Build along: S.Mtn.Rifle: Inletting lockplate

[mikemeteor]

Throwing up some more pictures of my 2nd build.
Again, this is mostly for entertainment of new guys - you vets will find this boring.
However, if the vets see some mistakes, or have a better way and weigh in with some pointers, then we all learn - and that's good! :grin:

Caveats for beginners: This is only my 2nd build.
I'm no expert! - some of these other guys are pros - or could be if they wanted. Dang near everything I do I learned on this forum.
For a pro's view, check out Mike Brooks' tutorial at the top of this forum index.
I'm just adding a few pictures, plus some things that aren't always obvious to newbies at first.

Positioned the lock and marked the bolster inlet- there are numerous threads on this in the forum. You can see where I located my venthole, and measured/marked in my wood web between barrel and RR channels. These 2 landmarks determined where the lock goes. You can see I'm a lipstick guy for transfer medium.

When you're chopping in your bolster slot, be careful with this particular down-chop - any prying action - or even just the chisel bevel, will split the wood along that axis - I'm 2 for 2 now - SuperGlue to the rescue. :shocked2:

If you're a 1st-timer and you're like me - God help you - you're wondering what to do with that fragile-looking neck of wood above the bolster - I'm saying leave it there - backing up your pan fence nice and tight - later on you will work most of it off - most everything above the pencil ine will end up coming off, and much of the side-to-side width of it will be gone (very soon).

Filed the slight draft around the lack plate and laid if tight on your lock panel. Here's where I changed schools from rifle #1 to #2 - I like the exacto knife for inlet edges. I use a blade modified on the grinder - this one won't snap off the long thin pointy blade in the wood (again, picked up that tip here). Plus the wider sides help me keep it square and flush with the lockplate sides.

The sharp radius around the nose needs a smaller blade. I don't have a gouge of the correct radius - (see Mike B.s tutorial) - that would be a help - cutting a smooth curve around the straight wood grain is a PITA.

I also do the backcut with the knife. Hands out of the way for picture - in practice I have both hands pretty close to business end - one pushing/guideing & the other pulling.

Took out the field wood with a 1/2"' chisel - two times around, and the lock plate sets at about the right depth - except the pan
is still a quarter inch from the barrel - so now its decision time :shocked2: !

You can:
1) keep inletting deeper and deeper until the pan lies on the barrel, or
2) take down the surface of the lock panel, and start shallow inletting again, until the pan hits the barrel.
so... ya gotta ask yourself - can I keep inletting deeper and deeper and keep the sides straight and true ?
Be honest with yourself - because the truth shall be revealed later!

On gun #1 - I did option #1 - and ended up with a big gap on one corner of the lockplate.
I learned here, after that, about tactic #2, and I used it with this gun. VERY glad I did - it worked much better. :thumbsup:

So here it is with the pan on the barrel and the lockplate face near the finished grade.
Was advised to leave a little extra on top to absorb the abuse in remaining building process - take it to final grade once we get nearer the end.

Clamped the plate in place and drilled the lock bolt holes. Learned on gun #1 to be careful with that rear hole location :shake: - miss the bridle lip, but try to keep some wood around it (behind the barrel).

Not sure if drilling thru the breechplug bolster is desireable or not - I'm 2 for 2 on it. I think I might file that excess bolster away on #3 - drilling thru it causes problems initially getting the barrel out of the stock because of metal run-out.
Anyway, here it is all cleaned up:

lastly, tapped the new holes thru the stock. No problems this time! Some readers may remember I broke a tap on gun #1 - I was free-handing it. This way seemed much more solid. I'm applying tapping-oil in the tap head slots with a nail-dropper in the pic.

enough for now.
Again, I just post these pics as one new guy's efforts - always looking for tips !

 

[Bean]

Great stuff. I'm just getting ready to start my first. It really should help.
I too am curious about the hole in the breech plug?

 

[Birddog6]

I am curious to why the lug on the breechplug is slanted from the bottom going up to the tang, instead of 90 deg & vertical ? What I see is the recoil of the barrel is riding up a slope on the lug & that = putting pressure on the tang bolt.

