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Posted: 12/23/2010 6:34:44 PM EDT
| Does a commercial tube use a commercial end plate or are they universal? |
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A mil spec end plate can be tight on a commerical collapsible tube. Contrary to what the "experts" have to say!!!!!!!!!!!!! I have experienced this problem.
And yes there is such a thing as a commercial astle nut that will not fit on a mil spec tube, carbine or rifle. When you've swapped out a few, you'll run into this. |
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Quoted:
A mil spec end plate can be tight on a commerical collapsible tube. Contrary to what the "experts" have to say!!!!!!!!!!!!! I have experienced this problem. And yes there is such a thing as a commercial astle nut that will not fit on a mil spec tube, carbine or rifle. When you've swapped out a few, you'll run into this. +1 |
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Come on guys think about it. The threads are all the same on a mil-spec or a commercial tube. If they weren't you would have to buy mil-spec or commercial lowers. Castle nuts, end plates are all universal, some may be out of spec and not fit as well but they are all intended to be the same. |
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Quoted:
Come on guys think about it. The threads are all the same on a mil-spec or a commercial tube. If they weren't you would have to buy mil-spec or commercial lowers. Castle nuts, end plates are all universal, some may be out of spec and not fit as well but they are all intended to be the same. This. Show me where you can buy "commercial" endplates and castle nuts by name. |
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You do not understand that things are not always manufactured correctly or the same. There is no standards organization for ar parts making sure they meet some certain specifications. Everyone has not had access to spec prints. Over the years some things seem to be made by one manufacture saying I need something to fit over this thing I am making here it is make me some to fit.
Also there is no real commercial spec. Commercial tube are not even all dimensioned the same. If you think the thread diameter is the same on commercial and mil spec tubes all I can say is you don't read enough or have not worked with the stuff enough. It is getting better now than it has been in the past as far as parts fitting. But to give you an example I bought two different company's "mil spec stock kits" last week and the stock from one will not fit but 2/3 the way onto the tube from the other company's stock kit. |
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The extention thread specs in a lower receiver are 13/16-16 UN3* special, minor 0 1.1212-1.1291
Nominal Size,TPI, Series] class] Max Major/Max Minor] Min Major/ Min Minor] Max Pitch] Min Pitch] UNR Minor Dia/Major Dia(Min) Ext. 13/16-16 UN 2A 1.1860 1.1766 1.1454 1.1403 1.1115 Int. 2B 1.1340 1.1200 1.1535 1.1469 1.1875 Ext. 13/16-16 UN 3A 1.1875 1.1781 1.1469 1.1431 1.1130 Int. 3B 1.1283 1.1200 1.1519 1.1469 1.1875 Commercial buffer- thread diameter 1.170 1-3/16-16 UN See Note 3 Threads have truncated (flat) peaks Note 3. PART ID: Threads have truncated (flat) peaks and measure equal or less than tube diameter of approximately 1.170. Mil Spec buffer- thread diameter 1.185 1-3/16-16 UN See Note 3 Threads have well-formed peaks Note 3. PART ID: Threads have well-formed peaks and measure greater than tube diameter of approximately 1.145 Not quite the same fit.http://www.efunda.com/designstandards/screws/unified.cfm?start=228&finish=301 edit: B* inadvertant copy error. |
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Quoted: A mil spec end plate can be tight on a commerical collapsible tube. Contrary to what the "experts" have to say!!!!!!!!!!!!! I have experienced this problem. And yes there is such a thing as a commercial astle nut that will not fit on a mil spec tube, carbine or rifle. When you've swapped out a few, you'll run into this. Here we go again....  |
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"Come on guys think about it. The threads are all the same on a mil-spec or a commercial tube. If they weren't you would have to buy mil-spec or commercial lowers.
