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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#1
Posted to rec.crafts.metalworking
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Removing Freely Rotating Swaged Steel Pin
The collegiate pistol team I help coach has two Russian target air
pistols that have broken cocking linkages. I have replacement parts, but I need to disassemble a linkage that has a swaged pin in it. The ends of the pin are even with the sides of a piece I need to rescue undamaged. I had originally planned on drilling/milling out the center of the swaged part enough to press the pin out, but I discovered that the pin is free to rotate. There's nothing exposed enough to hang onto that I don't need to largely cut away. I can probably grind out the swaged bit VERY carefully with a Dremel, but it's going to be tedious & fussy. The pins are about 5/16" in diameter, and each end has a shallow drilled out section. It looks like they pressed ball bearings into the ends to spread them. The linkage the pin goes through is countersunk on both sides, so the swaged bits hold everything together. There a picture he http://www.pyramydair.com/blog/image...inkage-web.jpg The pin is the large one with the dimple just left of center in the image. The only way I can think of to physically hang onto the pin is to make an expanding collet that goes into the drilled out pocket on the far end of the pin. That is going to be tenuous at best, and it's a lot of work to fabricate for a high likelihood of failure. One other option would be to crazy glue everything together, mill out the swaged bit, and then soak it in acetone until the pieces free up. That assumes the crazy glue can handle the machining forces. Before I drag out the Dremel, does anyone have any better sugestions? Thanks! Doug White |
#2
Posted to rec.crafts.metalworking
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Removing Freely Rotating Swaged Steel Pin
Doug White wrote: The collegiate pistol team I help coach has two Russian target air pistols that have broken cocking linkages. I have replacement parts, but I need to disassemble a linkage that has a swaged pin in it. The ends of the pin are even with the sides of a piece I need to rescue undamaged. I had originally planned on drilling/milling out the center of the swaged part enough to press the pin out, but I discovered that the pin is free to rotate. There's nothing exposed enough to hang onto that I don't need to largely cut away. I can probably grind out the swaged bit VERY carefully with a Dremel, but it's going to be tedious & fussy. The pins are about 5/16" in diameter, and each end has a shallow drilled out section. It looks like they pressed ball bearings into the ends to spread them. The linkage the pin goes through is countersunk on both sides, so the swaged bits hold everything together. There a picture he http://www.pyramydair.com/blog/image...inkage-web.jpg The pin is the large one with the dimple just left of center in the image. The only way I can think of to physically hang onto the pin is to make an expanding collet that goes into the drilled out pocket on the far end of the pin. That is going to be tenuous at best, and it's a lot of work to fabricate for a high likelihood of failure. One other option would be to crazy glue everything together, mill out the swaged bit, and then soak it in acetone until the pieces free up. That assumes the crazy glue can handle the machining forces. Before I drag out the Dremel, does anyone have any better sugestions? Thanks! Doug White How about setting up so the opposite side is pressed against a multi-flute countersink to act to stop the pin from turning? |
#3
Posted to rec.crafts.metalworking
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Removing Freely Rotating Swaged Steel Pin
On Thu, 26 Dec 2013 19:45:16 -0500, "Pete C."
wrote: Doug White wrote: The collegiate pistol team I help coach has two Russian target air pistols that have broken cocking linkages. I have replacement parts, but I need to disassemble a linkage that has a swaged pin in it. The ends of the pin are even with the sides of a piece I need to rescue undamaged. I had originally planned on drilling/milling out the center of the swaged part enough to press the pin out, but I discovered that the pin is free to rotate. There's nothing exposed enough to hang onto that I don't need to largely cut away. I can probably grind out the swaged bit VERY carefully with a Dremel, but it's going to be tedious & fussy. The pins are about 5/16" in diameter, and each end has a shallow drilled out section. It looks like they pressed ball bearings into the ends to spread them. The linkage the pin goes through is countersunk on both sides, so the swaged bits hold everything together. There a picture he http://www.pyramydair.com/blog/image...inkage-web.jpg The pin is the large one with the dimple just left of center in the image. The only way I can think of to physically hang onto the pin is to make an expanding collet that goes into the drilled out pocket on the far end of the pin. That is going to be tenuous at best, and it's a lot of work to fabricate for a high likelihood of failure. One other option would be to crazy glue everything together, mill out the swaged bit, and then soak it in acetone until the pieces free up. That assumes the crazy glue can handle the machining forces. Before I drag out the Dremel, does anyone have any better sugestions? Thanks! Doug White How about setting up so the opposite side is pressed against a multi-flute countersink to act to stop the pin from turning? That would be my suggestion.. Clamp the gun so the pin is forced against either a countersink or another drill bit. Using a drill bit on both sides, one end or the other (or both) will be drilled out enough to release the pin. |
#4
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Removing Freely Rotating Swaged Steel Pin
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#6
Posted to rec.crafts.metalworking
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Removing Freely Rotating Swaged Steel Pin
