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View Full Version : EDM...I gotta get one of these!

Rbertalotto
10-14-2011, 02:07 PM
At the heart of the machine shop are the EDM’s (Electric Discharge Machine). These machines use electricity to cut our dies. We have both wire feed EDM’s and plunge EDM’s (otherwise referred to as a sinker EDM.) Because the dies are made of extremely hard material, some of them have an incredibly long life span.

The wire EDM sends an electrical current through the wire via electrical contacts in the upper and lower heads, which move independently giving the machinists the ability to cut very complex shapes. Below is an example of what the wire EDM is capable of. The machine was programed to cut a #1 on one side of a solid steel block and a #2 on the other.
http://www.barnesbullets.com/wp-content/uploads/2011/09/October-2011-Tech-Tips-Machine-Shop-Tour-1-012.jpg

http://www.barnesbullets.com/wp-content/uploads/2011/09/October-2011-Tech-Tips-Machine-Shop-Tour-1-017.jpg

http://www.barnesbullets.com/wp-content/uploads/2011/09/October-2011-Tech-Tips-Machine-Shop-Tour-027.jpg


The sinker EDM is used to machine various shapes into very hard materials. We use these machines to cut the shapes of the bullets nose or ogive as well as other applications in the bullet building process. This machine uses an electrode to burn its way into the material. The EDM’s can hold very tight tolerances – up to .0001 of an inch which is equal to the diameter of a human hair sliced lengthwise into 30 equal pieces. As an example of its capabilities, pictured below is an item produced by the Sinker EDM machine. This is a solid piece of steel that has been machined to produce a ball inside that cannot fall out.

http://www.barnesbullets.com/wp-content/uploads/2011/09/October-2011-Tech-Tips-Machine-Shop-Tour-1-009.jpg

All of this from the Barnes Bullet newsletter this month...........
ab_bentley
10-14-2011, 02:20 PM
How much does an EDM machine run? Adam
Rbertalotto
10-14-2011, 02:21 PM
I'm sure it costs way more than I can afford.............:confused:
Vibe
10-14-2011, 03:09 PM
How much does an EDM machine run? Adam
You can actually make one yourself, they are not that complicated - at least not in the simplest forms - and there used to be some plans and schematics for building them on the web. The earliest ones were just tap burners for removing broken taps. We have a threading sinker at work for putting threads in tungsten carbide dies. But then again we have 2 fairly sophisticated CNC wire machines as well.
ray h
10-14-2011, 03:24 PM
If the firearms industry used more of these then they should be able to mfg some of the older firearms deemed too labor intense, like the Win. M-12 etc. And make them out of better steel to closer tolerances but I guess I'm dreaming.
Mntngoat
10-14-2011, 03:28 PM
You can actually make one yourself, they are not that complicated - at least not in the simplest forms - and there used to be some plans and schematics for building them on the web.

I think i still have that book " How to build an EDM"

ML
ray h
10-14-2011, 03:36 PM
Michael was that put out by the Home Shop Machinist mag?????
Mntngoat
10-14-2011, 04:22 PM
Ray

yes it was a several years ago
Chuck Miller
10-14-2011, 11:12 PM
Stiller uses one to cut the lug raceways on his Predator actions. I was over there one day chatting with Jerry and Curtis and got to watch one in action. Pretty sure it's black magic:D
ab_bentley
10-14-2011, 11:24 PM
Stiller uses one to cut the lug raceways on his Predator actions. I was over there one day chatting with Jerry and Curtis and got to watch one in action. Pretty sure it's black magic:D


That's what I want one for, cutting raceways. Adam
Mntngoat
10-14-2011, 11:47 PM
big deep adam, be prepared to pony up a couple hundred thousand dollars for a machine and training to use it.

ML
Vibe
10-15-2011, 12:21 AM
Pretty sure it's black magic:D
Kinda close to it...The graphite electrodes are black and it makes steel disappear like magic. LOL.
tommyn
10-15-2011, 02:28 AM
On Target Tec used edm to cut chambers and has a patent on the process.
Reddirt204
10-15-2011, 02:58 AM
I think I read some where that Surgeon use them for the pricise machining of their actions, I'm sure it's on their web site.

some rediculous tollerences (well lots of zeros and a 1:o) they would be a greats bit of kit to have on the shed... "I'm just going out to knock up a new action of 0.000001 tolerence":D

how deep would they go? how big is the head? how about a barrel with any sort of land profile and twist rate you can think of:) but I don't think it is possible, but we can dream

cheers

Reddirt204
george ulrich
10-15-2011, 08:07 PM
Kinda close to it...The graphite electrodes are black and it makes steel disappear like magic. LOL.

no not really close to it jerry uses a wire your thinking about a sinker,if you use graphite it would look black, copper graphite mix lasts way longer.
Reddirt204
10-16-2011, 02:43 AM
I wounder if some of the manufacturers, ie surgeon would make a small action to suit the hornet/M30 case? Like a mini remington how cool would that be, I know it would cost a fortune but hey it's only money :D

Cheers
Reddirt204
redrock ranger
10-16-2011, 02:31 PM
There was someone selling EDM action blanks awhile back on Benchrest Central if i remember correctly. Out sourcing might be inexpensive as compared to purchasing the machine . As long as quality is maintained .
Varminteer
10-16-2011, 03:15 PM
Being a machinist I have used Wire EDM's. They can hold extremely tight tolerances of .0002" easy. They cut hardened steel like butter. The one we operated used a .010" diameter brass wire to cut the steel. I changed employers a few years ago and now mostly run cnc mills.
kenbro
11-28-2011, 06:05 PM
If the firearms industry used more of these then they should be able to mfg some of the older firearms deemed too labor intense, like the Win. M-12 etc. And make them out of better steel to closer tolerances but I guess I'm dreaming.

Ray,

I wouldn't swop my 96 year old M12 x 20 gauge for a new one if they did make 'em again.
KB. :)
Kiwishooter
12-17-2011, 06:57 AM
That's what I want one for, cutting raceways. Adam

Adam it is a lot cheaper to buy action blanks from Gary, the photo attached shows that I'm happy with the product. They don't come threaded, I've threaded these.
Here goes his add on Benchrest Central.......Kiwi
http://benchrest.com/class/index.php?a=2&b=3593

http://i21.photobucket.com/albums/b267/kiwishooter/Allofthem.jpg

http://i21.photobucket.com/albums/b267/kiwishooter/Actionblank.jpg