dj.spencer Posted May 19, 2010 Share Posted May 19, 2010 i have several scale drawings at 7mm/ft that i would like to scale down to 4mm/ft. does anybody know of a easy way to do this? Link to post Share on other sites More sharing options...
Guest Natalie Graham Posted May 19, 2010 Share Posted May 19, 2010 Divide the dimensions by 7 and multiply by 4? Not as facetious as it sounds. I use a slide rule (who remembers them?) set to do just that and then it is simply a matter of taking the dimension and reading its equivalent form the slide rule. Link to post Share on other sites More sharing options...
ozzyo Posted May 19, 2010 Share Posted May 19, 2010 i have several scale drawings at 7mm/ft that i would like to scale down to 4mm/ft. does anybody know of a easy way to do this? DJ, divide the 7mm size by 1.75. eg 14 divided by 1.75 = 8. Or do you mean on a photocopier? OzzyO. Link to post Share on other sites More sharing options...
Guest jim s-w Posted May 19, 2010 Share Posted May 19, 2010 Hiya divide 100 by 7 - times by 4 to get the percentage Cheers Jim Link to post Share on other sites More sharing options...
shortliner Posted May 19, 2010 Share Posted May 19, 2010 On a photocopier or computer reduce the size to 67% - simples CHITCK! Link to post Share on other sites More sharing options...
ozzyo Posted May 19, 2010 Share Posted May 19, 2010 Hiya Seriously? You cant work out what the relationship of 4mm scale to 7mm scale is as a percentage? I am hoping you just asked the question without trying to think of an answer yourself first. (hey - we have all been there ) but you are a 21 yr old Mechanical engineer - what do they teach people these days? (where is the head banging smiley thing?) (divide 100 by 7 - times by 4) Cheers Jim Hi Jim, I dont think that you can do it in one hit (one hit gives you 57.142856 on my calc), I seem to remember that you have to do in two gos some thing like 40% then 3%. You also have to watch that it has reduced by the same amount in the vertical and horizontal plains. OzzyO. But hey he should know that. Link to post Share on other sites More sharing options...
dj.spencer Posted May 19, 2010 Author Share Posted May 19, 2010 yes jim, you were right, i did just put the question up without actually bothering to try and work it out for myself. anyways it's all done now, thanks for the tips Link to post Share on other sites More sharing options...
ozzyo Posted May 19, 2010 Share Posted May 19, 2010 On a photocopier or computer reduce the size to 67% - simples CHITCK! Hi Shortliner, are you sure about 67%? OzzyO. Link to post Share on other sites More sharing options...
10800 Posted May 19, 2010 Share Posted May 19, 2010 On a photocopier or computer reduce the size to 67% - simples CHITCK! Did you mean 57%? Assuming photoreduction, you need to be sure that the scale reduction is correct in both x and y directions. Draw two scale bars on the drawings of a known dimension, say 10ft, at right angles to each other. In 7mm scale these will be 70mm long. Make them as long as practicable for better accuracy. Take drawings to good copy shop where they have a photocopier with infinitely variable scaling, at least to the nearest 1%. Get them to demonstrate that they can photoreduce so that the lines you have drawn are now 40mm long (for the above example). If they can, to your satisfaction, pay them to do the others. If they can't, go somewhere else. Link to post Share on other sites More sharing options...
dj.spencer Posted May 19, 2010 Author Share Posted May 19, 2010 the way i did it was to enlarge to 143% giving me a drawing at 10mm/ft and then reduce as necessary (40% for 4mm, 35% for HO) it's not exact but it's near enough for me Link to post Share on other sites More sharing options...
shortliner Posted May 19, 2010 Share Posted May 19, 2010 Apologies - fat fingers = 57% is right Link to post Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.