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

[rmwarren]

Oh - and just in case anyone thinks I’m being metrically evangelical - yeah, we’re TOTALLY metric in the UK. Apart from the inconvenient truths that we drink our beer in pints, we measure our fuel consumption in miles per gallon, when asked for directions we say ‘turn right in 100 yards’, our railway track gauge is 4 feet 8.5 inches, we still go into stores and ask for 4 ounces of our favourite candy, we buy pints of milk, we weigh ourselves using stones and pounds, and measure our height in feet and inches.

That's the nice thing about standardized systems..... there's so many to choose from!

[big grin] [big grin] I visited the yard this morning to collect half a dozen doors and a pile of timber for an upcoming job. In the queue in front of me was a DIY guy pricing up materials for a home project. I swear the following conversation is EXACTLY how it happened;

Customer - “What sizes do your MDF sheets come in?”
Yard - “10x5, 8x4 and 6x3”.
Customer - Ah, OK. What thicknesses do you carry in stock?”
Yard - “25mm, 18mm, 15mm, 12mm, 9mm and 6mm.”
Customer - “I’ll need some skirtings (US = baseboards). What sizes do you carry in each profile?”
Yard - “5 inch, 7 inch and 9 inch. All 18mm thick”.
Customer - “What lengths do they come in?”
Yard - “5.4 metre, 4.8 metre, 3.6 metre and 2.4 metre.”
Customer - “Finally, I’ll need fence posts. What do you carry?”
Yard - “4”x4”, 5”x5” and 6”x6”. All in 3-metre lengths”.

[eek] [eek]

Too funny.

IIRC the advent of 32mm frameless cabinets was after WW2 as a means of getting by with limited materials and no surviving industrial base.

Sooooo brits were using a rational system and got reinfected by our system and never recovered... Else, who would'a standardized on 2440/1220? [poke]

RMW

 

[bwehman]

Honestly, the biggest challenge about switching to metric is having a concept of size. Like... I can picture in my head what 3 feet looks like, for example, but not 915 millimeters. That's just gonna take time I suppose.

 

[Packard]

There are online calculators and they are only as far away as my phone.  If I am converting a plan, then I make the imperial notations on the plan. 

My digital vernier toggles between mm, inches and fractions.  So any measurement under 6" is instantaneously available. 

But to the greatest extent possible I avoid measuring at all.  I transfer dimensions with a story stick, or marking directly onto the stock. 

 

[rmwarren]

Honestly, the biggest challenge about switching to metric is having a concept of size. Like... I can picture in my head what 3 feet looks like, for example, but not 915 millimeters. That's just gonna take time I suppose.

I've been transitioning for around 10 years and still think Imperial. "I need 4"... that's ~100mm".

Throw in fastener thread pitches and things get jumbled really fast.

RMW

 

[woodbutcherbower]

Honestly, the biggest challenge about switching to metric is having a concept of size. Like... I can picture in my head what 3 feet looks like, for example, but not 915 millimeters. That's just gonna take time I suppose.

Understood - but the easy way is to remember that a yard and a metre are about the same (36” vs just over 39”). You know what 6 feet looks like? 2 yards? It’s 2 metres or 2000mm. Another easy way to visualise stuff is to remember that a foot is around 300mm.

 

[smorgasbord]

I also recently converted to metric after years of saying I would. Won't go back now.

I find that the Shinwa metal rules are the best for me. No glare, sharp markings, reasonable price. I choose the ones that don't have ½ mm markings, as that just makes it too hard for my old eyes to read. I can easily split a mm if I need to. Starrett rules are great, too, but way more money. Some metal rules mix up mm/cm units in weird ways that make it hard for newbies on the longer ones (eg 600mm), but Shinwa's are straightforward, just counting mm.

For tape, the Komelon PG85 8m by 25mm Metric Gripper Tape is really good as well.

Both available on Amazon.

 

[thudchkr]

I've gotten the Woodpecker rules in 900, 600 and 300 lengths but tend to not rely on their measuring capability.  I will often use the multiple Starrett rulers that I have in my combo squares and double squares but my most consistent go to's are the Shinwa rules that I picked up off Amazon.  I also have some PEC hook rules that are nice as well. 

For longer measurements I use Tajima metric tapes that I've found to be spot on when compared to both the Shinwa's and the Starrett's.

I have some of the metric Fastcap's but don't use them from precise measuring.

 

[smorgasbord]

In a related note, I also use Incra metric scales/locking teeth on my tablesaw sled fence and on my miter saw fence. The dual flip stop is very stable and can be analog-micro adjusted to lock in repeatable weeks later length cuts.

 

[Coen]

And the date today is 44694  [tongue]
Seriously, open Excel, format an empty cell as date, input 44694, hit [enter] and it will promptly convert it to 13-5-2022  [tongue]

I’ve always felt that for the North American woodworker, being introduced to the metric scale must be like learning a foreign language. For Brits, Europeans and Scandinavians - it’s a common language we all speak. We can easily point out the flaws in the Imperial system - but it’s what you guys have grown up with, it’s what you know, and what you are comfortable with.

