Another way to keep lube on the lugs

[Smokepole]

I know most use the standard procedure of squaring off the back of the bolt head, then reordering the baffle and wave washer. While that works, and I've done it, I never have liked it. Turning off the well formed radius on the back of the bolt head introduces a hard corner that's a point of stress concentration. So, I've started turning several thousandths clearance into the ears on the baffle next to the bolt head. This keeps the radius, and keeps the bolt assembly ordered the same, and it keeps the lube on the lugs. It's harder than a banker's heart though so you know what you're in for ahead of time! Just wanted to throw it out as another idea.

[bigjohnson]

Why not just move the wave washer in between the the bolthead and the baffle?

[laportecharlie]

You have to enlarge its ID where it hits the radius of the bolt head.
Charlie

[Smokepole]

You have to enlarge the ID of the wave washer or cut the radius off the bolt head to do the re-ordering. Both options are less than ideal to me. Holding the wave washer to do a good uniform cut is next to impossible; plus, it's already very thin.

[allan1066]

I've never tried it but is it not possible to just open up the inner diameter of the wave washer a little, maybe with a dremmel tool and a small grinding wheel? If you make a hash of it it can only be pennys for a new one.

[allan1066]

Ok - See you beat me to it Smokepole. What about making a jig out of an ordinary washer with the correct diameter as a guide.?

[Smokepole]

It would definitely help w making a uniform cut, but you'd still wind up w a pretty flimsy wave washer in the end I'd think.

[BillPa]

I've never tried it but is it not possible to just open up the inner diameter of the wave washer a little, maybe with a dremmel tool and a small grinding wheel? If you make a hash of it it can only be pennys for a new one.



LOL...yeah and it takes a lot less time and effort. Open the ID just enough to allow the washer to seat flat on the bolthead with out any side to side play. Go too much and it can drop down and hang up in the action. A few passes with a Dremel and some trial and error it takes about 10 minutes.

I used to recut the radius at the same I trued up the bolt face and take a pass across the lugs, but now I just open the washer ID a bit.

Bill

[sharpshooter]

The radius at that juncture is only there for one reason and one reason only, and it's not even on purpose. It has nothing to do with shear strength or sharp corners or any other made up reason. The early production models all had a square corner at that juncture and they were fine. They were tested to destruction and never had a lug shear, I got that right from the horses mouth.

[SHL540KB308]

Smokepole, I hope you don't mind me posting a couple pictures. I "assume" you do it this way. Thought some of the people might be interested to actually see what you guys are talking about. I do it for no real reason except to keep the washer in the original position.
http://i11.photobucket.com/albums/a195/SHL540/65saum24.jpg

I machine .030 off the front of the baffle lugs.

http://i11.photobucket.com/albums/a195/SHL540/65saum22.jpg

Later, Brad

[Smokepole]

That's exactly it. I appreciate the pics and definitely don't mind.

"It has nothing to do with shear strength or sharp corners or any other made up reason." Well, Sharpshooter, I appreciate the comment 'straight from the horse's mouth' I suppose, but I'd rather you not act like a different part of a horse's anatomy. I don't doubt your intel and info at all. I was not aware early models didn't have the radius. But I can tell you this, that radius does help reduce the stress concentration of two perpendicular surfaces. I'd rather leave it. Enlighten us on your not 'made up' reason if you don't mind. Besides, you haven't heard all of my 'made up' reasons for the radius anyhow. ;D And now, for the obligatory google-fu:

http://nptel.iitm.ac.in/courses/Webcourse-contents/IIT%20Kharagpur/Machine%20design1/pdf/Module-3_lesson-2.pdf

You'll notice the first way to combat stress concentration in a stepped shaft is a gradual change in the geometry--a fillet.

Almost forgot to add, I found a great lube to use. I've been using some white grease that is probably lithium based. It's OK, but swipes off real easy; doesn't seem to have a lot of adhesion. The stuff I found most recently is Proshot Progold grease. It's a gold colored stuff and it's uber-tacky, almost like the red Lucas stuff for a grease gun! It seems to have great adhesion to smooth steel as well. Seems to be a lot more of it wipes back on the lugs after cycling a few times; whereas, the moly seemingly would disappear after a couple.

[dcloco]

Almost forgot to add, I found a great lube to use. I've been using some white grease that is probably lithium based. It's OK, but swipes off real easy; doesn't seem to have a lot of adhesion. The stuff I found most recently is Proshot Progold grease. It's a gold colored stuff and it's uber-tacky, almost like the red Lucas stuff for a grease gun! It seems to have great adhesion to smooth steel as well. Seems to be a lot more of it wipes back on the lugs after cycling a few times; whereas, the moly seemingly would disappear after a couple.


What about ending up with a sticky bolt or a grease that traps unburnt powder, etc, etc in the action?

Prefer to use a semi synthetic or full synthetic that leaves a couple micron film on the surface areas that need lubricated.

