I was sent a Farley Action that had the lugs shear off of the bolt body.

[Cloudrepair]

The one thing that I am not 100% sure of is machining the curved surface between the bolt lugs.

My best though is to grind a radius tool on a 5/8 shank HSS tool, chuck the bolt up in the lath, mount the radius tool sideways and drag the radius on the bolt.
This steel is going to be pretty tough, but it might work. I can chuck the bolt up in one of my 18 inch lathes for stiffness and power.

Do you have a knee mill and a fly cutter.
you could put that ground hss in the fly cutter and cut it that way.
I would surface it on the cnc mill myself but you may not have that kind of setup.
Or stand it up in the cnc and cut the profile with a .375 end mill and finish it with the appropriate smaller endmill before welding.

 

[LVLAaron]

The one thing that I am not 100% sure of is machining the curved surface between the bolt lugs.

My best though is to grind a radius tool on a 5/8 shank HSS tool, chuck the bolt up in the lath, mount the radius tool sideways and drag the radius on the bolt.
This steel is going to be pretty tough, but it might work. I can chuck the bolt up in one of my 18 inch lathes for stiffness and power.

Mount it vertically in a rotary table?

 

[WSnyder]

It can be done horizontally in a rotary. First cut the lugs in. The edge of the cutter is then setup on the centerline of the bolt and to depth. The part is rotated towards the cutter a little at a time while traversing back and forth until you hit the corner of the lug. Rotate and do the other opposite 1/4 side. Re-setup the cutter to cut the remaining sides the same way. It’s two setups with four cuts. Hard to explain but not that hard to do.

 

[ricco1949]

The one thing that I am not 100% sure of is machining the curved surface between the bolt lugs.

My best though is to grind a radius tool on a 5/8 shank HSS tool, chuck the bolt up in the lath, mount the radius tool sideways and drag the radius on the bolt.
This steel is going to be pretty tough, but it might work. I can chuck the bolt up in one of my 18 inch lathes for stiffness and power.

I made a 3 lug rear entry action wrench which is a similar concept but not as precise on a rotary table with appropriate size end mill.

It's been over 10 years since I made it so I don't remember all of the details other than I received the lug specs from the manufacturer. I don't recall how I determined the number of passes between the lugs.

The arc mating to the body is very precise.

I cheated by making the lug portion and body separate and threading them together.

This might be crude for your application but the concept may be useable.

 

[Fast14riot]

Why not just mount it on its axis and just make passes back and forth with a regular end mill? Kinda like doing a radiused corner on a mill between parallels.

 

[jackieschmidt]

Do you have a knee mill and a fly cutter.
you could put that ground hss in the fly cutter and cut it that way.
I would surface it on the cnc mill myself but you may not have that kind of setup.
Or stand it up in the cnc and cut the profile with a .375 end mill and finish it with the appropriate smaller endmill before welding.

I have several Knee Mills.
But if the cutter is moving in sn arc, it won’t finish the tops of the lugs before hitting the main bolt body.

Why not just mount it on its axis and just make passes back and forth with a regular end mill? Kinda like doing a radiused corner on a mill between parallels.

We have several dividing heads. I am ordering several 1/8 ball end mills and all of the carbide drills I need to finish up.

The Heat Treat shop said it will be ready Friday.

I have it figured out, after reading many of suggestions given hear.

I have also decided to convert this to a drop port BR bolt face.like I did with my LV Farley. I have a Bat SAKO style extractor.

 

[Will Henry]

I do it just about as shown on ricco1949's action wrench (I make action wrenches the same way). In essence, I cut the left side of both lugs first, with the side of the cutter. After cutting the side of the lug. I index away from the lug by five degree IIRC, and repeat until I have removed material to 90 degrees. I then repeat for the other lug. After that, I move over and cut the right side of the lugs the same way (indexing in the other direction). I leave a cylindrical portion ahead of the lugs, when I make the blank, so I have a place the same diameter as the bolt body which I can touch to set up. WH

 

[DaveTooley]

The one thing that I am not 100% sure of is machining the curved surface between the bolt lugs.

My best though is to grind a radius tool on a 5/8 shank HSS tool, chuck the bolt up in the lath, mount the radius tool sideways and drag the radius on the bolt.
This steel is going to be pretty tough, but it might work. I can chuck the bolt up in one of my 18 inch lathes for stiffness and power.

