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Have been reading a thread below which asks about an oversized chamber. Part of the answers to that question mention factory chambers being oversized because of a new ("fresh") reamer....and that as the reamer wears a bit with every barrel cut, the chambers get smaller and smaller until the time the reamer is discarded. That answer makes good sense to me...probably because it matches my own opinion (guess) so far. Then a fellow later says that dull reamers (dulled presumably by wear) cut oversized chambers. Now a few questions: 1- Do the big gun factories regularly sharpen dull reamers during use? (Are we really dealing with dull reamers?) 2- Wouldn't sharpening reamers reduce their size very slightly each time? 3. If so, about how much would a typical re-sharpening reduce the size (diameter) of a reamer? This is important to me for two reasons... One), it helps me assess the truth about what happens in production line runs of chambers, and, Two), I have some reamers I am thinking of having re-sharpened by Dave Kiff or JGBS and would like to know in advance what dimensional range of diameter changes I can expect, if any. My country gal's just a moonshiner's daughter, but I love her still. | ||
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remember, there's sharpening and regrinding.. sharpening you might get away with to dress the edge .. if you have it reground, it is usually like 40 bucks, and they regrind it.. more or less a new reamer opinions vary band of bubbas and STC hunting Club Information on Ammoguide about the416AR, 458AR, 470AR, 500AR What is an AR round? Case Drawings 416-458-470AR and 500AR. 476AR, http://www.weaponsmith.com | |||
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The method in which a reamer is used will determine the size of the chamber. Poor machining practice causes oversize chambers. Proper machining practice creates a chamber that matches reamer dimensions. There are many ways to properly chamber a barrel, and none of the factory rifle makers use any of them!!! With proper care and use, one can chamber dozens of barrels without changing the dimensions of a reamer, or the need for re-sharpening. | |||
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Yeh, Jeffe, I had thought about that already. But thanks for reminding me of it anyway. The reamers I'm thinking about having "sharpened" were all bought used. A few are in pretty poor shape (my opinion, anyway) and they will doubtless have to be re-ground, which I know will reduce their sizes. Do you have any idea at which dimensional point reamer makers ordinarily refuse to regrind? Most of my recent used buys are in a condition where I can't really tell if they need any more than just touching up the edges or not. Even with just honing the edges, though, I'd think that in sum that might remove enough to be measurable with a good .0001" tool...or wouldn't it? Thanks for your input...it's appreciated. My country gal's just a moonshiner's daughter, but I love her still. | |||
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My country gal's just a moonshiner's daughter, but I love her still. | |||
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a dull reamer will cut oversize by allowing chips to ride on the cutting edge and by the fact that not all edges wear evenly allowing a dull edge to ride over the surface pushing the opposing cutting edes into the cut harder i think it's safe to assume that chamberas are cut on a large cnc multi-station machine these days. most of them have programs and sharpening systems built in to the machine. i would think the reamers are kept in pretty good shape throughout thier usefull size life and that large chambers are therefore intentionally cut for the above mentioned reasons. | |||
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is anyone a mathametician? the diameter is reduced by the co-tangent of the relief angle times the amount removed from the cutting face or radian surface of the flute. in otherwords, not much, a couple ten-thousanths at most, per grind. | |||
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Urban legend has it that the factories use unpiloted reamers in order to speed the cutting & better flush chips. If true, this could account for a myriad of dimensional variations. Regards, Joe __________________________ You can lead a human to logic but you can't make him think. NRA Life since 1976. God bless America! | |||
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stands to reason that they can get away with unpiloted reamers because the multi- machines keeps the reamers in good shape. | |||
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That depends on the guy doing the grinding. A careful tool grinder will only remove enough to get it sharp again But how much is that? Usually .002 to .005" on the diameter for a good clean up I have ground form reamers before and when I did it If the reamer was tapered i would set back the shoulder so it was dimensionally correct You do this till you run out of flute then get a new reamer blank and start over. www.KLStottlemyer.com Deport the Homeless and Give the Illegals citizenship. AT LEAST THE ILLEGALS WILL WORK | |||