On 2013-12-27, Pete C. wrote:
Doug White wrote: The collegiate pistol team I help coach has two Russian target air The only way I can think of to physically hang onto the pin is to make an expanding collet that goes into the drilled out pocket on the far end of the pin. That is going to be tenuous at best, and it's a lot of work to fabricate for a high likelihood of failure. [ ... ] Before I drag out the Dremel, does anyone have any better sugestions? [ ... ] How about setting up so the opposite side is pressed against a multi-flute countersink to act to stop the pin from turning? I see that I should have read ahead instead of just posting. The only thing that this doesn't have which I suggested is the starting with a smaller bit, and increasing sizes in steps of equal added hole area to keep the torque applied to the countersink about the same. Enjoy, DoN. -- Remove oil spill source from e-mail Email: | (KV4PH) Voice (all times): (703) 938-4564 (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html --- Black Holes are where God is dividing by zero --- |
#7
Posted to rec.crafts.metalworking
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Removing Freely Rotating Swaged Steel Pin
"Pete C." wrote in news:52bccd9c$0$29568$862e30e2
@ngroups.net: Doug White wrote: The collegiate pistol team I help coach has two Russian target air pistols that have broken cocking linkages. I have replacement parts, but I need to disassemble a linkage that has a swaged pin in it. The ends of the pin are even with the sides of a piece I need to rescue undamaged. I had originally planned on drilling/milling out the center of the swaged part enough to press the pin out, but I discovered that the pin is free to rotate. There's nothing exposed enough to hang onto that I don't need to largely cut away. I can probably grind out the swaged bit VERY carefully with a Dremel, but it's going to be tedious & fussy. The pins are about 5/16" in diameter, and each end has a shallow drilled out section. It looks like they pressed ball bearings into the ends to spread them. The linkage the pin goes through is countersunk on both sides, so the swaged bits hold everything together. There a picture he http://www.pyramydair.com/blog/image...inkage-web.jpg The pin is the large one with the dimple just left of center in the image. The only way I can think of to physically hang onto the pin is to make an expanding collet that goes into the drilled out pocket on the far end of the pin. That is going to be tenuous at best, and it's a lot of work to fabricate for a high likelihood of failure. One other option would be to crazy glue everything together, mill out the swaged bit, and then soak it in acetone until the pieces free up. That assumes the crazy glue can handle the machining forces. Before I drag out the Dremel, does anyone have any better sugestions? Thanks! Doug White How about setting up so the opposite side is pressed against a multi-flute countersink to act to stop the pin from turning? I thought about that. I suppose if I put a cutter on both ends, one fixed & one under power, one of them will do the job before the other one does. Or both will be the same, I don't care. My only concern is not being able to see what's going on underneath, and fixturing it so it can't scoot sideways. Doug White |
#8
Posted to rec.crafts.metalworking
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Removing Freely Rotating Swaged Steel Pin
Doug White wrote: "Pete C." wrote in news:52bccd9c$0$29568$862e30e2 @ngroups.net: Doug White wrote: The collegiate pistol team I help coach has two Russian target air pistols that have broken cocking linkages. I have replacement parts, but I need to disassemble a linkage that has a swaged pin in it. The ends of the pin are even with the sides of a piece I need to rescue undamaged. I had originally planned on drilling/milling out the center of the swaged part enough to press the pin out, but I discovered that the pin is free to rotate. There's nothing exposed enough to hang onto that I don't need to largely cut away. I can probably grind out the swaged bit VERY carefully with a Dremel, but it's going to be tedious & fussy. The pins are about 5/16" in diameter, and each end has a shallow drilled out section. It looks like they pressed ball bearings into the ends to spread them. The linkage the pin goes through is countersunk on both sides, so the swaged bits hold everything together. There a picture he http://www.pyramydair.com/blog/image...inkage-web.jpg The pin is the large one with the dimple just left of center in the image. The only way I can think of to physically hang onto the pin is to make an expanding collet that goes into the drilled out pocket on the far end of the pin. That is going to be tenuous at best, and it's a lot of work to fabricate for a high likelihood of failure. One other option would be to crazy glue everything together, mill out the swaged bit, and then soak it in acetone until the pieces free up. That assumes the crazy glue can handle the machining forces. Before I drag out the Dremel, does anyone have any better sugestions? Thanks! Doug White How about setting up so the opposite side is pressed against a multi-flute countersink to act to stop the pin from turning? I thought about that. I suppose if I put a cutter on both ends, one fixed & one under power, one of them will do the job before the other one does. Or both will be the same, I don't care. My only concern is not being able to see what's going on underneath, and fixturing it so it can't scoot sideways. Doug White My though is that one of the six flute countersinks pressed solidly against the pin should have more "bite" to keep it from rotating than a two flute drill applied more gently on the top. You could also fixture it horizontally so you can see the backside. |
#9
Posted to rec.crafts.metalworking
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Removing Freely Rotating Swaged Steel Pin
On Thursday, December 26, 2013 7:32:06 PM UTC-5, Doug White wrote:
