and how do they make molds? do they go in through a pilot hole, or do 1 half at a time and hope they match up? would like to ssee a pic of mold "cherry" if someone has one. thanks-Travis
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and how do they make molds? do they go in through a pilot hole, or do 1 half at a time and hope they match up? would like to ssee a pic of mold "cherry" if someone has one. thanks-Travis
I googled "bullet mold cherry" and got this:
https://www.google.dk/search?q=bulle...YUDt0Q_AUICigB
I'll admit the search is a bit advanced but it might answer your question.
Here are some NOE molds being made: https://youtu.be/xAGMob2vO90
I realize you can't see all the action but it's a good overview. The cherry is shaped like the bullet profile but has cutting edges on it. There was a video from Mihec where you could see the cavity being cut. But I can't find the video right now.
Good question. I've always wondered what they looked like myself. NOE had a video on their website, but the video was on the outside of the machine and hard to see the details IIRC. I'm pretty sure they do each half independently, but it has been a little while since I saw the video.
old school, using manual Mill
https://www.youtube.com/watch?v=m1YPTarNliw
You can find most answers on Google or Youtube.
You just need to ask the question right.
Hey - this is my Fred Leeth mold on the Internet in the first post for pictures ... :coffeecom
http://i222.photobucket.com/albums/d...s/PDRM2818.jpg
It's an adjustable of the original Sharps 45 bullet
ok, cool, I noticed a set on there that looked like it was made for making a mold on a lathe, the rest they just close the 2 blocks onto the spinning bit till they touch? I bet that's how most commercial makers do it, rather than on a lathe.
There are vises made that both jaws move together very precisely. the blocks are bolted into a special set of jaws and the cutter and coolant are turned on. This is normally a 3/4" to 1" flow on the cutter and blocks. Its normally High flow low pressure. The vise is then slowly closed on the cutter both blocks providing cutting force on each side of the blocks this helps reduce cutter flexing. the coolant flow helps keep chips from building up between the blocks.
We did a few muzzle loader moulds at work in cnc controlled mills, these cutters were ground under the smallest dia of the bullet by .020-.030 and a start hole drilled fist this cutter then ran into depth and a flat circle was cut cutting the form into the blocks. This worked well with heavy high pressure coolant to flood. I also did a couple in the cnc plunger edm. these were easier to do since no hardened cutter was needed to be ground up. A simple electrode turned up from copper tungsten or carbon was used. Blocks were made and clamped together in a vise cavity was burnt to depth and flat circle pocket burned the details into sides. A light lapping was all that was needed to finish. No burrs or tool marks from this method. On this machine a groups of blocks could be fixture into location and it would rough all the cavities then finish and finally polish with out anyone near it.
Open your Lyman 3rd Edition Cast Bullet Handbook, page 54, How Lyman molds are made. Has detailed pictures with description from Cold-rolled steel blocks to installing the sprue plate, cherrying drills are photo #7.
I only have the 2nd edition., the next book needs to be a book with more load (calibers too) info than it, more cast loads than lee's
the CNC machines use a 'cherry' too, but it cut's in an oscillating fashion.
the 'cherry' looks more like a warped fine thread dry-wall screw with a quick connect air hose fitting on the end.
but when you slow down the cutting/oscillating action in the machine you can see the outline of the bullet it will make.
you can also use the same cutter to make various diameters of the same design.
Good pics here
http://www.hallowellco.com/cherry%20...definition.htm
runfiverun, is that what places like accurate use?
Ok.Reb. my Eagan MX4.30 ARD is a Lathe bored Masterpiece, Fivefang
Most of the smaller custom mould makers are using CNC mills or lathes. Cherries are old school. The big companies had the older technology equipment. That is long since paid for so it's cost effective to keep using it.
I guess quality is all in the experience of the operator!
Basically a mould cherry looks like a end mill ground in the form of the bullet it cuts. Why nose pour moulds are rarer is the amount of extra work that goes into them. The small stem from nose dia to the bigger base of the bullet would be very fragile. grinding the form of the bullet is fairly straight forward and can be done in a lathe and tool post grinder. The big part of the operation is backing off the cutter so it has cutting edges that are sharp and don't grab or rub. The ones we did were 4 flute helical form on the ends of old end mills, normally HSS cobalt. These cut cleanly and left a good finish. We did one on a high helix flute end mill that really cut nice. They are basically a form cutter.
Imagine the cutter for the cavity of a round ball mold.
The cutter has a sphere shape (with cutting flutes of course), but must also have a small fluted stem, for attachment to the spindle and to cut the pour hole at the top.
So... It looks just like a cherry. And since the first zillion bullet molds ever made were round balls, the name stuck.
Tom [accurate] does it different.
I believe Dan at Mountain Molds does it similar to Accurate.
NOE does it the CNC way.
Hm-2 also does or did also, I watched them cut some of the first mold they cut for each new design. [and tested some of the proto-type molds before the final features were decided on]
and I believe Arsenal molds are cut on a CNC also.
If I would have had more patience for math as a school boy I would have liked machinist work. The ultimate practical problem solving vocation.
The Foxfire book on flintlock rifles had pictures of cherries designed to be used with a hand brace with soft iron or soapstone blocks.
Travis: Several ways to do this. You've seen most here.
The method being used by outfits like NOE and MP is called Circular Interpolation. This is where a cutter moves thru a circular path by working the X and Y axis' of the machine against each other to generate a circle or in the case of moulds half a circle.
In the case of moulds, the mould halves are machined separately and one half of each bullet cavity is cut into each side of the mould blocks. The real trick is getting both halves to line up perfectly and this obviously requires some very precise machining. I am not capable of this in my shop, er maybe I am, but just don't want to.
The cutter for the mould cavity looks exactly like the end product but slightly smaller. This allows mould cavities of different diameters to be machined with the same cutter by simply altering the program. This is necessary as the "Shrink Rate" of the metal used to make the boolits varies with the alloy. Harder alloy shrinks less as it cools and this must be accounted for.
An example of this was a RCBS .45-300FNGC mould I had which dropped Boolits made from Wheel Weights at .457. This was useless to me as I needed .459-460 to shoot right. RCBS had designed the moulds around the shrink rate of Linotype alloy which shrinks less and therefore delivered boolits of the correct size,,, Except nobody casts .45 cal boolits out of Linotype! I bitched to the head duck at RCBS and they made me a new mould that dropped linotype at .463-4 and wheel weight material at .460-1., and this worked perfectly.
All they had to do was alter the program slightly (change the dia of the cutter in the program) to make bigger cavities.
This is why the CNC method is being used now, it is very flexible. Once the position of the cavities in the blocks is dialed in,,, they all come out the same.
Randy