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taking .002-.005 off the radian surface would only reduce diameter by.002-.005 if the rekief angle was 45degrees. most reamers iwould guess are 3-5 degree at most. the actual outside diameter of the reamer's flute( where the relief angle is) is never touched. there's no way the o.d of a reamer is reduced .002-.005 ata grind. it is the face of the flute,the surface that is dimetrical to the center of the bore thats is ground. so it's diameter is reduced by the amount the new surface intersects with the outside diameter of the flute at whatever relief angle the outside diameter of the flute is ground at. so if .001 is taken off the radian face, the diameter reduces by the amount the relief surface projects up to the now gone intersection of radian and outside diameter before it was ground. to reduce a reamer by.002-.005 with a relief angle of 3 degrees, roughly thinking, the grinder would have to remove about .075" from the radian face. if a grinder did that, he'd be buying me a new reamer. if .005 had to be taken off to get an edge back, the reamer would have been making any chips at all, just smoke and some really bad noise. | |||
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AC, the base of the reamer, from the casehead to the end of the flutes, is generally, what, .75 or so long? if you regrind the reamer, -.01 from the neck, you cut an entirely new reamer, at your dims, many times. let me say it another way .. its possible to take a 300 weatherby reamer and have it reground to a 300win . possible, perhaps not practical .. but why? the 300 win is INSIDE the 300 weatherby, and the biggest part of the reamer, the belt, is the base diamter, on both... thats NOT coming out right.. call dave manson and ask him to explain it .. basically, if you regrind X reamer, you move the whole thing "down" the reamer..its like setting the barrel back and recutting ... man, that's still not coming out right... if they set the reamer back .01 and regrind, its a new reamer, for all practical purposes. so, if a NEW reamer was at "zero" and you set the to-be reground in, at -.01, since there is NO point on a case that is larger, from throat to belt/casehead/rim, you just regrind a new reamer .. so a .002 chip might require a .05 setback ... but if you have .75 to work with, it wouldn't matter opinions vary band of bubbas and STC hunting Club Information on Ammoguide about the416AR, 458AR, 470AR, 500AR What is an AR round? Case Drawings 416-458-470AR and 500AR. 476AR, http://www.weaponsmith.com | |||
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perhaps .. resharpen reduces diameter regrinding is "recreating" at a - distance towards the stem, and you have ALOT of room that direction opinions vary band of bubbas and STC hunting Club Information on Ammoguide about the416AR, 458AR, 470AR, 500AR What is an AR round? Case Drawings 416-458-470AR and 500AR. 476AR, http://www.weaponsmith.com | |||
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You guys really did a good job of answering my questions. I knew where the reamer was honed during resharpening, and that as a result we'd only get a pretty small amount of change, but I wasn't at all sure how much. I guessed it was in the .0002" or .0003" range, but guessing is a lot different than knowing. Thanks very much!! I did NOT know about the newer machines that can sharpen their own reamers. That is a real wowser! Jeffe- I understood your answer(s) perfectly, no sweat. You write a lot more clearly than you give yourself credit for. It is also interesting to me that factories may use pilotless reamers. That "sorta" gives me the heebie-jeebies. I guess it's because I carefully make pilots for my reamers that are within a few "tenths" to my barrels' bore diameters. But then, of course, I chamber very carefully, cleaning about three times as often as I figure I could get away with. Of course, I don't chamber for money or as a business, so I can creep along like that and still eat regularly. Thanks again, y'all. My country gal's just a moonshiner's daughter, but I love her still. | |||
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I was simply addressing the premise of the thread to begin with. And that is that reamers wear with every chamber cut, and that's the cause of the oversize chambers. Fact is that almost every chamber cut at Remington or Win, etc. is oversized due to the amount of runout induced by the chambering method. It doesn't matter if the guy doing the chambering is using a brand spanking new reamer or one thats cut 200 chambers. Oh, and BTW, what makes you think you can't cut a straight chamber without a pilot on your reamer? | |||
