Lug galling

[Smokepole]

Just swapped on an SSS recoil lug, lapped the locking lugs, and reset the headspace on a Stevens 200. In the midst of setting the headspace, I got a tad tight w no lube yet on the lugs and slightly galled a portion of one. I was able to clean most of it up w the lapping compound. There's certainly no high spots left, but only a couple pits smaller than a pencil lead both in the bolt head and in the integral lugs. All in all, I think there's still much more contact now that there was stock. I haven't got a chance to fire it again and see what the groups are like. Has anyone else had a similar experience, and if so, how did you deal w it? I know shaving the surface of the lugs and swapping the bolt head would be the ideal solution, but I don't yet have an action truing jig built. Which brings me to another question. I know that Savage doesn't dial in a precision ground rod in the bore of every action to do machining steps. I know that awhile back, each feature of the receiver was done separately on various machine tools so the action had to be rechucked/setup a lot on the line. So, if a fella isn't desiring to do make the perfect cut as a precision aftermarket smith w a jig might, could he get stock results by simply chucking on the OD of the receiver?

[BobT]

I don't think that most people lap the lugs on a Savage/Stevens bolt , it's not required because of the floating bolt head.



I know that Savage doesn't dial in a precision ground rod in the bore of every action to do machining steps. I know that awhile back, each feature of the receiver was done separately on various machine tools so the action had to be rechucked/setup a lot on the line. So, if a fella isn't desiring to do make the perfect cut as a precision aftermarket smith w a jig might, could he get stock results by simply chucking on the OD of the receiver?


As far as an action truing jig I would think that anybody who had any business putting a rifle action in a lathe would know how to dial it in, the main reason for using a jig is convenience IMO but since I have never seen the Savage factory I really have no idea.



There's certainly no high spots left, but only a couple pits smaller than a pencil lead both in the bolt head and in the integral lugs.
I know shaving the surface of the lugs and swapping the bolt head would be the ideal solution, but I don't yet have an action truing jig built.


If I'm understanding you correctly you want to re-cut the lug seats in the receiver, if I were you I would just leave them as is.

[BillPa]

I know that awhile back, each feature of the receiver was done separately on various machine tools so the action had to be rechucked/setup a lot on the line. So, if a fella isn't desiring to do make the perfect cut as a precision aftermarket smith w a jig might, could he get stock results by simply chucking on the OD of the receiver?


Actually, Fred touched on this subject some time ago. When the actions are machined, the ring is bored, the abutments cut and threaded on the same machine, same setup, same time. Its why when doing a Savage action forget conventional thinking going off the bolt race. Index the action off the threads not the bolt race.

Since the "floating" bolt head will compensate for as much as .040" bolt body misalignment for all practical purposes its a non-issue. The only things to really pay attention to are the ring face, lug, nut face are square to the threads and if the action is in fact straight, not warped, bent or twisted.

As far as the cutting the lugs be careful. There is only .010" meat between the extractor spring bore and the lug face. Get carried away and you'll be buying a bolt head. IIRC the most I've ever have to remove was about a .002" if that. Most times after re-cutting the junction of the shaft and lugs to relocate the spring washer I'll take a pass over the lugs, but generally remove next to nothing.

You can't index off the exterior of the receiver, Savage or otherwise. Most all actions are lovingly and carefully finished "by hand", so if old Harry is a little heavy handed that day...... ;D Its not all that unusual for a 1.350" action to measure something less at one or more points around it. It also might make one wonder if mounts actually fit a receiver huh?

Here's one I snapped a picture of for S&G after doing a little grinding. ;D
http://i43.tinypic.com/30mqxir.jpg

Bill

[Smokepole]

Excellent, that's exactly what I needed BillPa. I will most definitely not use the OD of the action then! I understand what you're saying about the rest. If I do decide to do anything w the bolt head, I'll just buy another. I was more concerned w the pits on the integral lugs. It looks like it might take .005-.010 to get completely rid of all traces. I'll mull over how to go about that knowing this info now.

[Smokepole]

It looks like I have a piece of aluminum tubing I can use to make a 'spider' action truing jig, similar to what someone would use on a Remmy. 2 sets of 4x jam screws to adjust, each set of 4 on the front and rear receiver rings. I can make a mandrel that threads in and stops on the integral lugs. I'll leave about 8-10" sticking out to dial in on it in 2 places. That'll allow me to chuck the jig in a 3 jaw, do the necessary dialing in on the mandrel, then I can face the receiver and lugs. I haven't the skill nor the want to touch the threads, and since I'll be dialed in off them, there's no need to (and I want to use prefits or takeoffs as needed anyhow). And, for my other Savage, when I get the chance, I can simply chuck up the mandrel, screw the action onto it, and take the face cut there (since I have no need to face off the lugs in it). Does that make good enough sense? Also, I figure .010" off the integral lugs isn't going to matter, but what would be the max that could be taken off w/o cutting into the safety factors too much? The bottom lug has a pretty aggressive cut out of it for the feeding ramp.

[Smokepole]

Well, got a little bored and decided to keep lapping. I used some #45 diamond compound suspended in grease for the bulk material removal, then #15, then #6. I half expected to use the bolt head as a sacrificial lapping tool as I figured it would loose as much material as the receiver lugs. It probably lost .005", but has a decent ridge on it at about the bore of the raceway. I think I'll go ahead and spring the $20 for a new bolt head from Midway. The integral lugs are much more uniform and have a perfect surface finish now though. I'm satisfied.

I did all this after building the spider setup. I'm half glad I don't have to use it. The mill I have access to is pretty worn. The bolt holes are a little skewed in spots, but that really doesn't matter much except for aesthetics. I do intend to build the mandrel that screws into the threads and butts up against the integral lugs. That'll give me a chance to face it off like the pic above.