The collegiate pistol team I help coach has two Russian target air pistols that have broken cocking linkages. I have replacement parts, but I need to disassemble a linkage that has a swaged pin in it. The ends of the pin are even with the sides of a piece I need to rescue undamaged. I had originally planned on drilling/milling out the center of the swaged part enough to press the pin out, but I discovered that the pin is free to rotate. There's nothing exposed enough to hang onto that I don't need to largely cut away. I can probably grind out the swaged bit VERY carefully with a Dremel, but it's going to be tedious & fussy. The pins are about 5/16" in diameter, and each end has a shallow drilled out section. It looks like they pressed ball bearings into the ends to spread them. The linkage the pin goes through is countersunk on both sides, so the swaged bits hold everything together. There a picture he http://www.pyramydair.com/blog/image...inkage-web.jpg The pin is the large one with the dimple just left of center in the image. The only way I can think of to physically hang onto the pin is to make an expanding collet that goes into the drilled out pocket on the far end of the pin. That is going to be tenuous at best, and it's a lot of work to fabricate for a high likelihood of failure. One other option would be to crazy glue everything together, mill out the swaged bit, and then soak it in acetone until the pieces free up. That assumes the crazy glue can handle the machining forces. Before I drag out the Dremel, does anyone have any better sugestions? Thanks! Doug White If you can tolerate the pin spinning in the hole perhaps quite a bit I've found drilling rotating pins works if you angle the piece, idea is to angle the part so the drill spins the pin but off-center, on 'average' there will be a part where the bit is hitting where the bit surface speed will be larger than the pins. Maybe you could CA or loc-tite a small metal rod in the drilled end and clamp the rod in the vise? Dave |
#10
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Removing Freely Rotating Swaged Steel Pin
On Thursday, December 26, 2013 8:18:08 PM UTC-5, wrote:
On Thursday, December 26, 2013 7:32:06 PM UTC-5, Doug White wrote: The collegiate pistol team I help coach has two Russian target air pistols that have broken cocking linkages. I have replacement parts, but I need to disassemble a linkage that has a swaged pin in it. The ends of the pin are even with the sides of a piece I need to rescue undamaged. I had originally planned on drilling/milling out the center of the swaged part enough to press the pin out, but I discovered that the pin is free to rotate. There's nothing exposed enough to hang onto that I don't need to largely cut away. I can probably grind out the swaged bit VERY carefully with a Dremel, but it's going to be tedious & fussy. The pins are about 5/16" in diameter, and each end has a shallow drilled out section. It looks like they pressed ball bearings into the ends to spread them. The linkage the pin goes through is countersunk on both sides, so the swaged bits hold everything together. There a picture he http://www.pyramydair.com/blog/image...inkage-web.jpg The pin is the large one with the dimple just left of center in the image. The only way I can think of to physically hang onto the pin is to make an expanding collet that goes into the drilled out pocket on the far end of the pin. That is going to be tenuous at best, and it's a lot of work to fabricate for a high likelihood of failure. One other option would be to crazy glue everything together, mill out the swaged bit, and then soak it in acetone until the pieces free up. That assumes the crazy glue can handle the machining forces. Before I drag out the Dremel, does anyone have any better sugestions? Thanks! Doug White If you can tolerate the pin spinning in the hole perhaps quite a bit I've found drilling rotating pins works if you angle the piece, idea is to angle the part so the drill spins the pin but off-center, on 'average' there will be a part where the bit is hitting where the bit surface speed will be larger than the pins. Maybe you could CA or loc-tite a small metal rod in the drilled end and clamp the rod in the vise? Dave BTW CA gets gummy and lets go at a fairly low temp if you get tired of waiting for acetone to do its thing. |
#11
Posted to rec.crafts.metalworking
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Removing Freely Rotating Swaged Steel Pin
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#12
Posted to rec.crafts.metalworking
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Removing Freely Rotating Swaged Steel Pin
On Thu, 26 Dec 2013 17:20:35 -0800 (PST), wrote:
On Thursday, December 26, 2013 8:18:08 PM UTC-5, wrote: On Thursday, December 26, 2013 7:32:06 PM UTC-5, Doug White wrote: The collegiate pistol team I help coach has two Russian target air pistols that have broken cocking linkages. I have replacement parts, but I need to disassemble a linkage that has a swaged pin in it. The ends of the pin are even with the sides of a piece I need to rescue undamaged. I had originally planned on drilling/milling out the center of the swaged part enough to press the pin out, but I discovered that the pin is free to rotate. There's nothing exposed enough to hang onto that I don't need to largely cut away. I can probably grind out the swaged bit VERY carefully with a Dremel, but it's going to be tedious & fussy. The pins are about 5/16" in diameter, and each end has a shallow drilled out section. It looks like they pressed ball bearings into the ends to spread them. The linkage the pin goes through is countersunk on both sides, so the swaged bits hold everything together. There a picture he http://www.pyramydair.com/blog/image...inkage-web.jpg The pin is the large one with the dimple just left of center in the image. The only way I can think of to physically hang onto the pin is to make an expanding collet that goes into the drilled out pocket on the far end of the pin. That is going to be tenuous at best, and it's a lot of work to fabricate for a high likelihood