this is my first time lapping in a PTG bolt. They all have to be fitted by removing a few thousandths. I did this and then lapped with 320 and then 600 compound. This took me many hours of careful work. The bolt is so butter smooth and it will just barely fall down on its own with no play whatsoever. I am pretty damn sure I did an A+ job but I just wanted to confirm that is what I should be feeling.
question about lapping in bolt lugs
- Thread starter Gappa
- Start date
here is the action in question, it's a standard 700 SA but the bolt is brand new and that's what I had trouble with. When I got it I wondered why it wouldn't close then I called and they said "are you a competent gunsmith" you need to send it to a competent gunsmith and pay them to do it. I think I have done it as good if not better as I took a whole day very slowly removing microscopic amounts of metal till finally it feels and looks as close to perfect as I think it should. I have no play when fully closed front or back and still it's butter smooth. There is almost 100% contact patches where the lugs lapped together.
jpg images
jpg images
Yes the cam works just fine. I could lap it further to give it some play but the guy who does my chambering said wait until it is all done. He said the same thing that it could lock up when it gets hot after firing a long string. but this is not going to be a benchrest type gun.Preacher said:
Sounds like you have the basis for a tack drivin' rifle in the works. The smith will do the final touches if needed on the action before they cut the barrel to fit. Happy shooting
G'Day Fella's,
Comfort Technic, I'm not sure what it is that you are trying to achieve?
Do you want to lap the rear face of the bolts locking lugs, and their abutments in the receiver/action for full contact?
Or are you lapping the receiver/action raceways that the bolt lugs travel along, when the bolt is cycled?
Hope that helps
Doh!
Homer
Comfort Technic, I'm not sure what it is that you are trying to achieve?
Do you want to lap the rear face of the bolts locking lugs, and their abutments in the receiver/action for full contact?
Or are you lapping the receiver/action raceways that the bolt lugs travel along, when the bolt is cycled?
Hope that helps
Doh!
Homer
“I have no play when fully closed front or back and still it's butter smooth. There is almost 100% contact patches where the lugs lapped togetherâ€
“I called and they said (ask) "are you a competent gunsmith" “(if not) you need to send it to a competent gunsmith and pay them to do itâ€
Something I do not have to get used to is being approached in ‘a manner rather rude’. There are times when corresponding with a service department it is possible to find someone that would be better off just saying “I do not knowâ€.
The third lug, the Mauser from 98 forward has one on the bolt that is not visible when the bolt is closed in the receiver, the 03 Springfield variations have a third safety lug that is visible when the bolt is closed, Hatcher never noticed it, Springfield did not notice it, When Remington and bolt manufacturers built replacement bolts for the 03 the lug was moved forward. Then the British designed M1917, the bolt handle root is the third (safety) lug, the bolt handle is a limiter, it limits bolt travel forward and backwards. When someone gets carried away it is possible when fitting/lapping/grinding/ polishing the lugs to the receiver enough metal can be removed to allow the bolt root to contact the receiver, when this happens the bolt handle shares the load the front lugs were designed to carry.
Back to the response, someone thought the good fit as in no movement forward and or backwards could be caused by the bolt handle making contact at the same time the lugs engage. In no way am I saying you wasted your time, I am saying when the bolt would not close it would have been a good idea to determine if the bolt’s fail to close was caused by the bolt handle, in my opinion it would have been easier to remove metal from the back of the bolt or from the receiver to bolt handle bearing surface, I would choose to work on the back of the bolt.
And, I would prefer the bolt handle did did not have weight on it when the rifle was fired. Then there is seating and all those parts getting used to being close, I had rather have the bolt set back and have room behind the bolt handle for that purpose.
Bolt set back on the Springfield could have been tracked, in thousandths had anyone notice the exposed gap between the third lug and rear receiver ring.
F. Guffey
“I called and they said (ask) "are you a competent gunsmith" “(if not) you need to send it to a competent gunsmith and pay them to do itâ€
Something I do not have to get used to is being approached in ‘a manner rather rude’. There are times when corresponding with a service department it is possible to find someone that would be better off just saying “I do not knowâ€.
