RGG firing pin hole question

I\'m looking at sheet 48-20 10-4-94 at the moment.  It shows a 0.062\" wide by .050\" deep slot in detail B.  Seems like the idea is build in a drill guide which makes sense.  So how much clearance should I go for when I drill?  It isn\'t specified.  Should I ream the hole?  I\'m going to order the mold ejector pin for the firing pin.

Thanks,

Clutch

[Dave]

In the end it needs to be a 1/16 hole, After you solder the recoil pins in it, it gets drilled out to 1/16....... I had to de-solder one of my pins to get a broken drill bill out of it!

[cutter]

This worked for me.

   I used a 1/32 R convex cutter I purchased from McMaster.
  Holding the center line of the firing pin hole on a .102 radius
   of the recoil pin. This keeps the diameter of the pins inside
   the diameter of the counter bores for the cartridge rim.
   I drilled .063 diameter after assembly.
   .062 diameter ejector pin from McMaster.
       Good Luck

[quote name=\"cutter\"]This worked for me.

   I used a 1/32 R convex cutter I purchased from McMaster.
  Holding the center line of the firing pin hole on a .102 radius
   of the recoil pin. This keeps the diameter of the pins inside
   the diameter of the counter bores for the cartridge rim.
   I drilled .063 diameter after assembly.
   .062 diameter ejector pin from McMaster.
       Good Luck[/quote]

Okay, if I read this right, you used a 1/16\" D ballnose endmill to cut the slot.  Thanks for the tip on McMaster for the pins.  I\'m firing off an order in a moment.
Sure seems like a long hole for 0.001 total clearance.   I\'ll soon learn how well it works.

Thanks,

Clutch

[cutter]

It\'s not a ballmill  here\'s the #2820A71
I modified the pin heads before cutting them to length
#98378A400

[quote name=\"cutter\"]It\'s not a ballmill  here\'s the #2820A71
I modified the pin heads before cutting them to length
#98378A400[/quote]

For those that don\'t care to look it up, the cutter is somewhat like a woodruff key cutter.  

I wish I had learned that sooner.  Your tool has a long life and is easily sharpened.

The ball end mill I bought, well, it with a standard 1/16\" end mill will get it done but the tools will use up a lot of life.

Did you cut the slot on a Bridgeport type of machine or something else?

As for the pin, I purchased another part number that is the same pin so I didn\'t blow that.

Thanks,

Clutch

Make the bolt as one piece.

 

[attachment=9470:Bolt-id=93.JPG]

Here\'s a tip related to firing pin/hole. And it\'s counterbore.

Check for any excess silver solder or burrs way down in the bottom of the firing pin hole(counterbore) of the bolt.
The firing pin has a flat head that should land squarely on a flat hole bottom. My 1/4 inch bolt parts that were soldered \'in\' were +- on that \'land\' and some silver solder fillets had developed down there as well. Impossible to see and even harder to counterbore. I ground a long flat end cutter to clean them(10) up. Then diamond lapped the c-bore bottom.

Why?
Imagine the \'firing pin spring\' hammering the head of the firing pin onto an uneven surface or silver solder fillet on part of the radius. Those \'off center\' continuous hits will stress fracture the head of the pin/shaft and crack it.

[quote name=\"dburn\"]Make the bolt as one piece.[/quote]

Sweet. Two questions.

How did you drill a huge L/D hole and get it to work.

Did you use CNC and do 4th axis machining?  I suppose a dividing head and a Bridgeport could do the trick also.

Clutch