I think I would machine the lugs to width then use a smaller/narrower tool and work on the between the lugs. Less force needed probably means more time to think. Alan Hall used s shaper. Now a days it's a CNC mill.

 

[jackieschmidt]

I got my piece of 4340 from Heat Treat, did the lathe work tonight.

The RC hardness came to 38.5.

the most trying operation was drilling the .062 diameter firing pin hole. The bolt head extension is a light tap into the bolt body.

I will set one of my dividing heads on a mill and start on the lugs.

Here are a few pictures

 

[Cloudrepair]

I'm surprised no one mentioned a radius cutter but that could be a pain to .
Probably need to grind the end and tip the head.
Thanks for the pics it's good to see your work .

 

[Jonnyofalltrades]

I'm surprised no one mentioned a radius cutter but that could be a pain to .
Probably need to grind the end and tip the head.
Thanks for the pics it's good to see your work .

Not sure that I follow? Do you mean a concave tipped form tool laid sideways and used in a lathe like a shaper?
Or are you referring to an hourglass shaped form cutter in a horizontal milling machine?
There are so many different ways for shops that don't have CNC interpolation capabilities to cut out lugs. Probably a few that we haven't thought of yet.

 

[Cloudrepair]

Not sure that I follow? Do you mean a concave tipped form tool laid sideways and used in a lathe like a shaper?
Or are you referring to an hourglass shaped form cutter in a horizontal milling machine?
There are so many different ways for shops that don't have CNC interpolation capabilities to cut out lugs. Probably a few that we haven't thought of yet.

Concave tool in a mill.
I have used them on a lathe to put a accurate radius on the end a part.

 

[boltfluter]

Stand it up in the CNC mill and walk around it. Then come back in with a smaller end mill and clearance the 4 intersection points where the lug flat meets the radius. Just like on the nice Tikka bolt heads. A nice little radius would mitigate any stress points in the corners. At least this is how I would do it. Would be a fun little job. Many ways to accomplish this.
Paul

 

[gunsandgunsmithing]

Stand it up in the CNC mill and walk around it. Then come back in with a smaller end mill and clearance the 4 intersection points where the lug flat meets the radius. Just like on the nice Tikka bolt heads. A nice little radius would mitigate any stress points in the corners. At least this is how I would do it. Would be a fun little job. Many ways to accomplish this.
Paul

I was think like you. But as you say, multiple ways to do it. CNC would be easiest but a rotary table would get it done as well. Could probably do it horizontally in a simple collet indexer too, if it's all ya had. Jackie has plenty of tools to work with though.

 

[jackieschmidt]

I‘ll see if I can borrow a CNC Mill

 

[Will Henry]

In general, I do like the idea of a little radius in the corners. I didn't do it on the sides of the lugs though. WH

 

[Alex Wheeler]

Rotary table on the mill with the bolt vertical. Thats how Id do it with manual machines.

 

[Cloudrepair]

Stand it up in the CNC mill and walk around it. Then come back in with a smaller end mill and clearance the 4 intersection points where the lug flat meets the radius. Just like on the nice Tikka bolt heads. A nice little radius would mitigate any stress points in the corners. At least this is how I would do it. Would be a fun little job. Many ways to accomplish this.
Paul

That is what I was trying to say earlier but I'm not good with words just numbers

 

[WSnyder]

Lots of ways to do this

FWIW PTG used to cut them the way I described or in a very similar way. They used a large ~2” diameter cutter and they took four cuts. You could see the machining marks on some of the bolts that made it obvious that’s how they did it. I imagine they did it in a 4th axis CNC but maybe not back then.

 

[gunsandgunsmithing]

Lots of ways to do this

FWIW PTG used to cut them the way I described or in a very similar way. They used a large ~2” diameter cutter and they took four cuts. You could see the machining marks on some of the bolts that made it obvious that’s how they did it. I imagine they did it in a 4th axis CNC but maybe not back then.

I saw your other post but I still can't picture it in my mind, how your using a large fly cutter for this. I don't doubt ya at all, just still wondering. Lol! As has been said, more than one way to do this.