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Author Topic: Cast lock kit shrinkage.  (Read 3401 times)

Offline redheart

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Cast lock kit shrinkage.
« on: April 09, 2013, 06:40:00 PM »
Hey Guys, :-\

Does anyone know how much shrinkage is involved between the original lock parts and the cast copies. ???
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Offline FlintFan

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Re: Cast lock kit shrinkage.
« Reply #1 on: April 09, 2013, 06:54:37 PM »
Depends on the size, shape, thickness, alloy...etc.  But as a VERY general estimation, about 2-3% 
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Offline J. Talbert

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Re: Cast lock kit shrinkage.
« Reply #2 on: April 09, 2013, 11:57:16 PM »
I've always heard ~3%, but keep in mind that different shapes shrink to a greater or lesser extent.  There is a great deal of trial and error involved when trying to make the masters for a new lock kit.
Otherwise Jim Chambers would have left handed versions of all his locks... ;D

Jeff
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eddie

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Re: Cast lock kit shrinkage.
« Reply #3 on: April 10, 2013, 12:41:29 AM »
hello all, when patterns are made shrink has to be added to the patterns. i worked in the forging die business as a die sinker for a number of years and if i remember correctly the shrink factor we used for steel was 3/16 to the ft. for steel and 1/10 per ft. for aluminum. there shoul not be a trial and error you just measure what you want to duplicate and add shrink. eddie
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Offline rich pierce

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Re: Cast lock kit shrinkage.
« Reply #4 on: April 10, 2013, 01:51:15 AM »
Eddie, you're right- except in many cases patterns are not "made"- folks simply use existing parts as patterns.  This happens a lot in locks replicated from originals, all the way down to the corrosion or engraving.  I'm not talking about main-line lock manufacturers (Chambers, L&R, Davis, etc)- but outfits that cast from originals.  The same can happen with longrifle furniture (buttplates and guards) cast from originals.
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Offline Dphariss

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Re: Cast lock kit shrinkage.
« Reply #5 on: April 10, 2013, 07:14:43 AM »
If the mould maker is any good the parts are very close. If not they may be smaller.

Dan
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Offline Jim Kibler

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Re: Cast lock kit shrinkage.
« Reply #6 on: April 10, 2013, 04:35:49 PM »
In investment casting there are two issues.  Wax shrinkage and the metal shrinkage.  With complex shapes and varying section thicknesses, it's hard to predict on a linear basis.  I'm sure there are 3D modeling programs that try to predict this.  In this business, I'm sure it's more of trial and error and using past knowledge when designing new products.  Shrinkage rules, may be a rough guide, but it's really much more complex.
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Offline redheart

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Re: Cast lock kit shrinkage.
« Reply #7 on: April 11, 2013, 07:59:56 AM »
Thank you all kindly for all the info! :D
You gave me everything I need to know!

Best regards,

Redheart
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