Metric meets imperial

[MarkAR]

Alas we are forgetting machinists real life measurements, a Gnats Whisker, a Fannies Hair, the ubiquitous Tad and Smidgeon, all the way up to a Chunk.

[Mr Spock]

One of the biggest offenders is B&Q.

I have some of their replacement tap heads fitted to my kitchen taps. Last week I bought their replacement tap washers.

Guess what? The tap washers are 1/2" and the taps are 12mm... 

[andrew s]

6 hours ago, MarkAR said:

Alas we are forgetting machinists real life measurements, a Gnats Whisker, a Fannies Hair, the ubiquitous Tad and Smidgeon, all the way up to a Chunk.

When measuring for DIY if it's small I use mm but large ft/ in. 

No idea why .

Regards Andrew 

[Chriske]

I think the older guys here must be masters in using fractions.

When I was younger, even using metric units, I often would grab the wrong wrench for a certain hex-bolt I needed to fasten. After 'a few' years now I know what wrench to grab for any bolt.
Let's say you're working on a project assembled using Imperial hex bolts, different sizes. How do you know what wrench to grab when you took the wrong one in the first place.

Another thing, I do have a well equipped workshop. Among the many tools I have, also many drills. The smallest drill is 0.1mm. It goes up by 0.1mm per step, ending at 10mm. After that it continues to go up with 0.5mm per drill.
An example drill 5.0mm, next 5.1mm, next 5.2mm, next 5.3.....until 5.9, next 6.0....etc...
How do you(did you?) name these set of drills if it were imperial sizes only differ 0.1mm(equivalent)....?

I know you have that numerical system, but I'm talking before that system was used.
When I was at school we had to learn all about Imperial, The smallest we could measure with our calliper at the time was 1/128". There were even questions during exam about it....😡. At the time we all hated you....🤭   To be clear that was looooong before digital callipers existed.!

[Gina]

Oh yes, I remember that 😟  Hated fractions.  Much prefer metric but I do also still think in feet and inches.

And yes, when I was at school we had conversion tables on the backs of our exercise books.  With gear based on American standards I find myself needing to remember the conversion factors.  Inch = 25.4mm.  Foot = 305mm.  1/4" = 6.35mm (scope rings etc.).

[Tenor Viol]

10 hours ago, Corncrake said:

They are not SI base units, but they can be derived, I dont think they are named derived units though are they ?

(OT) I dont like named SI units. You can feel lbs/sq.in or kg/cm² but whats a Newton when its spread out ?

ducks

(/ot)

and dont get me started on cycles/sec, they just hertz.

I may have used the wrong terminology... I think they are recognised as being "metric" units - mensuration is not a speciality of mine so apologies if terminology is incorrect

[Corncrake]

40 minutes ago, Chriske said:

How do you(did you?) name these set of drills if it were imperial sizes only differ 0.1mm(equivalent)....?

At the time we all hated you....🤭   To be clear that was looooong before digital callipers existed.!

You really dont want to know, , , trust me , ,

Oh well if you insist - we used letters ! and would you believe even the sizes of the differences differed

A, B, C, D, differed by 4thou, all looks good, , , until you find that F is 7thou bigger than E. A few more 4thou intervals and then L is 9thou bigger than K

argh even we hated us !

Actually, "at the time" is good news ! I thought y'all still did ! lol!

 

 

Edited June 12, 2020 by Corncrake

[Corncrake]

2 minutes ago, Tenor Viol said:

I may have used the wrong terminology... I think they are recognised as being "metric" units - mensuration is not a speciality of mine so apologies if terminology is incorrect

No worries, all good for a giggle ! (unless one is trying to land on Mars, gulp )

[Chriske]

The only visible thing we still buy here is wood.
Buying a sheet of plywood, 95% we buy is still 1220x2440 mm, that is 8'x4' if I'm not mistaken.  Meaning, at a bigger scale lots of wood is lost because nobody works with Imperial sizes at this side of the channel...😁

[Oldfort]

When I was at (primary?) school, we had the delightful mixture of imperial weights and £/s/d.  This would lead to delightful questions along the lines of:

If X costs £1, 2shillings & tuppence halfpenny a pound, how much would 3 stone, 2 lbs and 5 oz cost?

