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LC Smith Project Gun Starting From Scratch

This is a discussion on LC Smith Project Gun Starting From Scratch within the High-End and Specialty Shotguns forums, part of the Shotgun Forum Discussions category; Hey All I once again set up my trusty sine bar and got out the 15 degree cut on the side of the trip that ...



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Old 11-08-2020, 11:29 AM   #61
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LC Smith Build--Two Cuts Done on the Trip, One More to Go

Hey All
I once again set up my trusty sine bar and got out the 15 degree cut on the side of the trip that engages the matching slot in the rotary bolt. I proceeded carefully, I wanted a tad more metal left to engage the slot, and for the trip to not quite be bottomed in the slot under spring tension to provide a bit of self tightening adjustment as the new trip and bolt wear in.

The sine of 15 degrees multiplied times the 5 inch center to center of the bar gives our side opposite, or the length of the riser block to get 15 degrees. This worked out to 1.294 inches, a size we could get with slide adjustable parallels we had on hand Picture #1.

The parallel tightened and placed under one end of the sin bar Picture #2--Yes there really is not an end to these neat toys you can buy for a machine shop.

Picture #3 the trip mounted in the vise at precisely 15 degree and Picture #4 the cut is completed, just ever so slightly shallower than the cut in the original trip. We should be very, very close to the ideal, but nothing positive; the fat lady don't sing til we get the parts fitted up.

Picture #5--The third and final cut to be made on the trip before it is sawed off from the extra stock and the finished length brought in. The surface opposed 180 degrees to the 15 degree cut has a draft cut in to it, presumably to clear the relieved area in the front of the rotary bolt just enough to allow the bolt to turn to bottom dead center. This draft measures .020 bigger at the flat end of the trip than it does at the end of the cut 7/16 down on the shaft. Right angle trigonometry gives an angle 2.62 degrees which in turn gives a side opposite/block for our sine bar of .228. I milled this block from a scrap of A36 1/4 inch flat stock on Friday, so next up Monday morning we will get this last cut set up in the mill and done.
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LC Smith Project Gun Starting From Scratch-dsc03681.jpg   LC Smith Project Gun Starting From Scratch-dsc03677.jpg   LC Smith Project Gun Starting From Scratch-dsc03678.jpg   LC Smith Project Gun Starting From Scratch-dsc03679.jpg   LC Smith Project Gun Starting From Scratch-dsc03680.jpg  


Last edited by 4575wcf; 11-08-2020 at 12:13 PM.
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Old 11-09-2020, 10:22 PM   #62
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LC Smiith Build--Third and Final Cut on the Trip Completed

Hey all
The Missus and I wound up taking a road trip to South Center of the state late Sunday night. A Maytag wringer washing machine (remember those?) came up for sale and we drove the missus's pickup down and purchased it for washing the shop towels. At any rate I was late getting in, but still made it up by 4:00AM and got off to work early Monday to get my "shotgun" hour in.

I got a jump on the cut last Friday this time, getting the sine block for the angled cut out, so I was able to get right to work. Picture #1 the .228 thick block under the off side of the sine bar to tilt our workpiece down Picture #2 at the appropriate 2.62 degree angle this time.

Picture #3--the cut is made, about .020 deep at the front end and drafting down to about .04 deep at 7/16 distance down the on the shaft.

That should wrap building the trip. I did wind up facing the flattened tip and moving the .240 flat down on the shank till I got into thick enough material at the 15 degree notched section to get the fit that I wanted in the notch in the rotary bolt. I had built the part a bit long in the eventuality of that necessity, so then it was only a matter of moving this drafted cut down on the shank the same amount.

I am happy with the final fit I achieved between the bolt and trip, and I was able to get through all the adjusting of the cuts in the hour I had available.
All has ended well so far.

Next up I will cut the finished trip free from the extra stock, finish the length and try it and its new spring in the blind hole provided for it--dead front bottom center under the rotary bolt in the frame.
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LC Smith Project Gun Starting From Scratch-dsc03690.jpg   LC Smith Project Gun Starting From Scratch-dsc03691.jpg   LC Smith Project Gun Starting From Scratch-dsc03692.jpg  

Last edited by 4575wcf; 11-09-2020 at 10:27 PM.
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Old 11-11-2020, 06:32 AM   #63
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LC Build--New Trip Finished and Preliminary Installed

Hey All
I sawed the new trip loose from the extra stock, and milled the sawed end to finished length of 17/32". Picture #1--The old and the new.

Rusti was obtained with the trip depressed into its seat, and very firmly rusted in place. This is the original trip spring which came out rusted in the closed position, and the new trip spring. Picture #2. I got the new spring right off the shelf at Ace Hardware. The diameter and tension seems about right, the original spring consists of 8 coils at about .028 diameter each, at least as closely as I can measure the remnants. The Hardware store version is plated, which, given the working environment, is not a bad thing. I merely clipped it to length, and closed up the shortened end with a bit of judicial bending.