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It seems like if the reamer is for a tapered case, the reamer could be reground a bit further back on the taper to yield sharp edges with all of the original dimensions. | |||
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We don't sharpen reams that way. Grinding a reamers flute is a very bad way to sharpen a reamer unless you are grinding at a new angle to keep the cutting edge neutral. If all you did was set back the edge by grinding the face of the flute you change the cutting edge to a negative rake which is poor tool geometry. It causes chatter and increases the load on the tool leading to tool damage. Now it is suggested that since I need to remove so much material the reamer must not have been cutting. when the reamer just start to dull you can hone it with a stone to bring back the edge but much after that you need to grind it back. And removing .001" to .0025" per flute is normal in cutter grinding Although you can grind the flute as suggested above I find this a very poor practice. Grinding the face only does nothing for your primary and secondary relief angles www.KLStottlemyer.com Deport the Homeless and Give the Illegals citizenship. AT LEAST THE ILLEGALS WILL WORK | |||
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I think what jpl is saying and my opinion is a sharpened reamer is the same, smaller, or larger. It you push the neck and shoulder back you are working on a fatter part of the reamer. Mine after sharpening are the same size. Butch | |||
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Correct This is how I have always ground reamers, end mills, form tools, what have you. It takes longer but your tool geometry stays correct and the tool will cut better www.KLStottlemyer.com Deport the Homeless and Give the Illegals citizenship. AT LEAST THE ILLEGALS WILL WORK | |||
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I thought that the factories were hammer forging the chambers right along with the bores. Same process, same time, no reamer in general use. Blair "Peace is that brief glorious moment in history when everybody stands around reloading". | |||
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It would actually make more sense to bore the chamber on a CNC machine while it is set up to be threaded. With the right tooling you could cut hundreds of chambers before a dimensional change occurred. And you could mount a head space gauge on a tool post to use a quality check if the head space gauge would not allow the tool turret to travel the needed distance the machine can be programed to stop and wait for a tool change www.KLStottlemyer.com Deport the Homeless and Give the Illegals citizenship. AT LEAST THE ILLEGALS WILL WORK | |||
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I think you guys are giving large firearms manufacturers credit for being up to date manufacturing entities. They have historically been poorly managed and very slow to adopt modern manufacturing processes. These companies frequently cease operations due to these issues. I remember seeing a photograph of one of these companies reaming chambers using a drill press. Even at that time it was considered poor manufacturing practice. | |||
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So wait??? Are the firearms manufacturers apart of the UAW union. In my own defense I did say it would make more sense.  I didn't say they they actually did anything like that.But it does make sense that failure to adapt and refine your manufacturing techniques will lead to loosing money and market share. I don't know what happened to Winchester but I remember they were the industry standard just twenty years ago not by market share or revenue but more of brand recognition. Remington was a close second and then started a marketing campaign that just killed any viable competition. Winchester failed somewhere and just about folded up While Remington has grown and was able to make some very good acquisitions such as Dakota Arms. I live near a very large aircraft manufacturing plant that years ago was the largest on the west coast I can say first hand that they failed to progress with the times. They have people there still making forms out of plaster and wood and that technique was out dated thirty years ago. Then they decided to get CNC machines to "Speed up" the manufacturing process Well no one told the machinist's that you can run a CNC much faster then a conventional machine. These guys are running CNC mills and lathes like they were using manual machines in 1960. They have also all but closed the doors there and that is just over the horizon. They are moving most of the manufacturing to Mexico for one reason that no one is willing to admit to. In Mexico the IAM (international association of machinists and aerospace worker union) has no power. They can make changes with out some jerk filing a grievance with the union. I know I may have just offended some of those on this board. let me just say this, Not all unions are bad. I'd say better then half have their act together enough to keep the industry they serve alive. But at this particular plant the Union is King. And they resist change like a bull. Doing things extremely slow and labor intensive just to keep some guy that should be retired employed They are not hiring new blood in to the plant and most people that are there are at or near retirement. There will be a huge gap once the majority do decide to retire www.KLStottlemyer.com Deport the Homeless and Give the Illegals citizenship. AT LEAST THE ILLEGALS WILL WORK | |||