I want the base of the lug of the breech plug flat & vert. straight up & bedded in the back of the stock inlet just like the barrel is. I want ALL of the recoil straight back & solid.

Maybe others see it differently. :idunno:

 

[Birddog6]

Also, I suggest next time to take the wood on the lock panel down to the top edge of the lock panel. This gives you 1/8" of protection while building the rifle. If you take it all the way down to the beveled edge & should happen to bump it on the vice or gouge it, now you have no protection & no way to sand it out, cause you have already removed all the excess wood. :hmm:

And, before you start all of this, draw a centerline down from the entrypipe inlet or RR hole center, down the center of the lock & trigger inlet area, up the bottom of the wrist to the toe. Keep this reference mark to center the bottom of the lock panels & to put the trigger in the center, etc.
Take the lock panel down a little, then to to the other side & take the sideplate panel down same amount. Keep doing it evenly as you go so you keep everything even & square on Top & Bottom.

:thumbsup:

 

[MSW]

i agree with Birddog as regards the tang- some careful file work, followed by some bedding compound is in order, i think. while i realise that many see bedding a barrel as a non PC-HC anethema, i think it makes the system stronger, and since nobody sees it, i don't see the harm.

just one guy's opinion, and no doubt worth what you just paid for it.

than glitch aside, i'd say you're well on your way to making good smoke.

best of luck with the new build, and keep the pix comming!

 

[Zonie]

You didn't mention how you located the rear screw hole in the lockplate but for the newcomers I'll mention a few things that I feel help assure it is in a good place.

To locate the rear screw hole look at the inside of the lockplate. You will notice the raised bolster area that is just in front of the tumbler.

That raised area is where this rear screw should go.

I try to locate the hole as far aft as possible making sure I am far enough away from the edges so that the threads won't break out the sides of the raised area.

I then punch mark the exact location I want the hole and then use the TAP DRILL to drill thru the lockplate.
All of this is done from the inside with the lock removed from the stock.

After drilling this rear hole thru I then install the lock into the stocks lock mortice, position the stock so that I will be drilling straight thru and use the pre drilled hole in the lock plate as a drill guide for the TAP DRILL.
Use the TAP DRILL to drill the hole thru the stock and thru the breechplug bolster under the tang. The drill needs to break out thru the far side of the stock.

The forward hole lock screw hole must be carefully located so that the screw will miss the ramrod groove. If it nicks the barrel channel that isn't a real big problem.
Of course, the forward screw also has to miss the mainspring so be careful in locating it in the lockplate.

I use the same method of drilling the forward hole thru the wood as I did with the rear lock screw hole.
Again. Make sure you are using the TAP DRILL to drill these holes.

The reason I keep saying TAP DRILL is I have known people to be in such a big rush they mistakenly drilled the holes thru the lock using the screw CLEARANCE DRILL! :cursing:
Needless to say, this is easy to do if your not careful and it will often ruin the lockplate because the next size screw is usually Way Too Big.

OK. I'll get off of my soap box. :grin:

 

[Birddog6]

I always drill my locks with a 1/8" bit for a pilot hole, put the lock in the rifle, take to drill press with drill point on the press & drill the tap holes with the lock in place & thru the stock, and especially the bolster hole. I drill half way, then turn it all over & go the other way to they meet, then drill a clearance hole to the lockplate & then tap the hole.
IMHO, if you drill the holes with the lock out of the stock, should the sideplate to lock screws end up not being perfectly parallel, there is a good chance you will break the tap off when you try to tap the holes thru the stock because the hole you drilled is not straight with the tap.

And if you tap the holes out of the stock, the screws may not start in the lockplate cause they are not straight with the hole in the stock.

Well, of course the first thought is the holes & screws should be straight & etc. Sometimes it just don't work out that way for a multitude of reasons. RR holes misdrilled & in the way, mainsprings in the way, side plate ya chose means holes will need moved a tad, lots of things. Thus why I drill the lockbolt holes & them then with the lockplate in the rifle, clamped & secure so nothing can move & tape it that way as well.
:thumbsup:

But anyway, everyone builds them a lil differently, this is just my way of doing this part.

