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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 Here in picture #1 is the coupler stud hole drilled into the back of the rotary bolt. The picture is shot from the ...



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Old 07-30-2020, 06:36 AM   #31
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LC Smith Project--Modified Tooling for Drilling the Carrier Stud Hole

Hey all
Here in picture #1 is the coupler stud hole drilled into the back of the rotary bolt. The picture is shot from the relative downward angle following the hole. The coupler stem Picture #2 is a stepped stud consisting of a small turned forward section .125 (1/8) diameter by .156 (5/64) long, followed by another section .1875 (3/16) by .250 (1/4) long. The back of the coupler is a yoke slotted through for the top lever and mounted with a pivot screw so the coupler is free to move up and down a bit as it is swung through its arc by the top lever. Picture #3 is the coupier stem stepped hole viewed from the slotted side of the rotary bolt. The hole is angled into the off side of the slot with something less than about half of the hole diameter exposed. Because the hole is started on an angled surface, I think it best to drill it with a center drill, the best tool for this kind of cut. The very top section of the hole can be plunged with a 1/8 end mill first if starting on the angled side becomes problematic. The correct angle will be determined by calculation. The drill must pass through a "ghost point" .375 (3/8) above the bolt on dead center (this represents the the hinge point of the carrier) and then drilled into the bolt at .1250 (1/8) off center through the .250 (1/4) carrier stud relief counter bore. A #4 center drill should give us the correct diameter and length of hole to clear the first turned section of the carrier stud, but behind that size the center drill will need to be cylindrically ground to .1875 (3/16) to put in the second .1875 (3/16) diameter.

Okay we are planned and laid out about as well as we can be for our next few cuts, so we can proceed with finishing the bolt. First we will plunge the clearance counter bore, then calculate the angle, and drill the hole into the back side of the bolt through it. Then we will have the trigger plate welded up and dress it out, and then fit the plate to the receiver to gain our bottom bearing point for the top lever. At this point, finally, we can assemble the original locking assembly and test the fit all around with our new rotary bolt, trouble shoot any issues, and get it working exactly like the original.
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LC Smith Project Gun Starting From Scratch-dsc03471.jpg   LC Smith Project Gun Starting From Scratch-dsc03470.jpg   LC Smith Project Gun Starting From Scratch-dsc03336-1-.jpg  

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Old 08-03-2020, 10:32 PM   #32
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LC Smith Project--Plunging the Rotary Bolt Carrier Clearance Counterbore

Hey all
Monday morning I arrived early at work, and got on the project. First I clamped the new bolt in the vise with the notch facing forward against the movable jaw, Picture #1, then coaxial indicated the bolt to center and zeroed the DRO. A bit of calculation was in order. You will remember that last time we found the clearance counter bore to be out .093 in x and y. Working backwards, we know the sin and cosine of any 45 degree angle to be always equal, and we know the sin and cosine of 45 to be .707. There are a hundred and one ways to approach anything mathematically, but this time we can use a percentage to find our vector. So .093 is 70.7% of what number? 1/8 inch works out to .088, very close to what we found earlier, and this dimension fits with our other measurements. Our counter bore vector has a value of 1/8 inch at 45 degrees in x and y positive. We move the mill table to reflect (.088,.088) in positive x an y and carefully plunge the cut 1/8 inch deep. Picture#3. This cut extends through the .0625 web at the back of our bolt behind the notch. Picture #4. In Picture #5 we see the new and old (right side) bolts, and the stepped holes under the counter bore are at last visible in the original part. So far so good.

Next up, some more angles and math and to drill the last two holes. Probably we will forgo the center drill modification, set the bolt up in the vise jaws 45 degrees out in rotation, and also on the sin bar at the appropriate angle. Then plunge the last two holes on location with a 1/8 end mill, and a 3/16 end mill, respectively, which tools we have. . . .
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LC Smith Project Gun Starting From Scratch-dsc03509.jpg   LC Smith Project Gun Starting From Scratch-dsc03510.jpg   LC Smith Project Gun Starting From Scratch-dsc03511.jpg   LC Smith Project Gun Starting From Scratch-dsc03512.jpg   LC Smith Project Gun Starting From Scratch-dsc03513.jpg  

