New to metric but not to Festool - need advice for measuring

[Axis39]

Count me in the camp of trying to convert to metric....  After almost 40 years in the trades here in the US.

I started watching Festool videos with Sedge, and a number of others over the years.  It got me thinking I could give it a try...  Materials I buy all seem to come in some metric size (even the S3S hardwood I buy is actually 20 mm), and measuring in fractions, and trying to convert, or divide some weird number...  it's just tiring.  Plus, every building I'm working in, is in imperial, but, the materials I buy are metric.  So, I decided to try it out.

I bought a few metric/standard tape measures and have spent a few days working in nothing but metric.  My son and I build and install custom furniture, cabinets, built-ins, etc. 

Half (actually, probably more like 90%) of the hardware I buy is made in the metric cabinet standard (divisions of 32 mm, I believe?  I've seen the videos, just not quite ready to make that switch yet)...

Like others, right now, the hardest part is imaging the proper size.  I can reach into the SAE socket set and know which socket to grab 95% of the time.  But, if it's a metric thing?  I am wandering aimlessly in a garden full of sockets I don't recognize....  But, I do recognize that larger numbers mean bigger bits and pieces.  [big grin]

I have tapes and rules in imperial down to the 100th.  I only have a few metric measuring devices and few of them are marked below 1 mm.  Maybe in a few instances on the first 10 cm, or some short measure, one or two are marked in some tiny little increments.  but, those are on more specialized tools.  I need to buy some hard metal measuring devices in metric...  combo squares, etc.

I do wish I could just switch over...  Just wake up tomorrow and everything in the shop be metric...  But, I have some imperial Incra stuff, with 1/32 tip reference screws....  So, until I hit the lottery, we'll be doing mixed couples, please and thank you...

 

[Bob Wolfe]

I have been 90% metric for some years. Some tips I have learned.

— use a metric tape, not a metric imperial combination , then you can read from both sides of the tape. Much less confusing than a combination tape.  Fastcap makes a good one. I prefer a white tape, much easier to read.
— lee valley makes a great folding metric rule. ( not sure why they don’t supply a blade for their double squares in metric.
—Woodpecker sells an excellent metric square #1812, kind of too big sometimes, so finally ordered a 150 mm one but don’t have it yet.

When you get the hang of metric measuring it is soooo much easier

My experience
  BW

 

[Bob D.]

"I wish my cad program allowed me to input metric units when drawing in imperial and it would automatically do the conversion. "

I am surprised that is not possible with other CAD software. SketchUp allows you to input using either system right from the command line. If my drawing/model is metric and I want to input an imperial measurement I only have to include " after the value, such as 5' 3". Same goes for a model with imperial units, just add the metric unit after the value (m, cm, mm) and it will be drawn at the correct length.

 

[Crazyraceguy]

It is a bit weird reading imperial measurements in this thread after not using imperial for so long and that is from someone who grew up with imperial and converted back in the 1970's. Ask me what 2"6" looks like and I would not have a clue.

That stupid 2' 6" thing is some kind of carry-over that architects here in America will not let go of for some reason? Part of the job that our engineering department guys have to do, when converting the architectural plans into "shop drawings", is getting rid of that. Everything on the shop drawings is strictly in inches. That would be shown as 30"
It continues confusingly into retail stores too. I would love to know how many doors get returned to home centers because someone bought a 3-0 thinking that it was 30", and it turns out to be 36" because the 3-0 was 3 feet 0 inches.

 

[Willy Eckerslike]

We still struggle in the UK though because our schools teach metric - in centimetres! 

Most trades will work in millimetres or metres.  Four foot (in old money) is quickly/roughly converted by older trades to either 1.2m or 1200mm without confusion, we all know what we mean.  A younger client will come along asking for something 120cm to be met with blank stares.

As a young child I was helping my father lay some ready mix concrete for new floors in our house.  He had very carefully worked out how much concrete to order (a teacher not a tradesman) even digging the floors a little deeper in one spot so it would be exactly four cubic yards.  When he placed the order, the supplier said they'd just gone metric so it's cubic metres now - everyone happy, delivery arranged.  On the day, we were doing really well and just finishing the last room and my father casually asked how much more concrete there was to come.  "About 20 minutes" was the reply.  We are still the proud owners of a concrete patio!

 

[Michael Kellough]

We still struggle in the UK though because our schools teach metric - in centimetres! 

Most trades will work in millimetres or metres.  Four foot (in old money) is quickly/roughly converted by older trades to either 1.2m or 1200mm without confusion, we all know what we mean.  A younger client will come along asking for something 120cm to be met with blank stares.

