ACTION WORK VS HEADSPACE

[7br]

I do most of my own work but I’m not a gunsmith, so I hope that this doesn’t sound too ignorant. Does lapping the bolt lugs have any effect on the existing headspace? When in doubt I’d check the headspace anyway, but as I’ve never lapped bolt lugs “I JUST GOTS TA KNOW!!” Hoping to hear from the more experienced folks here.

 

[Judd]

Yes…depending on how much you take off the lugs…lapping It is most definitely changing/affecting headspace.

Example, you take off .001 between the lugs and the action…you just changed your HS measurement by one thou.

 

[WayneShaw]

Before you lap, determine what the headspace is. If you are at zero, you can lap a few thou and still be within tolerance. But if you are already plus 2 or 3 thou, you can go to far quick.

 

[DaveTooley]

In this application lapping takes a high spot on one surface and makes a low spot on the other. Both surfaces should be machined true prior to lapping which mates the two surfaces together. You can make a piloted lapped of aluminum which you can square up between centers as the lap wears. I power it by putting it in a drill press with action in hand. Then true the lugs on the bolt. Light lap to mate the surfaces and you're done.

 

[gunsandgunsmithing]

In this application lapping takes a high spot on one surface and makes a low spot on the other. Both surfaces should be machined true prior to lapping which mates the two surfaces together. You can make a piloted lapped of aluminum which you can square up between centers as the lap wears. I power it by putting it in a drill press with action in hand. Then true the lugs on the bolt. Light lap to mate the surfaces and you're done.

By hand, you'll wear yourself out before you remove much material with lapping but yes, you do remove some. If doing your own work though, why not just cut things true and you won't even need to lap much, if at all. When I do it on one I true up, it's mainly to verify contact patch and move on. If you do it under power as Dave said, just be careful and check it often. And like he said, the high spots will be removed and faster than the rest but that's kinda the point of doing it. Once flat and good contact, it'll be slow to remove much material but a high spot can move fast.

Sorry Dave. I don't think I intended to quote you but you brought up good points, as always.

 

[Carl S]

If your machining prior to lapping don't over do it.your going to change headspace and primary extraction also.Remingtons especially.

 

[338 Mollett]

I would mark the back of the bolt lugs to see what kind of contact first unless you have already done so .