Scribing 7 inch planks in 1/76 scale

[J25]

I need to reproduce a small area of 7 inch planking. This distance doesn't line up with any mm or 1/2mm lines on a steel rule. Does anybody have any tips or know of any tools for reproducing accurately space lines?  Is a divider and a magnifier the only way forward? Any suggestions would be most welcome.

[Enterprisingwestern]

 

Use the depth gauge end of a micrometer and make nicks at the relevant points on the plastic sheet.

 

Mike.

[Il Grifone]

Hold the rule at an angle so that the total number of planks required is a whole number of mm.

e.g. For twelve 7" planks mark two parallel lines 28mm apart and line up the rule at 36 mm. Each plank is then 3mm wide.

 

7" planks sounds like a P.O. mineral wagon? The top two planks were usually 9", just to be awkward.

[Gordon A]

7" is 2.333 mm. I would use a set of Vernier callipers to lightly scribe the parallel lines, then go over the lines again with your preferred scribing tool, say a metal scriber.

 

Gordon

[Terra-Nova2]

It may prove useful to go old school. 2.33mm is, at a reasonable level of accuracy, 3/32”. This measurement is available on good steel rules.

[Compound2632]

Three planks is 7 mm, so that can be done using just the steel rule; the lines in between can be eyeballed or use @Terra-Nova2's suggestion, which introduces only 2% error. Once you're happy with the two interpolated lines, these can be reproduced at 7 mm intervals. 

Edited December 1, 2019 by Compound2632

[ikcdab]

I think we would be very constrained if we only ever used 1mm or 0.5mm units! Measuring 2.3mm isn't really that difficult. To take account of the 0.03, just round up...so 2.3, 4.7, 7.0, 9.3, 11.6, 13.9, 16.3.. until you get to your desired total distance.

[J25]

Thanks for all the replies. The maths is not a problem, but my eyesight is. I will have a go at some of the suggestions. The panels are for a cut-and-shut Bachman cattle wagon to represent an LMS d1661.

[Il Grifone]

I'd go along this route and consign Bachmann's awful thing to the bin (or eBay).

 

https://www.xxleimarket.com/index.php?main_page=product_info&products_id=414000

 

(No connection with the seller - it's what came up on Google.)

[sharris]

If you have access to a computer with a drawing program and a decent printer, you could draw a template with the correct line spacing magnified on the screen and printed actual size. 

 

A 600dpi printer (which is probably the minimum spec for anything in the last 10 years - a £29.99 HP printer from PCWorld claims to be 1200x4800dpi) should be able to print lines with a precision of 0.04mm.

 

P.S. If you want a more model railway orientated supplier than Il Grifone's example, the Parkside wagon is also available direct from Peco (I bear no responsibility if you get tempted into other wagon purchases too - very pleased with the quality of the last Parkside kits I built). 

 

Edited December 5, 2019 by sharris

[Campaman]

For this type of marking out I use my cheap Digital Vernier from Lidls, set it to the required dimension and then use the internal measuring tips to mark out.

 

The top tips in the image below.

 

[Roy Langridge]

Mount what you are scribing vertically (against an angle plate) and use a Vernier height gauge? They can be picked up cheaply.

Roy