time yet you don't carry any, of course the issue might be they just don't have a good source for them.

His pseudo-inch comment is spot on and what I mentioned before.  If you do dual scale, or cm, you will never get change.  And really we need mm tapes to be at every store.  I keep one at work simply because the excuse not to do something in mm once was that there are no tape measures in metric, so I keep it there waiting for that again.  I'm forced to work with inch and metric for work, and the excuses for not using metric are endless and of course has a large age dynamic. The host on the video summed up how younger folk in the country generally feel.  As he touches on in the video, mm have been with us in this country for a long time.  People have been making excuses not to change for a long time and I've heard a ton of them. Oh, we probably shouldn't go down the "ton" discussion.

I'll have to look to see if his longer presentation is online.  I'm sure he removed stuff.  The stuff on decimals leaves out the key part for folks to understand that people can do  97+15  way faster than they can 9.7+1.5  you think it's the same, but it's not, the human brain just doesn't do decimal places well. Also curious if he talks about all the places we do use metric, which is just as important, that a lot of the US is metric, it's just hidden to most folks. Showing people it is all around them is a big help to getting acceptance.

 

[Cheese]

This is referencing a recent thread I did on machining an MFS support bracket.

[attachimg=1]

This is how I make sense of items when both metric and imperial dimensions are needed.
In this case, the metric sized angle is sold by the inch.  [eek]  So both metric and imperial dimensions are used for the part. The wooden support block is a 2 x 6 so imperial dimensions are used. The slotting and the spacing between the slots will all be done on the MFS so it's back to metric. And even though M5 fasteners will be used in the slots, the only aluminum cutting router bit I could find was 7/32" in diameter so it gets thrown in the mix.  [big grin]

If I wanted to duplicate this job in 3-4 years, it's easier to just look at the drawing with the native dimensions and realize what items I used at the time. If every dimension is changed to metric or imperial, there's just a lot of confusion as to what individual items were used. 

It may not be everyone's panacea, but it works for me.

[attachimg=2]

 

[DeformedTree]

Fairly standard practice.  Our rule is you keep the part what it was. So if it's an inch designed part, you model it and put it in cad as an inch part.  If it was metric, you keep it metric.  The system adjust.  Of course that doesn't mean nominal hole patterns and such work out.  Bigger issue is when someone comes along and wants something all one system (always inch), so now records like you have will be messed up because something is now all sorts of funky numbers.  Too many people convince themselves that if you take something designed in mm, and re-model/document it in all soft converted inches that it is the same thing.  So we end up with a lot of metric things modeled in inches.  Bearings are a big hang up of mine. Almost all bearings are metric and basically always have been.  But where I work they will document them in inches because some folks/customers want to pretend metric doesn't exist.

What you show is no different than me modeling up something metric, but I need an inch based threaded hole.  It will be a metric drawing, but the hole called out can be 1/4-20 UNC , it is what it is.  And sure enough you will have people argue you can't do that and want the part redesigned in inch, and then the system it goes into redesigned in inch, so so everything is all the same system.

Like you show with your slot. Most metric prints I've ever made when it comes to thru holes, or fillets, and the like are often going to be converted inch values simply because of drills and mills that are on hand.  This is changing though.  If your only making a single part and having a small shop make it, your not going expect them to go get a metric drill or mill, though really at this point they have them, it's just the collective mind thinking places don't.

The issue is when people don't understand these things and you have stuff where lets say it was designed in metric.  Now in the US all information on it gets converted to inches because that's what people do.  Do you know if the hard or soft converted, did they make a mistake in conversion, etc.  You start getting all these back and forth conversions with no idea how much rounding happened each time, even worse is someone throws fractions in there.  Or they dual dimensioned something and you have no idea which is the native unit.  Stuff can get out of whack in a hurry.  I don't like inches, but if something was designed in inches, keep it that way.  Same for metric stuff.  I hate trying to find stuff in the US that you know was made in say Europe and all the information in the US shows not just inches, but fraction inches.  Now you have no idea what you are working with.  I wouldn't be surprised if the same happens in Europe, something from the US comes over and the documentation gets converted to mm and becomes non-sense.  Like with Festool stuff, you end up having to go to the UK sight to figure things out.