 

[Birddog6]

Anyway, here it is all cleaned up:

I have had 2 sent to me with breechplugs lugs modified similar to this. One of them was not as sloped & a couple passes with a wire welder with 20 min. waits between weld passes repaired the lug & to the belt sander & I was back to 90 deg. at the base going up to the tang. The other one I replaced the tang because I didn't want to build that much up on the lug as it needed 1/2" of weld on the bottom. Probably would have worked, but just felt more comfortable with a new B/plug plus I had one at hand.

I was told they modified the back of the plug to make it easier to inlet down into the stock. This could well be true, it appears it would be easier.But is is also NOT the correct way to inlet that tang. You don't grind away the base or lug of the b/plug on the Rear.... You want the Rear of it 90 deg going up towards the tang so the rear of it puts pressure Straight Back to the breech inlet upon recoil. To me you need to change this immediately before you proceed any further. The sides of the lug are to be slightly beveled to let it down into the inlet & so it will go in & out easier, but the rear of it stays straight & vertical, not sloped up to the tang.

Also saw one years ago the guy ground all of the lug off to have it all flat on the breech of the barrel. so it would clear the lock bolt at the bolster.... Made a good solid flat bed at the breech, but had real problems when he had to take the B'plug out as he had no lug to turn it with & broke off the tang trying to use it. :shake:

Others mileage may vary, but this is how I see it.

:wink: :shake:

 

[mikemeteor]

Thanks Birddog !
I agree with your force/vector thing arguing against a sloped tang bolster.
I didn't shape the tang that way myself - it came with that profile from TOW.
And me being a greenhorn, I figured it musta been OK - and "assumed" ( :shake: ) they really didn't mean for me to remove close to 1/4" of steel.
But I'm learning more and more what "assuming" does !
I also thought about what it would look like if I filed it square - not much for my wrench to hang onto - a situation you have graphically recounted .


At this point, I think maybe I'll just file a couple 32nds off the rear of that bolster, such that it does not contact the stock. :hmm:
Then the contact surface between back of barrel and stock will take 100% of the recoil - and that is the perpendicular-straight back vector that we want.
Earlier, I was advised that the rear of the tang bolster does not in fact need to be in contact with wood.
Realizing, of course, that opinions about this may differ, even amongst you veterans.


Zonie - had taken a picture to illustrate your point about lock bolt hole locations.

Hole "X" has to be just far enough forward to miss the bridle tab (at least on Siler lock guts - don't know about others) (new guys - put the bridle on and mark where that is - you can see my temp. scratch mark on the bolster).
Any further forward than necesary and you weaken the wood bridge between the bolthole and the barrel.
And yes you can ask me how I know this....

I'm certainly listenin' to you vets about desired technique for drilling and tapping lockplate holes. I don't have enough experience either way.
But I DO know this - if you are in the situation where you are drilling that rear hole through your tang bolster - DO NOT do the clearance drilling with the barrel in the rifle !
Run-out of the metal and shavings will make you sad - if you like nice clean wood-to-metal surfaces.


And, fellow greenhorns, Birddog makes another good point about the sideplate - some of the preshaped ones don't give you a lot of freedom about the relation between hole "X" and hole "Z" - lay it out ahead of time!
I'm using independent sideplates/inlays for each bolt on this gun, so I could put the bolts wherever I wanted.

 

[Mike Brooks]

I always put a couple degrees of bevel on the back of my breech plugs, easier to inlet. I also don't have the back of my breech plug touch wood, I depend on the back of the barrel for that.

 

[Birddog6]

Earlier, I was advised that the rear of the tang bolster does not in fact need to be in contact with wood.
Realizing, of course, that opinions about this may differ, even amongst you veterans.


Zonie - had taken a picture to illustrate your point about lock bolt hole locations.