of failure. One other option would be to crazy glue everything together, mill out the swaged bit, and then soak it in acetone until the pieces free up. That assumes the crazy glue can handle the machining forces. Before I drag out the Dremel, does anyone have any better sugestions? Thanks! Doug White If you can tolerate the pin spinning in the hole perhaps quite a bit I've found drilling rotating pins works if you angle the piece, idea is to angle the part so the drill spins the pin but off-center, on 'average' there will be a part where the bit is hitting where the bit surface speed will be larger than the pins. Maybe you could CA or loc-tite a small metal rod in the drilled end and clamp the rod in the vise? Dave BTW CA gets gummy and lets go at a fairly low temp if you get tired of waiting for acetone to do its thing. Another suggestion is to mount 2 drills in a lathe, place the center punched pin between them and slowly turn it. One or both drills will intermittently grab and give you a hole that you may use an easy out in to allow you to drill out the other end. Please let us know what works. To reply to this message please remove the AT after the kgs1 in the reply to address. To a conservatist's it truly is a free country, YOU may do whatever they wish. KG |
#13
Posted to rec.crafts.metalworking
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Removing Freely Rotating Swaged Steel Pin
On 27/12/2013 8:42 PM, KG wrote:
On Thu, 26 Dec 2013 17:20:35 -0800 (PST), wrote: On Thursday, December 26, 2013 8:18:08 PM UTC-5, wrote: On Thursday, December 26, 2013 7:32:06 PM UTC-5, Doug White wrote: The collegiate pistol team I help coach has two Russian target air pistols that have broken cocking linkages. I have replacement parts, but I need to disassemble a linkage that has a swaged pin in it. The ends of the pin are even with the sides of a piece I need to rescue undamaged. I had originally planned on drilling/milling out the center of the swaged part enough to press the pin out, but I discovered that the pin is free to rotate. There's nothing exposed enough to hang onto that I don't need to largely cut away. I can probably grind out the swaged bit VERY carefully with a Dremel, but it's going to be tedious & fussy. The pins are about 5/16" in diameter, and each end has a shallow drilled out section. It looks like they pressed ball bearings into the ends to spread them. The linkage the pin goes through is countersunk on both sides, so the swaged bits hold everything together. There a picture he http://www.pyramydair.com/blog/image...inkage-web.jpg The pin is the large one with the dimple just left of center in the image. The only way I can think of to physically hang onto the pin is to make an expanding collet that goes into the drilled out pocket on the far end of the pin. That is going to be tenuous at best, and it's a lot of work to fabricate for a high likelihood of failure. One other option would be to crazy glue everything together, mill out the swaged bit, and then soak it in acetone until the pieces free up. That assumes the crazy glue can handle the machining forces. Before I drag out the Dremel, does anyone have any better sugestions? Thanks! Doug White If you can tolerate the pin spinning in the hole perhaps quite a bit I've found drilling rotating pins works if you angle the piece, idea is to angle the part so the drill spins the pin but off-center, on 'average' there will be a part where the bit is hitting where the bit surface speed will be larger than the pins. Maybe you could CA or loc-tite a small metal rod in the drilled end and clamp the rod in the vise? Dave BTW CA gets gummy and lets go at a fairly low temp if you get tired of waiting for acetone to do its thing. Another suggestion is to mount 2 drills in a lathe, place the center punched pin between them and slowly turn it. One or both drills will intermittently grab and give you a hole that you may use an easy out in to allow you to drill out the other end. Please let us know what works. To reply to this message please remove the AT after the kgs1 in the reply to address. To a conservatist's it truly is a free country, YOU may do whatever they wish. KG you beat me to it! That'd be my approach too. |
#14
Posted to rec.crafts.metalworking
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Removing Freely Rotating Swaged Steel Pin
KG wrote in
: Another suggestion is to mount 2 drills in a lathe, place the center punched pin between them and slowly turn it. One or both drills will intermittently grab and give you a hole that you may use an easy out in to allow you to drill out the other end. Please let us know what works. The double cutter approach seems to be the favorite. I had originally been thinking of doing this in a mill, but upon further reflection, I agree that a lathe is easier. I don't have to make a fixture for the cutter on the "bottom" end, I can just put it in a collet. I also have full visibility on both ends to see how things are progressing. With all this in mind, I took a few measurements. The pin is smaller than I thought, it's 6 mm in diameter. The dimple is too shallow to allow using even a 90 degree countersink, so I'm left with drill bits or end mills. I think a pair of 1/4" ball end mills might work, but something smaller would be better. The swaging isn't perfectly centered, and I want a little margin so I don't end up cutting into the link. I only need to get the swaged part thin enough that I can easily press out the pin without distorting the link. A pair of 13/64" ball end mills should do it. That works out to 0.203", compared to 0.236" for 6 mm. Time to go shopping. Doug White |
#15
Posted to rec.crafts.metalworking
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Removing Freely Rotating Swaged Steel Pin
Ball end mill cutters are generally side cutting, in that there is very