As a young child I was helping my father lay some ready mix concrete for new floors in our house.  He had very carefully worked out how much concrete to order (a teacher not a tradesman) even digging the floors a little deeper in one spot so it would be exactly four cubic yards.  When he placed the order, the supplier said they'd just gone metric so it's cubic metres now - everyone happy, delivery arranged.  On the day, we were doing really well and just finishing the last room and my father casually asked how much more concrete there was to come.  "About 20 minutes" was the reply.  We are still the proud owners of a concrete patio!

So your father had to quickly build a frame to contain the surplus concrete. Was was his formula for converting “20 minutes” into cubic whatever’s?

 

[Crazyraceguy]

We still struggle in the UK though because our schools teach metric - in centimetres! 

Most trades will work in millimetres or metres.  Four foot (in old money) is quickly/roughly converted by older trades to either 1.2m or 1200mm without confusion, we all know what we mean.  A younger client will come along asking for something 120cm to be met with blank stares.

I can completely understand that. I don't like the centimeter thing either. Logically, it doesn't take much to figure it out, but I would much rather someone say 1200mm.

Like the FS guide rails, they are in millimeters. It's 800, 1080, 1400, 1900, 2700, 3000, etc
80 centimeters or 300 centimeters would just sound funny.

 

[squall_line]

We still struggle in the UK though because our schools teach metric - in centimetres! 

Most trades will work in millimetres or metres.  Four foot (in old money) is quickly/roughly converted by older trades to either 1.2m or 1200mm without confusion, we all know what we mean.  A younger client will come along asking for something 120cm to be met with blank stares.

I can completely understand that. I don't like the centimeter thing either. Logically, it doesn't take much to figure it out, but I would much rather someone say 1200mm.

Like the FS guide rails, they are in millimeters. It's 800, 1080, 1400, 1900, 2700, 3000, etc
80 centimeters or 300 centimeters would just sound funny.

What, no decimeters?  [wink]

 

[Crazyraceguy]

No, that overcomplicates it even more.  [scared]
The guys I work with are amazed that I do the fraction/decimal thing with such ease. There is a "cheat sheet" taped up on the monitor stand of the beam saw, because you have to program it in decimal dimensions. The machines are actually built with the intention of metric, but when converted to imperial, it needs decimal equivalents. I stand there just fluidly entering numbers, never thinking one thing of it, and get the funny looks. How do you do that?
"Old-school" schooling, machinist training, and time. Millimeters are the place where I have to think about it.

 

[4nthony]

80 centimeters or 300 centimeters would just sound funny.

Or abbreviated...800 mils vs 80 cents. Cents sounds funny to me. Does anyone abbreviate centimeters to cents?

 

[Crazyraceguy]

80 centimeters or 300 centimeters would just sound funny.

Or abbreviated...800 mils vs 80 cents. Cents sounds funny to me. Does anyone abbreviate centimeters to cents?

Strangely enough, I don't use mils or mil either. I say millimeter all the way out. Mil is a thickness scheme all it's own. equivalent to .001" or .025mm Plastics, paint layers, etc. are measured in mils. I don't really know why, since they are equal to another form of measurement? and not seemingly arbitrary like gauge for metal or wire.

 

[Bob D.]

It is a bit weird reading imperial measurements in this thread after not using imperial for so long and that is from someone who grew up with imperial and converted back in the 1970's. Ask me what 2"6" looks like and I would not have a clue.

That stupid 2' 6" thing is some kind of carry-over that architects here in America will not let go of for some reason? Part of the job that our engineering department guys have to do, when converting the architectural plans into "shop drawings", is getting rid of that. Everything on the shop drawings is strictly in inches. That would be shown as 30"
It continues confusingly into retail stores too. I would love to know how many doors get returned to home centers because someone bought a 3-0 thinking that it was 30", and it turns out to be 36" because the 3-0 was 3 feet 0 inches.

I think it has to do with scale. That is the scale that that particular trade/profession is used to working in based on the size of the job. Things that fit within a normal size room can be handled easily in only inches. When you take on a whole building you need something more. Just as you said the drawings were 'converted' over to pure inches for use in your shop, and Architect could not (comfortably) work at their normal scale in only inches. Same goes for a Surveyor or Civil Engineer. If he were working in only inches the numbers would be huge. Decimal feet works best for him and most civil or dirt work.

 

[FestitaMakool]

Usually, we don’t say decimetre. It’s a bit odd.

And to frighten you even more: We say centimetre.. not millimetre, unless needed.

