The Accurate Reloading Forums THE ACCURATE RELOADING.COM FORUMS Guns, Politics, Gunsmithing & Reloading Gunsmithing Using a tap to recut action threads?Go | New | Find | Notify | Tools | Reply | |
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I know that some use a lathe to recut action tenon threads on a factory action "blue print". However I have seen a few cases (eg Darrel Holland's video)where a hand held tap is used. Interested to understand the merits of using a tap? Intuitively this would just be a clean up of the threads, since the tap would just follow the existing threads? If the threads are misaligned in some way, then the tap cant correct that? | ||
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For some reason it seems to be common in US to reshape the 55° threads of M98s to 60°; I have never quite understood why? A tap will follow the original thread. | |||
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I had a galled stainless barrel removed from a stainless steel action. Rather than set it up in the lathe and rethread it, I used a tap to clean up the threads. Had no illusion that it would square up the threads or make more accurate, just wanted to clean up the damaged area. dave | |||
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If you really want to true the threads to the receiver axis you have to lathe cut them. A tap will just follow the existing path unless held extremely rigidly and that is not the way to do it. Use taps just to clean up damaged threads. | |||
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Do any of the gunsmiths, who are re-cutting the action threads, check them for run out before re-cutting them? My wife and I have been shooting BR for years, and doing very well, with her 700 Rem and my 722 Rem actions, that I simply ran a tap in while held in the trueing jig. NRA Patron Life Member Benefactor Level | |||
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You would simply be amazed at the amount of runout. When the action is set up, in this case a Remington 700, I use a 1 1/16-16 TPI tap inserted in to the threads and checked with a dial indicator to see the amount of runout. I found one that had .032" TIR. Those need to be single pointed to true to the bolt raceway. Jim Kobe 10841 Oxborough Ave So Bloomington MN 55437 952.884.6031 Professional member American Custom Gunmakers Guild | |||
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First let me start by saying that, despite playing one on TV, I am not a Rem 700 expert. That said, I did see a demonstration once at Lassen where two 700 receivers needing truing were trued. One by the single point method, the other using Dave Manson's setup. End result was that there was no discernable difference between the two methods.  Aut vincere aut mori | |||
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Yes but Manson's tap truing system is held between centers; I think the OP is talking about a hand tap. | |||
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z1r, my point exactly! NRA Patron Life Member Benefactor Level | |||
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dpcd, Correct me if I am misunderstanding your post. Dave's truing system is not really held between centers. It uses two tapered guides that fit into the bolt raceway to align the tap mandrel. After you have cut the threads the action may be put into the lathe with the tap mandrel still threaded into the receiver. At that time you machine the face square with the threads. If you do not have a lathe there is a tool that guides off the tap mandrel to square the face. I have used one before I got my CNC lathe. It worked very well. The drawback is that you can only use it so many times. If you are a hobbyist doing less than 10 guns it would be good as long as you can justify the initial cost. Dirk Schimmel D Schimmel LLC Dirk@DoubleRifles.Us 1-307-257-9447 Double rifles make Africa safe enough for bolt guns! | |||
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A tap uniforms the threads and the extension diameter. Single pointing will uniform the threads and true to the action IF the setup is proper. Extension diameter can vary afterwards due to the amount of material needed to complete the operation. A system like Dave's combines the best attributes of both, uniform and true all in one package. | |||
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Thanks all That confirms what I was thinking | |||
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h20; yes you explained well how it works; I didn't explain it well. The point is that it is a guided and piloted tap and not a simple hand tap. After I posted I knew someone would nit pick it but I didn't go back and make it better. | |||
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How would oe compensate for an action that has more runout than the tap can clean up? From what I understand, the Manson tool only cuts .010" oversize. Not nearly enough to take care of the problem on some. Jim Kobe 10841 Oxborough Ave So Bloomington MN 55437 952.884.6031 Professional member American Custom Gunmakers Guild | |||
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Well, the tap concept has limitations; it is for those without a lathe. | |||
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How much run out is induced by the vibration of a lathe? Is that even possible to measure? I realize we need mathematics and precision to make decisions but there is always an iusse of materiality... For example here is a recent target from my 80 yr old Mosin Nagant after a good cleaning and load tuning...   Mike Legistine actu quod scripsi? Never under estimate the internet community's ability to reply to your post with their personal rant about their tangentially related, single occurrence issue.  What I have learned on AR, since 2001: 1. The proper answer to: Where is the best place in town to get a steak dinner? is…You should go to Mel's Diner and get the fried chicken. 2. Big game animals can tell the difference between .015 of an inch in diameter, 15 grains of bullet weight, and 150 fps. 3. There is a difference in the performance of two identical projectiles launched at the same velocity if they came from different cartridges. 4. While a double rifle is the perfect DGR, every 375HH bolt gun needs to be modified to carry at least 5 down. 5. While a floor plate and detachable box magazine both use a mechanical latch, only the floor plate latch is reliable. Disregard the fact that every modern military rifle uses a detachable box magazine. 