|
|
Post by hankinsrfls on Oct 6, 2014 16:17:48 GMT -5
When you fire your rifle,,,,,,,,,,,,,,,everything stretches and or flexes. The barrel will expand, the plug will expand, the locking lugs will flex, primers swell and or bulge, and most every thing can relax back to its normal shape.....,, Maybe the tungsten bushings are so (strong, hard) that they will not allow themselves to flex. When they are forced to expand, they split down the middle.. Just a thought... Jeff.
|
|
|
|
Post by rangeball on Oct 6, 2014 16:20:33 GMT -5
Not disagreeing but even then Earnhardt has fired multiple T-rex loads without issue, beat on them with a hammer and punch, no problems.
Other guys put normal mid psi loads through them and they split. Sure seems to point at a quality control and or nature of producing the rod from the material problem.
|
|
|
|
Post by rambler on Oct 6, 2014 16:26:45 GMT -5
Not disagreeing but even then Earnhardt has fired multiple T-rex loads without issue, beat on them with a hammer and punch, no problems. Other guys put normal mid psi loads through them and they split. Sure seems to point at a quality control and or nature of producing the rod from the material problem. My thoughts exactly. I'll be putting 70gr of IMR4198 with 250SST's, plus 275 and 300 parkers thru it and maybe some duplex loads with SR4759, time permitting.
I anticipate no problems and with any luck we can put this issue to rest.
|
|
|
|
Post by fishhawk on Oct 6, 2014 16:26:49 GMT -5
Typical, you didn't upset me at all.  As it sometimes happens, emotion can't be read in words. You stated that one end didn't have a chamfer. If you seen one without it was likely the old Tungsten Carbide. |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Oct 6, 2014 16:28:40 GMT -5
IMO we are chasing a rabbit that has never been let out of the cage, I have used many bushings in the last two years of both varieties without a problem. I have removed those same bushings on several occasions and while it takes a good deal of force all come out without breakage. IF one chooses to remove do so with a flat faced object of dia close to 5/32 in the savage plug or if used in another application the largest size the flash hole will allow.
As has been stated there is no real reason to remove the pure tungsten if you drill the carbon out with a bit ground flat to reach all the way to the bushing. it should last a long long time...
|
|
|
|
Post by hankinsrfls on Oct 6, 2014 16:31:47 GMT -5
Maybe, just Maybe.. some bushings are under size of the hole diameter in the plug. This would allow the bushing to expand... Earnhardt has total quality control over his plug and bushings to make sure they are all the same. This might explain why he has had none to crack. Jeff.
|
|
|
|
Post by fishhawk on Oct 6, 2014 16:32:08 GMT -5
Jeff's Locktite bearing locker is not a bad idea to try. Even if you want to remove it a little heat should release it if needed.
|
|
|
|
Post by rambler on Oct 6, 2014 16:36:44 GMT -5
Typical, you didn't upset me at all. As it sometimes happens, emotion can't be read in words. You stated that one end didn't have a chamfer. If you seen one without it was likely the old Tungsten Carbide. Here is the one that split on me. Chamfer is easy to see, even my blind ask can spot it. Now on this one it looks like one end may have more of a chamfer on it so I'd be inclined to put that at the bottom of the bushing hole, facing away from the retainer ring. I've got another one now and I don't my ask ain't chamfered
If the new one splits so be it. I can't blame anyone or anything. I think it will work tho and like advised I'll leave it in there and put some meat in the freezer.
I for one appreciate all the innovations and testing. I feel very privileged to have this kind of technical support.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Oct 6, 2014 18:19:59 GMT -5
Maybe, just Maybe.. some bushings are under size of the hole diameter in the plug. This would allow the bushing to expand... Earnhardt has total quality control over his plug and bushings to make sure they are all the same. This might explain why he has had none to crack. Jeff. My bushing seemed to be a tight fit in my plug... workmanship with both the plug and bushing seemed to be very good and professionally done..My bushing lasted only 80 shots before splitting...Go figure..Too bad I really liked the way it shot. Zen |
|
|
|
Post by hankinsrfls on Oct 6, 2014 18:34:34 GMT -5
Well I did say Maybe...
I use tungsten electrodes for scribes in my shop. I have one laying on every work bench. They will sharpen to a very fine point and make nice scribe marks on things when necessary, but the point will brake off very easy if you apply to much pressure. And you can not use them for leverage or they will snap in a second... But put it in my tig welder and they will last a long time... Just the nature of the material, very heat resistant but brittle as heck.. Jeff.
|
|
|
|
Post by fishhawk on Oct 6, 2014 18:50:37 GMT -5
Part of the problem could be that the threads are partially cut into the area where the bushing sits. The hardness of the finished Savage plug makes it almost if not impossible to use a bottoming tap, so we use one with a longer lead. I could have the threads burned in with a carbon probe EDM, but that would add greatly to the price. Jeff is making a batch of Savage type plugs, he might have better luck stopping the threads at the top of the bushing pocket. Maybe another material to test is in order. I can get 98% Tungsten Carbide. I might get some Tungsten with 2% Thorium. Something else? I think anything that will withstand shots near what pure Tungsten can will be fragile. Another alternative would be press in bushings, but you will not be able to change then or clean the plug completely. And due to the slightly varied outside diameter of each bushing each would have to be done individually. I'm very open to ideas, but the low failure rate makes testing for crack resistance difficult.
|
|
|
|
Post by edge on Oct 6, 2014 18:55:27 GMT -5
Sometimes there are inclusions in material, especially if it is extruded which I suspect that this is prior to sintering.
