Truing threads questions

[Alex Wheeler]

Im one of those guys that doesnt think theres 1000 ways to skin a cat. When you true and action, you cut the threads, face, and lugs with the action indicated in on the centerline of the bore. Then you cut the back of the lugs and bolt face with the bolt body indicated in behind the lugs and in front of the handle. Any other method is NOT being done because its a better or more accurate way, its being done in the name of speed, ease, or profit. Ok, flame suit on.

 

[copperking81]

Im one of those guys that doesnt think theres 1000 ways to skin a cat. When you true and action, you cut the threads, face, and lugs with the action indicated in on the centerline of the bore. Then you cut the back of the lugs and bolt face with the bolt body indicated in behind the lugs and in front of the handle. Any other method is NOT being done because its a better or more accurate way, its being done in the name of speed, ease, or profit. Ok, flame suit on.

This seems to me to be the only logical way to do it. Squaring up the other surfaces wouldn't matter if the barrel is screwed on wonky because the threads aren't trued. Do you see any benefit to doing the other surfaces without the threads?

 

[TRA]

V threads do not self center them selves. If you want radial alignment you will need to fit a barrel shoulder to a recess in the action.

Anyone following these subjects have heard of the 3-4 thread engagement and the practice of cutting extra loose threads to avoid galling issues. Add the 3-4 thread claim and the loose threads, would just about negate the necessary of re cutting the thread's If you are really enlarging the action .010 total, the 3-4 threads and the loose fit would have covered any irregularities. Add the clearance of the bolt and the bolt clearance at the rear under the rear bridge, while the trigger is forcing the bolt, and the logs are being held tight against the lug faces.....BY what?????.... the compression of the cartridge.

Anytime these trick of the week modifications, surface the reason, procedure, and results are illogical. Too much of the perceived results are not logical.

 

[ireload2]

Sorry but they are way more logical than doing nothing.
A 700 Rem receiver is often bent upward at the rear of the receiver due to heat treat after machining. The 40X BR recceivers were heat treated before machining to avoid this. Because the machined 40X BR receiver is heat treated the model number on the bill board was applied with an etching process.
If you are actually competent with a lathe you can turn a mandrel that will allow you to face, turn, bore and thread on axis to the bolt bore in the receiver. You may have to make a steady rest bearing to make it work or the receiver OD can be turned true so the steady rest can run on the receiver.
The bolt nose can receive a minimum clean up. The c'bore in the barrel can be sized to center the bolt nose. The rear of the bolt body can be modified with shim stock to fit the bolt bore. I think some vendors supply oversize bolt bodies to permit fitting of the bolt to a receiver.
If none of that satisfies you, you are at least in a position to judge how bad the receiver is and do your best to save the dog or make a hunting rifle out of it.

PS. When the internal threads are single pointed on axis to the bolt bore and the receiver is faced square to the bolt bore the Vee threads certainly will self center. What do you think happens if the thread is a little loose and the flank of the male thread hits the 30 degree flank of the internal thread? The barrel shank is just crowded away from that side of the receiver until the slopes on the opposite side flanks begin to bear also. If you don't believe this you need to cut a few miles of threads. With a close fit thread there is very little clearance for the barrel to be off axis regardless of your theory.

V threads do not self center them selves. If you want radial alignment you will need to fit a barrel shoulder to a recess in the action.

Anyone following these subjects have heard of the 3-4 thread engagement and the practice of cutting extra loose threads to avoid galling issues. Add the 3-4 thread claim and the loose threads, would just about negate the necessary of re cutting the thread's If you are really enlarging the action .010 total, the 3-4 threads and the loose fit would have covered any irregularities. Add the clearance of the bolt and the bolt clearance at the rear under the rear bridge, while the trigger is forcing the bolt, and the logs are being held tight against the lug faces.....BY what?????.... the compression of the cartridge.

Anytime these trick of the week modifications, surface the reason, procedure, and results are illogical. Too much of the perceived results are not logical.

 

[Ray F.]

What's everyone's take on truing threads? Generally, I'm reluctant to do it since it significantly and permanently changes the receiver from it's standard / factory config. Seems most just true up the receiver face, bolt face, and lap the lugs.

That said, if the threads aren't trued, wouldn't that really negate any truing work done to the receiver face, bolt face, lugs, etc if you just trued those components? It seems to me that truing those surfaces wouldn't do much good if the barrel isn't screwed on as straight as possible. Sort of a... "do it all or nothing" thing.

Personally, I've never had any of my 700's faces trued without having the threads done, as well. I'd hate to be close to what I think is ideal accuracy on a quality barrel and think "Man, I wonder if truing the threads would've got me there."

That said, however, I can see not truing threads for a Rem/Age barrel. Those barrels are only cut for factory receiver threads. In this case, you can't touch the threads and your only options are true the face to the current threads or leave it alone.