Drillin' holes in a barrel

Wilbur,
Not quite the good vibrations you were seeking.
Barrel diameter,hole size,rod size and weight angle and amount would affect your project.
Talk to some of your engineer pals.
Works well on scope stands.
 
jGEE said:
Mr Greysun i think my math is correct -but it has been 45 years since i was in the 8th grade -maybe i have made a mistake. My original guess does seem to be close. Mr. Greysen i would appreciate it if you would point out my mistake, i don't want to mislead anyone here at BC. thanks joe:)

29DRILLBIT.jpg
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My friend Joe, I was not disputing your ability to cipher. It's your reasoning I call into question. No matter how minute a proportion of a square inch you come up with it will have 20,000/24,000 or whatever psi applied to it.

D R
 
Jim

MKnarr said:
Mr Pacecil, I thank you for your astute observation. I did indeed multiply instead of divide, however the answer is still correct because when I did it on paper I did it correctly. Please don't be embarrassed by someone else's mistake. It is for them to be embarrassed, not you. Fortunately you are not the only engineer on this forum, and having seen your past mistakes, I would think you would be more embarrassed then me. If Wilbur so chooses to delete this thread because I typed an error, It won't bother me in the least because your post will go with it.

Jim Brossman - Senior Engineer and consultant.

When I make a mistake I will own up to it and use my real name. Will you?
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Jim, Pacecil is a rimfire benchrest keyboard shooter. He has never shot rimfire benchrest so the only reason he is on this forum is to point out how little we know about rimfire benchrest shooting. For someone who has never shot in a benchrest match he sure has a lot to say about it. Most of it seems to be in the form of advice to benchrest shooters. If he would shoot just one target with a great benchrest rifle he would realize how little he knows about this sport. Pacecil, I also use my real name.
 
Let me add a bit to what James just said. There is a lot of advice given on this forum by non competitive shooters. Their advice may be accurate but may also be pure BS. Each association has a history on their home page. See for yourself how these posters finished withen their association before you take their expert testamony as gospel. I don't believe there are many that would purposely lead you down the wrong path but the reason that these people finish as far down the standings as they do is because they don't know sh!t.
 
jgee said: divide the area of the drill bit into 1 sq inch -divide that number into 20,000 and you will get the pressure pushing on the bottom of your drilled hole. Probably not going to be over several hundred psi
Don't you understand the difference between pressure and force? It doesn't make any difference what the hole size is, it has 20000 psi acting on it. What you meant to say was, it has several hundred pounds force acting on it, not several hundred psi. O, wait a minute I think at one point you had 289,855 psi acting on the hole!!!!
Hey, other people tried to explain this to you, I guess we're all pompous fools! oldswede's got it figured out though - he thinks both you and MKnarr know what you are talking about!

I see MKnarr has realized he made the same sort of error, and apologized, but at same time he accused me of errors. If I make 'em, point them out, but don't just tell me I'm wrong, tell me where I'm wrong!

I think george in ky has the real answer to wilbur - he just uses filler screws to block a hole in barrel!
 
Wilbur said:
If I were to drill into a 22LR barrel perpendicular to the bore, how close can I get to the bore and remain safe? Consider the question as it would apply to a whole bunch of holes.
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Boy trying to communicate is kinda tuff sometimes: Can we start again:

From what i read Mr. Wilbur was asking if he drilled a hole straight down into the bbl how close can he get to breaking thru and still be safe. Maybe i missed what he was asking.

My original reply was "Probably not going to be over several hundred psi -which doesn't take much thickness to contain. my view joe". I thought i was refering to the pressure the thickness under his drilled hole would have to contain. Several hundred pounds in my view would be 2 or 300 psi.

I don't see where i ever said the 289,855 psi.. i don't think any reasonable person would construe my hen scrathin as that number... 289.855 or 290 psi.

Yes i made an assumption on the 20,000 pounds -simple deduction from knowing a lot of centerfire is in the 40,000 psi range. I would think if Mr Wilbur wanted exact it would be easy to plug in the numbers of the ammo he intended to use.

Mr. MKnarr did not make the same kind of mistake, you should read his note -he did it correct on papaer but his mistake was coping it wrong to this thread -his answer is correct.

I certainly appreciate Mr. Georges answer but please reread Wilbur's original question - read Mr. Wilbur wanted to drill a hole not plug an existing hole.

Mr pacecil i stand by my answer and i respectfully suggest you take a course in reading comprehension.
my thoughts joe:)
 
I KNOW MKnarr knows of what he speaks. He, like all of us, is capable of an error. That does not make him "laughable". Behaving like an ass, however, DOES make one "pompous".
 
to jgee

you said:
Several hundred pounds in my view would be 2 or 300 psi.

I don't see where i ever said the 289,855 psi.. i don't think any reasonable person would construe my hen scrathin as that number... 289.855 or 290 psi

I won't say a word! I love you guys!

(Note: when you mean pounds force, say "pounds" , when you mean pounds per square inch, say "psi")
 
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pacecil said:
you said: Several hundred pounds in my view would be 2 or 300 psi.

I won't say a word! I love you guys!
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lol... ok mr pacecil i still don't see my error, i guess it's there.
How would you say how much pressure would be under the #29 drilled hole. I know it's not 20,000 psi. Maybe if you would post the correct number a light buld would go off, plz i need helpppp here.
thanks joe:)
 
Another engineer.

All right guys - here's another engineer's explanation.....

It looks like some folks may be confusing the measure and units of pressure (psi) with the measurement and units of force (pounds).

