Model Boat Mayhem

Technical, Techniques, Hints, and Tips => Other Technical Questions... => Topic started by: croakle on October 10, 2006, 08:37:39 PM

Title: Conversion of scale
Post by: croakle on October 10, 2006, 08:37:39 PM
Hello all

Can anyone advise a quick way of converting a measurement in 1:48 to 1:32 please?

Thanks and best wishes

Julian
Title: Re: Conversion of scale
Post by: DickyD on October 10, 2006, 08:41:34 PM
Pardon??   ??? ??? ???
Title: Re: Conversion of scale
Post by: Eddy Matthews on October 10, 2006, 08:43:39 PM
Multiply by 1.33 to convert from 1:48 to 1:32

Regards
Eddy
Title: Re: Conversion of scale
Post by: croakle on October 10, 2006, 08:45:14 PM
Eddy

Thanks very much

Best wishes

Julian
Title: Re: Conversion of scale
Post by: Colin Bishop on October 10, 2006, 08:55:50 PM
If you are working off a plan then it may pay you to make up a set of fixed ratio proportional dividers. I made mine from brass stock and needles etc. but you can see the principle. It saved me a great deal of time reducing from plans I had.
Title: Re: Conversion of scale
Post by: croakle on October 10, 2006, 08:58:18 PM
Colin

Thanks for the tip.  Yes I've got a 1:48 drawing but cannot get the hull at that scale but can get one at 1:32.

Best wishes

Julian
Title: Re: Conversion of scale
Post by: Colin Bishop on October 10, 2006, 09:07:00 PM
Julian.

The other option is to have the plan resized at a copy shop - shouldn't be too expensive either!  :)
Colin
Title: Re: Conversion of scale
Post by: JayDee on October 11, 2006, 12:33:07 AM

Colin,
Don't put too much trust in the Copy Shop, you are working with a "Plan", Copy Shops work mostly with Text.
IF, there is any distortion in the copy machine it does not show up with Text, but your Plan will be wrong!.

A Tip, take a round plastic plate with you, get the plate copied to the same size as the plan will be and check that the resulting image is still "round".

I have done this and some machines make Pear Shapes out of circles.
Could save a lot of grief with "odd shaped Frames" later on in the Build!.

A refusal from the owner of the machine to allow this check, you both know the machine is wrong!.
John. ;)
Title: Re: Conversion of scale
Post by: Colin Bishop on October 11, 2006, 08:57:51 AM
John, You are quite correct that you have to be careful with copyshops but I was thinking of the more specialised ones used to dealing with graphic material. There was a thread about this a while back on the other site I think. Your plate tip is a good one - hadn't thought of that!

Colin
Title: Re: Conversion of scale
Post by: Dave Leishman on October 11, 2006, 09:47:45 AM
Multiply by 1.33 to convert from 1:48 to 1:32

Regards
Eddy

At the risk of being wrong here I have to query this...

When working between scales I divide the scale I have into the scale I want, so 48/32 = 1.5 (multiply by 100 gives the scale factor in percentage, so 1:32 is 150% larger than 1:48, or simply put, half as big again).

When I saw the reply from Eddie I questioned what I was doing and found the following conversion chart after a little searching www.wwi-models.org/misc/scalecon.html (http://www.wwi-models.org/misc/scalecon.html) which seems to match what I'm doing.

So, put simply, I reckon you have to multiply 1:48 measurements by 1.5 (not 1.33) to convert to 1:32...

Can anyone confirm/deny what I'm doing???
Title: Re: Conversion of scale
Post by: Eddy Matthews on October 11, 2006, 10:06:00 AM
My fault Dave, your absolutely correct!

It should be x1.5 to convert from 1:48 to 1:32 - I'll blame the amber nectar that I consumed last night, gave me brain fade! :)

Regards
Eddy
Title: Re: Conversion of scale
Post by: Dave Leishman on October 11, 2006, 10:29:49 AM
Phew!!!

Cheers Eddie - I don't have to scrap the model of the fishing boat Accord I've been building from scratch after all ;)

I've been working off photos and using the method I outlined above to convert scales in the photos to the 1:32 the model's being built in...

I guess we can deduce that amber nectar is proven to have a detrimental effect on arithmetic then, so the new Christmas campaign is Don't drink & Model ;D
Title: Re: Conversion of scale
Post by: cbr900 on October 11, 2006, 11:42:01 AM
What about when you go from 1/100 to 1/29 scale, I found I had to multiply by 3.53 to get the correct size, or have I screwed up badly.....




Roy
Title: Re: Conversion of scale
Post by: Colin Bishop on October 11, 2006, 12:02:54 PM
Using the link above it seems to come out at 3.44!

This is a bit of a minefield if you don't have a mathematical mindset! This is why I would either use a copyshop (accurate one!) or make up a pair of fixed ratio proportional dividers.

If you have to work direct with a calculator then once you have figured out what the conversion ratio is and treble checked it, set up a spreadsheet with a series of conversion lengths (as many as possible) using this formula. e.g. 25mm on the original=15.5mm on the model. (check those too!). Print out the spreadsheet as a conversion table. Then, if you are making calculations on the fly you can refer to the two nearest original values on your spreadsheet and if your calculated value is not between these then you've pressed the wrong buttons and your crew will bump their heads on the deckhead or fall down the scuppers!
Title: Re: Conversion of scale
Post by: maninthestreet on October 11, 2006, 12:17:46 PM
100/29 = 3.448, or 3.45 correct to 2 decimal places.
Title: Re: Conversion of scale
Post by: Dave Leishman on October 11, 2006, 12:52:52 PM
100/29 = 3.448, or 3.45 correct to 2 decimal places.


I'd agree with that :)
Title: Re: Conversion of scale
Post by: croakle on October 11, 2006, 07:02:10 PM
Maths!  ::)
Title: Re: Conversion of scale
Post by: croakle on October 11, 2006, 07:02:59 PM
Should have also said thanks all for the input...much appreciated.
Title: Re: Conversion of scale
Post by: algiecrook on October 11, 2006, 08:32:13 PM


Julian the answer to your problem...... is Scalemaster the link below is where youll find it  and its freeeeeee.......................Alan      http://www.starshipmodeler.com/tech/scalemaster.htm                                                                                       .. it'll do all the things you want and some besides
Title: Re: Conversion of scale
Post by: malcolmfrary on October 11, 2006, 10:52:32 PM
Apart from using the software  mentioned before, probably the easiest way is to multiply the measurement by the scale that the drawing is, then divide that by the scale you want.  Universal and works every time.  A calculator helps, and the dividers are a good check against figner trouble with the calculator.
Title: Re: Conversion of scale
Post by: cbr900 on October 12, 2006, 01:59:28 AM
Thanks for the help guys, I will now go and start to recalculate all my figures as they appear to be out a mite...



Roy
Title: Re: Conversion of scale
Post by: Dave Leishman on October 14, 2006, 03:00:24 PM
I'd been meaning to put together a couple of pages on scale on my website for a while now, and this thread has prodded me into action.

The pages can be viewed on my site at the following address: Trawler Models Scale Pages (http://www.trawlermodels.co.uk/general_modelling/scale.php)
Title: Re: Conversion of scale
Post by: Colin Bishop on October 14, 2006, 05:17:35 PM
Very informative Dave - thanks.
Title: Re: Conversion of scale
Post by: cbr900 on October 16, 2006, 04:29:46 AM
Algiecrook,

Thanks for that address it does work quite well and has solved a lot of problems, thanks again mate....




Roy