Hole "X" has to be just far enough forward to miss the bridle tab
Any further forward than necesary and you weaken the wood bridge between the bolthole and the barrel.

But I DO know this - if you are in the situation where you are drilling that rear hole through your tang bolster - DO NOT do the clearance drilling with the barrel in the rifle !

Yes, the contact points at the breech are a controversial thing. I like all the recoil support I can get there, as always figured the more contact area the less chance of anything ever cracking. Others think the rear of the barrel is enough. I can agree that it could be adequate IF the rear of the barrel is ground or filed down even with the breechplug so it all fits flush to the wood, to give more surface contact area.
However, allot of the barrels I have seen & used, the breechplug is recessed, so actually the only thing touching the wood at the breech are these two half-sided rings of barrel on each side...... :hmm: Now on a small bore .40 cal & under this may be fine. But on larger bores & especially the .54's & up, you go shooting heavy charges & you may come up with a issue there..... Every single barrel I have removed with a crack at the tang, had this half ring on each side & a recessed breechplug, thus the barrel beat back into the inlet, the barrel half rings didn't provide adequate support, then tang didn't have adequate clearance on the end to compensate, = crack at rear of the tang.
Maybe I am overbuilding it there or being over concerned, but I am the type that likes to eliminate problems & issues before they occur. :v

As to your mark for the rear lock bolt hole on the bolster, it appears to be perfectly placed. Depending on the lock, rifle, barrel, etc. personally I like the rear hole to go thru the breechplug lug & not 1/2 in or out, but that is a personal preference. Also dif barrel makers use dif plugs & depths so sometimes it just ends up they way yours is.

As for drilling the breechplug lug as you drill the hole from sideplate to lock ? not a good idea. :shake: Normally you are hitting a tapered lug = the bit walking down = hole is not where ya need it. I drill that thru hole with a wedge of wood in there to support the inlet (rather than the barrel) Then when I am drilled & tapped, take the wedge out, put the barrel in & take the drill & turn it in the hole & mark the lug on each side with the drill bit thru the hole. Then remove barrel & drill the lug & go oversize of the 8-32 or 10-32 bolt so you have plenty of clearance.

Lots of dif ways of doing these things & end up with the same results. Dif guys end up with ways they are comfortable & that work. I figure it is always better to play it safe & overbuild than underbuild. And I always build it well enough to satisfy me, and most will tell you I am one picky feller !! ha ha !! :rotf: :rotf: :redface:

 

[mikemeteor]

well ....:hmm: .... I do have a recessed breechplug and am left with the half circles of barrel for contact.

But I DID Accraglass the contact surface there - would that "prevent" any reverse embedding of the barrel due to recoil ?

Maybe, if and when I'm feeling the mojo :idunno: , I'll make the top picture
look like the bottom picture, and glass in that bottom half.
And make sure the top-half angle is free of contact.

 

[Birddog6]

You are about to get out of my comfort zone on the tang you keep cutting on......

As for the rear of the barrel bedding..... did you fill the plug out to level with modeling clay when you bedded it ? If so that comes out when you take the barrel out. = you have 2 half rings bedded now. You still are only supported by 2 half rings.... not my cup of tea & am not comfortable with it.

Myself, if I was doing it, that breechplug would come out & I would do it like it should be done. But that is me, others & you may be comfortable with this, I am uneasy with what you have. Sorry........ :hmm:

 

[rdillion]

That tang is getting a little scary. A new tang is not that expensive and better safe than sorry.

 

[mikemeteor]

to clarify - the tang still looks like the top picture - same as when this thread started.
the bottom picture was computer generated - showing what I was contemplating doing.
"...if I was feeling the mojo."
after your responses, I ain't feelin the mojo ! :slap:

But, as it is... perhaps I'll just ease the rear of it off the wood by a 32nd or so and leave it alone !

thanks fellas. :hatsoff:

 

[Model19]

Great info form all of you guys. When my kit is in my hands I'll be reviewing this all again before I lift a chisel or chuck up a bit.
Well done!

