Don't lap your lugs

[Dennis Sorensen]

I trued a magnum 700 action today that was so screwed up from someone lapping the lugs...

A tremendous amount of taper to the lug recesses and to the bolt lugs.

I guess that was why it was for sale...

Lapping lugs is highly over rated in my opinion.

[Roger T]

I presume your saying that a HOME lap is not a good idea, not a good Smith.

[Pete Wass]

it's waste of time withthe Rem type actions. The angled sear jacks the back of the bolt up taking one of the lugs off the face of the lug abuttments so what ids the point? Why hot jack the bolt up while trueing so that when the bolt is closed both lugs will contact the face of th action?

[Dennis Sorensen]

I presume your saying that a HOME lap is not a good idea, not a good Smith.

Not me... I much prefer to true the action lug recesses and true the locking lugs... no lapping required... or leave it as is from the factory unless a lug is galled... then lapping is useless anyway...

I think it was created as a money maker...

[Hal D.]

I'm with Dennis. Lapping was created by gunsmiths that didn't have the knowledge or tooling to properly true an action.

[crb]

I also think that lapping the abutments with the bolt is bs. I made a full circle arbor to lap the abutments. I turn it with a cordless drill motor. I wanted a polished abutment surface so there was less friction when opening the bolt on a fired case.

[ultramagmed]

I'm with Dennis. Lapping was created by gunsmiths that didn't have the knowledge or tooling to properly true an action.

Nail on the head!!!

IMO (whatever that is worth)

Med.

[akshooter]

maybe not on 700 rem, i think it started on mausers with miss matched bolts.

[NesikaChad]

I lap as a form of quality control. That's it. Its a quick way to tell if things are touching. That and the bulk of customers will drag you into the street and stone you if you don't do it or even try to tell them its not needed.

That all being said I consider myself a patient fellow when it comes to this stuff. I think I'd rather suck start a Glock pistol that invest the time it would take to lap a taper on a set of lug surfaces. I think even with the most aggressive compound out there it'd still be a daunting task to really destroy/hurt something that way.

JMO.

Chad

[Dennis Sorensen]

I lap as a form of quality control. That's it. Its a quick way to tell if things are touching.

Chad

700's are the only action I true and that is all that is required after truing a 700. I use 600 grit just to confirm the fit after truing... about 10 swipes of the bolt handle with my finger pushing back on the bolt face... you can see a light pattern wipe on the leg recesses. That lapping changes nothing.

[Peter]

it's waste of time with the Rem type actions. The angled sear jacks the back of the bolt up taking one of the lugs off the face of the lug abuttments so what ids the point? Why hot jack the bolt up while trueing so that when the bolt is closed both lugs will contact the face of th action?

an intelligent observation.

[Dennis Sorensen]

it's waste of time with the Rem type actions. The angled sear jacks the back of the bolt up taking one of the lugs off the face of the lug abutments so what ids the point? Why not jack the bolt up while truing so that when the bolt is closed both lugs will contact the face of the action?

I prefer to true the bolt lugs and bolt lug recesses square with the bolt race... The ever so slight angle that the trigger causes the bolt to 'sit at' when cocked is neutralized when the firing pin is released and hits the primer... and when 60,000 pounds of pressure hits the case the bolt lugs are held against the lug recesses fairly firmly...

[Pete Wass]

I prefer to true the bolt lugs and bolt lug recesses square with the bolt race... The ever so slight angle that the trigger causes the bolt to 'sit at' when cocked is neutralized when the firing pin is released and hits the primer... and when 60,000 pounds of pressure hits the case the bolt lugs are held against the lug recesses fairly firmly...

Is there a noticable difference in wear on the abutments after using the rifle for a time? The wear marks look exactly like the results of the bolt being jacked up.I guess for this reason I don't buy the free fall theory. This shows up in the best of custom actions that I have owned.

I don't have the equipment to measure whatever the difference is but it sure is visually different.

[bob3700]

Dennis,

Do you, have you bushed a Rem bolt body? That will certainly take the "Tilt" out of the locking lugs that the striker/trigger sear induce.

Once you true the lug abutments and the lugs themselves, no lapping is required cause they are in contact due to the lack of slop in the bolt to receiver area.

It's something that I do on my own Rem actions and it is a valuable mod in my opinion.

Bob

[Dennis Sorensen]

Dennis,

Do you, have you bushed a Rem bolt body? That will certainly take the "Tilt" out of the locking lugs that the striker/trigger sear induce.

Once you true the lug abutments and the lugs themselves, no lapping is required cause they are in contact due to the lack of slop in the bolt to receiver area.

It's something that I do on my own Rem actions and it is a valuable mod in my opinion.

Bob

I bump the odd one (top and bottom) with dovetails and steel inserts... These should be called "Leeper Lumps" as Bill Leeper was the first to use this method that I know of...
http://photoshare.shaw.ca/image/3/b/d/203599/700boltbump-0.jpg

[Donald]

Very nice work Dennis. Now if everyone would just use the floating bolt head like the Savage........

