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Post by KerryB on May 23, 2008 16:32:22 GMT -5
I think you can expect 50-60 or more shots with highly erosive powders like 5744 and upwards of 80-90 with less erosive powders such as N120. I usually shoot many different powders, primers and bullet combinations before changing or checking ventliner wear, so it is difficult to attribute percentages of wear to any one powder. A good hard ventliner and N120 seems to last a long time though..................
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Post by richard on May 23, 2008 19:09:17 GMT -5
Ed: I did "WACK" one of those hardened screws with a 3 lb. sledge against a piece of railroad tie and it did not shatter. It only slightly marred it. I could NOT however scratch it with a new file! Unfortunately, I have still not heard back from Mr. DeGrande on the status of my rifle so I cannot do any "real world testing!" Richard
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johnd
Eight Pointer
Posts: 213
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Post by johnd on May 23, 2008 22:03:14 GMT -5
Richard I see you are from NC. are there many public shooting ranges in NC. Thinking about relocating to the Apex, Raleigh area?
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Post by E.T. on May 24, 2008 6:21:09 GMT -5
Ed: I did "WACK" one of those hardened screws with a 3 lb. sledge against a piece of railroad tie and it did not shatter. It only slightly marred it. I could NOT however scratch it with a new file! Unfortunately, I have still not heard back from Mr. DeGrande on the status of my rifle so I cannot do any "real world testing!" Richard Richard Now you’ve really peaked my interest as I expected to at least hear of it being cracked or breaking into a few pieces because of the hardness you described. Look forward to hearing how long one of these will last. Believe that may be some time to wait. Ed
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Post by edge on May 24, 2008 7:23:11 GMT -5
E.T.,
While smashing a hard object may seem like a good test, that is not the mode of breakage with a bolt.
Torque shears the metal at the area of least resistance. That is almost always at the thread root closest to the "seized" point. Think about a bolt that is broken off, there is rarely a large section of bolt sticking out of the object, no, it is almost always flush or just below the surface because that part did not move. The rest of the bolt "shared the load" and only bent.
That is why the head of a bolt breaks off. A non hard bolt hit with a hammer deforms, a fairly hard bolt will damage the hammer, and a fully hard bolt 60+Rc may shatter IF you have a thin area.
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Post by rrbou on May 24, 2008 7:44:57 GMT -5
I hardened two of the savage factory vents this morning. neither would be scratched with a file. Put a nut in the vice screwed in a vent then put the wrench on it and proceeded to break it. As Edge said it broke at the bolt head. It took a lot more torque than I figured it would, I would never tighten one that tight. It would be very possible to break one trying to remove one that was stuck though. As Richard said just get a carbide drill is you need to remove a broken vent. I have my screws and bits on order. When they get here I will try this with them. In the mean time I am going to do some shooting with the last hardened factory vent today.
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Post by E.T. on May 24, 2008 11:21:47 GMT -5
E.T., While smashing a hard object may seem like a good test, that is not the mode of breakage with a bolt. Torque shears the metal at the area of least resistance. That is almost always at the thread root closest to the "seized" point. Think about a bolt that is broken off, there is rarely a large section of bolt sticking out of the object, no, it is almost always flush or just below the surface because that part did not move. The rest of the bolt "shared the load" and only bent. That is why the head of a bolt breaks off. A non hard bolt hit with a hammer deforms, a fairly hard bolt will damage the hammer, and a fully hard bolt 60+Rc may shatter IF you have a thin area. I agree that this basic test is not indicative to shear or transverse forces that are applied to a bolt. I totally agree with comments as the hardness goes up past a certain point a bolt is more prone to shear with less force. Was looking for a reaction to the level of brittleness that would automatically set off alarm bells. If so much as a small chunk broke off near the top of the head or a crack appeared at the bottom of the head (stress riser location) I personally wouldn't even consider trying it. Eventually I am going to first try oil quenching and some tempering when I get a chace to have a go at it. Ed
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Post by richard on May 24, 2008 20:39:29 GMT -5
johnd: I have no idea of the public shooting areas out near Raleigh? I am over next to Hickory. I am the president of a 300+ member private club about 20 miles away from where I live. Raleigh is about 2 1/2 hr. east of me. The club web site is: www.cvwc.org This weekend we are hosting the NC Traditional Archery Tournament. Richard I do shoot with some shooters from that area and could find out whats available there. I will see them this coming weekend at my 1,000 yd. match.
