View single post by Darryl Hudson
 Posted: Sat Mar 1st, 2014 04:46 am
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Darryl Hudson



Joined: Mon Nov 14th, 2005
Location: Aiken, South Carolina USA
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 Yes I think original components would fit the boxes I made as I used the original spacing/dimensions as the original, even though there was shrinkage of the gearbox casting, I compensated by keeping the gears same size and spacing, and grinding away a little more of the internal wall of the gear box so the gears would clear it.  I can't speak for those that others have made.

Edit:  I'm not sure what the shrinkage factor is with brass, but with cast iron you generally lose .015" per inch.  In other words if you have a 6" long part and have it cast in cast iron,  the product will be .015" X 6 shorter than the original, or .090", which is about 3/32".  In a gearbox where you have clearance, alignment, and engagement features, 3/32" is a LOT!

2nd Edit:  A good caster can make adjustments for shrinkage if he will take the time to do it.  As in the case of something such as an oscillator arm linkage, He first must make a casting of the original, then on that repro he can cut it half into and add whatever the shrinkage factor is and make the repro longer, and then cast it again so that when it shrinks it ends up the same length of the original.   For something as complex as the gearbox, I don't know how he would make the correction, but I don't do foundry work.   I'm sure those guys have their secrets.
A good example is the back castings of the Victor Luminaire fans.  Those things must be 14" across.  I won't call any names but years ago a member had some of those backs done in cast iron because so many of those Luminaire fans have the backs broken out of them there is a good demand for them, but when the product was done the back was 1/4" too small in diameter and would not line up with any of the holes where it mounted.






Last edited on Sat Mar 1st, 2014 05:03 am by Darryl Hudson