If we assume that a uniform pressure (20,000 psi) exists throughout the barrel (big assumption), then the pressure (psi) at the location of a #29 hole is indeed 20,000 psi. However, the amount of force that is exerted at the location of the #29 hole is only 290 pounds or so (I didn't do the calculation myself, so I'm relying on the earlier statements).

If you are careful with the units of measure, then the answer will come out with the correct units. (That's how I got through thermodynamics - always check the units).

"Pounds" is a unit of force

"Pounds per Square Inch" is a unit of pressure

The difference may seem pedantic to some, but it's important for the purposes of engineering calculations.

SteveM.
 
Many HI Standard .22 pistol barrels have a row of holes on the bottom for attaching weights. The weights helped with the balance of these target pistols. BUT, my tests using a Ransom Rest, showed that accuracy suffered with the weights attached.

Al Kunard
 
jGEE said:
How would you say how much pressure would be under the #29 drilled hole. I know it's not 20,000 psi. Maybe if you would post the correct number a light buld would go off, plz i need helpppp here.
thanks joe:)
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Joe:
Yes, the pressure under the #29 hole would be 20,000 psi. However, due to the relatively small cross sectional area of this hole, the force applied to the hole would only be 290 pounds. (again, I didn't do the actual calculation, so the 290 pound number was taken from an earlier post).

Steve.
 
No one has answered the question

Wilbur asked, "If I were to drill into a 22LR barrel perpendicular to the bore, how close can I get to the bore and remain safe? Consider the question as it would apply to a whole bunch of holes".


Wilbur's question, related to drilling a bunch of holes, and I'm going to assume, the purpose would be to remove weight from the barrel but maintain the original barrel contor. Therefore, I would suggect that the depth of the hole or holes, would be no deeper than if one were to flute a barrel for the same purpose. As to the depth, I'll let the real experts fumble with that one. Somewhere I read, that any changes to the exterior surface of a barrel, would have some adverse effect on the bore. Some barrel makers say that a lot of BS, but others will notl allow their barrels to be fluted and still honor their warranty. In sanctioning bodies, were fluting would be illegal, just drilling some random holes would skirt the rules but not break it. Am I correct Wilbur?
 
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How close.....

Okay, with a bunch of assumptions as follows:

1. The diameter of the holes will be 0.100"
2. The holes will be flat on the bottom
3. There will be a uniform 20,000 psi pressure present in the barrel
4. The yield strength of the barrel steel will be 100,000 psi


Then I figure that you can drill to within 0.016" of the actual bore before the pressure in the barrel exceeds the yield strength of the steel. That's pretty close in my book. If you stay 0.050" away from the bore, then you would be REALLY OK.

If the assumptions change, then the distance from the bottom of the hole to the bore of the barrel will change.

SteveM.
 
Wilbur:

Drill as many holes as you like. As long as you stay .150" from the bore, you should be safe.. Don't know what the accuracy will be, but you won't blow up the barrel..

Dave
 
Guys!

It's obvious that all involved knows what jgee was gettin' at - even me. An example would be the rush that centerfire guys got in a while back where we were reducing the diameter of our firing pins so we could increase the velocity (more powder) and not "blank' the primer.

I'm making a "porcupine" barrel.

Some years ago a guy at the nuclear plant put a single "quill" on a pump casing and transferred the shaft vibration to the quill. It was a small pump that circulated hot water for building heat. You could put your finger on the 24 inch threaded rod he used and actually hear the transfer of vibration back to the pump. Later, working with a problem vibration on a much larger safety related pump (the variety that shuts the plant down) they discovered that sliding a weight up and down the rod made a difference and that it didn't matter much about the orientation of the rod to the pump shaft.

Then.....the Georgia "Mafia" reported a largely ignored phenomena where the muzzle velocity changed when the tuner was adjusted.

Probably will use a straight taper and while I'm at it orientate the quills both perpendicular and angular to the bore. At least have the holes drilled where I can put more or less as I go. I suppose I should ask of the machinist types how difficult it would be to drill/make a hole ...say...60 degrees to the bore??
 
I see MKnarr has realized he made the same sort of error, and apologized, but at same time he accused me of errors. If I make 'em, point them out, but don't just tell me I'm wrong, tell me where I'm wrong!
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At least I have enough brains to delete a double post. Oh I guess that's not a mistake, just dumbness. Is pointing out someone's mistake in a sarcastic manner fun for you or is it just your natural charm.

Sorry Wilbur, I will go back to sleep now.
 
Feelings

Wilbur:
Have you discussed this with the porcupine? Will they give up their quills willingly for such a cause?
 
Porcupine

Wilbur (sir):

In thinking about your porcupine endeavor, I have a question. Is it necessary to drill the barrel to install the "quills", or could the same result be accomplished by adding rings to the outside of the barrel, from which extend the "quills"? This would eliminate any stress relief on the bore from drilling holes. I ask this because I "think" what you are trying to accomplish is not only the addition of objects to which vibration will be transferred, but also the addition of objects at various radial locations with respect to the barrel that provide multiple "moment forces" acting to dampen vibration. I guess these quills in one fashion would act as a tuner with mass farther from the bore, thus providing more angular leverage. And also the mass could be added along more of the length of the bore than what is involved in the use of a muzzle device. Please note my serious avoidance of units of measure, either on a per unit basis or absolute basis.

Am I totally off base? My thoughts first centered around the use of symetrical weights hung from a dampener on target bows. The dampener extends at right angles in front of the bow and the weights hang at angles from the dampener.

Feel free to ignore this if I am sounding stupid.

regards,
Dan
 
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