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Old 08-04-2020, 08:07 PM   #33
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LC Smith Project Preparing to Drill the Carrier Stud Holes in the Rotary Bolt

Hey All
Got on the project this AM per usual. Picture #1 is some Right Angle Trigonometry applied to finding the angle of the vector extending from the center of the carrier hinge out to the tip, and into the matching hole in the back of the rotary bolt. I arrived at 19.45 degrees. Picture #2 shows an approximate angle with the protractor of the direction the drill holes will take. Picture #3, more Trigonometry to find the correct length of block to place under one end of the sine bar to create a parallel that will hold the bolt in the milling machine vise tipped out at the correct 19.45 angle, Picture #4, milling the first side of our block, a scrap of 1 3/4 inch A36 Hot Rolled, then rotate it 180 degrees clockwise, and mill the second side, adjust and finish at 1.665, our calculated dimension.

continued next post. . . .
Attached Thumbnails
LC Smith Project Gun Starting From Scratch-dsc03514.jpg   LC Smith Project Gun Starting From Scratch-dsc03515.jpg   LC Smith Project Gun Starting From Scratch-dsc03516.jpg   LC Smith Project Gun Starting From Scratch-dsc03517-1-.jpg   LC Smith Project Gun Starting From Scratch-dsc03518-1-.jpg  


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Old 08-04-2020, 08:23 PM   #34
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LC Smith Project Preparing to Drill the Carrier Stud Holes in the Rotary Bolt part 2

Hey all

continued from last post. Picture #1 our sine bar in the vise with the 1.665 long block to give the angle 19.45 degrees to the rotary bolt, held left side against the sine bar fence. A pusher must be incorporated into the set up to clamp just the bolt, and not the sine bar before drilling commences, and a means to accurately index the bolt notch to 45 degrees must be thought up to give the correct compound angle. Picture #2 More Trigonometry to find the exact center of the bolt in this new tipped out position.

Next up--Let's drill 'em, but proceed carefully
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LC Smith Project Gun Starting From Scratch-dsc03519.jpg   LC Smith Project Gun Starting From Scratch-dsc03520.jpg  
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Old 08-08-2020, 07:49 AM   #35
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LC Smith Project--Drilling the Carrier Stud Holes in the Rotary Bolt cont.

Hey all
Friday morning I arrived at work early, the milling machine vise was on and ready to go. Things took a turn when I set up the sine bar to match my calculated angle. The angle was very obviously not steep enough. I got out our wire size drill index and began trying progressively larger shank diameters in the hole in the original bolt, starting with .125 (1/8). .140 (9/64 equiv) gave a very good fit Picture #1. As I mentioned before, there is a constantly changing relationship between the coupler stem and its matching seat as the rotary bolt is turned in the receiver, so this clearance of .0151 (1/64) between the stem and the seat allows for a bit of running room. Since the error in the angle was not steep enough, a new block had to be made to go under the sin bar Picture #2.. I made an educated guess and sized it to give an angle of 25 degrees, which I figured too steep. Then it was only a matter of milling the height block down a bit at a time. In picture #3 the angle is closely approaching 23 degrees, but as you can see we are still a bit out. I ran out of time and had to quit for the morning, but I am pretty sure now the angle will settle at 22 1/2 degrees, exactly half of a 45. That makes a bit of sense, the bolt being swung almost 90 degrees, making two 45 degree rotations, one on each side of center. Not where I figured it, but hey if it ain't broke don't fix it, and we do not want to reinvent the wheel. This bolt was in and working with the angle LC Smith built into it, so that is the precise angle we want to end up with.

Next up--correct the angle, check it again, and then on to the drilling.
Attached Thumbnails
LC Smith Project Gun Starting From Scratch-dsc03522.jpg   LC Smith Project Gun Starting From Scratch-dsc03523.jpg   LC Smith Project Gun Starting From Scratch-dsc03524.jpg  

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Old 08-12-2020, 05:56 AM   #36
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LC Smith Project--Corrected Angle for the Carrier Stem Hole

Hey All
I made a bit of progress this week. I clocked in a bit early Monday to get a local mint farmer's peppermint oil trying tank repaired, and clocked out a bit late Tuesday to help get the sawmill back up, again. I found time to correct the angle of the carrier stem holes, with only the drilling left to do. No one has asked me why exactly I am going to the trouble to build a new rotary bolt when I have a functioning one already. I found a couple pics online to post, and a picture is worth a thousand words.