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Post by DW on May 25, 2008 9:49:47 GMT -5
Correct me if I'm wrong, but by hardening these vents, isn't the possibility of one of these shattering and flying out the barrel a big risk? If this happens, a barrel may be ruined from scratches. Also I believe someone had a barrel bulge or something to that effect when Lil Gun got back by the primer due to a over sized vent which would possibly be the case here depending on how much carbon has built up, even if the carbon stops the powder from getting back by the primer I doubt it would stop all the pressure that is going to be flowing back towards the primer and the shooter on ignition. This is the one thing that worries me about using a bushing plug, what happens if the bushing comes out?
I applaud you guys efforts on this but as much money as you are saving by making your own vents, is it really worth the risk?
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johnd
Eight Pointer
Posts: 213
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Post by johnd on May 25, 2008 17:04:28 GMT -5
Thanx Richard
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Post by rrbou on May 25, 2008 17:47:02 GMT -5
60 shots fired over the last two days on the hardened savage vent. Started at .031 and an .033 drill rod will still not go through it. I see very little wear. The load was from 73-75 gr 10X
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Post by E.T. on May 25, 2008 18:51:38 GMT -5
DW
In the steel industry a lot of components are hardened to different levels for different applications. Drill bushings are hardened steel, cold chisels and assorted tooling is hardened steel. Now not all steels are created equal because there are many different compositions to different grades of steel. Some alloy steels can be really hardened to a high level without showing brittleness and maintain their strength better than others.
My past reading of grade 4140 shows it can be hardened and tempered to RC-51 and still be quite usable for many different applications. I have no literature (yet) for 4140 past RC-51 say such as impact tests. I believe as Edge pointed out that shear strength has to be taken into account for a possible tight/stuck ventliner when getting into a high level hardness. But while it is housed and supported in the BP a significant high RC hardness should be useable without concern for causing any damaged.
Rrbou
60-shots and no sign of wear sounds like a good start. I think the big question on my mind and others is if any difficulty experienced removing the vent liner and re-installing? Look forward to future test results.
Ed
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Post by rrbou on May 25, 2008 19:41:55 GMT -5
E.T.
The vent came right out. But I use a good amount of The Stick anti seize. And I only finger tighten the vent by spinning the allen in my fingers.
I did remove the vent and check on it after the first 15 shots, then shot the next 45. Then a good cleaning of the BP and reinstalling the vent.
I am going to make a barrel cooler tomorrow as I hate the time between shots.
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Post by DW on May 25, 2008 19:53:39 GMT -5
Thanks Ed.
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Post by thelefthand on May 25, 2008 20:10:57 GMT -5
Guys, do yourselves a favor and stick to the oil quench. Quenching a steel faster than it was intended will make it harder, but will also make in a LOT more brittle. You are not going to get any tool steel up over 62 Rc with out sending it out to a heat treat facility, and trying to do so will cause you more headaches than it's worth. Vent Liners are small, and it doesn't take much of a bubble to throw things off. If you are able to gain anything at all by using some form of water bath, the results will not be consistent. In the end, I believe what you are looking for is a VL that consistently lasts a long time, so a water or brine bath is not going to get you there. If you want to learn a good deal about quenching, go look at some knife making forums. If the Holo-chrom screws are O-1 tool steel, then that's about as good as you are going to get. Anything better is going to require some fancy (read expensive) equipment, a controlled environment, and you'll probably have to hold the steel at 1750 degrees for over an hour in a special oven.
When O-1 is quenched, it will be in the neighborhood of 60 Rc, which is the same hardness as a standard file. By comparison, I believe that carbide is around 90 Rc. If you want to temper O-1 tool steel, throw it in your oven for an hour at around 350~400 degrees. Make sure you clean it off good first, and I would put a piece of aluminum foil in there to set it on. I do this with my knife blades, and they do fine. A little side note here - This is where your choice of quenching mediums becomes a little more critical. Almost any oil will work. Most machine shops will use motor oil because it's easy to get, and it sounds manly. Most knife makers will use some kind of vegetable oil because it has a higher flash point, and when they temper the blade in their wifes oven, she's not as ticked off when she smells the vegetable oil burning off in her oven as if she would be had you used motor oil. Personally I use olive oil, and it does a fine job. Tempering also helps to transform more of the Austinite to Martinsite. VL might be small enough for this not to matter, but normally it's impossible for ALL of the Austinite to be transformed correctly when it is quenched. Tempering elevates the temperature of the steel high enough to allow the process to finish a little more. It also elevates the temperature high enough to relieve any internal stress that was created as the steel cooled. The outside will always cool faster than the inside, so there's always stress. Also, if the steel has any corners (like threads), the stresses will be a lot higher in this area. These are the areas where the steel will start to crack. Ideally, when you temper O-1 tool steel, it will turn a light straw color. If you are able to do this, then you didn't loose much, if any of the hardness. If you temper at a higher temperature, the steel will start to turn blue, and even purple. At this point you've lost some hardness, but not too much. You're still around 50~55 Rc. The good news is that you don't have any of that nasty stress that will cause the screws to want to crack at the first thread. They will still break at that point, but only because that's the point with the least material. Honestly, I'd be very surprised if someone can break a properly hardened and tempered 10-32 flat head with a wimpy little 1/8" allen wrench. The screw should have more material than the wrench, and it should be one heck of a lot stronger. But that's just my opinion.
