- Joined
- Jan 5, 2018
- Messages
- 28
OK So I have a rifle I needed to make a screw for, to hold a stock on the receiver.
A company offers a bolt that threads into the receiver, but it's a wee bit too short for my liking, and the old recoil tube more effectively meshed with the threads in the receiver.
My solution was to cut the head off of the bolt, and weld it to the recoil tube at the proper length. The head of the commercial hold has the correct taper to mate with the stock I want to put on the weapon. So I couldn't just weld on any old bolt head.
I have watched a few youtube videos on machining, and they taught me little for actual machining. When it came down to chucking a piece in the chuck and cutting the metal, it was extremely trustrating and demoralizing. Lots of chatter, and sloppy, dull cuts that looked like I had removed metal with friction, and not with any cutting.
My mom's boyfriend is an aerospace machinist, to give you an idea, the tolerances he works with are 50/1,000,000" (That's fifty one MILLIONTH lol) came by and showed me just a few things with the lathe, that changed my entire outlook. His wisdom opened my eyes, and after that, I was cutting metal much more effectively. He pointed that out and told me how he uses the tailpiece to get his cutting bit properly positioned, because eyeballing the work it's that effective. He gets his a thousandth or so under centerline.
I was having issues with concentricity in my non adjustable chuck, and he switched the teeth around until I was 1/1000" out. We checked the spindle in the lathe and the runout indicator literally did not move. He was amazed this old Atlas Craftsman was that precise.
He gave me some tips on welding the piece, mainly, tack it in 3 parts, then bridge the distances between tacks. His other advice was cut an internal taper on the threaded tube, and an external taper on the bolt head. I tried for 45 degrees. At one point I ran out of room on the lathe so I had to approach the tube from the other side, and because my lathe didn't have a reverse, I had to mount the cutting tool upside down... but it worked lol.
Other people said machining a weld is hard because it's a hard metal, but I made sure the high speed steel cutting tool was nice and sharp with an aggressive cutting edge, and it really did cut the weld effortlessly.
At the base of the tailstock, the bolt was was 3/1000" out of concentricity after welding, and machining the bolt weld, even before machining the bolt body down a little. The weld didn't move it at all, or pull it out of alignment, so the taper idea worked perfectly. Also pushed the tailpiece hard into the bolt, so hard at one point it pushed the bolt head into the chuck.
I would have liked 0/1000" (Like the lathe spindle was lol) but I reckon that's pretty good for my first try.
The bolt did work fine, and actually I had to turn it down the body a wee bit because the fit was so close the threads did not want to catch (It's complicated) so I took maybe 50/1000 off of the overall diameter (Left the threads alone obviously) and it worked!
Man it's satisfying watching those chips get carved off of the metal
A company offers a bolt that threads into the receiver, but it's a wee bit too short for my liking, and the old recoil tube more effectively meshed with the threads in the receiver.
My solution was to cut the head off of the bolt, and weld it to the recoil tube at the proper length. The head of the commercial hold has the correct taper to mate with the stock I want to put on the weapon. So I couldn't just weld on any old bolt head.
I have watched a few youtube videos on machining, and they taught me little for actual machining. When it came down to chucking a piece in the chuck and cutting the metal, it was extremely trustrating and demoralizing. Lots of chatter, and sloppy, dull cuts that looked like I had removed metal with friction, and not with any cutting.
My mom's boyfriend is an aerospace machinist, to give you an idea, the tolerances he works with are 50/1,000,000" (That's fifty one MILLIONTH lol) came by and showed me just a few things with the lathe, that changed my entire outlook. His wisdom opened my eyes, and after that, I was cutting metal much more effectively. He pointed that out and told me how he uses the tailpiece to get his cutting bit properly positioned, because eyeballing the work it's that effective. He gets his a thousandth or so under centerline.
I was having issues with concentricity in my non adjustable chuck, and he switched the teeth around until I was 1/1000" out. We checked the spindle in the lathe and the runout indicator literally did not move. He was amazed this old Atlas Craftsman was that precise.
He gave me some tips on welding the piece, mainly, tack it in 3 parts, then bridge the distances between tacks. His other advice was cut an internal taper on the threaded tube, and an external taper on the bolt head. I tried for 45 degrees. At one point I ran out of room on the lathe so I had to approach the tube from the other side, and because my lathe didn't have a reverse, I had to mount the cutting tool upside down... but it worked lol.
Other people said machining a weld is hard because it's a hard metal, but I made sure the high speed steel cutting tool was nice and sharp with an aggressive cutting edge, and it really did cut the weld effortlessly.
At the base of the tailstock, the bolt was was 3/1000" out of concentricity after welding, and machining the bolt weld, even before machining the bolt body down a little. The weld didn't move it at all, or pull it out of alignment, so the taper idea worked perfectly. Also pushed the tailpiece hard into the bolt, so hard at one point it pushed the bolt head into the chuck.
I would have liked 0/1000" (Like the lathe spindle was lol) but I reckon that's pretty good for my first try.
The bolt did work fine, and actually I had to turn it down the body a wee bit because the fit was so close the threads did not want to catch (It's complicated) so I took maybe 50/1000 off of the overall diameter (Left the threads alone obviously) and it worked!
Man it's satisfying watching those chips get carved off of the metal
.