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Kerry, I got my first Operating Engineer's 'book' (non-union folks read: local union membership card) back in the mid-70s and one of my best friends is/was the BA (read: Business Agent/REAL power) of the Laborers' local at that time, so I've been able to get a close look at union labor from several sides. IMO you are correct in all you say, and I can assure you that there's enough stupidity distributed around any union/industry negotiating table to contaminate all who are present. When you think about the fact that the industry folks have probably never worked 'on their tools' and the union leaders are elected in an often-rigged popularity contest, it's no wonder that together they've ruined this country's working class and industrial capacity. Sorry, end of rant, regards, Joe __________________________ You can lead a human to logic but you can't make him think. NRA Life since 1976. God bless America! | |||
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I've seen pics of it being done with a HAND DRILL...it was corded at least  | |||
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remington - highly modernized -- accurate rifles savage - excellent barrels wincheter/browning -- NO outated equip left at those sights ruger - once the figured out their barrel problem, no more problems.. high end machining centers weatherby - made in japan, nothing more to say... just not seeingt th esloth these days .. winchester being the last luddite of them biggins opinions vary band of bubbas and STC hunting Club Information on Ammoguide about the416AR, 458AR, 470AR, 500AR What is an AR round? Case Drawings 416-458-470AR and 500AR. 476AR, http://www.weaponsmith.com | |||
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Certain weapons do have hammer forged chambers; mostly military. Mandrels are expensive to make. It doesn't pay to make a different mandrel for every catridge of the same caliber as would be needed by someone like Remington. You'd need seven or eight different 30 cal mandrels alone. OTOH, it is a very practical way to make thousands of barrels for the Steyr AUG in 5.56 NATO. "Experience" is the only class you take where the exam comes before the lesson. | |||
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AC Not a machinest (but I do work for a company that does tool coating), but my understanding is a sharp reamer "shaves" the surfaee, while a dull one digs in than tears out metal as it cuts. What's realy "interesting" is that a coated reamer, even though the coating makes it larger in diameter, cuts a smaller hole than the same reamer uncoated. The same thing is true with other coated cutting tools also (drills, taps). | |||
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That IS interesting. Never even thought about that. I have both coated and uncoated tools, but have never tried to make that sort of comparison. Thanks for tossing that into the mix. A guy can learn a hell of a lot here sometimes. My country gal's just a moonshiner's daughter, but I love her still. | |||
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OH, and where did you read me saying that? I don't believe I did. I use a well fitting pilot and a floating reamer holder as a back-up (safeguard) in respect of getting the chamber dead concentric with the bore...that is, the middle of the chamber the same as the middle of the bore at the point on the barrel where the reamer quits cutting when completely run in and the chamber is complete. That, as you may know, is not necessarily the same as where the middle was where the reamer originally entered the bore....not unless the bore is PERFECTLY straight, which it may not be. Using a pilot may not help, but then I don't figure it will hurt any, either. At any rate, I DON'T use a pilot to assure a straight chamber, do you? My country gal's just a moonshiner's daughter, but I love her still. | |||
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AC, I'll have to agree with Pointblank on cutting a good chamber without a fitted or loose bushing. I use a loose bushing the way I chamber inorder that a crooked bore doesn't influence my reamer. I have posted on this before and don't want to 2 finger type my method again. You can do a search. Butch | |||
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Sorry, I worded that question poorly. What I was getting at is what Butch eluded to in his last post. I use the same method as Butch. | |||