The third lug, the Mauser from 98 forward has one on the bolt that is not visible when the bolt is closed in the receiver, the 03 Springfield variations have a third safety lug that is visible when the bolt is closed, Hatcher never noticed it, Springfield did not notice it, When Remington and bolt manufacturers built replacement bolts for the 03 the lug was moved forward. Then the British designed M1917, the bolt handle root is the third (safety) lug, the bolt handle is a limiter, it limits bolt travel forward and backwards. When someone gets carried away it is possible when fitting/lapping/grinding/ polishing the lugs to the receiver enough metal can be removed to allow the bolt root to contact the receiver, when this happens the bolt handle shares the load the front lugs were designed to carry.
Back to the response, someone thought the good fit as in no movement forward and or backwards could be caused by the bolt handle making contact at the same time the lugs engage. In no way am I saying you wasted your time, I am saying when the bolt would not close it would have been a good idea to determine if the bolt’s fail to close was caused by the bolt handle, in my opinion it would have been easier to remove metal from the back of the bolt or from the receiver to bolt handle bearing surface, I would choose to work on the back of the bolt.
And, I would prefer the bolt handle did did not have weight on it when the rifle was fired. Then there is seating and all those parts getting used to being close, I had rather have the bolt set back and have room behind the bolt handle for that purpose.
Bolt set back on the Springfield could have been tracked, in thousandths had anyone notice the exposed gap between the third lug and rear receiver ring.
F. Guffey
I had the same problem with my new PTG bolt for my XP-100 . My smith removed metal from the front face of the bolt handle to make it fit . He advised not to try fitting by removing that much metal from the bolt lugs or lug recess . And yeah you should have about .002" wiggle room , or it could result in lock up . Evidently this is not happening on all of PTG bolts , so it's hit and miss in the manufacturing process . Sounds like someone's not checking their dimensions on the finished product .
I'm only going to say this once, and not to hurt any feelings, but it is what it is. The one piece PTG bolts are this way by design. They require fitting. This fitting can be done different ways, but the only "right" way would be to do it it the action truing setup. This allows the competent gunsmith to remove a few thou from the inner receiver lugs while truing the action, and at the same time, set the clearance for the handle and proper primary extraction. The rest of the fitting can be done on the other end with the barrel tenon, while chambering/fitting it to the action.
Lapping lugs, contrary to popular belief, should only be done just enough to "check" contact...not to improve it, per se. What you have done is lap a taper into the lugs on both the bolt and the receiver, because the leading edge of both are exposed to more abrasive and for a longer time with each stroke than the trailing edge.
I can see that you have taken pride in trying to do the best job, but sometimes the word "competent" should not be ignored. Again, I don't post this to step on your toes, but to enlighten you with the how and whys of the proper way to do it.
Lapping lugs, contrary to popular belief, should only be done just enough to "check" contact...not to improve it, per se. What you have done is lap a taper into the lugs on both the bolt and the receiver, because the leading edge of both are exposed to more abrasive and for a longer time with each stroke than the trailing edge.
I can see that you have taken pride in trying to do the best job, but sometimes the word "competent" should not be ignored. Again, I don't post this to step on your toes, but to enlighten you with the how and whys of the proper way to do it.
comforttechinc. as a suggestion and back to '’I do not know’, You could have gotten off to a bad start, that does not mean the bolt and receiver has been rendered scrap.
I would suggest installing a dial indicator on the receiver to determine the bolt advance in thousandths, the dial indicator will also indicate if the bolt closes on a full taper. As suggested the the bolt handle must be fitted first.
Stock removal, taking a measurement from the front of the receiver ring down to the bolt face before starting will (would have aided) aid in determining the amount of stock removed when lapping the bolt to the receiver.
F. Guffey
I would suggest installing a dial indicator on the receiver to determine the bolt advance in thousandths, the dial indicator will also indicate if the bolt closes on a full taper. As suggested the the bolt handle must be fitted first.
Stock removal, taking a measurement from the front of the receiver ring down to the bolt face before starting will (would have aided) aid in determining the amount of stock removed when lapping the bolt to the receiver.
F. Guffey
Upgrades & Donations
This Forum's expenses are primarily paid by member contributions. You can upgrade your Forum membership in seconds. Gold and Silver members get unlimited FREE classifieds for one year. Gold members can upload custom avatars.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.