Gunsmithing Anyone here do EDM hole cutting on barrels?

[sirhrmechanic]

Looking for someone who can EDM cut about 12 - 16 holes in a rifle barrel. They will go all the way around the barrel and are a pressure relief/diversion. Holes will be about .1875" in diameter and round. Need to do 2 barrels. I can post or send a print if needed. But here is roughly what I am looking for.

^^^ These holes are a bit large, but are on a prototype c. 1940's. Above is the print and the holes are about 3/16th. .1875 ish. Not too critical... so large tolerance on these.

If anyone can do this or has a good source... let me know!

My backup plan is to cut most of the way through with a drill and then do the 'breakout' cut with a mill. But that still risks having some burrs in the rifling.

Cheers,

Sirhr

 

[MK20]

Delisle build?

 

[Simonsza1]

This is what structured barrels does in Arkansas. Reach out to John and ask him.

 

[Simonsza1]

Structured Barrels

tacomhq.com

 

[msgriff]

If you don't go the EDM route, Cogsdill makes internal de-burring tools (Burr-Off). There are some limitations on minimum bore diameter, which vary depending on the hole diameter, unless you modify the tool. New products have gotten expensive in the last few years, especially for single or low quantities, but look at places like Ebay for used ones.

 

[Makinchips208]

A friend insisted I mill some ports in 3 rifles for him. Similar to magnaporting. I said he will get burrs inside but he insisted.
So I made a few small endmill with a 45degree helix. The idea being that the drastic upcut would leave the burr on the top. It worked pretty good! A real gunsmith thought it looked usable. Without a Cnc it is hard to do that in a circle though.

An alternative is actually contact Magna Port. I believe they do EDM.

https://www.magnaport.com/

 

[sirhrmechanic]

A friend insisted I mill some ports in 3 rifles for him. Similar to magnaporting. I said he will get burrs inside but he insisted.
So I made a few small endmill with a 45degree helix. The idea being that the drastic upcut would leave the burr on the top. It worked pretty good! A real gunsmith thought it looked usable. Without a Cnc it is hard to do that in a circle though.

An alternative is actually contact Magna Port. I believe they do EDM.

https://www.magnaport.com/

Thanks! I tried Mag-na-Port a few years ago and they only do... Mag-na-porting. Not specialty.

But appreciate it!

Cheers,

Sirhr

 

[sirhrmechanic]

This is what structured barrels does in Arkansas. Reach out to John and ask him.

Thanks! I know John well and have been to his shop! I don't remember him having EDM, but I'll definitely reach out!!! He has another barrel underway for me. Great stuff they do!

Cheers,

Sirhr

 

[sirhrmechanic]

Delisle build?

Yup... dusted the project off some.

Sirhr

 

[MK20]

I wonder if taper reamers with barrel held horizontally in a mill would work well?

 

[sirhrmechanic]

I wonder if taper reamers with barrel held horizontally in a mill would work well?

Still probably going to leave a burr.

Drilling a barrel without leaving a burr is always a tough nut to crack!

Sirhr

 

[jwSubMOA]

I have done some work like this over the years. I didn't have access to EDM stuff so I had to come up with a burrless way to do it. Measure just short of and just past where you want your holes. Knock pure lead sinkers down the bore with a wooden dowel, easier than you think, to fill the area you are machining. Drive them firmly from both ends to compress an voids. Use an .125 4 flute carbide end mill first, then a .187 4 flute carbide to plunge through, just enough to break through. You probably can just do .187 since you aren't concerned with the diameter tolerance. Just make sure you run the endmills at high speeds. Worked for me, the lead "backing" and carbide endmills worked great.

 

[Modoc]

I have done some work like this over the years. I didn't have access to EDM stuff so I had to come up with a burrless way to do it. Measure just short of and just past where you want your holes. Knock pure lead sinkers down the bore with a wooden dowel, easier than you think, to fill the area you are machining. Drive them firmly from both ends to compress an voids. Use an .125 4 flute carbide end mill first, then a .187 4 flute carbide to plunge through, just enough to break through. You probably can just do .187 since you aren't concerned with the diameter tolerance. Just make sure you run the endmills at high speeds. Worked for me, the lead "backing" and carbide endmills worked great.

I like this! Another option are pure lead round ball for muzzleloading. These are what I use in conjunction with sections of wooden dowel to slug bores.

 

[jwSubMOA]

I like this! Another option are pure lead round ball for muzzleloading. These are what I use in conjunction with sections of wooden dowel to slug bores.

Exactly, those will work perfectly and slugging bores was how I came up with trying it.

 

[akmike47]

I like this! Another option are pure lead round ball for muzzleloading. These are what I use in conjunction with sections of wooden dowel to slug bores.

Exactly, those will work perfectly and slugging bores was how I came up with trying it.

Would Cerrosafe be a good option for this or is it too soft when solidified? Never messed with it myself but the low melting point may be a factor also without coolant I’d guess