[Smokepole]

True that. It would definitely be a problem for someone that isn't anal about cleaning such things. Me, I clean my actions and work on them probably much more than I shoot them due to the weather right now. I can imagine that grease might be an issue in ultra low temps. I think it's rated for a big spread though.

[sharpshooter]

Mr. Smokepole....this may be long, so you might wanna get a cup of coffee.
Although I understand the principles of stress modulus and the relationship of stress affecting 2 perpendicularly surfaces, I referred to your theory as a "made up idea" for the fact that it is not applicable to this situation. Your references were geared towards examples of punches and shafts that have a completely different function. If that was what we were discussing, you would be 100% correct, but we are talking about an entirely different function. A bolt head is never under compression from end to end, the only part subjected to compression and that is under stress is the lugs them selves. The tail end of the bolt head only connects it to the bolt body. There is neither any rotational torque to speak of, only to rotate the bolt to open it, and it is so minimal it can be measured in inch/pounds.
For this application, the stress modulus theory does not hold water. Which brings me to my next point.
To reaffirm the statements I made, I reconsulted the horse's mouth. The horse's mouth is Bob Greenleaf, retired design engineer from Savage. He is the man responsible for all the major changes to the Savage 110 back in 1966. The changes included the bolt head and the trigger.The original design utilized a protruding bolt snout that held a snap ring like extractor much like a Remington 700,only on the outside of the bolt snout instead of internal. http://i2.photobucket.com/albums/y48/sharp-shooter/earlybh.jpg
The newly designed bolt head used a pin in the rear of left lug, and a corresponding notch in the baffle that acted as a stop to limit the rotation of the baffle to 90 degrees. These bolt heads had a sharp 90 corner at the stem junction, with the baffle washer between the bolt body and baffle for obvious reasons.http://i2.photobucket.com/albums/y48/sharp-shooter/earlybaffle.jpg

In 1969, the boltheads and receiver went through another change to reduce cost and incorporate the anti-bind feature. The anti-bind feature is nothing more than a fin protruding on the right lug of the baffle that rides in a corresponding groove in the receiver. At this point, the bolt heads were still made in house from solid bar stock and the new baffles were made from sintered metal, a cost saving feature.
During this time period, a few occurances of blown up rifles came to Savage's attention by gunsmiths that acquired specimens from customers. On every gun it was determined through admission that every instance was handloader error. Savage decided to test some rifles to duplicate the scenario for data.
I was slightly erroneous when I stated that they were tested to destruction and never sheared a lug. They were pressured to the point of shearing lugs, but this was past the pressure it took to fail the receiver.
The front baffle essentially did the job it was supposed do...block gases from the shooters face. This worked well for a blown primer, but in the event of a catastophic failure, the baffle was the first thing to break. Even though it broke in half, it still remained in place, but in the process the vast amount of gas could not escape fast enough through the small vent holes and the receiver expanded and split where the anti-bind groove was. It was estimated at 90,000-100,000 psi.
To get to the point where the lugs actually sheared off, it took over twice the amount of proof pressure (150,000+ psi). At this point, lug shear was a bonus because the received had already failed.
Some proto-type bolt heads were made up that did not use a front baffle, but were left the same diameter as the bolt body in the same location that the baffle occupied. This left the gas to escape quicker, causing less damage to the receiver, but potentially more danger to the shooter. When these were pressured to the point of lug shear, it took slighly less pressure to shear the lugs than the new design. The reason that was given was that the lugs were better supported closer to the lug abuttments giving a sharper shear angle. The bolt head using a baffle is not supported this close to the body diameter and tended to bend before being sheared, much like a worn out pair of tin snips.

The idea of replacing the baffle washer between the bolt head and baffle washer originated from Bob Greenleaf. He suggested this idea to retain grease on the lugs and it was accepted by the higher ups. Some left the factory in this condition, but due to a communication problem within the white collars and the assemblers, most left they way you see them now.
In 1988, Savage went through some financial troubles and make some radical changes to stay in business. One of their cost cutting measures was to contract work out to other vendors. The bolt heads were no longer made in house, but contracted to an outside vendor who was current on the latest machining technology. These bolt heads are now made on a Swiss type machining center from profiled extruded stock. The special profile stock was more expensive than round bar stock, but half the machine time was cut down and the scrap rate dropped. The machine time consisted of turning and counter boring the bolt face mostly and less time milling. To turn high production parts, carbide inserted tooling is used. To turn profiled stock versus round, a special insert is used for interrupted cuts. The insert uses a radius point for extreme tool life.
It was looked into a secondary operation to square the corner, but in the long run it was determined that the slight cost difference per piece added up to big savings over several thousand units. Bottom line...adding to the production cost was not going to sell more guns, so they nixed it.
That is the reason for the radius,... and no other "made up" reason. ;D

[Smokey262]

150K+ PSI? Whew!