little/none cutting at the tip of the ball, unless you can source cutters that are similar to split-point drills. The same goes for countersink cutters.. they're just not as effective without a properly sized hole to feed into. After using the Dremel to center the divots at the ends of the pin, proceeding with 2 split-point drills from opposite sides would likely be the easiest approach. Split-point drills begin to cut immediately upon contact with the workpiece, whereas conventionally ground drills require feed pressure to force the drill's web into the workpiece. -- WB .......... "Doug White" wrote in message .. . The double cutter approach seems to be the favorite. I had originally been thinking of doing this in a mill, but upon further reflection, I agree that a lathe is easier. I don't have to make a fixture for the cutter on the "bottom" end, I can just put it in a collet. I also have full visibility on both ends to see how things are progressing. With all this in mind, I took a few measurements. The pin is smaller than I thought, it's 6 mm in diameter. The dimple is too shallow to allow using even a 90 degree countersink, so I'm left with drill bits or end mills. I think a pair of 1/4" ball end mills might work, but something smaller would be better. The swaging isn't perfectly centered, and I want a little margin so I don't end up cutting into the link. I only need to get the swaged part thin enough that I can easily press out the pin without distorting the link. A pair of 13/64" ball end mills should do it. That works out to 0.203", compared to 0.236" for 6 mm. Time to go shopping. Doug White |
#16
Posted to rec.crafts.metalworking
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Removing Freely Rotating Swaged Steel Pin
wrote in
: On Thursday, December 26, 2013 7:32:06 PM UTC-5, Doug White wrote: The collegiate pistol team I help coach has two Russian target air pistols that have broken cocking linkages. I have replacement parts, but I need to disassemble a linkage that has a swaged pin in it. The ends of the pin are even with the sides of a piece I need to rescue undamaged. I had originally planned on drilling/milling out the center of the swaged part enough to press the pin out, but I discovered that the pin is free to rotate. There's nothing exposed enough to hang onto that I don't need to largely cut away. I can probably grind out the swaged bit VERY carefully with a Dremel, but it's going to be tedious & fussy. The pins are about 5/16" in diameter, and each end has a shallow drilled out section. It looks like they pressed ball bearings into the ends to spread them. The linkage the pin goes through is countersunk on both sides, so the swaged bits hold everything together. There a picture he http://www.pyramydair.com/blog/image...inkage-web.jpg The pin is the large one with the dimple just left of center in the image. The only way I can think of to physically hang onto the pin is to make an expanding collet that goes into the drilled out pocket on the far end of the pin. That is going to be tenuous at best, and it's a lot of work to fabricate for a high likelihood of failure. One other option would be to crazy glue everything together, mill out the swaged bit, and then soak it in acetone until the pieces free up. That assumes the crazy glue can handle the machining forces. Before I drag out the Dremel, does anyone have any better sugestions? Thanks! Doug White If you can tolerate the pin spinning in the hole perhaps quite a bit I've found drilling rotating pins works if you angle the piece, idea is to angle the part so the drill spins the pin but off-center, on 'average' there will be a part where the bit is hitting where the bit surface speed will be larger than the pins. Maybe you could CA or loc-tite a small metal rod in the drilled end and clamp the rod in the vise? Dave Because the holes are mashed up, getting a good fit will be tricky. I don't want to spin the pin too much, because I don't want any more wear in the holes I'm trying to save. So far, the winner seems to be a double cutter set up. Doug White |
#17
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Removing Freely Rotating Swaged Steel Pin
Doug White wrote:
Before I drag out the Dremel, does anyone have any better sugestions? Maybe a job for an EDM shop? bob prohaska |
#18
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Removing Freely Rotating Swaged Steel Pin
User Bp wrote in :
Doug White wrote: Before I drag out the Dremel, does anyone have any better sugestions? Maybe a job for an EDM shop? I'm trying to do this on the cheap. The team lost their varsity status several years ago, and runs mostly on donations now. If I could get parts more easily, I'd just replace the whole assembly. The US importer would only sell me the pins & broken arms, and only two of each. For some reason, they abruptly stopped selling parts entirely last spring. I found another source for some more common parts, but no one who works on these has ever seen a broken linkage before, so they don't have those pieces. Doug White |
#19
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Removing Freely Rotating Swaged Steel Pin
On 2013-12-27, Doug White wrote:
The collegiate pistol team I help coach has two Russian target air pistols that have broken cocking linkages. I have replacement parts, but I need to disassemble a linkage that has a swaged pin in it. The ends of the pin are even with the sides of a piece I need to rescue undamaged. I had originally planned on drilling/milling out the center of the swaged part enough to press the pin out, but I discovered that the pin is free to rotate. There's nothing exposed enough to hang onto that I don't need to largely cut away. I can probably grind out the swaged bit VERY carefully with a Dremel, but it's going to be tedious & fussy. I can see that. The pins are about 5/16" in diameter, Likely 8mm then. That is one of the ponts where metric and inch measurements come close. (5/32", 5/16", 5/8"). and each end has a shallow drilled out section. How shallow? I can't tell from the photo. It looks like they pressed ball bearings into the ends to spread them. The linkage the pin goes through is countersunk on both sides, so the swaged bits hold everything together. There a picture he http://www.pyramydair.com/blog/image...inkage-web.jpg