Lapua does not drill their flash holes

[Grimstod]

I have visited Petersons Brass factory and they punch their brass also. They told me that drilling is less consistent and getting rid of the bur just requires sharp dies. Other manufacturers use dull dies and that is why the have burs.

 

[Grimstod]

Any thought about calling Lapua and getting the fact/s straight from the horse's mouth ?

Read an earlier post. I did. Though not through that exact route.

 

[MattPeetz]

Any thought about calling Lapua and getting the fact/s straight from the horse's mouth ?

You fail to read anything and just ASSume!

 

[hemi]

A lot cheaper to punch. Drilling brass with HSS drills requires specially ground cutting edges to prevent the drill bit from being pulled in to the material. That and you're looking at drill motors running expensive carbide bits in the neighborhood of 5000 rpm.

I spend 12 years producing an automotive screw machine part in Brass that had a .080" dia. hole drilled to .430" depth. The operation took 7/10th of a second with a single HSS drill. We produced 3+ million parts annually on a single machine and each drill without sharpening would last nearly a half a million parts. A HSS drill goes through Brass like butter given the proper speeds and feeds. A drill is designed to pull into the material (creating a straight hole) and at the same time push the chips created out through the flutes.
Those same screw machines turned the extractor grooves in rifle cases for many years until case manufacturers went to designing dedicated machines to perform the operation. The Brass case itself is best manufactured in a progressive die, deep draw stamping operation and punching out the flash hole lends itself well to that type of process. As previously stated, maintaining the punch geometry and clearance between it and the backup die will produce a clean, burr free hole.

 

[hogpatrol]

hemi, just curious, was that a through hole and was there lube or coolant?

 

[Dusty Stevens]

I spend 12 years producing an automotive screw machine part in Brass that had a .080" dia. hole drilled to .430" depth. The operation took 7/10th of a second with a single HSS drill. We produced 3+ million parts annually on a single machine and each drill without sharpening would last nearly a half a million parts. A HSS drill goes through Brass like butter given the proper speeds and feeds. A drill is designed to pull into the material (creating a straight hole) and at the same time push the chips created out through the flutes.
Those same screw machines turned the extractor grooves in rifle cases for many years until case manufacturers went to designing dedicated machines to perform the operation. The Brass case itself is best manufactured in a progressive die, deep draw stamping operation and punching out the flash hole lends itself well to that type of process. As previously stated, maintaining the punch geometry and clearance between it and the backup die will produce a clean, burr free hole.

Was that on a davenport? I used to run 4-5 of those at a time for 10hrs a day (felt like 2 hrs)

 

[hemi]

hemi, just curious, was that a through hole and was there lube or coolant?

The parts were produced on a Davenport 5-Spindle Automatic Screw Machine. They are entirely mechanical machines, with cams and gears driven by a 7 1/2 hp electric motor. They can perform up to ten machining operations simultaneously and are a mechanical marvel/monstrosity. They are built to this day in Rochester, NY. The hole drilled in the brass automotive application was a blind hole using "cutting oil" as a flood coolant that also serves to flush away the chips.

 

[hemi]

Was that on a davenport? I used to run 4-5 of those at a time for 10hrs a day (felt like 2 hrs)

Why yes, that is exactly correct..... a Davenport. We had another 12L14 steel part that we produced over 55 million in 8 years with a "one second" cycle time. The OAL of the part was just over 1 1/8" and would go thru five 12ft bars of steel (a load) every ten minutes. One man running 5 machines was quite an orchestrated challenge. That's a whole lotta collet slappin !!

 

[6MMsteve]

Why yes, that is exactly correct..... a Davenport. We had another 12L14 steel part that we produced over 55 million in 8 years with a "one second" cycle time. The OAL of the part was just over 1 1/8" and would go thru five 12ft bars of steel (a load) every ten minutes. One man running 5 machines was quite an orchestrated challenge. That's a whole lotta collet slappin !!

collet slappin dreams are bad for house cats

 

[Dusty Stevens]

Why yes, that is exactly correct..... a Davenport. We had another 12L14 steel part that we produced over 55 million in 8 years with a "one second" cycle time. The OAL of the part was just over 1 1/8" and would go thru five 12ft bars of steel (a load) every ten minutes. One man running 5 machines was quite an orchestrated challenge. That's a whole lotta collet slappin !!

My palms just started hurting again- thanks alot.

 

[johara1]

View attachment 1163961 Lapua 6br flash hole of recent manufacture.

What I see is your decaping pin isn't centered, and if it were uniformed with a reamer the flash hole would be round. .....jim

 

[SSeal]

What I see is your decaping pin isn't centered, and if it were uniformed with a reamer the flash hole would be round. .....jim

They look the same when new.

 

[hogpatrol]

Drilling primer holes the same way as an automatic screw machine with coolant would introduce another process, cleaning the brass, not to mention the capital outlay and maintenance of the machinery. Apples and oranges if you will. Punching is cheaper but I wonder how many holes they get out of one set of dies.

 

[SSeal]

New unmolested piece.

 

[johara1]

They look the same when new.

In your first pic I can see where pin hit that spot, ask me how I know..... there are two different diameters on a flash hole, the one with the bulb and the punched one Flash holes are of the place in size and go over the .0625 reamer I use..... jim

 

[SSeal]

I uniform all of my Lapua brass now. About half of it that I have used has this burr inside.

 

[D-4297]

Early in my machinist career , I trained on B/S - 00 , ( Double Ought ) machines making aerospace parts that were extremely small . Materials were brass , aluminum , Stainless of varying types , and some exotics . I've seen parts made on many automatics that were burr free with a drilled hole , but as every machine operator here has stated , it takes the correct speeds & feeds . Good cutting lube , and sharp , correctly ground tooling . And the majority of my parts were QC'ed with a microscope , and not a comparator or Opti-visor . It is possible , as others have said . But highly cost prohibitive . Perfect don't come cheap in machine trades . And major kudos to the people who make and set-up the Lapua dies . And those who do the grinding maintenance on them . Special people , with special skills .

 

[rkittine]

At least I am not sorry now that I bought my flash hole drill!

 

[sqrlgtr]

The last box of lapua br brass I got had pretty good size burr around flash hole also.Needless to say I started deburring lapua brass.K and M makes a great deburr tool for the .0595 flashhole of the br brass...

 

[Dave Way]

I feel like i was listening to a tattletale or something. Ive never heard of a flash hole being drilled by anybody in the know. Can you imagine the production cost on that?

Actually Dusty, I know someone with original brass from the development of the 6br case and the cases have no flash holes. This was from early development when they were testing flash hole size and how it affected accuracy. As far as how much of this brass went out to the public, I can't say.

Dave.