Castle nuts, end plates are all universal, some may be out of spec and not fit as well but they are all intended to be the same." iNeXile556 Unfortuately this is rocket science. The tread specs on a commercial tube and a mil spec tube are different. 0.015" different. Yeah hard to grasp, I know. The lower receiver extention thread accepts both tube variations. But the commercial thread is always loose in a lower receiver compared to a mil spec thread. |
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Quoted: Yep, It must be Thursday already!Quoted: A mil spec end plate can be tight on a commerical collapsible tube. Contrary to what the "experts" have to say!!!!!!!!!!!!! I have experienced this problem. And yes there is such a thing as a commercial astle nut that will not fit on a mil spec tube, carbine or rifle. When you've swapped out a few, you'll run into this. Here we go again.... |
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Quoted: Unfortuately this is rocket science. The tread specs on a commercial tube and a mil spec tube are different. 0.015" different. Yeah hard to grasp, I know. The lower receiver extention thread accepts both tube variations. But the commercial thread is always loose in a lower receiver compared to a mil spec thread. Difference is due to the truncated peaks of the commercial threads not the size or pitch. If your having trouble with your parts fitting together you may want to stop buying chicom airsoft parts. |
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Quoted:
http://docs.google.com/viewer?pid=bl&srcid=ADGEESj6sKs2geyQfnwELzzLN2R_vY6pilSc0N7kUTUwd883FOaGkMqMUAwR6fzBBzMO5W7-fzK16kXaid_evWOFo9cIW88pxZvcDg-izciYSigM0-jhc5ejfZ5Xuw0tVKWk_-Ntm4Vt&q=cache%3AX5y9J76sv_kJ%3Astore.magpul.com%2Fdownloads%2FReceiver_Extension_Comparison.pdf%201-3%2F16-16%20UN%20B*&docid=f116f7429bece268b7f4ca8ac1a187dd&a=bi&pagenumber=1&w=772 1-3/16-16 UN B* Not sure where you got this info for but it is wrong. This is the standard for uncoated hot-rolled threads. Bad link, that diminsion came from a Magpul print. |
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Why is it a bad link? Can you not see the print? Or does Magpul not make proper parts? Or is because it just doesn't agree with your argument? The information you posted on Mil-Spec tubes is wrong: Mil Spec buffer- thread diameter 1.185 1-3/16-16 UN B* 1-3/16-16 UN B is for unplated coldrolled threads. Both Mil-Spec and commercial tubes are threaded 1-3/16-16 UN class 2A The only difference being that the commercial threads are truncated which naturally decreases the diameter. ETA: The tight or loose fit is not due to different sizes between mil-spec and commercial. It is due to tolerance stacking. This is going to happen sometimes even on the best parts. It will happen more on cheap parts. You can almost count on it with chicom parts. |
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all this discussion on extension threads is well and good... we KNOW there is more variance in commercial extension's than milspecs... and the quality control from piece to piece with commercial has much more variance as well. Whether you are talking about the diameter of the tube or the cutting of the threads... you can't expect reasonably to find a reliable measurement on commercial tubes.
But the question is this... do they actually make "commercial" endplates and castle nuts? Or are they all 1 theoretical size? I have never heard of a commercial sized castle nut... or a milspec sized castle nut for that matter... its all just 1 size. As was posted earlier... any variances in castle nuts or endplates is just due to manufacturer tolerances and quality control? We need someone who actually makes/buys these things in here.. |
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Quoted: What are you trying to prove? That you have no idea how to read a print? These drawings prove my point.http://magpul.com/pdfs/buffertube-civilian-M4.pdf http://magpul.com/pdfs/buffertube-Milspec-M4.pdf http://www.scribd.com/doc/24712370/Ar15-Lower-Receiver-Blueprint Notice that both the commercial and the Mil-Spec drawing both spec 1-3/16-16 UN for the thread? Now notice how the commercial one also says that the threads have truncated (flat) peaks? See the drawing below it? It shows that the diameter of the thread from flat peak to flat peak to be 1.170. You following this OK? Now notice it refers you to note 3. Look at note 3, it says that the threads "have truncated (flat) peaks and measure equal or less than the tube diameter of appox. 1.170" This means the tube is appox. 1.170 diameter (same as the thread diameter) Now look at the mil-spec drawing. See how it still shows the thread is 1-3/16-16 UN (just like the commercial one)? Notice how it says that the threads have well formed peaks? Now notice the tube drawn below that one, it shows the diameter of the thread from peak to peak to be 1.185. This is because the peaks are not flattened like the commercial threads. It does not mean the threads are different. If the well formed peaks of the mil-spec threads were the same diameter as the truncated threads of the commercial tube then the pitch of the threads would be different. Then the two tubes would be different threads. What this does mean is that there is more area on the mil-spec threads mating with the threads in the receiver. This results in a stronger fastening. Now look at note 3 of the mil-spec drawing. "Threads have well formed peaks and measure greater than the tube diameter of appox. 1.145." This 1.145 is the tube diameter, not the thread diameter. The .015 you keep saying is a difference in thread is not. It is the difference in the height of the threads due to the "points" being flattened on the commercial tube. Here's a experiment for you. Take a bolt with a fitting nut. Now file the threads down a little so they are slightly flat instead of sharp (truncated). Now have you changed the pitch or count per inch of the threads? No. Now screw the nut on, see how on still fits? That is because you still have the same threads that you started with. The points are just flatter so the diameter is slightly smaller. Just like the threads on the tubes. Does it make sense to you now?  |
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Quoted: If everyone stopped buying and using "commercial spec" (aka out of spec) REs, we wouldn't have to deal with this anymore. Yes but it will never happen. If anything it will go the other way. It is cheaper to make the threads the same size or smaller than the tube, such as the commercial RE, then it is to make the threads larger than the tube as found on the mil-spec RE. |
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