Scale rules

[melidman]

Hi all i have noticed that most drawings are in feet and inches, are feet and inch scale rules still available or do you have to convert to metric when taking dimensions of a plan?

[Timmo]

While the USA sticks doggedly to using feet and inches I suspect their buying power will keep all manner of imperial measuring devices in production. 

I'd certainly be cautious about converting to metric, especially if you don't plan on doing a full lofting. While the inaccuracies in conversion can be small, they do seem to compound somehow to create issues when pulling the boat together.

Tim.

From: "melidman [via UK HBBR Forum]" <[hidden email]>
Date: Wed, 8 Jun 2011 12:53:47 -0700 (PDT)
To: Tim O'Connor <[hidden email]>
Subject: Scale rules

Hi all i have noticed that most drawings are in feet and inches, are feet and inch scale rules still available or do you have to convert to metric when taking dimensions of a plan?

[Port-Na-Storm]

Most designs are in feet and inches either because they are very old, or because that's how the Americans measure things.

As Cee Dubbs has just demonstrated elsewhere some of us are of and age where we use both. I tend to measure in metric but think in imperial, especially when it comes to boat length.

If you wander down the tools isle at your friendly B&Q  you'll find that tape measures show both, which just goes to prolong our bi linear habit. I think you can still get 12 and 18 inch rules which have a bit of both on them too.

I cant remember seeing and with gnats' dicks' though, which was a common surveying measurement. As in
" Its not a gnats dick off 22m"

I should be packing...............  

[Jeremy]

I too was brought up using Imperial measurements, but chose a career where SI units were de rigueur , so have, by default, become bi-linear.  It's compounded in my case by having machine tools with dials that are mixed (the lathe is Chinese and in mm, the small milling machine is American and in thou), but this has had the effect of causing me to memorise the mantra 1 inch = 25.4mm, or 1mm = 40 thou.

Whilst the gnat's dick might be a colloquial descriptor for a very small increment in some regions, in Cornwall I was brought up to refer to this particular unit as a naffigravit...............

Anyway, to get back on track, scaling is unaffected by units of measurement, so a drawing that's at 1/10th scale in imperial remains at 1/10th scale in SI units.  I will admit to preferring SI units, particularly as I get older, if only because doing sums that are multiples of 10 seems simpler.

Somewhere I still have a triangular scale rule lying around that I think is old enough to be Imperial.  I will try and find it and bring it along to Beale Park.

Jeremy

[Paul H (admin)]

Port-Na-Storm wrote

As Cee Dubbs has just demonstrated elsewhere some of us are of and age where we use both. I tend to measure in metric but think in imperial, especially when it comes to boat length.

Yep, in Junior school I learned gineas, pounds, crowns, shillings, pence, yards, feet, inches and fractions
then in senior school decimalisation changed us to metric.....but fractions are a lost art I think.

I measure in mm because at its more accurate than 1/16th and 1/32nd is too small to read. Also try adding 3 5/8 and 7 3/4 and dividng by 2 within 5 seconds....the maths is far quicker in metric. Occasionally I use inches for less accurate measurements that just have to be consistent e.g. 2 lengths of wood each 12in long

In my professional job in CAD/CAM I met a New York cabinetmaker who said he uses millimeters. When I asked why he said "because its easier than inches" QED.


-Paul

[WalneyJohn]

On the subject of metric or imperial, I heard a great quote last week:

"That if God had wanted us to use the metric system; Jesus would have chosen 10 disciples"

John,

[Port-Na-Storm]

On the subject of tape rules,

Somewhere there is a tape with the measurements printed the other way up. So you read the tape from right to left instead of the conventional left to right. This means for most right handed people you hold the tape in your left hand while marking off with your right which has got to be a lot easier than the kack-handed way I do it.
Of course the easiest way to take off measurements from a scale drawing is by using a pair of dividers, then "walking" them along the piece to be marked, or when measuring off the actual boat use a spileing stick. No measurement units required in either case. Simples.

Off to Beale, Yippee!  

[melidman]

What happens when working off a drawing that say has a 1 3/4" to 1 foot scale.  That goes to 45mm to 300mm
How does that work?
Sent from my Windows Phone

---

From: Port-Na-Storm [via UK HBBR Forum]
Sent: 09 June 2011 07:13 AM
To: melidman
Subject: Re: Scale rules

On the subject of tape rules,

Somewhere there is a tape with the measurements printed the other way up. So you read the tape from right to left instead of the conventional left to right. This means for most right handed people you hold the tape in your left hand while marking off with your right which has got to be a lot easier than the kack-handed way I do it.
Of course the easiest way to take off measurements from a scale drawing is by using a pair of dividers, then "walking" them along the piece to be marked, or when measuring off the actual boat use a spileing stick. No measurement units required in either case. Simples.

Off to Beale, Yippee!  

---

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[alopenboat]

On 8 Jun 2011 at 15:59, adminHBBR [via UK HBBR Forum] wrote:

 
> In my professional job in CAD/CAM I met a New York cabinetmaker who
> said he uses millimeters. When I asked why he said "because its easier
> than inches" QED.

The designer of the Paradox, though an American, drew the plans in
millimetres and, when asked, gave the same reason.

--
Hoping for calm nights

Alastair Law,      
Yeovil, England.
<http://www.little.jim.freeuk.com>          

[alopenboat]

On 8 Jun 2011 at 16:29, WalneyJohn [via UK HBBR Forum] wrote:

>
>
> On the subject of metric or imperial, I heard a great quote last week:
>
> "That if God had wanted us to use the metric system; Jesus would have
> chosen 10 disciples"
>
> John,

That *might* explain the inches, but what about the yards, miles,
chains, poles ............ ?

--
Hoping for calm nights

Alastair Law,      
Yeovil, England.
<http://www.little.jim.freeuk.com>          

[Port-Na-Storm]

I think the short answer is , it doesn't!

Is this an actual example you've seen?

A more common example is 1 1/2" to 1 foot.

1 1/2" = 12/8ths.  so 1/8th on the drawing = 1" on the boat.

this gives a scale ratio of 1:8 where one unit of anything on the drawing is equal to 8 of the same units on the boat.

[melidman]

Sorry it was not an actual example i was getting 1 1/2" and 3" to the foot mixed up been burning midnight oil unfortunately not on my build but earning brownie points decorating the sons new house. when he moves out of my basement i am going to loft plans on what was his bedroom floor. On the plus side he has found me some lovely pieces of oak looks like they have come out of a roof  8" x 4" x 14 ft and 3 huge 14" x 10" x 6ft