10mm = 1cm (centimetre)
10cm = 1dm (decimetre)
100cm = 1m (metre)

So, 120cm is the same as 1200mm or 1 metre and 20 centimetre.
So, 120,2cm is the same as 1202mm or 1 metre and 20,2 centimetre - indicating that ,2 is in millimetre - same as 2 tenths of a centimetre (Everything is divided by 10 up or down making it consistent. If you say 1” and 1/8th of an inch, it’s the same way of saying. Metric keeps everything in tenths - mostly.

If you look at a tape measure or ruler, “numbers” that falls between 1 millimetre is referred usually !only! as half a millimetre (unless you use a caliper.. then maybe a tenth of a millimetre)
In most instances, half a millimetre is usually close enough! Period!  [scared] [big grin] [big grin]
At least in woodworking..

 

[Crazyraceguy]

Yes, but you wouldn't, in conversation, say 1 meter and 20 centimeters, would you? and that is leaving out the 2mm at the end.
Isn't it just 1.2 meters? kind of assuming that the 2mm is not that important. (Unless you would need to be that precise, then 1202mm seems like the best way?

I think it has to do with scale. That is the scale that that particular trade/profession is used to working in based on the size of the job. Things that fit within a normal size room can be handled easily in only inches. When you take on a whole building you need something more. Just as you said the drawings were 'converted' over to pure inches for use in your shop, and Architect could not (comfortably) work at their normal scale in only inches. Same goes for a Surveyor or Civil Engineer. If he were working in only inches the numbers would be huge. Decimal feet works best for him and most civil or dirt work.

Bob D, I would buy that to some degree. Sure, sight plans which include the entire perimeter of the property, the outside dimensions of the building itself, and maybe even the rooms, but once you narrow it down to inside the rooms themselves? You no longer need the scale to be that big.
Most of the projects we get involved with, we don't need to know about the entire building. With limited exceptions like the sizes of doorways. On some, the entire scope of the job is in one room.

The really funny thing is that every drawing I ever saw in a machine shop has a tolerance, either with each dimension (if they are critical) or for the entire object.
It's just not done like that with shop drawings? Seems odd that something with inherently looser tolerances in the first place, doesn't specify them?
In the metal shop class, we were taught that fractional dimensions had the loosest tolerances, but I never saw one draw that way?

 

[FestitaMakool]

CRG, those are two examples.
One with a millimetre content, the other 120cm/1200mm really has none millimetre content.
120 centimetres are 120cm - as it’s needless to say 120,0

We say one twenty or hundredandtwenty in one word.
If there’s a millimetre that need to be spoken, it’s: hundredandtwentypointtwo centimetres (120,2) Sheetgoods, (who knows why… [blink]) it’s 1220mm or 122cm or 1m & 22cm..

But, if I get to the lumberyard, I ask for and look for: 2x4” (Which is, in reality 48x98mm/4,8x9,8cm (,8 indicates millimetre) When I learned the dimensions - back then a 2x4” was exact 2x4” - also in centimetres/millimetres - now none of metric or imperial is true to what it exactly is!
Still, 2x4, 2x6, 2x8 is the daily spoken..

 

[FestitaMakool]

A smart way to get metric naturally in your thinking is start measuring things around you.
Things that are imported, pre-built - that way you’ll get a sense of how many centimetres (remember, there’s 10mm in one centimetre!)

I did learn to visualise imperial by looking at and measuring: Speaker elements, wheels on cars, lumber, screens (TV’s), boats (always by foot), folding rules with both systems (still use..)
If we can visualise, we can learn faster, if the numbers results in “blank” then we struggle..

So, for me a speaker element is known as 13cm/5” and 16cm/6” - Not always correct when measuring, but you have a picture in your head - I think we all do know speaker elements.

The confusion for us (Europeans) is when you divide your inch in separate, 3 scales in fact, of what I know.. in 8’ths, in 32ths and in 64ths - We do 10 and half’s of that 1/10th or tenth of a tenth..

 

[Axis39]

CRG, those are two examples.
One with a millimetre content, the other 120cm/1200mm really has none millimetre content.
120 centimetres are 120cm - as it’s needless to say 120,0

We say one twenty or hundredandtwenty in one word.
If there’s a millimetre that need to be spoken, it’s: hundredandtwentypointtwo centimetres (120,2) Sheetgoods, (who knows why… [blink]) it’s 1220mm or 122cm or 1m & 22cm..

But, if I get to the lumberyard, I ask for and look for: 2x4” (Which is, in reality 48x98mm/4,8x9,8cm (,8 indicates millimetre) When I learned the dimensions - back then a 2x4” was exact 2x4” - also in centimetres/millimetres - now none of metric or imperial is true to what it exactly is!
Still, 2x4, 2x6, 2x8 is the daily spoken..

It's funny how we think of scale, and accuracy....

