Imperial vs Metric

[billw]

It's dawned on me that some tools I have are metric and some imperial. Now I don't particularly see an issue with it, given that the conversions by 16ths are a maximum of less than 0.5mm out either way and the average is about 0.25mm

Given the only time that these seemingly come into play for accuracy purposes is for chisels and some specialist planes because their blades are imperial, does it actually matter that much or do most people pick one or the other for their tools and stick to it?

 

[MikeG.]

It makes no difference. Everything I do is designed in metric measurements, but most of my tools were manufactured when the inch ruled the world.

 

[marcros]

I have a bit of a mix too. the only issue that I would warn against is a plan in metric and measuring equipment in imperial. That is asking for issues.

 

[Nigel Burden]

I use imperial for most length measurements, but sometimes metric might be easier. Imperial is easier to divide up though. For lighter weights I tend to use metric, but I usually weigh in stones.
So, being of an age where we were taught imperial, I use that more than metric.

Nigel.

 

[AES]

Much the same here - mix of both Metric & Imperial tools. The only thing I would say is that on a per-project basis decide which system you'll use and stick to it "religiously". For me that decision is usually based on which system is used on whatever plans/drawings I'm working from.

And I'm not being at all "sniffy", but in most woodwork (all?), and especially for the sort of "woodwork" I do (!!!), any differences that arise from converting Imp to Met and vice-versa are well within the normal allowable tolerances anyway (That's SOMETIMES a different story if we're talking metal working, but for me anyway, most of what I do relies on "fits and feel" anyway, so once we've got to the rough dimension, the actual measurement number is largely irrelevant).

 

[MikeG.]

........ Imperial is easier to divide up though.........

Really?

I have a bannister 4'-10 3/8" long and want to space the 12 ballusters out equally. What's my spacing?

Whilst you're doing that, I'll divide 1483 by 13 and then go and make us both a cup of tea. You might be done by the time I'm back.

 

[MikeK]

Really?

I have a bannister 4'-10 3/8" long and want to space the 12 ballusters out equally. What's my spacing?

Whilst you're doing that, I'll divide 1483 by 13 and then go and make us both a cup of tea. You might be done by the time I'm back.

That's easy, the spacing would be 4 51/104" on center. Now where did I put that tape measure?

I've been using metric for over 25 years for the ease of calculations and because all of the material and tools readily available to me are metric.

Update: I remembered last night that all of my chisels and plane irons are imperial.

 

[Phil Pascoe]

I have no idea what sizes my chisels are - I just use the one that's the right size for what I'm doing.

 

[Rorschach]

I have old imperial tools and newer metric tools. I work in both depending on the job. Rough work for breaking down materials I use imperial, bigger units make it easier to mark and divide. Precision work and smaller work is done in metric. Lathe is imperial so I added a DRO to make my life easier.

At the end of the day, use what works for you, as long as it fits it doesn't matter how you measure it.

 

[Nigel Burden]

Really?

I have a bannister 4'-10 3/8" long and want to space the 12 ballusters out equally. What's my spacing?

Whilst you're doing that, I'll divide 1483 by 13 and then go and make us both a cup of tea. You might be done by the time I'm back.

Ok, I capitulate.

114.0/1 = somewhere around 5 33/64" or thereabouts.

Now, where's my cup of tea?

Nigel.

 

[AndyT]

Well this is all refreshingly pragmatic.

I also understand and use both systems. I learned both at school but lean towards inches for most woodworking, mostly because my tools and old books are in inches.

Having a mixture is useful for near-miss sizes, such as the choice between a 12mm or a half inch hole, for a tight or loose fit.

 

[Distinterior]

That's easy, the spacing would be 4 51/104" on center.....

.....I dont even know what those numbers you have written are supposed to signify...?

I was taught to work in both Imperial & Metric scales but I certainly find Metric easier, especially when getting down to really small sizes....What is 51/104ths anyway...?.....Is that a knats bits less than 1/2" on a humid day..?

 

[MikeG.]

A couple of weeks ago I watched the guys building Acorn to Arabella dividing up lengths along each frame to get their planking widths individually at each station. They are American, so it was in Imperial. They first converted measurements in inches and eighths to metric inches (ie 10ths), then did the maths, then converted back to 8ths. It took three of them forever. All the comments on Youtube were along the lines of "do it in metric" and "how did you guys ever get to the moon?"

 

[MikeG.]

.....I dont even know what those numbers you have written are supposed to signify...?........

Humour. Or irony.

 

[MikeG.]

.......Now, where's my cup of tea?.........

Over there, on the worktop. Next to the kettle.

 

[MusicMan]

I was brought up in Imperial then early metric (cgs) for scientific subjects. I began to use metic exclusively for design when I began as a research student almost 60 years ago and think exclusively in metric (apart from miles). Most of my tools are metric, even the old lathes, miller and bandsaw, since I bought German Boley, Swedish Arboga and Swiss Inca. Only the Wadkin saw is Imperial. Easily overcome for a saw, and anyway I measure using a steel rule to the blade rather than the built-in Imperial rule for width of cut. Considered changing that to metric too, but didn't like to change an original part. A set of Imperial spanners live by that saw and everywhere else is metric. Oh I suppose the old chisels aren't, but I rarely use those where the width is critical (the mortiser is metric). I detest anything other than whole numbers of inches or feet in metric!

 

[Distinterior]

Humour. Or irony.

A bit of both Mike..

 

[Distinterior]

A couple of weeks ago I watched the guys building Acorn to Arabella dividing up lengths along each frame to get their planking widths individually at each station. They are American, so it was in Imperial. They first converted measurements in inches and eighths to metric inches (ie 10ths), then did the maths, then converted back to 8ths. It took three of them forever. All the comments on Youtube were along the lines of "do it in metric" and "how did you guys ever get to the moon?"

I think I remember something similar being said on the "Tally Ho" project....perhaps that's where you saw it Mike?

 

[Just4Fun]

And I'm not being at all "sniffy", but in most woodwork (all?), and especially for the sort of "woodwork" I do (!!!), any differences that arise from converting Imp to Met and vice-versa are well within the normal allowable tolerances anyway (That's SOMETIMES a different story if we're talking metal working ...

A friend designed a car that he eventually put into production as a kit car. When he built the prototype he marked out all the metal for the chassis and was puzzled by an error of about 1mm when he compared the total length of material he had marked out compared to the total required by his design. He spent 3 days tracking down the probem before he would cut a single piece. It turned out to be the cumulative effect of numerous imperial to metric conversions.

 

[MikeG.]

I think I remember something similar being said on the "Tally Ho" project....perhaps that's where you saw it Mike?

No, it was definitely A2A. Here, at 23 minutes onwards.