If you are really really worried about it being too brittle, pre-heat the olive oil to around 115 degrees. I do my knife blades in my charcoal grill, and just set an old steal bread pan full of olive oil on the rack thingy that's in the lid. I keep a meat thermometer in it to keep an eye on it.
As far as heating the screws go, make sure they go non-magnetic. Austinite is not magnetic, so when the all the steel in the screw has turned to Austinite, it will not stick to a magnet. When a magnet won't stick to them, they are ready to quench. If you heat them past this point, you are basically burning them which releases a fair amount of the carbon that's in the steel.
Case hardening VS hardening. When you case harden, you only harden the surface. This is usually done with low carbon steel (CRS, 1018, 1020 and so on). The steel pulls carbon out of the oil when it is quenched. The result is a higher carbon content on the surface of the steel, which makes it harder, but the base material is still pretty much the same. When you actually harden a piece of steel, it already has sufficient carbon content for the process to work. Others have already posted a lot of information on how the process works. When you harden a piece of steel, you not only increase its hardness, but you also increase its overall strength. It's been years since I took my metallurgy classes, so bear with me here. On a fully annealed piece of steel, there is a point where it starts to bend (permanently bend, not just deflect and spring back), and there is a point where it breaks. Hardening the steel increases both of these values, but in increases the bending strength at a faster rate. Thus the steel becomes harder and "stronger", but more brittle. It will not deflect as far before it breaks, but it takes more pressure to cause it to deflect to that point. One of the main purposes of adding alloys is to try to maintain the gap between the bending strength and the breaking strength of the steel. This is commonly refereed to as the toughness of a particular alloy. No matter the steel, a hardness of 60~70 Rc is pretty darn hard. O-1 is relatively brittle at this hardness, but D2 is not so much, and S90V is still VERY tough at 60 Rc.
Hope this helps some, Mark
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Post by E.T. on May 25, 2008 21:20:05 GMT -5
Thelefthand
Thanks for that summation that made this understood a lot easier than some text book and the tip on using vegetable/olive oil for quenching.
I believe the two terms you were looking for were Yield and Tensile strength.
Ed
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Post by rrbou on May 31, 2008 13:40:11 GMT -5
I now have 230 shots on the hardened savage vent and it is now a little larger than 034 but an 035 bit will still not go through. I have been cleaning and re-lubing the screw after every 30 shots.
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Post by E.T. on May 31, 2008 18:00:03 GMT -5
I now have 230 shots on the hardened savage vent and it is now a little larger than 034 but an 035 bit will still not go through. I have been cleaning and re-lubing the screw after every 30 shots. Rrbou You’ve been really putting some shots down range since your last posting. 230-shots in total and still not having an opening of .035 is a great tally so far. Just wondering if you could pick the color from the chart that you heated these vent liners too before quenching? No big deal if you don’t remember off hand. Just curious as to how hot you made them before quenching. Ed
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Post by rrbou on May 31, 2008 18:38:19 GMT -5
Ed I would say that it was an orange color. I went from working 6 days a week 10 hrs a day to 4 days 10 hrs so I have some extra time ;D. I also made a barrel cooler so the time between shots has dramaticly reduced . I was not worried about groups as I just wanted to see how maney shots it would take to wear the vent. As a comparison I was getting between 70 and 100 shots with 10x on savage vents.
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Post by E.T. on May 31, 2008 19:35:47 GMT -5
rrbou
Thanks for the reply and appreciate the info you have provided.
250-300% life span increase of a ventliner ain't to shabby for some additonal work of heating and quenching. Look forward to when I can make some time at work to use the torches and heat some of my home-mades.