I've built and remodeled houses for years.  If I said to someone on the crew "5 and three eighths, heavy" they knew to cut it at 60 13/32"-ish.  These days, if I say "5 and 6 heavy' to my son, and co-worker, knows we are talking about 16ths.  So, he'd cut it at 5 foot (60 inches, of course) and in between 3/8" and 13/32".  But, yes, when we've worked in metric, a half mm seems accurate enough for most work.  Especially since the pencils we use are .5mm. (But, we still use light and heavy, or discuss thousandths....)

However, a lot of the time setting up machinery or jigs, I have to be much, much more precise.  As you mentioned, a caliper is probably gonna be in use at some point...  But, at that point, I do work in thousandths.  So, I would need something like 1200.01 mm.  (Although I don't think I have anything that actually measures in metric to that accuracy....  hmmmm).

Funny little anecdote, we were doing some finishing this week and needed to do some mixing.  I pulled out my digital postal scale and began measuring...  About a half a second in, I thought 'Do it in metric dummy, the math will be easier'.  This time, the dummy was correct!

 

[Crazyraceguy]

See, that's just funny  [blink] Everybody "knows" what a 2 x 4 is, yet there is literally no such thing. LOL They are 1 1/2" x 3 1/2" here. That was standardized decades ago when most of them were actually 1 5/8" x 3 5/8" and it made for odd dimensions during construction. A residential interior wall would be covered with 1/2" drywall (gypsum board) resulting in a total thickness of  4 1/2". Getting rid of those 1/8ths seemed to help.

I am always surprised by the simple things that are done in other countries, which are based on American standards. Years ago, when I first heard about "Baltic Birch" plywood and that it was supplied in 60 x 60 sheets, I thought it was odd? Why be different in the first place? but also why in inches? 1500mm? that would be 59"

I just can't get with the folding rule thing. I don't really know why, but they seem crude and clunky. They were commonly used when I was a kid, but not any more.

The 1220 x 2440 thing was just metric conversion from American 4' x 8', but again, why? Is it just that common over there to stick with it as a standard, even though it does not "fit" with the metric measurements?

 

[FestitaMakool]

Exactly Crazyraceguy, I remember this was a part of transition to metric (48x98mm)
Then I thought, why on earth not 50x100? so much easier - then someone said it’s about adding with other dimensions and drying of lumber.. slippery slope - I think that’s why 2x4 stayed.. easy to remember and speak out - and visualise.

Should I advise, try round up (or down) to closest fully centimetre - leave the metric fractions out when thinking metric.

A systainer is something you all are familiar with: It’s built to fit a 30x40cm space with slight wiggle room [wink] - Euro packing size..
Visualising in whole, round numbers are easier. If you must have it in Millimeters - add a “0” and you have it.
Or, subtract a “0” from Millimeters, and you have centimetres.

 

[Crazyraceguy]

It's funny how we think of scale, and accuracy....

I've built and remodeled houses for years.  If I said to someone on the crew "5 and three eighths, heavy" they knew to cut it at 60 13/32"-ish.  These days, if I say "5 and 6 heavy' to my son, and co-worker, knows we are talking about 16ths.  So, he'd cut it at 5 foot (60 inches, of course) and in between 3/8" and 13/32".  But, yes, when we've worked in metric, a half mm seems accurate enough for most work.  Especially since the pencils we use are .5mm. (But, we still use light and heavy, or discuss thousandths....)

However, a lot of the time setting up machinery or jigs, I have to be much, much more precise.  As you mentioned, a caliper is probably gonna be in use at some point...  But, at that point, I do work in thousandths.  So, I would need something like 1200.01 mm.  (Although I don't think I have anything that actually measures in metric to that accuracy....  hmmmm).

Funny little anecdote, we were doing some finishing this week and needed to do some mixing.  I pulled out my digital postal scale and began measuring...  About a half a second in, I thought 'Do it in metric dummy, the math will be easier'.  This time, the dummy was correct!

That's a bit of a "code" though between a fitter and his cutter, not exactly normal conversational use.
Generally, heavy or light is 1/16" when the number is given in 8ths and 1/32 when the number is given in 16ths. That gets worked out over time between guys who work together often.

My days as a machinist would have me looking down on calipers as accurate. They are "ok" for simple things and are a far less costly alternative over a greater range of measurements, but not nearly as accurate.
Back when I first started in the machine shop (1981) metric was still considered a bad thing that was forced on us in elementary school. Even though I worked for the Coromant division of Sandvik, we used imperial measurement down to .0001"  That plant was closed and a few of them were consolidated in another state. That's how I eventually ended up with wood. The processes are similar in many ways, once you learn the differences in terminology to mean the same thing.