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That depends on the material being cut but in the case of 4140 and 410/416 you are correct. Not only that but a Tin or a Tian coating will increase the life of the tool buy a minimum of 5 fold. and you can run it at higher feeds and speeds. Those Talon branded coating are the best thing going for tool life www.KLStottlemyer.com Deport the Homeless and Give the Illegals citizenship. AT LEAST THE ILLEGALS WILL WORK | |||
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Please tell me what we are dooing wrong. Our borereamers cuts 0.0004 larger bore after TICN coating, compared to the testcut done after setting the reamer up, but before coating. Our expierince is limited to 5 mile of barrelbore pr year | |||
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You should be coating your reamers prior to testing. that it the only way to get a true reading on what the reamer will produce www.KLStottlemyer.com Deport the Homeless and Give the Illegals citizenship. AT LEAST THE ILLEGALS WILL WORK | |||
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If we prepare apx 50 reamers pr batch, and test maybe 5 before the coating, there still is the same diference betwen before and after coating. they all "grow" 0.0004" after coating, and the actual reamed hole does the same. The "before" testing, is only to determin what reamers actualy "grow" after coating | |||
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jørgen, please check your PM box. Thanks. Philip | |||
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Sorry to get back to this so late. Anyway these coatings allow the cutting tool to get a better bite on the material they also allow the reamer to last many times longer then uncoated especially on tough materials like Titanium. I guess what you are getting at it that we are saying most reamers cut undersize and your are cutting over size and you don't know why. Is that correct? If that is the case, Then it is due to the geometry of your reamer. For what ever reason your reamer is cutting over size. But here the deal, Your quality control has shown a predictable growth of the reamer and hole respectively. I would not worry about it. You have a point of reference order your reamers undersize to allow for the coating the go from there. That is the best option I can offer. www.KLStottlemyer.com Deport the Homeless and Give the Illegals citizenship. AT LEAST THE ILLEGALS WILL WORK | |||
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All of my reamers have negative rake on the face except the ones which were ground wrong and dig in and chatter. The faces are staggered and all are set ahead of center to rpoduce the negative rake (a very small amount, mind you) I can't speak for all the factories but Remington uses a reamer which is a through-the- bore type to finish their chambers. The reamer turns and the barreled action is held in a Vee block setup. Some factories do hammer forge the chambers to finished dimensions but Remington isn't one of them. I always suspected Winchester might have done so on some models. H-K does. Hammerli does. Boring a chamber on a cnc set up sounds great but the reality would be less satisfactory. Tool flex, tool wear, chip clearance (or lack thereof), and setup errors will all rear their ugly heads to spoil the job. After many attempts to bore cavities in hydraulic valve bodies, we found the use of a shaped reamer to be the best way to consistently produce consistent dimensions and finishes. Reamers which are coated and grow .0004" then produce a hole that size are not cutting oversize. They are cutting TO size which is what we would all like our reamers to do. If a reamer cuts undersize, it isn't cutting. The tendency for a reamer to cut oversize can be traced to faulty setup or drive or to heat buildup in the tool. Perhaps a solid argument in favor of the flow-through coolant systems for chambering. Regards, Bill. | |||
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I disagree I have setup for production many CNC screw machines. 4140 compared to some of the materials I was tasked with proving out for production is dead soft and easy to machine. Try machining CP Titanium. That stuff tears up tooling. Cobalt, Carbide, High temp coated what ever it eats tooling and doesn't blink. Then there's Hastalloy, Waspalloy, Inconel etc. The problem with boring a chamber is not the tooling life for chrome-alloy or stainless It's being able to measure the chamber and all of the features once completed. Thats the hard part. Measuring a taper on a hole as small as .170" and being sure it's accurate to +/-.0005" Not something I'd care to do but it can be done with the correct investment of time. Yeah I blew it on how I worded that post He is reaming ON size www.KLStottlemyer.com Deport the Homeless and Give the Illegals citizenship. AT LEAST THE ILLEGALS WILL WORK | |||
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