Ed
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Post by richard on May 31, 2008 19:47:35 GMT -5
Ed: I'll bet when I heated mine, (I was using the cutting torch head) they were in the 1700 to 1900* range. I should probably use a smaller welding tip in the future. Richard
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Post by E.T. on May 31, 2008 20:11:43 GMT -5
Ed: I'll bet when I heated mine, (I was using the cutting torch head) they were in the 1700 to 1900* range. I should probably use a smaller welding tip in the future. Richard Richard Don’t think the type of tip matters as much because you can adjust the oxygen level (ratio mixture) some to soften the flame for slower heating. Because there is such a small cross section to heat on a screw quicker heating can be used. What to watch for is that the color is even throughout. By that I mean that the center area does not appear to have a darker color shade. This says the core has not reached the same temperature as outside. Ed
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Post by richard on May 31, 2008 20:40:14 GMT -5
Its just that the cutting torch has too big a head (surface area) where one of my smaller welding tips would make it easier to control. It was a spur of the moment thing and the cutting torch was attached ;D Richard
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Post by KerryB on May 31, 2008 22:12:08 GMT -5
Wow, 230 shots!! Hold it! Stop the press! Has anyone considered how much money it costs for 230 bullets, 230 sabots, 230 primers, 230 loads of powder, just to see how long a $3.00 vent liner will last? Maybe it would have been more prudent to just buy a couple of extra vent liners, not worry about how long they last, and save all the loading supplies! ;D
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indyml10
Eight Pointer
my buck
Posts: 182
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Post by indyml10 on May 31, 2008 23:02:40 GMT -5
ok i used an injection torch with map gas got them light cherry to orange waited 30 sec to a min in the almost invisible part of the flame so they were temp stabilized through out then dropped 'em 2 inches into synthetic mercon transmission fluid (high flash point)in a quart jar full SO how hard are they? they were black oxide finish and are now kinda like an OLD REVOLVER case finished bronze black color or should i have used veg oil or motor oil? ??
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Post by E.T. on Jun 1, 2008 6:30:29 GMT -5
Indy10ml
Not having gotten into my own hardening and quenching routine just yet I won’t be able to answer all your questions. Do feel confident you are over a hardness of RC-50 but without certain test equipment for checking hardness it would be impossible to say what exact hardness they are. Using transmission fluid is a new one on me but don’t see why it couldn’t be used.
When I get started I will be doing a few tests with mine like the hammer impact and torque test that Edge recommended to see what it would take to snap a head off. If uncomfortable with a specific hardness I can always adjust the level of initial heating to reduce or increase the hardness.
With others forging ahead with experimenting on hardening vent liners I feel kind of left behind and need to get my butt in gear soon.
Ed
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Post by rrbou on Jun 1, 2008 10:39:09 GMT -5
Wow, 230 shots!! Hold it! Stop the press! Has anyone considered how much money it costs for 230 bullets, 230 sabots, 230 primers, 230 loads of powder, just to see how long a $3.00 vent liner will last? Maybe it would have been more prudent to just buy a couple of extra vent liners, not worry about how long they last, and save all the loading supplies!
Kerryb I am not married, drink very little, and don't smoke. I make good money where I work. So I have a good amount of income to spend on my self doing something that I am passionate about. (Burning gun powder) Saving a few bucks on a vent is not why I am doing this. I want to make a better product. It would be much more prudent to buy a dozen vents and use them until accuracy goes then replace them. But if a guy could buy 3, harden them, get 300 + shots from them would that not be much more prudent?
I am sure that the mileage from the vents will be on a vent to vent basis as we are not dealing with controlled quenching. possibly the next vent will be gone in 50 shots or less.
It is possible that we are not getting ahead but behind with this venture. We will not know until we have more reports from others venturing down this path.
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Post by richard on Jun 1, 2008 12:34:11 GMT -5
What I am liking about the hardened vents is the fact you will get many many shots with little spread in the venthole diameter. With the standard vents if you start shooting with say a .0345 hole, during the course of say 20 to 25 shots at the range, you could easily be at .037" and not realize it. All the while your groups are getting slightly bigger. As ET said, I will also be doing some more testing with these ventliners. Richard
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Post by E.T. on Jun 1, 2008 14:13:35 GMT -5
Just wonder how the fellows who are using 45 or 40-cal loads with higher pressures using a savage plug might enjoy having a possible vent liner that lasts longer than what they are experiencing now? Yes there are some costs involved but how much have others just spent with their learning curve with the 10ML-II to start with? Wonder just how much was spent by others with going beyond factory recommended loads to produce the accurate combination of different bullet/sabot loads we now enjoy today? How often do we gain something from other’s who have invested some of their own time and money with their experiments to provide results from trying something different?
As for me with a 50-cal having a vent liner with a flame orifice that opens much slower should produce more consistent accurate groups over its longer life span. Experimenting and learning is part of this for me also. Sure I could go with the flow of just buying/using quick disposable vent liners instead of drilling my own and if I just planned to hunt a few times of the year this would be the wise way to go.
Ed
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nemo
Six pointer
Posts: 55
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Post by nemo on Jun 1, 2008 18:42:01 GMT -5
Gotta Question: How do you cut the hole to handle the allen wrench to install and remove the ventliner?
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