When I arrived at home Tuesday evening, I assembled the new locking components all together for the first time. The trip and its spring went into the blind hole under the bolt, the trip depressed on its spring and the bolt slid into place in its pocket, then the coupler pin inserted into the hole in the back of the bolt, then the top lever put in from the top through the slotted coupler and captured at bottom by the bearing surface and screw in the trigger plate.

Picture #3--Front view, with the bolt locked up on the trip notch. Alignment is all I could ask for the bolt is held with the locking tooth about .03 from the side of the slot, providing clearance for the rib extension.

Picture #4--Front view, with the trip depressed and the bolt rotated into the locked position. The parts are not sliding smoothly at this point, but they are sliding!

The tip of the coupler is about .020 long, so the coupler screw won't quite slip through, Picture #5, but the assembly is close enough to begin working as it should. Let the fitting begin!
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LC Smith Project Gun Starting From Scratch-dsc03693.jpg   LC Smith Project Gun Starting From Scratch-dsc03695.jpg   LC Smith Project Gun Starting From Scratch-dsc03696.jpg   LC Smith Project Gun Starting From Scratch-dsc03697.jpg   LC Smith Project Gun Starting From Scratch-dsc03699.jpg  

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Old 11-17-2020, 06:27 AM   #64
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LC Smith Build--Some Fitting Accomplished on the Internals

Hey All
I have made two minute cuts on the end of the new coupler, shortening it first by about .02, and then again by about .015 more. Binding at the end of the coupler tip in the bottom of its hole has been corrected. Picture #1.

I placed the original beat up trip back in its hole with the new trip spring and a bit of lapping compound, and proceeded to work it up and down against the spring. There was some roughness and burrs in and around the top edge of the hole, and the trip travel was smoothed considerably.

Here is my 'schematic" so far with all the working parts laid out in position Picture #2.

The short leg of the new top lever spring latches into the radiused area at the top rear of the frame cutout in the picture when pushed into place from the back of the frame. The long leg bears just ever so slightly short on the top lever lug when the assembly is in place with the spring. Logic would indicate that a slight amount of material removed from the front edge of the short leg should cause the spring to move back and out of the recess a little, lengthening the engagement area. I only need something on the order of 1/32 to 1/16 movement to arrive at maximum engagement between the two parts.

Picture #3--Here is pictured the famous LC Smith reassembly issue that gets all the press. The spring loaded top lever must be pushed inboard under full tension in order to align the bottom bearing stud with its matching hole in the trigger plate. With the stock installed, the parts are not accessible. This encourages some LC Smith owners to drill a hole in their incredibly expensive wood and insert a bent coat hanger wire into the gap between the long leg of the spring and the side of the frame cutout. Blocking the spring's travel in this fashion, and subsequently unloading the spring pressure then makes it easy to assemble the top snap bearing and trigger plate with the wood on, then the wire is withdrawn out the hole. Original LC Smith wood has no such hole, and if the maker intended the assembly to be installed in that fashion they would most certainly have provided one. Alternately, a very short strong and tight fitting punch is inserted through the trigger plate and into the #4-40 hole in the end of the top lever. Side pressure is provided by a pushing device, preferably a wooden non marking one, acting on the punch. Properly vising the gun upside down helps immensely. When done without the vise probably the best way is to press the punch over with a longer wooden stick using your stomach, freeing your hands to snap the trigger plate into place over the bearing stud at the bottom of the top lever. The punch needs to be very close to the tap drill diameter of the #4-40 hole, extend full length into said hole, and handled carefully to prevent damage to the threads. Some would use a long #4-40 screw in lieu of the punch, but threads are really just cracks already in place in a side loading application of this sort, so the screw is much more likely to break off in the threaded hole under side pressure than is the smooth punch.
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LC Smith Project Gun Starting From Scratch-dsc03700.jpg   LC Smith Project Gun Starting From Scratch-dsc03701.jpg   LC Smith Project Gun Starting From Scratch-dsc03702.jpg  

Last edited by 4575wcf; 11-19-2020 at 01:10 AM.
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Old 11-20-2020, 06:33 AM   #65
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LC Smith Build--Continued Fitting of the Internals

Hey All
I have tested my theory of working down the short leg of the new top lever spring to extend it out of its cutout a little, and this seems to be the correct method to fit this part. Also, there is a small area where the radius of the top lever spring cutout designed to catch the short spring end, at least on my shotgun, where the cut has extended completely through the wall of the frame and into the left cocking lifter recess. i found when the short spring end was correctly shaped to completely fill this small resulting slot, visible in the cutout for the left lifter, the spring was then correctly fitted to the top lever stud. See Picture #1.