 

[paulvallandigham]

I will never understand why builder will NOT remove that extra metal from the rear of the barrel so that the barrel and plug are flush. The barrel companies LEAVE extra metal at the back of the barrel on all their barrels to accomodate slightly different lengths of breechplugs. Its suppose to be removed.

As for that existing lower tang, its left there to give some purchase for a wrench, should the it be necessary to remove the plug after its seated, for any reason. I would square the upper portion of that angled lower tang, NOT REMOVE more metal from the bottom, as the computer image picture show.

Leave the hole alone, except consider using a rat tail file to enlarge the hole just a bit towards the barrel, so that the plug is not transferring recoil to that lock bolt.

Because of the location of that lock bolt hold in the lower tang, I would definitely bed the barrel and the back of the barrel mortise with epoxy( filling the sunken plug area in the barrel with modeler's clay, to produce a flush surface to take any recoil. Steve is absolutely correct on you wanting to have something more than the half moon arcs of the edges of that barrel pushing the recoil against the wood of the stock.

When you have finished bedding the stock, consider filling that sunken area in the barrel with something durable, to transfer the recoil forces to the epoxied recoil "shield" you created. I have left the modeler's clay in the breechplug and its proven to be very durable. It doesn't hold up to solvents use in cleaning the barrel, very well, so once in a coon's age you may have to put some new clay there. :hmm:

 

[Allan Gray]

I always put a couple degrees of bevel on the back of my breech plugs, easier to inlet. I also don't have the back of my breech plug touch wood, I depend on the back of the barrel for that.

Ditto;

I never gave any thought to having the breech plug hard up against wood. I aim for a snug fit at the back of the barrel.

 

[mikemeteor]

well... shows to go ya, there's more than 1 way to skin a possum, and knowledgable people can disagree.

I will never understand why builder will NOT remove that extra metal from the rear of the barrel so that the barrel and plug are flush. The barrel companies LEAVE extra metal at the back of the barrel on all their barrels to accomodate slightly different lengths of breechplugs. Its suppose to be removed.

I have left the modeler's clay in the breechplug and its proven to be very durable. It doesn't hold up to solvents use in cleaning the barrel, very well, so once in a coon's age you may have to put some new clay there. :hmm:

I KNOW I'm gonna regret this, but dadgummit Paul, I gotta respond.
One reason a builder (at least THIS builder!) would not remove that extra metal at the rear of the barrel is because they just flat didn't know it was the thing to do ! :idunno:
Maybe that step is in a book I don't have, but I've been reading and searching this forum for over a year now, and I swear on Davy Crockett's grave I haven't read anything about doing that.

I deduce that another reason, based on Mike B.'s and Mr. Gray's responses, is that some builders know about it and still believe it's unnecessary.

And Davy Crockett's ghost wonders how it came to be that you yourself claim to have left clay "in the breechplug", long enough to know that its proven to be durable. :hmm:
RSVP to address shown above. :wink:
Seriously now, Paul, this forum wouldn't be half as interesting or entertaining or informative without your input - but you gotta be patient with us greenhorns. We're just learnin. :hatsoff:

Anyway, a sincere thanks for all the input.
It definetly helps me, and if all this back-n-forth helps one or two other new builders, then its all worth it.
Yeah, I REALLY wish I could get out to shows and rendezvous' and handle guns and talk turkey with veteran builders etc etc, but life, wife, young kids, job sometimes takes precedence.
Rightly or wrongly, I count on this forum's exchange for much of my "continuing education".
Happy New Year to all!

 

[kanati]

(Just my opinion based on limited rifle building, but heavily on other experiences)

It is obvious that any surface heeling another surface at a right angle to the direction of force is going to be the optimum scenario. Angular surfaces will act as a wedge and could allow shifting over time. The more area contacting, results in less deflection of the wood that is in contact of the forces, and better lasting fit. Take the end cross section of the breech, subtract the area of the breech plug, and one can plainly see there is not much surface left to heel upon.

Again, just my opinion.

-Ron