Action truing options

Charles E said:
... Do the Kiff bolts come with a well-fitted shroud? Can you order them that way? Would make a difference to me as to which was less work -- redoing the existing bolt, or replacing it.
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[EDIT: PT&G bolts and shrouds are not a tight fit. About the shrouds,] talking to PT&G including Dave, the simple answer I got was no. So I called Dave and asked him if he was interested in making a shroud with oversized threads and a special tap to match as a kit or at the least a tool for me and availibility of oversized shrouds. I silver solder or braze over shroud threads then recut them. With a kit from Dave I wouldn't have to use the torches or lathe yet still have a tight fitting shroud. PT&G bolts and shrouds are not a tight fit.
 
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That can be a long discussion in itself. You ignore the offset threads that are machined outside of where they should be and the piloted tap cuts new threads where they should be... so no - the threads do not appear to be fully 'cleaned up' as part of that thread is already machined a bit too much.

I had doubts how this would work but testing before and after has erased those.
 
Dennis Sorensen said:
That can be a long discussion in itself. You ignore the offset threads that are machined outside of where they should be and the piloted tap cuts new threads where they should be... so no - the threads do not appear to be fully 'cleaned up' as part of that thread is already machined a bit too much.

I had doubts how this would work but testing before and after has erased those.
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Dennis,
We have some instrument with quick change nuts on them - nut that are bored at an angle to the threads. Once the are loos e, just tipping them sideways lets them pull off. So I can see how tipped threads can be cleaned up with the standard tap. However, what about threads that are offset to the bolt way? After the standard tap is run in, it would still be offset to the side. How would a barrel center up?

It's a long discussion I'd like to have. Please educate me.
Regards,
Ron
 
RJM said:
Dennis,
I can see how tipped threads can be cleaned up with the standard tap. However, what about threads that are offset to the bolt way? After the standard tap is run in, it would still be offset to the side. How would a barrel center up?

It's a long discussion I'd like to have. Please educate me.
Regards,
Ron
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The 'offset' is not large to start with, usually tipped more than anything. It is a piloted tap that is run in and it will cut the material that is 'inside' of this offset and not cut that which is 'outside' this offset. With 60 threads, this results in squaring up quite well in the actions I have done. I don't know how well it would work if one were to find a large offset.
 
The standard tap does have the advantage of being able to set back the barrel a few of threads & re-fit it.
 
Blue printing rem.700

mioduz said:
I will be blueprinting or truing my first remington 700 (22-250). Can someone tell me about what kind of accuracy gains I should expect from reaming the actions and getting an oversized bolt? vs truing off of the existing bolt raceways?
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There are a few people who have won HOF points with rem. actions....... Ron Hoehn ( sp.? )..... is one of them...... and I believe they sleeved the std. bolts....... and trued the raceway....... wish they would chime in......
bill
 
I know one well known smith that tells me that if you cut your tenon loose enough so that the barrel can seat evenly on the shoulder, and the front of the action, lug seats, bolt face and backs of lugs are square, and the recoil lug is ground parallel, that all other things being equal, the rifle will shoot. I am not saying that I know this from experience, just that it was said. On the subject of tenon fit, one prominent shooter that I know made an unintentionally small tenon, and after setting the barrel aside for some time, decided to try it. It shot just fine. This corresponds to some recent experience that I have had, and in my case, it was loose enough that I went back and did thread wire measurements and some geometry to make sure that it would be safe to shoot. It tightened up solid and shot lights out. After that, given that V threads self center when tightened, I only look at thread fit for tenons in terms of whether they are safe (not too small) and whether they are closer than I want. I think that a loose but safe fit may be better. That should stir things up a bit.
 
Ask any engineer who's worth his weight in salt and they'll tell you threads are not an alignment tool.

I'll add that that applies to axial alignment not radial concentricity.
 
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Boyd Allen said:
I know one well known smith that tells me that if you cut your tenon loose enough so that the barrel can seat evenly on the shoulder, and the front of the action, lug seats, bolt face and backs of lugs are square, and the recoil lug is ground parallel, that all other things being equal, the rifle will shoot. I am not saying that I know this from experience, just that it was said. On the subject of tenon fit, one prominent shooter that I know made an unintentionally small tenon, and after setting the barrel aside for some time, decided to try it. It shot just fine. This corresponds to some recent experience that I have had, and in my case, it was loose enough that I went back and did thread wire measurements and some geometry to make sure that it would be safe to shoot. It tightened up solid and shot lights out. After that, given that V threads self center when tightened, I only look at thread fit for tenons in terms of whether they are safe (not too small) and whether they are closer than I want. I think that a loose but safe fit may be better. That should stir things up a bit.
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After chambering the first barrel I ever did myself, I had what I thought was too loose of a thread fit. I took it to the range and shot an .080" group with it. Took the barrel off and rethreaded it and rechambered it, tightening up the thread fit. Never shot as well again. Found out the cardinal rule of gunsmithing, if it's not broke don't fix it.
 
Mike Bryant said:
After chambering the first barrel I ever did myself, I had what I thought was too loose of a thread fit. I took it to the range and shot an .080" group with it. Took the barrel off and rethreaded it and rechambered it, tightening up the thread fit. Never shot as well again. Found out the cardinal rule of gunsmithing, if it's not broke don't fix it.
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Mike, had you trued the action face beforehand?
 
