Model Boat Mayhem

Mess Deck: General Section => Model Boating => Topic started by: KEMO on January 18, 2013, 11:21:00 am

Title: Enlarging Plans.
Post by: KEMO on January 18, 2013, 11:21:00 am
Hiya,
         I have a set of plans for an MTB which are drawn at 1/48. I want to enlarge them to 1/24  so by what percentage should the copier at the printers be set.
Keith.
Title: Re: Enlarging Plans.
Post by: essex2visuvesi on January 18, 2013, 11:31:08 am
200%
Title: Re: Enlarging Plans.
Post by: grendel on January 18, 2013, 12:14:34 pm
the sheet size will be 2x in each direction 4x in area, ie from an A2 sheet to an A0 sheet size. or A3 to A1, A4 to A2. but 200% if the machine does it by scale - note its worth checking a dimension as the scaling can be slightly off by 1-2%, but this can be corrected by punching in 201% for example, but if you are paying for the copies you may have to accept what you are given, If I wasdoing it on a work copier I would fiddle until it was spot on.
Grendel
Title: Re: Enlarging Plans.
Post by: RMH on January 18, 2013, 12:25:21 pm
Good question. I want to enlarge 1/20th and 1/16th to 1/12th. Can anyone help out with this percentage increase please. Maths never has been my strong point
Title: Re: Enlarging Plans.
Post by: dreadnought72 on January 18, 2013, 12:34:23 pm
Simply divide 20 by 12 and 16 by 12.

The 1/20th plans therefore need to be 166.6% bigger.

The 1/16th plans need to be 133.3% bigger.

Andy
Title: Re: Enlarging Plans.
Post by: Colin Bishop on January 18, 2013, 12:54:05 pm
Setting the controls on the copier doesn't always give you exactly what you want. Sometimes it is better to select a dimension on the drawing you want to copy and simply say you want the drawing enlarged so that this dimension becomes xxxxx. To be absolutely sure, select a vertical and a horizontal dimension to guard against distortion.
 
Colin
Title: Re: Enlarging Plans.
Post by: grendel on January 18, 2013, 01:17:21 pm
In the drawing industry this is the biggest cause of complaint (and one of the reasons that plans the world over usually have a large note - do not scale.
this is because over a 1m long plan the stretch in the direction of printing can be up to 2%. furthermore changes in humidity can cause the paper to stretch by 1-2% on top of this.
so when printing we used to calibrate the printer to scale and then when printed the plan was at least accurate, but then if it was taken to a damp worksite the plan can have stretched.
a printed scale at the bottom can help as that will stretch and shrink with the paper.
then you come to enlarging of plans, this can be very tricky as the copier may not have an exact percentage and also may not be accurately calibrated. these things can be done but generally most users dont know this (I have never seen a copyshop large format machine that was accurately calibrated) - and when things dont measure accurately the customer gets upset (trust me this is 90% of the copier repair technicians work from what they have told me) when I ran a drawing office I made sure the printer was calibrated for every CAD workstation it was set up on and that the scanner was calibrated accurately etc, this was checked about once a month as that level of accuracy wasn't technically necessary, but we did it as a matter of pride. I know for a fact that most of the other drawing offices in the company didn't do this (either couldn't be bothered or didn't know how) but in my drawing office it was my policy to have everything correctly set up, just as I checked all the output from the team for accuracy / completeness before it went out (good quality control reduces the number of times a job comes back for amendments - saves time in the long run and gives good feedback from the end user).
Grendel
Title: Re: Enlarging Plans.
Post by: KEMO on January 18, 2013, 02:23:34 pm
Hiya,
       thank you all very much for that, a great help.  It's a 60ft MTB so it should come in at 30".
Keith.
Title: Re: Enlarging Plans.
Post by: RMH on January 18, 2013, 04:28:03 pm
Thanks Dreadnought
Title: Re: Enlarging Plans.
Post by: Pondweed on January 21, 2013, 10:40:56 am
. furthermore changes in humidity can cause the paper to stretch by 1-2% on top of this.

Is this true? A long time ago I rolled a plan up and it sat in a cardboard tube for 10-15 years. When I got it out again, the vessel was short like 5/8ths.
Title: Re: Enlarging Plans.
Post by: Perkasaman2 on January 21, 2013, 02:08:05 pm
IF you are taking the plan to a copyshop for rescaling  and/or  printing then take a cd or memory stick with you and ask for a file/ electronic copy of the plans. Electronic scanning of the plan is part of the printing process and in my experience involves no extra charge.
Title: Re: Enlarging Plans.
Post by: vnkiwi on January 21, 2013, 06:43:28 pm
As Perkasaman said, ask for an electronic file while your getting the prints done.
My local print shop doesn't charge for this when I get prints. Only charges a few dollars when I bring a drawing in to scan only.
cheers
vnkiwi
Title: Re: Enlarging Plans.
Post by: RAAArtyGunner on January 21, 2013, 08:37:30 pm
Never gave it a thought  :-)) :-))