Metric angle sold by the inch, yup, sounds right.  People just can't get on with the program.  Much like one of my favorites, plywood with "18mm" printed right on it and the store doing it's darnedest to call it some fraction or just 3/4, they just can't bring themselves to labels it 18mm, and even worse is they decide it's 3/4, and then to be "helpful" they call it 23/32, and then from there they convert to decimal inch and then convert that to metric and now you have 18.256mm plywood.....magic!

 

[MikeGE]

I do not have any metric measures and will be building the newest Ron Paulk workbench. His newest plans are only in metic. What specific metric measuring products would you suggest the not only cover this project, but will be nice to have I the future?

I apologize for straying from the current discussions, but whichever product you choose, be consistent with it.  I use several BMI 2m folding Class II steel rules and a Hultafors Class I 8m tape.

Prior to buying these, I had several folding wooden rules and assorted 2m and 8m tape measures scattered around the shop and garage.  Prior to building out my basement shop, all cutting was done in the garage.  I would measure what I needed in the basement with one device, then go to the garage and measure for the cut with another device.  None of the boards I was cutting in the garage were fitting, and it took me a while to figure out what the problem was.  The problem was worse when I was cutting boards to measure when the measurements were taken by someone else and passed to my by email or over the phone.

The "aha" moment hit me when I consolidated all of my measuring devices and compared them for consistency over two meters.  Out of eight items, none were the same at two meters, and only three were the same at one meter, or as close as my aging eyes could determine.  The variance over two meters was 4mm.  This is likely good enough for carpentry or brick laying, but not for cabinet making.  I tossed all but one tape measure (it lives in the center console of my truck) and bought the BMI and Hulfators. 

 

[Jiggy Joiner]

I noticed yesterday that any drawings we send to suppliers, or they to us, are in mm’s and often the mm’s aren’t even stated. Instead it’s common to see something like 3645 x 2150. Or, W: 2350 H: 2200 etc. Mtr’s are rarely mentioned unless something is over 10mtrs in size. Cm’s aren’t mentioned or indicated anywhere.

So, we’re in the mm only persuasion  [thumbs up]

 

[travisj]

I do not have any metric measures and will be building the newest Ron Paulk workbench. His newest plans are only in metic. What specific metric measuring products would you suggest the not only cover this project, but will be nice to have I the future?

I apologize for straying from the current discussions, but whichever product you choose, be consistent with it.  I use several BMI 2m folding Class II steel rules and a Hultafors Class I 8m tape.

Prior to buying these, I had several folding wooden rules and assorted 2m and 8m tape measures scattered around the shop and garage.  Prior to building out my basement shop, all cutting was done in the garage.  I would measure what I needed in the basement with one device, then go to the garage and measure for the cut with another device.  None of the boards I was cutting in the garage were fitting, and it took me a while to figure out what the problem was.  The problem was worse when I was cutting boards to measure when the measurements were taken by someone else and passed to my by email or over the phone.

The "aha" moment hit me when I consolidated all of my measuring devices and compared them for consistency over two meters.  Out of eight items, none were the same at two meters, and only three were the same at one meter, or as close as my aging eyes could determine.  The variance over two meters was 4mm.  This is likely good enough for carpentry or brick laying, but not for cabinet making.  I tossed all but one tape measure (it lives in the center console of my truck) and bought the BMI and Hulfators.

One of the first things I remember learning from my grandfather was to only have one tape measure out for a project.  Put the rest away in a  drawer/box so you aren’t tempted to grab a different one.

As to metric measuring devices.  I have some Woodpeckers items that I like and a few of the Fastcap tapes (blue 32mm, yellow combined metric/imperial, and grey storypole).  I use the yellow combined one often to get a quick conversion.  I switched to woodworking in metric, but I still think in imperial.

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