The only way I can think of to physically hang onto the pin is to make an expanding collet that goes into the drilled out pocket on the far end of the pin. That is going to be tenuous at best, and it's a lot of work to fabricate for a high likelihood of failure. My thought is to get a 5/16" diameter multi-flute countersink bit (used to be Severance, now some other company, IIRC), and mount it vertically so it sticks out just enough to allow the force to be applied to the cutting edges. Use it as an anvil to support one end of the pin, and use a smaller drill bit (perhaps 5/32" or so) to drill most of the way through. (You use the smaller drill bit so the torque from its cutting edges is likely less than the torque needed to start the countersink cutting.) When you get say 3/4 of the way through (set up the quill stop on the drill press to prevent the tip of the drill bit touching the tip of the countersink), flip it over and drill from the other side. Then increase the size of the bit to do something like the same hole area increase (5/32" would be about 0.245 square inches, so increase by the same for 0.395" diameter -- too big, looks like you can target the final diameter of 0.315" (8mm) on the second step. (Or, maybe you'll find that you need to start smaller, and increase by the area of the first bit which works. Maybe start with a 0.125" bit, then the next would be 0.176", and then the 0.216", and finally 0.315". Or -- maybe skip the final 0.315", and put it over a bench block and drive it out with a pin punch, as the walls will be thin enough to give way by this time. One other option would be to crazy glue everything together, mill out the swaged bit, and then soak it in acetone until the pieces free up. That assumes the crazy glue can handle the machining forces. I strongly doubt that the crazy glue will be strong enough, even if you could get it into the holes between the pin and the walls. Before I drag out the Dremel, does anyone have any better sugestions? You have what I would try, at least. It looks like you can remove that linkage assembly from the action by removing C-clips, so you won't be juggling as heavy a bunch of metal, and controlling it will be easier. Good Luck, DoN. -- Remove oil spill source from e-mail Email: | (KV4PH) Voice (all times): (703) 938-4564 (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html --- Black Holes are where God is dividing by zero --- |
#20
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Removing Freely Rotating Swaged Steel Pin
On 27 Dec 2013 04:51:11 GMT, "DoN. Nichols"
wrote: Before I drag out the Dremel, does anyone have any better sugestions? You have what I would try, at least. It looks like you can remove that linkage assembly from the action by removing C-clips, so you won't be juggling as heavy a bunch of metal, and controlling it will be easier. Good Luck, DoN. And putting it back together..consider an allen lock screw inside of a slotted pin and have it expand when you screw in the lock screw..and can be removed the next time easily. -- "Owning a sailboat is like marrying a nymphomaniac. You don’t want to do that but it is great if your best friend does. That way you get all the benefits without any of the upkeep" --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com |
#21
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Removing Freely Rotating Swaged Steel Pin
Gunner Asch wrote in
: On 27 Dec 2013 04:51:11 GMT, "DoN. Nichols" wrote: Before I drag out the Dremel, does anyone have any better sugestions? You have what I would try, at least. It looks like you can remove that linkage assembly from the action by removing C-clips, so you won't be juggling as heavy a bunch of metal, and controlling it will be easier. Good Luck, DoN. And putting it back together..consider an allen lock screw inside of a slotted pin and have it expand when you screw in the lock screw..and can be removed the next time easily. In theory, this is a one time deal. Some bright students decided that closing the action by pushing the cocking lever against the bench was easier than doing it by hand. Before we could stop this practice, they'd put their weight behind the process & broken two of the linkages. These two got busted a couple years ago, and we haven't had a repeat performance since. We still have to keep an eye open in case one of the older students remembers this trick & recommends it to one of the newbies. With time, it will fade from the collective memory and then we just have to watch out for somebody re-inventing it. Every year the students come up with new ways to screw up. We keep adding things to our list off do's & don't's, but its a challenge to keep up with them. This is at MIT. If you are interested in science & technology these days, the path of least resistance is to play with computers. The students have never taken hardware apart, and just have no mechanical intuition at all. Most of them don't have any idea how to operate a screwdriver properly. They either let things get loose & wonder why they can't shoot well, or they overtighten them, either cross-threading them, stripping the threads or breaking things. It wouldn't be quite so bad, except all of the target pistols are European or Russian, and many are out of production. Getting parts for the ones that are still being made is hard enough. The previous coach was difficult to get along with, and largely did everything himself because nobody wanted to deal with him to help. He was no gunsmith, and was disorganized. We inherited a lot of broken guns with no idea what was wrong with them, and quite a few that weren't labled as being broken. One student has been shooting a single shot .22 free pistol with no extractor. Nobody told him he wasn't supposed to have to fish out every fired round by hand, so he never mentioned it to anyone. I only found out it was missing by accident. At least now I know what I will be doing with my retirement... Doug White |
#22
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Removing Freely Rotating Swaged Steel Pin
