Casting Ruler

[captainkirk]

I found a Lufkin shrink ruler a local Antique shop it's kind of expensive and I'm not sure how usefull it will be for making patterns. Can you still get these type of rulers and if so where/
What shrink values are used for the different types of metal
Aluminum, brass/bronze,iron, etc.

[Harold_V]

Hey Cap'n,

Yeah, shrink rules are still available. Starrett sells them and I'm sure others do as well. I bouught two of them a few years ago, one a Starrett C370, 1/8"/ft. shrink and the other a Starrett C375, 3/16"/ft.. These rules are a nice satin chrome finish and very easy to read. Current catalog price is $55 each. [img]/ubb/images/graemlins/shocked.gif"%20alt="[/img]

In general, proper shrink for iron is 3/32"-1/8"/ft., yellow brass 7/32"/ft., common brass 3/16"/ft., bronze 5/32"/ft., steel 3/16"/ft.. It appears that values are variable, which makes sense to some degree. Pouring temperatures would have a profound effect on the amount of contraction, along with other factors. [img]/ubb/images/graemlins/smile.gif"%20alt="[/img]

Hope this helps some~

Harold

[captainkirk]

Thanks for the reply, that's the info I needed

[JEB]

That reminds me of when I first went to work for the company that I just retired from. One of the tools I had to buy before I reported to work was a 6" scale. So I went down to the old time hardware store in town and bought what I thought was a 6" scale. I used it for several years until I happened to lay it down to another 6" scale. Hmmmm, why is mine a little longer than the other one? Took a close look and it read "shrink rule 3/16" / ft". Took a lot of ribbing that day. [img]/ubb/images/graemlins/smile.gif"%20alt="[/img]

Jim

[WSHBaker]

That must have been about 1960 give or take. Right? [img]/ubb/images/graemlins/smile.gif"%20alt="[/img]

[GeneT]

Anyone know of an economical source of rules *now*? I love my Starret stuff, but $55 bucks for a ruler seems a bit pricey, even with the Starret name. GsT

[GeorgeGaskill]

draftsman's ruler. Make a 1:1 drawing of a ruler using your CAD program, then print it out at differing scales such that you get the extra 3/8" per foot (or whatever you need) in the printed version. Cut it out and glue it to the ruler. You can have six scales on one stick.

[generic]

There is a specific method taught in drafting class, well it used to be [img]/ubb/images/graemlins/smile.gif"%20alt="[/img]
A pic is attached (I hope).

A ruled line is drawn vertically, another is pivoted at a common corner(becomes center of radius) and lengthened to the proper radius.
Then equally divided (12 spaces.)
Then marked at these divisions which 'each' have their share of the total expansion.

Yes, its a manual method. But doable in cad and printable.

[GeneT]

Doh! Cool, I hadn't even thought about making my own! I'm thinking now, that even without CNC a rule could be engraved pretty well with a manual machine. Another project! (#768)
Thanks guys,
GsT

[coldformer]

hello
i just use a calculator and dual dim my drawings (doodles)
jerry

[coldformer]

aluminum 8-12% + beer factor
jerry

[Rolly]

Thanks generic
Cheep was to lay out a scale. I use AutoCAD