The greatest single advantage of metric, however, is its linearity. Everything  - like EVERYTHING -  can be measured in mm rather than yards, feet, inches, halves, quarters, eighths, sixteenths, thirty-seconds and sixty-fourths. There’s virtually zero math involved when you need to add two bizarre lengths together, for example = for us, it’s just 242 + 147 = 389. The Imperial equivalent of that would inevitably involve a world of fractions. I couldn’t imagine subtracting 4 and 3/8ths from 12 and 17/32nds all day long.

To answer your question = a quality square-ended tape is a must - a good one will give accurate measurements in almost every case. For most applications involving accurate short-scale measurements - high-quality steel rules are your best friend, usually bought over here as a set of four - 1000/600/300/100. Check out the UK Axminster Tools website. There’s some beautiful stuff on there and they ship worldwide.

Oh - and just in case anyone thinks I’m being metrically evangelical - yeah, we’re TOTALLY metric in the UK. Apart from the inconvenient truths that we drink our beer in pints, we measure our fuel consumption in miles per gallon, when asked for directions we say ‘turn right in 100 yards’, our railway track gauge is 4 feet 8.5 inches, we still go into stores and ask for 4 ounces of our favourite candy, we buy pints of milk, we weigh ourselves using stones and pounds, and measure our height in feet and inches.

But an 8’ x 4’ sheet of plywood? NO !! It’s 2440 x 1220mm !!!!

Good luck in your new world.

Weird gauge you have. But nice that the Eurostar fits on it too. It rides on 1435mm on the continent  [tongue]

I've always said you Brits were kinda weird. I also said that if the Eurocrats in Brussels had not have stiffed Cameron Brexit would have never happened.

Untill I joined the FoG I had never realized 2440x1220 comes from some imperial origin.

That being said, for lengths longer than 12" I've been using a FastCap metric tape measure with a flat tape. Thing is, the measurement can be millimeters off depending on how square the end of the tape measure is on the reference surface, and when I'm trying to nail the position of a domino, it matters.

Huh? If you hold your tape diagonally it's gonna be off no matter the end of the tape  [huh]

 

[FestitaMakool]

When on the move.. consider trying folding rules as well.
And no; don’t put the end of the workpiece and the look up the number you want.
Do the opposite; place the measurement/number you want at the end of the workpiece, then mark at the end of the ruler - just as you would with a combination square.

Another thing; get those flat carpenters pencils, sharpen to FLAT/WIDE/knife edge tip, never round like some (Ie: Irwin) pencil sharpeners that make wide flat pencils with a round tip.. [crying] Use a sharp knife. Can also be fine tuned on a piece of fine grit sanding paper. [wink]
The tip when sharpened correctly will stay sharper way longer than any round tipped pencil.
“Hairline” thick that is.

Place pencil at a 45° angle at the end of the folding ruler and mark. Cut the pencil line just away.

 

[Crazyraceguy]

AND then there's the 3rd system of using decimals.  I tend to use a mix of imperial and metric for measuring and then draw everything in autocad in imperial decimal.  I wish my cad program allowed me to input metric units when drawing in imperial and it would automatically do the conversion. Even though I know the the decimal equivalent down to 1/16th out to 3 places off the top of my head I dont have my metric equivalents down yet so I have to use a cheat sheet for the most common metric sizes

5mm = .1969
8mm = .315
9.5mm = .374
15.5mm = .610
20mm = .7874
32mm = 1.2598
36mm = 1.417
36.5mm = 1.437
37mm = 1.457
46.5mm = 1.831
49mm = 1.9291
96mm = 3.7795

I do the same thing. My vocational training, decades ago, was in we would call "manual machining", since it was before CNC. Because of the precision required with metal work, we were diligently taught to know decimal equivalents. It was like learning the multiplication tables in elementary school. So, when I started with woodworking, I was already at an advantage. I can add fractions in my head too, but it gets annoying when you go too far with it. Decimals are just easier. Since I got into Festool, several years ago, I decided to embrace the metric, rather than fight it, so I kind of mix them.
I would rather the entire shop go metric, especially since so many of the big machines could make the switch in just seconds, but I don't see it happening.

 

[rmwarren]

AND then there's the 3rd system of using decimals.  I tend to use a mix of imperial and metric for measuring and then draw everything in autocad in imperial decimal.  I wish my cad program allowed me to input metric units when drawing in imperial and it would automatically do the conversion. Even though I know the the decimal equivalent down to 1/16th out to 3 places off the top of my head I dont have my metric equivalents down yet so I have to use a cheat sheet for the most common metric sizes

5mm = .1969
8mm = .315
9.5mm = .374
15.5mm = .610
20mm = .7874
32mm = 1.2598
36mm = 1.417
36.5mm = 1.437
37mm = 1.457
46.5mm = 1.831
49mm = 1.9291
96mm = 3.7795

I do the same thing. My vocational training, decades ago, was in we would call "manual machining", since it was before CNC. Because of the precision required with metal work, we were diligently taught to know decimal equivalents. It was like learning the multiplication tables in elementary school. So, when I started with woodworking, I was already at an advantage. I can add fractions in my head too, but it gets annoying when you go too far with it. Decimals are just easier. Since I got into Festool, several years ago, I decided to embrace the metric, rather than fight it, so I kind of mix them.
I would rather the entire shop go metric, especially since so many of the big machines could make the switch in just seconds, but I don't see it happening.