Scrounging around in our miscellaneous punch drawer here at work, I stumbled upon this rather large combination bent and straight pick that has been broken off at both ends at some time, and the ends pointed up as a regular short scriber would be. See Picture #2. I tried it in the threaded hole in the end of the top lever, and found it would go in nearly full depth and that it fit the hole rather nicely. LC Smith has obviously provided some extra drilled length into this small tapped hole to accept a longer punch as an aid to the assembly of the trigger plate. See Picture #3. The frame is vised upside down, the pick is inserted through the trigger plate into the top lever bottom screw hole, and the sprung top lever is then easily pried over to align the bearing stud with the matching hole in the trigger plate. This shortened pick tool, I think, will be my new to me LC Smith trigger plate assembly tool.

The new rotary bolt is still binding a little in its rotation, enough to overcome the power of the top lever spring and stall on occasion. I drew a small line front to back on the rotary bolt with a black sharpie, worked the top lever a couple of times, and a bright rub spot appeared on the front radius of the rotary bolt. See Picture #4. This is a pretty common problem that you run into, mostly when fitting bearings up to shafts, when the radius at the fit point of the bearing is greater than the radius on the bearing, and the bearing rides on the radius rather than seating flatly as it should. I will pull the bolt, radius the ends a bit more, perhaps .015 R each, and once the bolt front corner radius exceeds the radius in the bottom of the matching pocket that should be the end of the interference and rubbing.

The next issue is that the trip is not reliably employing completely into its detent in the rotary bolt when the top snap is opened every time. A bit of material needs to be removed somewhere from the trip to stop it from occasionally hanging up. I will blue up the various parts, assemble them, and see if I can spot a small surface that is hanging up in the trip/notch fitment.
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LC Smith Project Gun Starting From Scratch-dsc03712.jpg   LC Smith Project Gun Starting From Scratch-dsc03708.jpg   LC Smith Project Gun Starting From Scratch-dsc03707.jpg   LC Smith Project Gun Starting From Scratch-dsc03710.jpg  

Last edited by 4575wcf; 11-21-2020 at 05:52 AM.
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Old 11-21-2020, 06:55 AM   #66
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LC Smith Build--The Culprits

Hey All
A very close examination between the old and new rotary bolts with the high powered visage head gear that we machinists occasionally wear under crummy light conditions takes place, and the two main bad actors in the rotary bolt assembly are revealed. In building the new rotary bolt, I had left off the rather heavy chamfer on the outside edge of the lug remaining when the front clearance for the trip had been machined. Also a closer look reveals that this lug has a minor dovetailed undercut of about 60 degrees to accept the sharp side of the flattened end of the trip, allowing the bolt to rotate a little further and fully engage the trip and trip notch.

A bit of judicious needle filing in the dovetailed area, and flat filing on the outside chamfer and we have duplicated the original bolt profile closely, and our fits are improving steadily.

I think the rotary bolting assembly as it is fits now will wear in, it is about at the point where you would expect a brand new shotgun to be prior to the smoothing that takes place in the first hundred rounds or so.

By the time I get the rib extension of the wooden try barrels slotted and engaging the bolt, and then the actual monobloc engaging as well I think the mechanism will be sliding and locking like an LC Smith shotgun should.
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Old 11-24-2020, 06:29 AM   #67
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LC Smith Build--Getting Out the First Pillar Block

Hey All
The tangs of the LC Smith seem to have settled into their happy place with the locking assembly installed. The locks, triggers and safety mechanism appear to have enough running room all around for everything to fit properly. At this point the assembly goes together much like a muzzle-loading rifle does, and a fellow develops something of an "eye" for these details, having worked on and built a few of those. It is time to lock the tangs up in position, where they will remain for the service life of the shotgun.

The pillar block(s) when finished, will extend between the top tang and the trigger plate with the tang screws through them. Both tangs will bottom on them when tightened, so the parts fitted with the stock off will remain in the same exact position when the stock is on.

Because capillary action will invariable suck atmospheric moisture into any crevasse, the pillow blocks will be made of non corrosive stainless steel to prevent any future rusting between the screws and the pillar blocks.

First a measurement is taken between the tangs where the front screw will extend through from the top tang under the top snap into the trigger mounting block. .960" will give a snug fit. Picture #1.

The 3/8 stainless hex hardware screw. Picture #2.

The screw is chucked up and the head center drilled in the lathe. Picture #3

A #9 drill (.193) drill is selected to give a few thousandths clearance over the #10-32 (.188) tang screw. Picture #4

The hex screw is drilled ! inch deep plus the thickness of the head to get a long enough shank length for the pillar block. Picture #5

To be continued. . .
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LC Smith Project Gun Starting From Scratch-dsc03714.jpg   LC Smith Project Gun Starting From Scratch-dsc03715.jpg   LC Smith Project Gun Starting From Scratch-dsc03716.jpg   LC Smith Project Gun Starting From Scratch-dsc03717.jpg   LC Smith Project Gun Starting From Scratch-dsc03719.jpg  

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