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Post by fishhawk on Oct 1, 2014 10:05:23 GMT -5
I have reports of 2 pure Tungsten bushings breaking in plugs that I machined. Three others were broken by one member in a day or two, but he done his own plug modification. I am replacing the first 2 out of my pocket. The last stated that he had the ring "lightly snugged". Maybe it was too loose? This is the best material we have found so far to withstand big loads and numerous shots. The failure rate is very low, but I made these more from need than profit. I only make a few dollars doing plugs, bushings, and bolt work. Most goes for material, electrodes, tooling and outside labor (my brother and others). By the time I package and run to the post office my time more than uses up any profit. In the future there will be no warranties on bushings by me or Luke.
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Post by rangeball on Oct 1, 2014 10:11:18 GMT -5
More than fair.
Any feedback on how the first two broke?
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Post by edge on Oct 1, 2014 10:29:08 GMT -5
How did they break, and how did the person know it?
Were they found by inspection or by the primer bulging/bursting? Just curious as to whether they are getting broken by people removing for cleaning or something like that. I often use ceramic bushings which I would have guessed to be even more fragile than the tungsten and once I install I would rarely if ever remove it. After very few shots the primer crud seems to make a nest for it and it can't move anywhere. I do fire 10-20 primers without powder and bullet to get the crud started.
edge.
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Post by fishhawk on Oct 1, 2014 10:31:50 GMT -5
Tungsten is very hard, which usually equates to brittle. Some pieces may have a flaw in the structure. The material varies some in diameter. We have the source eliminating undersize rods and grinding down oversize before shipping. The plugs are machined in a fixture on a mill to ensure everything is as square as possible. Who knows?
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Post by fishhawk on Oct 1, 2014 10:39:51 GMT -5
How did they break, and how did the person know it? Were they found by inspection or by the primer bulging/bursting? Just curious as to whether they are getting broken by people removing for cleaning or something like that. I often use ceramic bushings which I would have guessed to be even more fragile than the tungsten and once I install I would rarely if ever remove it. After very few shots the primer crud seems to make a nest for it and it can't move anywhere. I do fire 10-20 primers without powder and bullet to get the crud started. edge. Edge, the bushing I saw a picture of was split right down the middle. It was discovered during cleaning. The crudding thing may be a good idea. This was a .040" bushing. Earnhardts experiments show little if any flame channel fouling with the larger bushing holes, maybe they should be left assembled and fouled first. Like I said, this was 2 bushings out of probably a couple hundred.
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Post by 03mossy on Oct 1, 2014 10:43:20 GMT -5
I have one of these bushings made in the same batch as the first two that cracked. So far my bushing is ok but what should I watch for? What could happen if I fire the gun with a cracked bushing?
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Post by edge on Oct 1, 2014 10:45:55 GMT -5
SNIP. It was discovered during cleaning. SNIP Could they have been removing the bushing for cleaning and used a punch to knock it out? IMO, once a bushing is in place it should not be removed unless you are replacing it for some specific reason. edge. PS cracked may or may not be a huge problem since it is nicely sandwiched inside the BP, if it can't move it probably won't cause any more issue than wearing faster...or it could be a symptom of a defect in the tungsten rod.
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Post by fishhawk on Oct 1, 2014 11:12:59 GMT -5
I agree with Edge, unless it breaks into multiple pieces it can't go anywhere. Once it's carboned up it has more support than clean. Bad thing is if you don't remove it, I doubt you would know it's broken.
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Post by rambler on Oct 1, 2014 11:28:21 GMT -5
SNIP. It was discovered during cleaning. SNIP Could they have been removing the bushing for cleaning and used a punch to knock it out? IMO, once a bushing is in place it should not be removed unless you are replacing it for some specific reason. edge. PS cracked may or may not be a huge problem since it is nicely sandwiched inside the BP, if it can't move it probably won't cause any more issue than wearing faster...or it could be a symptom of a defect in the tungsten rod. I am one of the two bushing owners that had theirs break. I'm not sure what I did or didn't do. Bushing was tightened up good when firing, only had about 20 shots on it.
Applied ample anti seize, (copper variety) yellow taped the plug..ect...
I guess it's just a one or two time deal, as fishhawk stated hundreds have been used with no prob. He is replacing mine but as previously stated no more replacement warranties going forward.
I am with edge, when I get the replacement it's going in the plug and staying in the plug.
Up until this it worked great and fishhawk did an awesome job retrofitting my plug with the bushing.
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Post by jims on Oct 1, 2014 11:34:52 GMT -5
I hope to get the tungsten bushings in the future. One of the key reasons was so that I would not have the orifice grow and to avoid removing the same as I would do on a steel vent liner. Thus the plan was to leave it be. Nice to advise all of that as any brittle material may be hard but "fragile" if handled in a particular manner. Not saying that happened here but it is a wise thing to know. I used to broach brass materials years ago. The tooling was expensive and would get oily but my foreman was very definite in how I handled and treated the same as it could be prone to damage. Thanks for the update.
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Post by Deleted on Oct 1, 2014 12:05:21 GMT -5
Fishhawk that was very generous to replace those bushings. I never thought there was a warranty on the bushings, I figured no risk no reward. I am also very much so for the idea of set it and forget it. If it isn't worn out I'm not gonna take it out of the plug unless I'm ready to be done with it.
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Post by rangeball on Oct 1, 2014 13:23:12 GMT -5
Based on this and the brittle nature of the material, could it have been over tightened? Or is this even possible with the little retaining ring?
How much torque should be used to tighten it?
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Post by Deleted on Oct 1, 2014 13:43:04 GMT -5
What a bummer....but at least now we know of a good way of removing a worn out one..just break it.....I'm running an un pure .030 and have a spare...shooting fine so far with around 40rnds....haven't checked erosion....
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Post by rambler on Oct 1, 2014 14:32:46 GMT -5
Based on this and the brittle nature of the material, could it have been over tightened? Or is this even possible with the little retaining ring? How much torque should be used to tighten it? The one I had was tightened down well but not with brute force. I'm not sure what happened. It only had about 20 shots thru it and none of the loads were over 65GR of IMR4198.
I think it was just an unfortunate occurrence. In the future I'm installing it accordingly in the bushing and there it will stay.
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Post by Deleted on Oct 1, 2014 14:42:58 GMT -5
I'll stick to the old .030 bushing. I'm glad I did in the new build after reading this
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Post by rangeball on Oct 1, 2014 14:49:29 GMT -5
Had you removed it and reinstalled it at all during those 20 shots?
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Post by rangeball on Oct 1, 2014 14:50:46 GMT -5
I'll stick to the old .030 bushing. I'm glad I did in the new build after reading this Is yours the pure tungsten or the previous blend? Do you think orifice size contributed to the breakage?
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Post by Deleted on Oct 1, 2014 15:16:18 GMT -5
My .030 ain't Tungston. No idea why peoples broke but too expensive of a bushing for me if it broke.
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Post by rambler on Oct 1, 2014 15:50:10 GMT -5
I'll stick to the old .030 bushing. I'm glad I did in the new build after reading this Is yours the pure tungsten or the previous blend? Do you think orifice size contributed to the breakage? bushing was pure tungsten .040. I'm not sure what made it break, it was in no way abused or improperly installed.
Like I said earlier in this post I think it was just a rare occurrence.
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Post by Deleted on Oct 1, 2014 16:00:27 GMT -5
I've got a new .030 tungsten bushing plug going in a new build, I plan on antiseezing the heck out of it and never taking it out again, unless it's a must..
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Post by rambler on Oct 1, 2014 16:01:46 GMT -5
I've got a new .030 tungsten bushing plug going in a new build, I plan on antiseezing the heck out of it and never taking it out again, unless it's a must.. Me too, only mine is a .040
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Post by lakeplainshunter on Oct 1, 2014 16:48:17 GMT -5
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Post by hammer on Oct 1, 2014 21:32:05 GMT -5
I split two pure tungsten bushings before I realized that they need to have a press fit the full length of the bushing.
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Post by fishhawk on Oct 1, 2014 22:14:08 GMT -5
Again, only two of several hundred have split in plugs I modified that I know of. If you split bushings of mine or your own in plugs you worked on, start your own thread. The member that broke three at the same time in a plug I didn't modify was asked to send me his plug(s) to study the dimensions of the pocket. I hoped to learn from what might have happened, he has declined to do so.
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Post by hemicuda on Oct 1, 2014 22:17:06 GMT -5
Are the 94/6 tungsten carbide holding up? Maybe that's the way to go and stay away from pure tungsten. Most alloys have better properties than pure. We need to keep looking for better materials- it would be nice to have this problem fixed.
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Post by Deleted on Oct 1, 2014 22:21:48 GMT -5
I've gone through many 94/6 bushings and I currently have 10 or 12, 100% pure bushings. Never had one crack like that. In fact, I recently had an allen set screw get stuck in the threads because I neglected to unscrew the set screw to get the crud out. Tried heat and that didn't work. And it stripped out.
So I used a hammer and a 1/8" punch to drive the bushing out. It worked before, the allen screw just let loose and pushed out.
I smashed the punch several times...and broke the punch.
But the bushing was still unbroken.
My guess is that the bushings weren't seated all the way down in the plug and when the powder ignited it slammed the bushing back into the plug a little.
Were the bushing pockets clean? Was there any crud built up in the bottom so the bushing could be seated flat?
I've changed many pure tungsten bushings while testing various sized bushing holes. I use a hammer and a punch every time. Two good cracks and it comes loose. And I've never broke one.
I have no idea how yours broke.
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Post by hankinsrfls on Oct 1, 2014 22:33:56 GMT -5
I will agree with Hammer.. The bushings need a very slight press fit and should be installed using Green Loctite bearing retaining compound. Once installed, never remove it.. It becomes a permanent part of the plug. If you want two bushing sizes buy two plugs, the cost is minimal if you brake a bushing trying to remove it.
IMO, if a bushing cracks in half, it should still work fine and dandy.. The only real reason it's there is to stop the powder from falling through the vent hole, so if its still doing its primary job, keep shooting it... Jeff.
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Post by Typical171 on Oct 6, 2014 10:31:19 GMT -5
"My guess is that the bushings weren't seated all the way down in the plug and when the powder ignited it slammed the bushing back into the plug a little. Were the bushing pockets clean? Was there any crud built up in the bottom so the bushing could be seated flat?" As Earnhardt said, any obstruction to keep the bushing from fully seating be it brand new before firing or after cleaning, would cause the bushing to slam against the shoulder possibly/likely causing breakage....even if the obstruction was just a few thousands of an inch. Also as I recall one end of the bushing has a ample chamfer around the O.D. and the other end had almost none,another possible cause is if the sharper end was installed toward the bushing seat and if the machined inside edge of the seat was rounded enough from the cutting tool to keep the bushing from seating fully against the shoulder could also cause problems.
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Post by fishhawk on Oct 6, 2014 14:06:11 GMT -5
Both ends of the pure Tungsten bushing are chamfered. This was done to help seat the bushing flat in the hole. The hole is finished with a reamer cut to a sharp corner, but it does wear a little before it gets squared off again. It may leave a tiny radius, that is the reason for the chamfer. I do all I can to keep everything square and to close tolerances. The plugs are machined in a fixture that is squared to the mill.
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Post by Typical171 on Oct 6, 2014 16:08:08 GMT -5
Both ends of the pure Tungsten bushing are chamfered. This was done to help seat the bushing flat in the hole. The hole is finished with a reamer cut to a sharp corner, but it does wear a little before it gets squared off again. It may leave a tiny radius, that is the reason for the chamfer. I do all I can to keep everything square and to close tolerances. The plugs are machined in a fixture that is squared to the mill. Fishhawk, The bushings I have seen are very well made. I wasn't suggesting the quality wasn't there, you do very fine work. I was mentioning possibilities that might cause an issue so others can be aware that the bushing need to seat solidly against the plug shoulder, more as food for thought. My apologies.
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