On Fri, 27 Dec 2013 13:33:48 GMT, Doug White
wrote: Gunner Asch wrote in : On 27 Dec 2013 04:51:11 GMT, "DoN. Nichols" wrote: Before I drag out the Dremel, does anyone have any better sugestions? You have what I would try, at least. It looks like you can remove that linkage assembly from the action by removing C-clips, so you won't be juggling as heavy a bunch of metal, and controlling it will be easier. Good Luck, DoN. And putting it back together..consider an allen lock screw inside of a slotted pin and have it expand when you screw in the lock screw..and can be removed the next time easily. In theory, this is a one time deal. Some bright students decided that closing the action by pushing the cocking lever against the bench was easier than doing it by hand. Before we could stop this practice, they'd put their weight behind the process & broken two of the linkages. These two got busted a couple years ago, and we haven't had a repeat performance since. I hope nobody ever finds the bodies. evil grinne We still have to keep an eye open in case one of the older students remembers this trick & recommends it to one of the newbies. With time, it will fade from the collective memory and then we just have to watch out for somebody re-inventing it. Every year the students come up with new ways to screw up. We keep adding things to our list off do's & don't's, but its a challenge to keep up with them. Stupidity seems to mutate at a higher rate than smart cells. This is at MIT. If you are interested in science & technology these days, the path of least resistance is to play with computers. The students have never taken hardware apart, and just have no mechanical intuition at all. Most of them don't have any idea how to operate a screwdriver properly. They either let things get loose & wonder why they can't shoot well, or they overtighten them, either cross-threading them, stripping the threads or breaking things. Talk about a truly distressing trend in our "society"... Morons In Technology? 'Tis a sad, sad era. It wouldn't be quite so bad, except all of the target pistols are European or Russian, and many are out of production. Getting parts for the ones that are still being made is hard enough. Yeah, it's hard enough getting American-made replacement parts now that 90% of them are offshored. The previous coach was difficult to get along with, and largely did everything himself because nobody wanted to deal with him to help. He was no gunsmith, and was disorganized. We inherited a lot of broken guns with no idea what was wrong with them, and quite a few that weren't labled as being broken. One student has been shooting a single shot .22 free pistol with no extractor. Nobody told him he wasn't supposed to have to fish out every fired round by hand, so he never mentioned it to anyone. I only found out it was missing by accident. Hoboy... At least now I know what I will be doing with my retirement... You're a Value Added Alumnus, Doug. Bestest Kudos, sir. -- Worrying does not take away tomorrow's troubles, it takes away today's peace. --Lifehack |
#23
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Removing Freely Rotating Swaged Steel Pin
"DoN. Nichols" wrote in
: On 2013-12-27, Doug White wrote: snip I strongly doubt that the crazy glue will be strong enough, even if you could get it into the holes between the pin and the walls. Before I drag out the Dremel, does anyone have any better sugestions? You have what I would try, at least. It looks like you can remove that linkage assembly from the action by removing C-clips, so you won't be juggling as heavy a bunch of metal, and controlling it will be easier. Good Luck, DoN. This seems to be the concensus. I'll check out my countersink supply & see what I can find. The swaged bit is quite shallow. If I start out small and drill with ever increasing drill bits, hopefully I can open it up without the countersink slipping. Doug White |
#24
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Removing Freely Rotating Swaged Steel Pin
"Doug White" wrote in message
. .. The collegiate pistol team I help coach has two Russian target air pistols that have broken cocking linkages. I have replacement parts, but I need to disassemble a linkage that has a swaged pin in it. The ends of the pin are even with the sides of a piece I need to rescue undamaged. I had originally planned on drilling/milling out the center of the swaged part enough to press the pin out, but I discovered that the pin is free to rotate. There's nothing exposed enough to hang onto that I don't need to largely cut away. I can probably grind out the swaged bit VERY carefully with a Dremel, but it's going to be tedious & fussy. The pins are about 5/16" in diameter, and each end has a shallow drilled out section. It looks like they pressed ball bearings into the ends to spread them. The linkage the pin goes through is countersunk on both sides, so the swaged bits hold everything together. There a picture he http://www.pyramydair.com/blog/image...inkage-web.jpg The pin is the large one with the dimple just left of center in the image. The only way I can think of to physically hang onto the pin is to make an expanding collet that goes into the drilled out pocket on the far end of the pin. That is going to be tenuous at best, and it's a lot of work to fabricate for a high likelihood of failure. One other option would be to crazy glue everything together, mill out the swaged bit, and then soak it in acetone until the pieces free up. That assumes the crazy glue can handle the machining forces. Before I drag out the Dremel, does anyone have any better sugestions? Thanks! Doug White You may be able to angle the Dremel such that the pin rotates slowly as you open up the dimple, so you can thin the wall fairly evenly all around enough that it can compress when you drive it out. Supporting the far end may help. A drill bit held at an angle may deepen the hole while it spins the pin. I wouldn't use a good bit from a set for this. |
#25
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Removing Freely Rotating Swaged Steel Pin