Picture #1. This is an LC Smith with some miles on it. The fit between the trip and the cutout in the rotary bolt, I assume, is washed out a bit very similar to the one in my project. Look closely at the breech slot, that square member in the bottom is the trip. The rotary bolt is locked up on the trip as it should be, but the bolt is a held a bit out of rotation with the right side of the slot in the bolt extending out into the receiver slot. Some interference between the rib extension and the bolt will occur on closing.

Picture #2 This is another LC Smith that has an unworn trip, bolt assembly. The receiver slot is pretty much perfectly lined up, and the rib extension will drop through, push down the trip, and the bolt will engage, all without any rubbing or interference. This is the fit we want to see with the new bolt.

Picture #3 The angle for the drilled holes corrected to 22 1/2 degrees, right where LC Smith placed them.

Picture #4 The riser block, equal to the sin(22.5) times 5 or 1.913 inches, Picture #5 placed under the sine bar to give our angle, pictured outside the vise.

Next up, time willing, we can finally get the holes drilled in . . . .
Attached Thumbnails
LC Smith Project Gun Starting From Scratch-lc-smith-bad-bolt-fit.jpg   LC Smith Project Gun Starting From Scratch-lc-smith-good-bolt-fit.jpg   LC Smith Project Gun Starting From Scratch-dsc03528.jpg   LC Smith Project Gun Starting From Scratch-dsc03530.jpg   LC Smith Project Gun Starting From Scratch-dsc03529.jpg  


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Old 08-14-2020, 05:56 AM   #37
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LC Smith Project--Repairing and Fitting the Triggerplate

Hey all
I finished the last cuts on the rotary bolt, it is as far along now as it can be until the final fitting and assembly. Next up is to get the trigger plate fitted to the receiver, providing the bottom bearing surface for the top lever. Here in Picture #1 is the top lever parts group assembled with the original bolt, and in Picture #2 the same group assembled with the new bolt. In Picture # 3 the repair on the trigger plate is about to get started. This original trigger plate is plenty hard, I would guess upwards of 55 Rockwell. I was able to barely drill it with the high speed steel center drill, but it would not finish well. I stopped and did a bit of spot annealing with the torch and tried drilling it again, but not much improved. I next loaded a 3/16 (.1875) carbide end mill and spotted the hole, removing all rusted material down to bare metal, Picture #4. A 1018 cold rolled steel pin was then turned to size, both surfaces degreased, and pressed into the hole Picture #5. The assembly then went to the TIG bench. This brings up a question I did not think to ask before. I have read a great deal about the case color hardening process, but I have never carried it out. What I have read has always involved treating new soft finished and polished parts. I wonder if the same process is applied directly to parts already casehardened, or if they need to be annealed first? This seems to be another valid question for the Practical Machinist Forum. A proper anneal would certainly make the fitting up of the plate much easier to carry out.

. . . . next up, dress the weld and fit up the plate to the receiver
Attached Thumbnails
LC Smith Project Gun Starting From Scratch-dsc03531.jpg   LC Smith Project Gun Starting From Scratch-dsc03532.jpg   LC Smith Project Gun Starting From Scratch-dsc03533.jpg   LC Smith Project Gun Starting From Scratch-dsc03534.jpg   LC Smith Project Gun Starting From Scratch-dsc03535.jpg  

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Old 08-16-2020, 10:48 AM   #38
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Project--Weekend update

Hey All
Sunday AM and I am taking a break from all this strenuous LC Smith building activity. I ordered some parts to go into the project, shipping during this Covid 19 epidemic can be pokey, so I thought I better get a jump on things.
First up, I am about ready for the top snap spring. I fully intend to build some v springs for various projects, but this is not a good one to start with. Even experienced spring guys voice difficulties getting this one out with enough tension to do the job. Also I am short a mainspring in my right hand lock. I opted to order new made ones from Numrich. They ran about $16 each plus tax and ship got them up around $21-22 per. In the interest of those who may come after me, I will evaluate these new made springs from Numrich. As the time arrives I will fit them, test them, and report back on them my opinions of them both good and bad. I do not know where the professional restorers of these guns get their springs, or if these Numrich ones are considered top notch. