When checking bolt-lug face surface % with a sharpie...
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Alex Wheeler
Well-Known Member
Im not speaking hypothetically. This is from experience, we all know how to lap and especially the manufactures that do it at the factory. Its not only about the unseated rear edge, its also about the fresh compound that builds up in front of the edge. Its not a hard thing to measure.
ntsqd
Well-Known Member
Until it is both measured and scientifically proven to have an undesirable effect on accuracy I'll continue doing it the way that I do.
Alex Wheeler
Well-Known Member
Im just putting some info out there, not trying to get you to change. Very little if anything we know today about accuracy has been "scientifically proven". Usually it comes from some Benchrest shooter testing then winning and others copy it.
ntsqd
Well-Known Member
In racing we call that the "Green Valve Cover" syndrome. If the guy who wins has green valve covers there must be something to it. Next race 90% of the valve covers are green w/o anyone really knowing why. I've known racers to deliberately do strange things to throw off the competition. His competitors see what the guy wanted them to see and they don't see the actual nuance that made the difference.
Kent Duckworth, the "worth" of Cosworth Racing Engines, is known to have said "Don't read, you become misinformed." I've no idea of the context to which he was referring and I'm quite sure that it was said pre internet, but it's something that I keep in mind as I'm reading tech on anything.
I can accept that a leading edge build-up of lapping compound will unduly effect the edge, but not that it will lead to a fully tapered lug & seat. Not if the lapping is done correctly.
Kent Duckworth, the "worth" of Cosworth Racing Engines, is known to have said "Don't read, you become misinformed." I've no idea of the context to which he was referring and I'm quite sure that it was said pre internet, but it's something that I keep in mind as I'm reading tech on anything.
I can accept that a leading edge build-up of lapping compound will unduly effect the edge, but not that it will lead to a fully tapered lug & seat. Not if the lapping is done correctly.
Alex Wheeler
Well-Known Member
One thing I do 100% agree with is the internet is a poor place for good info.
ntsqd
Well-Known Member
The problem isn't that good info isn't out there. The problem is the old wheat from the chaff problem.
My turn again I guess......
I agree with both of you - for the most part. Unfortunately, I am an engineer. I love data and science.
Yes, there is a lot of good stuff on the net and a lot of BS too. My education and experience usually (but far from always) makes it pretty easy to separate the wheat from the chaff.
In our world (rifle accuracy) there are some terrific smith's, outstanding rifles, amazing shooters, and incredible results...... but not much science. I am constantly looking for it and if it's there, I seem to be blind to it. I end up spending way too much time trying to make sense of the data instead. Lots of that out there but it's really hard to find the science to match it. So I tend to use statistics and common sense to improve credibility.
BTW, I did think of a great way to explain the lapping ramp effect. Lapped barrels! It's pretty common knowledge that barrel lapping causes a cone effect at both ends. That's because the ends are just like a hard stop and therefore anything shorter than the bore lap (lapping plug) gets lapped less than the rest of the bore. That's why we cut the ends off!
All I really want to add to this thread is that I love it when people start thinking and challenge the assumptions. The debate is good and healthy, and we can all learn from it provided we don't let our egos, emotions, and stubbornness blind us.
My own background is 35 years of automotive R&D and academic research. Unlike rifle accuracy, there is a crap load of science behind automotive technology and only a few green valve covers. In the rifle accuracy world, almost everyone has green stocks and almost nobody has any real science. It's actually quite amazing that we do as well as we do.
Insert big huge giant sigh here......
I agree with both of you - for the most part. Unfortunately, I am an engineer. I love data and science.
Yes, there is a lot of good stuff on the net and a lot of BS too. My education and experience usually (but far from always) makes it pretty easy to separate the wheat from the chaff.
In our world (rifle accuracy) there are some terrific smith's, outstanding rifles, amazing shooters, and incredible results...... but not much science. I am constantly looking for it and if it's there, I seem to be blind to it. I end up spending way too much time trying to make sense of the data instead. Lots of that out there but it's really hard to find the science to match it. So I tend to use statistics and common sense to improve credibility.
BTW, I did think of a great way to explain the lapping ramp effect. Lapped barrels! It's pretty common knowledge that barrel lapping causes a cone effect at both ends. That's because the ends are just like a hard stop and therefore anything shorter than the bore lap (lapping plug) gets lapped less than the rest of the bore. That's why we cut the ends off!
All I really want to add to this thread is that I love it when people start thinking and challenge the assumptions. The debate is good and healthy, and we can all learn from it provided we don't let our egos, emotions, and stubbornness blind us.
My own background is 35 years of automotive R&D and academic research. Unlike rifle accuracy, there is a crap load of science behind automotive technology and only a few green valve covers. In the rifle accuracy world, almost everyone has green stocks and almost nobody has any real science. It's actually quite amazing that we do as well as we do.
Insert big huge giant sigh here......
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Alex Wheeler
Well-Known Member
No money to be made from such research, so you will never see it in print. Lapping is however well studied and understood in the tool maker field. Plenty of good info from them on how it should be done and for what purpose.
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Ya, I accept that. In fact I contemplated drawing an analogy between automotive research, the consumer's money, and gov't regulations vs the average shooter and a gun maker. Then decided it was overkill. But yes, if there was money to be made, perhaps the science would exist.
The best I've ever been able to find is in a book called Rifle Accuracy Facts by Vaughn. He is an academic and an engineer but his background is military research. That said, even there I find the science lacking - too many simple tests without validation.
I would also say that a lot of the people in the BR community are not average people. They are often highly technical in their own rights. So perhaps you are right again. The Science might be there but it isn't often shared......
The good lord knows that NEVER happens in industry.....
The best I've ever been able to find is in a book called Rifle Accuracy Facts by Vaughn. He is an academic and an engineer but his background is military research. That said, even there I find the science lacking - too many simple tests without validation.
I would also say that a lot of the people in the BR community are not average people. They are often highly technical in their own rights. So perhaps you are right again. The Science might be there but it isn't often shared......
The good lord knows that NEVER happens in industry..... Before I retired I worked around a lot of people that thought knowledge was the only power they had so didn't want to share it but wanted you to give them yours some of them even went so far as to throw away the manuals to new equipment or hide them so others wouldn't know about how it was supposed to function .
Alex Wheeler
Well-Known Member
Oh theres a lot of very good testing and data, but since its a competitive advantage to those who do it, its not shared too often publicly. Rifle Accuracy facts is a good book. Just keep in mind the barreled action that was used and the group sizes fired. Quite a bit of the conclusions in that book I highly disagree with, and would say I have proof to the contrary. However, he did the testing with the equipment he had and I very much respect him and his results.Ya, I accept that. In fact I contemplated drawing an analogy between automotive research, the consumer's money, and gov't regulations vs the average shooter and a gun maker. Then decided it was overkill. But yes, if there was money to be made, perhaps the science would exist.
The best I've ever been able to find is in a book called Rifle Accuracy Facts by Vaughn. He is an academic and an engineer but his background is military research. That said, even there I find the science lacking - too many simple tests without validation.
I would also say that a lot of the people in the BR community are not average people. They are often highly technical in their own rights. So perhaps you are right again. The Science might be there but it isn't often shared......
RE the book. - Agreed 1000%!
People like that are still out there. My daughter has a co-worker who just did exactly that. After he finished the user course, she saw him take the manual to their new CMM home, but he denies it, and now he brags that he is the only one smart enough to use it
I told her not to worry about it. It will be his anchor someday soon.