Donald

[j mckinnie]

picture,I like the idea and methodology (is that a word?).
jim

[jglenn]

speaking of bushing the remington bolt anyone have any input on his method of using glass bedding to take up the bolt slack.. may be an interesting method

apparently he is going to have this method in one of his next videos

[Butch Lambert]

Donald,
If you had made the Shilen Swap Meet you would have seen their new receiver. It has an exact Remington footprint, uses Remington pattern triggers, has a Savage floating bolt head, and the Savage barrel and nut setup. I call it the ultimate switchbarrel. You can change barrels and bolt heads at home and be able to shoot several cartridges. They will be available as complete rifles, barreled actions, and actions. They will also be available for the wrong handed people.

Butch

[PEI Rob]

Also, if they are lapped too smooth grease has a hard time to stick.

These videos are pretty good, even though they are out of focus.
This one relates to lapping, sort of. Sorry if it upsets you.
http://www.youtube.com/watch?v=SiPfycHkTjw&feature=channel

If that didn't make you ill, this one should.
http://www.youtube.com/watch?v=KnfEw640mV4&feature=channel

[404tbang]

Donald,
If you had made the Shilen Swap Meet you would have seen their new receiver. It has an exact Remington footprint, uses Remington pattern triggers, has a Savage floating bolt head, and the Savage barrel and nut setup. I call it the ultimate switchbarrel. You can change barrels and bolt heads at home and be able to shoot several cartridges. They will be available as complete rifles, barreled actions, and actions. They will also be available for the wrong handed people.

Butch

Howdy Butch,
Any idea of when this action will be available?
Will it have easier bolt lift than Remington?
Will it presumably be trued better than a factory Remington?
Any guesstimation of the price?

Southpaws of the world, unite!:D

Thanks!
Greg

[Pete Wass]

I bump the odd one (top and bottom) with dovetails and steel inserts... These should be called "Leeper Lumps" as Bill Leeper was the first to use this method that I know of...
http://photoshare.shaw.ca/image/3/b/d/203599/700boltbump-0.jpg



very nice solution.

[Butch Lambert]

Greg,
The bolt timing is excellent. It also has a provision to replace the bolt knob.
Call Shilen about delivery date and price. They are built on CNC machines and are to the same specs as your BR receivers. No, you will not have to do anything to it.
Butch

[404tbang]

Howdy Butch,
Thank you!

Greg

[alpacca45]

Dennis, those dovetailed bumps look excellent. I'd been toying with the idea of set in bumps at 10 o'clock and 2 o'clock on the closed bolt, under the receiver bridge and loctited set screws to centre the bolt. your's looks the far better idea.

From what I can make out, all that loose abrasive is good for is making the parts bright. Whitworth de-bunked the use of loose abrasive for making accurate surface plate and machine surfaces back in the 19th century, clearly stating that you have no control over where the stuff goes, or where it takes metal off.

Loose abrasive shouldn't really be called "lapping". Actual lapping with a series of accurate laps with embedded abrasive, and proper checking control over flatness and squareness is something completely different.

Whitworth's preference was for scraping.

I was reading an article on comparitive wear tests of scaped, periphery ground and cup ground surfaces in varying grades of cast iron and case hardened steel.

After 20,000 metres (about 12 miles) of sliding travel with proper lubrication, the least wear was between scraped surfaces, or with scraped on cup ground second.

Among the possible claims for scraped surfaces were greater flattness and better contact, retention of lubricant, and possibly locked in compressive stresses in the surface, where grinding locks in tensile stresses.

When surfaces of differing hardness were slid against each other, the harder surface suffered more wear. Irradiating the surfaces before running them, then taking radiographs after running, showed that wear particles from the hard surface embedded in the soft.

Now, what will the "gunsmithing" (bubba's garage tinkering) writers in gun magazines have to write about next month, after what you guys have said?:D.

[Dennis Sorensen]

Dennis, those dovetailed bumps look excellent. I'd been toying with the idea of set in bumps at 10 o'clock and 2 o'clock on the closed bolt, under the receiver bridge and loctited set screws to centre the bolt. your's looks the far better idea.

.

If you use dovetailed 'bumps' remember the fellow that first came up with the idea... at least he is the first I know of to use this method. Bill Leeper a Canadian gunsmith. I refer to these bumps as 'Leepers Lumps'.

[Butch Lambert]

I'm not the smartest guy on the block, but how is Gordy going to use fiberglass bedding to tighten a bolt?
Butch

[jglenn]

beats me

maybe glass the area the bolt rides in to tighten it up?

http://www.gordysgunsmithshop.com/dvds.html

[alpacca45]

beats me, maybe glass the area the bolt rides in to tighten it up?

What a great way to scuff the hell out of the bolt body.

My little digi camera has a plastic bit on the strap, it's almost worn through the stainless front of the camera. later models have a rubber bit on the camera body to keep the plastic from rubbing on the stainless.

I'm sure part of the problem is the mineral dust (probably silica) used as filler in the plastic, but embedded grit from the environment is going to play a part too.

Part of a rifle primer composition is silica or broken glass, to cause sufficeint friction to ignite the primer,

so, even if the plastic is free from abrasive filler and the rifle is never in a dusty environment, some of that primer dust will still get into the plastic.