[andrew s]

11 minutes ago, Oldfort said:

When I was at (primary?) school, we had the delightful mixture of imperial weights and £/s/d.  This would lead to delightful questions along the lines of:

If X costs £1, 2shillings & tuppence halfpenny a pound, how much would 3 stone, 2 lbs and 5 oz cost?

Nooooo, I hated arithmetic love maths. (68 yrs going on 6 yrs mental age)

Regards Andrew 

[JamesF]

1 hour ago, Chriske said:

Buying a sheet of plywood, 95% we buy is still 1220x2440 mm, that is 8'x4' if I'm not mistaken.  Meaning, at a bigger scale lots of wood is lost because nobody works with Imperial sizes at this side of the channel...😁

Lots of sheet materials are sold here in 2440x1220mm sizes, but then others have been changed to 2400x1200mm.  For example when I was building the observatory I had a couple of sheets of 2440x1200  OSB left over from another project that I used for the roof, but I needed four so I ordered a couple more.  The new ones were 2400x1200.  A full sheet of plywood however still comes as 2440x1220.

James

[Chriske]

Some brands here start to sell 1.25x2.5m.

[MarkAR]

I think timber starts as imperial, say 2" x 2" when it is rough sawn. Then gets reduced to 44mm square as planed all round.

 

[johnturley]

3 hours ago, Chriske said:

I

Another thing, I do have a well equipped workshop. Among the many tools I have, also many drills. The smallest drill is 0.1mm. It goes up by 0.1mm per step, ending at 10mm. After that it continues to go up with 0.5mm per drill.

 

I can't imagine a drill bit as small as 0.1 mm, what does it look like, and what is it used for, my smallest drill bit is 1.5 mm, and that is very delicate.

John 

[Chriske]

These very small drill-bits need a Dremel of course.
0.7 and 0.8 are in use right now.

Drillbit 0.1mm is not visible because it is right above one of the tape measure's black marking.

Getting a bit closer....

Damn...!!! Making this picture I notice 0.2mm is broke..

But 0.1 is still ok. Using these small drillbits you need a Dremel it needs about 35.000 rpm. I made a special tool to hold my Dremel around the tailstock's barrel. Works perfect.
Why do I need these small drill bits...? : to make holes for 3D-printing nozzles.
The one I use the most is 0.25, 0.3, 0.35 and 0.4mm. But that is for friends. Except for the 0.4mm I never use these small drill bits myself because mostly I use very big nozzles. The biggest I use very often is the 1.5mm.  Busy building a bigger printer(on hold right now) to make very large parts using a 2.5(!)mm nozzle. But that's another story.

 

[wimvb]

3 hours ago, Oldfort said:

If X costs £1, 2shillings & tuppence halfpenny a pound, how much would 3 stone, 2 lbs and 5 oz cost?

You can have that stone that broke my knee cap last winter, for free. 😁

[Gina]

My smallest drill bit is 1mm but I can't find it ATM - probably hiding in the pile of the carpet!!

[Gina]

Those micro drill bits must take a lot of very careful handling, Chris!!

[Chriske]

You don't wont to know how many I broke until now...😱

[Chriske]

Here I'm busy drilling with a 0.4mm drill bit.

[Gina]

I imaging a lot of miniature drills must have broken!  My little cheapo Chinese clone of a lathe would not be accurate enough! 

Edited June 12, 2020 by Gina

[Chriske]

Possibly, a friend has such a cheapo Chinese clone, and in his case the tail-stock's barrel is not centred with the chuck at all. And there's no way to adjust it.

[Tenor Viol]

I don't know the veracity of this, but allegedly the "Japanese inch" at 0.96" which used to be common for eyepieces was caused by inadvertently transposing 25.4mm to 24.5mm for the conversion from Imperial to metric....

[MarkAR]

Anyone got any smaller drills that they've successfully drilled with ?

This is the best I managed.

Edited June 12, 2020 by MarkAR