On Fri, 27 Dec 2013 00:32:06 GMT, Doug White
wrote: snip The pins are about 5/16" in diameter, and each end has a shallow drilled out section. It looks like they pressed ball bearings into the ends to spread them. The linkage the pin goes through is countersunk on both sides, so the swaged bits hold everything together. snip Any thought to simply getting a 6m/m- pin and an arbor press and pushing the pins out with a block to support the linkage, possibly soaking the assembly in penetrating oil first and some heat? I do like the suggestion of two stub drills in a lathe to weaken the swedge, perhaps drilling and then pressing. Sounds like a good compact method to retain pins. Is this strictly a Russian technique, European, or? Anyone know if the holes in the linkages are straight or have a slight taper for this technique. Center drilling both ends of a pin and a suitable punch for assembly sounds attractive for the right application. -- Unka' George "Gold is the money of kings, silver is the money of gentlemen, barter is the money of peasants, but debt is the money of slaves" -Norm Franz, "Money and Wealth in the New Millenium" |
#26
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Removing Freely Rotating Swaged Steel Pin
In article , F. George
McDuffee wrote: On Fri, 27 Dec 2013 00:32:06 GMT, Doug White wrote: snip The pins are about 5/16" in diameter, and each end has a shallow drilled out section. It looks like they pressed ball bearings into the ends to spread them. The linkage the pin goes through is countersunk on both sides, so the swaged bits hold everything together. snip [snip] I do like the suggestion of two stub drills in a lathe to weaken the swedge, perhaps drilling and then pressing. Sounds like a good compact method to retain pins. Is this strictly a Russian technique, European, or? No, I recall reading a 1970s or 1980s ad from a US maker of relays crowing that they used this method to assemble their relays. Don't know if they invented the method or not. As I recall, they left the ball in the pin, so drilling would be difficult. Joe Gwinn |
#27
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Removing Freely Rotating Swaged Steel Pin
On 12/27/2013 2:32, Doug White wrote: Before I drag out the Dremel, does anyone have any better sugestions? Weaken one end of pin with dremel by hand using either rod-shaped grinding wheel (slow) or an engraving "end mill" cutter at dremel. Just remove as much material at center of pin as possible. It will work ok even though the pin rotates a little. After that, firm impact with a hammer and small punch to center to remove the pin - it will break the pin at the weakened end at interface between the pin round body and bigger diameter end, leaving the pin and a ring. Preferable dremel a hole that is bigger than punch diameter. That's how I would try it. It has worked on similar cases as the pins are usually quite hard and break (fracture) easily with such impact.. Kristian Ukkonen. |
#28
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Removing Freely Rotating Swaged Steel Pin
On 12/26/2013 6:32 PM, Doug White wrote:
The collegiate pistol team I help coach has two Russian target air pistols that have broken cocking linkages. I have replacement parts, but I need to disassemble a linkage that has a swaged pin in it. The ends of the pin are even with the sides of a piece I need to rescue undamaged. I had originally planned on drilling/milling out the center of the swaged part enough to press the pin out, but I discovered that the pin is free to rotate. There's nothing exposed enough to hang onto that I don't need to largely cut away. I can probably grind out the swaged bit VERY carefully with a Dremel, but it's going to be tedious & fussy. The pins are about 5/16" in diameter, and each end has a shallow drilled out section. It looks like they pressed ball bearings into the ends to spread them. The linkage the pin goes through is countersunk on both sides, so the swaged bits hold everything together. There a picture he http://www.pyramydair.com/blog/image...inkage-web.jpg The pin is the large one with the dimple just left of center in the image. The only way I can think of to physically hang onto the pin is to make an expanding collet that goes into the drilled out pocket on the far end of the pin. That is going to be tenuous at best, and it's a lot of work to fabricate for a high likelihood of failure. One other option would be to crazy glue everything together, mill out the swaged bit, and then soak it in acetone until the pieces free up. That assumes the crazy glue can handle the machining forces. Before I drag out the Dremel, does anyone have any better sugestions? Thanks! Doug White This is a trick for removing broken off bolts, etc. Take an appropriate nut and weld it to the swaged pin. You now have a "handle" that is fairly easy to grip in a vise of some type. You should now be able to drill out the opposite swaged end and, hopefully, remove enough parts to grasp the drilled end to work on the nutted end. -- ___________________________________ Keep the whole world singing . . . Dan G remove the seven |
#29
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Removing Freely Rotating Swaged Steel Pin
On Fri, 27 Dec 2013 00:32:06 GMT, Doug White
wrote: snip The collegiate pistol team I help coach has two Russian target air pistols that have broken cocking linkages. I have replacement parts, but I need to disassemble a linkage that has a swaged pin in it. snip Given this is a high tech university, there should be a ram type EDM or hole shooter on campus in one of the machining labs. Have you tried a few phone calls or a visit to the lab? http://fab.cba.mit.edu/classes/S62.1...le/peters.ben/ http://dspace.mit.edu/handle/1721.1/67120 http://www.ll.mit.edu/ http://web.mit.edu/mact/www/Blog/Mac...ShopIndex.html -- Unka' George "Gold is the money of kings, silver is the money of gentlemen, barter is the money of peasants, but debt is the money of slaves" -Norm Franz, "Money and Wealth in the New Millenium" |
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