I wonder what the velocity was

[Smokepole]

I didn't have coffee, but I had a tall glass of sweet tea which was made to suffice. I highly appreciate the explanation. Indeed, I was placing much emphasis on the rotational force or torque transmitting ability of the shank of the bolt head. It is a minuscule amount as said (unless you clamp the headspace down too much and gall the lugs like I did :o). And I agree that the bolt head is never in compression from end to end as said. Really, everything past the lug bearing surface is just there to get the bolt head in place mostly. With that said, I stand corrected. But, in my opinion, I still like the radius and prefer leaving it just to help resist shearing from those few in-lbs of torque it takes to close the bolt. And for another reason I'll detail below. For an end user like me, it's no big deal to shave the baffle down as aggravating as it is. For a semi-high volume custom job-shop like yourself, I can surely see how that move is not near as cost effective as just knocking down that radius on a bolt head that you're already going to clean up the lug bearing surface on. I reckon it's a difference in scale that motivates the different methods of solving the same problem.

It is very interesting what you said about the removal of the baffle feature and it's replacement w a larger diameter shank on the bolt head in that section. That actually introduced a sharp corner that was well supported so shearing could occur more readily. That makes perfect sense. So, w the current, baffled bolt head, it'll actually take more pressure since it bends slightly rather than just shearing the lugs off. That bending is more likely to produce a stress fracture if it has a sharp corner to propagate from, which is another reason the radius is good. I'm sure it's not the reason it's there, but it is a reason that it is good nonetheless. The bolt head is in effect turned into a beam simply supported on either side by the lugs and loaded in the center by the case head. The stem of the bolt head and the radius both serve a purpose as deepening the section where the bending occurs. But, that is all academic and really moot since the receiver is going to grenade first based on your talks w the OEM. I knew the bolt head looked like a weird bird from a manufacturing standpoint. I couldn't figure out if it was some type of high pressure sintering, machined from a billet and tumbled, etc. Now my curiosity is satisfied w the bit about the extruded bar stock.

I suppose I don't like my initial thoughts being called 'made up' with shots from the hip. But then again, I suppose you've probably heard a lot of this before and are weary of the same ole thoughts. One thing that troubles me though, is that there's no such thing as 'stress modulus' or at least I've never heard it stated as such. I believe you're speaking of Young's Modulus or the Modulus of Elasticity---the slope of the stress/strain curve for elastic materials, i.e., steel. And as long as the material is elastic (behaves linearly for the first portion of the stress/strain curve), it ALWAYS applies. The bolt head is steel (by definition ductile and elastic) and it's subjected to stress and it deforms. In fact, as you pointed out, it is stressed both by bending and shear in combination. Those stresses can be combined with Von Mises stress or Tresca. But, for this piece, the cross section is way too complicated to complete the analysis analytically on paper. A good FEA program would serve the purpose. If I have time, I'll 3D model it and complete the analysis both with and w/o the radius just for the heck of it.

[efm77]

If I read that right you're saying the action blew at 90,000-100,000 psi right? I thought bolt actions were made to withstand much more than that. Not that I would try to load something that hot to tempt fate but I read on another website that all modern bolt actions could withstand 150,000+ psi. That wasn't a he said he said kind of thing either. It was from a manufacturer's website (Dakota Arms). I'm not sure if it's still on there or not or if I could find it again because it's been several years since I read it but it was in an article they had written about the arguments of which bolt action is the strongest.

[Smokepole]

I would have hoped for more than a 1.5 safety factor myself, particularly in a consumer product meant for the masses w serious consequences both to life and limb as well as sales. But, in this case, the loading is well known and well defined by industry standards. And, the scapegoat is/will always be the ammunition or an obstruction. If factory ammo approaches that level, even remotely, it will be more to blame than the firearm. If it's not the ammo, then it's easy to say the bore was obstructed. If it's handloads, all manufacturer liability is out the door anyhow.

It would be interesting to know how the bolt was tested to a pressure of 150ksi if the receiver failed at 90-100ksi. I guess they used a purpose built receiver or some type of receiver reinforcement to get it to that level. Or maybe a hydraulic press or the like was utilized to load only the bolt face w the bolt head itself in a specialized testing fixture of some sort. I'd like the latter the best.

[dcloco]

There is a certain Savage Target action with a custom 32" barrel that propels 338 caliber 300 gr Sierra Match Kings at 2950 fps....on a regular basis. I monitor the bolt head, body, and cross pin continuously for signs of impending failure.....of which, none have occurred so far. This receiver, bolt assembly, and barrel have over 500 rounds down range/field.

[sharpshooter]

There is a certain Savage Target action with a custom 32" barrel that propels 338 caliber 300 gr Sierra Match Kings at 2950 fps....on a regular basis. I monitor the bolt head, body, and cross pin continuously for signs of impending failure.....of which, none have occurred so far. This receiver, bolt assembly, and barrel have over 500 rounds down range/field.

The bolt body and cross pin won't show any signs of pressure. One sure way to tell if you have pressure is to remove the barrel and examine the lug abutments. If you see a "footprint" of the bolt lugs, you have excessive pressure.