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Thread: Bullet Mould
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16-07-2017, 21:19 #1
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Bullet Mould
Made a mould for 155 gn bullets for a friends' AK. Turn the mould upside down, and you can cast ssg (8mm) lead shot.
3 bullets and 4 ssg's.
First planned best use of the aluminium block on a CAD package. It was an offcut from another job, so size was pre-defined.
Bullet and ball cutters. The ball cutter disintegrated due to a heat treatment shortcoming on my part :(
Finished off with an 8mm carbide burr I found amongst my tools. The other pieces below are the alignment pins,
and the sprue-cutter hinge pin.
Custom mould handles made from cheap wire stripper ex local chinese shop. Wooden handles added later.
R20 for the stripper was a bargain for the handles, which are otherwise very tricky to make.
The aluminium blocks were glued together, faces machined, and bullet cavities bored. The cavities landed up being slightly oversized. More work for the sizing die.
Blocks were separated, and the hemispherical cavities machined.
After finishing off other details like gates for the spherical section, sprue cutter, alignment pins, I tried it out. Just plain scrap lead of unknown
source or composition.
For a first attempt at a mould, I am quite happy. The next one will be better.
These are intended for powder coating, so no grooves for lube, or gascheck shoulder.
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16-07-2017, 21:31 #2
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Re: Bullet Mould
Very nice, I'm impressed!
Do you use HSS for the cutters?
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16-07-2017, 21:38 #3
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Re: Bullet Mould
Those cutters are just silver steel. HSS is not necessary for aluminium, and heat treatment of HSS is far beyond my judicious application of the oxy torch....
The ball cutter was not tempered properly, so a stress concentration at one of the sharp corners initiated its failure. (helped by my heavy hand as well ).
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16-07-2017, 21:46 #4
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- Jul 2010
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- Witbank
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Re: Bullet Mould
Excellent craftsmanship...it really looks very goodLet us know how the bullets group???
How about a 450 gn bullet , .451 diameter bullet mold for my Martini Henry to use a paper patch bullets..the bullet with paper patch will amount to .460 diameter..exactly what I need for my Martini Henry...
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17-07-2017, 08:14 #5
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Re: Bullet Mould
nice
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17-07-2017, 08:37 #6
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Re: Bullet Mould
Thanks Epsilon, but what is silver steel? Did you turn it to get to final diameter before cutting the flutes?
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17-07-2017, 08:58 #7
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Re: Bullet Mould
Silver steel is a high-carbon tool steel. Very easy to harden and single stage temper.
I din't include pictures of the cutter being made as it would be too pic-heavy. The bullet profile is turned first as a series of cones. The ogive is then created by rounding the cone "walls".
It is then polished, and the cylindrical portion (the bullet size) is polished down to required size. In this, the AK case, .312"
The flutes are then cut with a lathe toolpost milling attachment I made. Simple, and works exceptionally well.
Only once fluting is complete do you even think of removing the cutter from the lathe chuck!
Heat treating follows removal from chuck. Do not de-burr flutes before heat treating. The burrs protect the metal composition of the cutting edges.
After tempering, a diamond file relieves the cutting edges, and removes the protective burrs. Razor sharp cutting edges result.
Often a cutter will be made to exact bore size, or even slightly smaller. One then uses one of the cast lead bullets to polish the mould larger to get up to exact size.
This also takes care of shrinkage of the lead as it cools.
The cutter is the bulk of the work (about 60%) so it makes sense to make a multi cavity as in this case. The lead shot just makes better use of the aluminium block.
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17-07-2017, 09:32 #8
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Re: Bullet Mould
Sounds like a lot of precision work, very interesting. I suppose you use carbide tool inserts to turn the silver steel, would HSS cut it?
Opens up a whole new world in terms of bullet casting possibilities.
Would love a picture of the toolpost milling attachment?
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17-07-2017, 10:02 #9
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Re: Bullet Mould
I use carbide and HSS tooling. Hardened silver steel will cut un-hardened silver steel. Just keep speeds down.
I'll take a photo of the milling attachment when next in my workshop. Maybe tonight if it is not too cold. It is crude, but gives better results than I first expected.
This is one attachment that is well worth making as it opens up the possibilities of making so many tools like reamers and other straight fluted cutters.
PM me your email address. I'll send decent resolution pics.
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17-07-2017, 10:04 #10
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Re: Bullet Mould
Thanks Epsilon. My lathe is starting too take more of my time than I can afford...
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