Reading thru this post I realized I do the same in reverse, i.e. 1/4" = 6.35mm. My memorized Metric-ifcation tables only go up to around 4" though. Anything over that and I stop and puzzle whether I need to divide/multiply by 25.4.

I also find myself mixing systems when in the shop. I use a lot of 80/20 15 series (38.1mm) with .312" (~8mm) slots and 5/16" hardware.

RMW

 

[woodbutcherbower]

[member=8955]Coen[/member] Everything in the UK comes from an imperial origin. Our standard internal door size, for example, is 1981 x 762mm. Do the math and you’ll immediately see that’s 6’6” x 2’6” in metric. Our sheet materials have however now standardised at 2400 x 1200 rather than 2440 x 1220 - largely because the drywall industry adopted it first. The framing carpenters suddenly needed to get their verticals nailed at 600mm centres so the 8’ x 4’ sheet edges would hit the centreline of the vertical stud.

And yeah. Us Brits are weird. In a lovable, special way.

PS - I’m loving this thread. It’s so great to see so many open-minded NA guys willing to try something new, and almost certainly outside of their decades-long comfort zone. Enormous respect to you guys  for that.

 

[Crazyraceguy]

For small fractions there are quite a few "usable" overlaps.
Of course, the most common is 3/4" and 19mm. Many cheap socket (or wrench) sets don't even come with both. You are expected to know that the same one fits either size.
1/4" and 6mm. Close, but not close enough for tools to interchange. Most of the sheet goods available in the US are actually 6mm, but sold as 1/4".
5/16" and 8mm. There is only .003" difference in them. 5/16= .312 , 8mm= .315
This also multiplies by 2 to make 5/8" and 16mm the same
15/16"= .937 is also very close to 24mm. It's actually 23.8mm
Even 1/8" and 3mm are very close, but the smaller you get overall, the bigger difference it makes.

 

[Jim_in_PA]

I switched to fully metric a few years ago, at least for everything that I have the choice. (one client prefers decimal inch for the stuff I do CNC work for him and construction/home improvement stayed inches) I have a bunch of dual scale steel rules I use and have metric rules for my squares. For longer than 700mm or so, I use a metric tape measure, but I would have done that with inches anyway. BTW, I also make frequent used of a digital caliper for measuring thickness.

 

[rmwarren]

Sheet goods thickness is the most frustrating aspect to deal with. I frequently get 3/4" material anywhere between 17.5 and 20mm. I even got some 1/4" MDF that was 7mm thick.

I'd be thrilled if everything was consistently 6/12/18mm.

RMW

 

[Mini Me]

Another thing; get those flat carpenters pencils, sharpen to FLAT/WIDE/knife edge tip, never round like some (Ie: Irwin) pencil sharpeners that make wide flat pencils with a round tip.. [crying] Use a sharp knife. Can also be fine tuned on a piece of fine grit sanding paper. [wink]
The tip when sharpened correctly will stay sharper way longer than any round tipped pencil.
“Hairline” thick that is.

Place pencil at a 45° angle at the end of the folding ruler and mark. Cut the pencil line just away.

I sharpen carpenters pencils on the side of a grinding wheel but you have to be careful or you will have a short pencil in nothing flat.

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.

 

[Crazyraceguy]

Sheet goods thickness is the most frustrating aspect to deal with. I frequently get 3/4" material anywhere between 17.5 and 20mm. I even got some 1/4" MDF that was 7mm thick.

I'd be thrilled if everything was consistently 6/12/18mm.

RMW

Yeah, and it can very that much from sheet to sheet within the same stack. We get "factory" banded units, so it not like a mixed mess of "who knows what" from a retail store, and it is still like this.
Particle board and MDF are more consistent, ply is the worst.

When we get 1/4" MDF, it is usually pretty close, but 1/4" "Case back" which is precoated with white, is 6mm.

 

[smorgasbord]

Ask me what 2"6" looks like and I would not have a clue.

Um, no-one has a clue what 2" 6" is.  [huh]

Is that 8"? Or, maybe a negative 4"?  [unsure]

On a more serious note, Imperial gets it wrong not only by using fractions, but by having larger units not be multiples of ten. For inches to feet, you're dealing in base 12. For feet to yards, base 3. And for yards to miles, base 1760 - which means feet to miles 5280.

With metric you deal with base 10 everywhere up and down the chain. Just move the decimal point.

And of course, there's Dan Ackroyd's Decabet.

 

[Coen]

2"6" is 12"^2  [wink]