Jerry, yes, I had. The first project with that Jet lathe when I first started doing my own work was truing a 40XBR action and installing a barrel. Nothing like jumping in with both feet and single pointing the threads on a receiver. Good thing I had cut a few practice pieces before doing it to find out that the compound wasn't marked off the perpendicular when setting the compound on 29.5 to cut threads. It was scaled opposite of what it should have been. When the compound was set to what showed 30 degrees on the scale it was actually 60 degrees on the perpendicular. Feeding in with the compound with it set at app. 60 degrees doe not work. The first "thread" I cut was the ugliest thing you ever saw looking more like a buttress thread than a 60 degree thread. Years later I was talking to Harold Broughton at the Buffalo Shoot. He made the statement that has stuck with me. The only difference between a tight thread and a loose thread is that the loose thread will have more clearance between the rear of the barrel tenon thread flank and the front flank of the receiver thread when the barrel is tightened. No matter how tight the thread is cut, there will always be clearance. He made the statement clearance is clearance and that a little looseness in the thread doesn't hurt a thing.
 
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Mike, think about this. If an action face is perpendicular to the bolt axis, and the action threads are out some, a loose thread will allow the barrel tenon shoulder to seat up totally where a tight thread and a slightly off action face will not make firm contact and this will allow the barrel to shift as it heats and cools.

(And then there is the issue of where the firing pin strikes the primer if there is much misalignment)



.
 
JerrySharrett said:
Mike, think about this. If an action face is perpendicular to the bolt axis, and the action threads are out some, a loose thread will allow the barrel tenon shoulder to seat up totally where a tight thread and a slightly off action face will not make firm contact and this will allow the barrel to shift as it heats and cools.

(And then there is the issue of where the firing pin strikes the primer if there is much misalignment)



.
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I've seen that. Cut a tight thread and the barrel shoulders up on one side of the receiver face and not the other. A little looser thread lets it shoulder up fully.
 
Mike Bryant said:
I've seen that. Cut a tight thread and the barrel shoulders up on one side of the receiver face and not the other. A little looser thread lets it shoulder up fully.
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But then the threads are not making 100 percent contact.

If a thread and it's seating surface are not truly straight and square with each other, one of the two will not have full contact.......short of stretching the metal.
 
Jackie, you are doing the same thing when you want a little shake on the barrel when you're cutting the threads. I think a too tight thread will hurt you more than a slightly loose thread. But, that's why it's best for the action to be trued. Nothing better than for the barrel to shoulder up and then when the barrel is tightened it makes about an 1/8 of a turn or so and that's it. When you're barreling for customers, you do what they want done. If they don't want the action trued, you don't do it. With an action that's out of true, the barrel may hit the shoulder and then it keeps on tightening as much as a half turn or more before it tightens up. It's not a good thing. Thankfully, just about every Remington I have come in the shop gets trued per the customers request. Some actions are worse than others. Most 700 actions true up pretty quickly, but every once in awhile you run across one quite a ways out of true. Those actions that are so far out are probably the ones that benefit the most from truing.
 
Threads too loose

I have a very well known custom action that is about 20 years old with very loose threads , I believe it actually has either an oversize thread insert in it or something was bad with the original threads and it was retapped at the manufacturer. The gunsmith who was installing the first barrel called me up one night and told me the fit was terrible. When a little loose the barrel wobbled all over the place.That sloppy fit when properly tightened up against the shoulder got me my only ever top 10 finish (100HV) at the Super Shoot. And it has gone on to do a lot of other good shooting first as a PPC and now as a 30. However admittedly I now cut oversize threads for it.
Dick
 
The only reason for a close thread fit is so, when the barrel is removed, the guy thinks to himself "Nice fit". Same thing for a nice, smooth cut and nicely radiused corner at the shoulder. "Nice work". The performance ain't gonna change much.
Square threads, I like to do fairly snug but truth is, they center up too; though not as positively as "V" or ACME threads. I had a real good shooting Enfield based rifle on which the barrel rattled pretty significantly when loosened off. A second barrel, threaded snug, shot good too but no better. Still, I felt better about it. On my 303 "F" class gun (a somewhat modified P14), I cut the threads quite tight and lapped them to get the barrel to seat. Great shooter but likely would have been just as good if cut with some clearance. Still, it's my gun and I can do what I want! Regards, Bill.
 
When I'm threading a barrel in the lathe, if I get it to where the action screws onto the barrel with no shake of the action against the barrel right before it shoulders up, I'll make one more pass running the compound in a thousandth and call it good. Just finished chambering a 6.5-284 barrel today on a trued 700. When I tightened the barrel in the barrel vise, it hit the shoulder turned just a little bit and that was all it would go. I really doubt if you can tell any difference between an action trued using the PTG or Manson piloted tap as long as you have good fitting bushings front and rear than single point threading after indicating in a piloted rod with the two dial indicator method. I get asked a lot on the phone about truing actions. Just like Mickey said a long time ago if the action isn't out much there probably isn't much benefit from truing. I ask them how it shot originally, if it always shot well, then it probably won't benefit much from truing. If it never shot well, then it may benefit from truing. I've seen some pretty crappy bedding jobs though that you put the truest action and best job of chambering in and you're fortunate to shoot an inch and a half at 100 yards. It all works together as a system.
 
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