6. The Remington 700 is unreliable regardless of the fact it is the basis of the USMC M40 sniper rifle for 40+ years with no changes to the receiver or extractor and is the choice of more military and law enforcement sniper units than any other rifle. 7. PF actions are not suitable for a DGR and it is irrelevant that the M1, M14, M16, & AK47 which were designed for hunting men that can shoot back are all PF actions. 8. 95 deg F in Africa is different than 95 deg F in TX or CA and that is why you must worry about ammunition temperature in Africa (even though most safaris take place in winter) but not in TX or in CA. 9. The size of a ding in a gun's finish doesn't matter, what matters is whether it’s a safe ding or not. 10. 1 in a row is a trend, 2 in a row is statistically significant, and 3 in a row is an irrefutable fact. 11. Never buy a WSM or RCM cartridge for a safari rifle or your go to rifle in the USA because if they lose your ammo you can't find replacement ammo but don't worry 280 Rem, 338-06, 35 Whelen, and all Weatherby cartridges abound in Africa and back country stores. 12. A well hit animal can run 75 yds. in the open and suddenly drop with no initial blood trail, but the one I shot from 200 yds. away that ran 10 yds. and disappeared into a thicket and was not found was lost because the bullet penciled thru. I am 100% certain of this even though I have no physical evidence. 13. A 300 Win Mag is a 500 yard elk cartridge but a 308 Win is not a 300 yard elk cartridge even though the same bullet is travelling at the same velocity at those respective distances. | |||
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If your lathe is vibrating it is time to re-level it, or something is out of balance. I also have Mosins that shoot like yours does; the Mosin action is very rigid. has a long barrel shank and has a floating bolt head, all of which make for very accurate rifles. With new barrels they really shine. | |||
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DPCD, I wasn't referring to the lathe bouncing around or making noise. I am not a machinist at all...in fact I am often not even allowed to pick up hand tools. I do have a rudimentary understanding of physics, are you saying that a lathe doesn't vibrate at all when it is running? Are you saying a glass of water sitting on a lathe table shows no vibration. The reason I ask is we are speaking in thousandths or ten thousandths of an inch in these discussions. Mike Legistine actu quod scripsi? Never under estimate the internet community's ability to reply to your post with their personal rant about their tangentially related, single occurrence issue. What I have learned on AR, since 2001: 1. The proper answer to: Where is the best place in town to get a steak dinner? is…You should go to Mel's Diner and get the fried chicken. 2. Big game animals can tell the difference between .015 of an inch in diameter, 15 grains of bullet weight, and 150 fps. 3. There is a difference in the performance of two identical projectiles launched at the same velocity if they came from different cartridges. 4. While a double rifle is the perfect DGR, every 375HH bolt gun needs to be modified to carry at least 5 down. 5. While a floor plate and detachable box magazine both use a mechanical latch, only the floor plate latch is reliable. Disregard the fact that every modern military rifle uses a detachable box magazine. 6. The Remington 700 is unreliable regardless of the fact it is the basis of the USMC M40 sniper rifle for 40+ years with no changes to the receiver or extractor and is the choice of more military and law enforcement sniper units than any other rifle. 7. PF actions are not suitable for a DGR and it is irrelevant that the M1, M14, M16, & AK47 which were designed for hunting men that can shoot back are all PF actions. 8. 95 deg F in Africa is different than 95 deg F in TX or CA and that is why you must worry about ammunition temperature in Africa (even though most safaris take place in winter) but not in TX or in CA. 9. The size of a ding in a gun's finish doesn't matter, what matters is whether it’s a safe ding or not. 10. 1 in a row is a trend, 2 in a row is statistically significant, and 3 in a row is an irrefutable fact. 11. Never buy a WSM or RCM cartridge for a safari rifle or your go to rifle in the USA because if they lose your ammo you can't find replacement ammo but don't worry 280 Rem, 338-06, 35 Whelen, and all Weatherby cartridges abound in Africa and back country stores. 12. A well hit animal can run 75 yds. in the open and suddenly drop with no initial blood trail, but the one I shot from 200 yds. away that ran 10 yds. and disappeared into a thicket and was not found was lost because the bullet penciled thru. I am 100% certain of this even though I have no physical evidence. 13. A 300 Win Mag is a 500 yard elk cartridge but a 308 Win is not a 300 yard elk cartridge even though the same bullet is travelling at the same velocity at those respective distances. | |||
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I like these machinist threads I learn a lot ________________________________________________ Maker of The Frankenstud Sling Keeper Proudly made in the USA Acepting all forms of payment | |||
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Don't think I will jump in on this post. | |||
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Running a tap into a hole that is not concentric to the tap and longtitudal axis of the receiver, sounds like bad practice. I would never do that when precision machine tapping a new hole, and I would also not want someone doing it to my custom rifles action while they are attempting to true-up & accurize it. | |||
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My lathe will make water vibrate slightly (I just tried it at 90 rpm; it is belt drive mounted on a sheet metal stand, and it is the belt that makes it vibrate) but if your fixturing is solid, it will cut truly. A very heavy, solid base lathe will not vibrate at all. | |||
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So said the toolroom Machinist.  jc | |||
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I do make a few chips now and then  ________________________________________________ Maker of The Frankenstud Sling Keeper Proudly made in the USA Acepting all forms of payment | |||
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