We have made bronze bushings that split down the center after machining.
Sometimes an inclusion gets elongated an inch and sometimes it can be most of the length of a 12 foot bar.
I suspect that all of the cracked bushings came from a single bar, if that is the case then the problem should have run its course with however many bushings can be made from a bar.
edge.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Oct 6, 2014 19:06:34 GMT -5
Could the bushings be set in a sleeve ?....then they would be contained at all times and might not be as fragile....
|
|
|
|
Post by hankinsrfls on Oct 6, 2014 20:13:39 GMT -5
Part of the problem could be that the threads are partially cut into the area where the bushing sits. The hardness of the finished Savage plug makes it almost if not impossible to use a bottoming tap, so we use one with a longer lead. I could have the threads burned in with a carbon probe EDM, but that would add greatly to the price. Jeff is making a batch of Savage type plugs, he might have better luck stopping the threads at the top of the bushing pocket. Maybe another material to test is in order. I can get 98% Tungsten Carbide. I might get some Tungsten with 2% Thorium. Something else? I think anything that will withstand shots near what pure Tungsten can will be fragile. Another alternative would be press in bushings, but you will not be able to change then or clean the plug completely. And due to the slightly varied outside diameter of each bushing each would have to be done individually. I'm very open to ideas, but the low failure rate makes testing for crack resistance difficult. Jeff has not started those Savage plugs yet. He is waiting on a final print.... |
|
|
|
Post by edge on Oct 6, 2014 22:46:52 GMT -5
Could the bushings be set in a sleeve ?....then they would be contained at all times and might not be as fragile.... That is how I got around the problem with one of my first ceramic bushings dougva.proboards.com/thread/2264edge. |
|
|
|
Post by rlp10ml on Oct 22, 2014 6:24:23 GMT -5
Bump to the top
|
|
|
|
Post by rossman40 on Oct 22, 2014 11:02:19 GMT -5
Thorium is added to TIG and even other welding rods to increase current capacity. Thorium is also slightly radioactive. When tungsten is used as switch/relay contacts silver or copper is added. The reason tungsten is used is that it won't melt and weld with arcing.
The problem may be is that most tungsten products are sintered because of the high melting temp. Basiclly they use tungsten oxide powder. Another factor is impurities ups the brittlness when you get in the +98% range. China produces 85% of the worlds supply of tungsten and we all know of their QC.
|
|
|
|
Post by jims on Oct 22, 2014 14:05:47 GMT -5
Posted in the wrong spot, deleted message.
|
|
|
|
Post by ET on Oct 22, 2014 15:11:58 GMT -5
I have a curious inquiry. Would the supplier for tungsten for bushings be able to tell you what sintering process was used? My curiosity stems from an article I read. Specifically related to the “Conclusion” found at the bottom of the article. www.mri.psu.edu/faculty/agrawal/media/189.pdfEd |
|
|
|
Post by fishhawk on Oct 22, 2014 15:48:42 GMT -5
I have a curious inquiry. Would the supplier for tungsten for bushings be able to tell you what sintering process was used? My curiosity stems from an article I read. Specifically related to the “Conclusion” found at the bottom of the article. www.mri.psu.edu/faculty/agrawal/media/189.pdfEd I will talk to the supplier and see if they know which process is used. Maybe I will just put it in my microwave at home before machining.  |
|
|
|
Post by fishhawk on Oct 22, 2014 15:50:33 GMT -5
When you fire your rifle,,,,,,,,,,,,,,,everything stretches and or flexes. The barrel will expand, the plug will expand, the locking lugs will flex, primers swell and or bulge, and most every thing can relax back to its normal shape.....,, Maybe the tungsten bushings are so (strong, hard) that they will not allow themselves to flex. When they are forced to expand, they split down the middle.. Just a thought... Jeff. Sound more like your describing the heads of the does you shot! |
|
|
|
Post by ET on Oct 22, 2014 16:11:59 GMT -5
I will talk to the supplier and see if they know which process is used. Maybe I will just put it in my microwave at home before machining. Bet you'll only try that once.  Ed |
|
As it sometimes happens, emotion can't be read in words. You stated that one end didn't have a chamfer. If you seen one without it was likely the old Tungsten Carbide.
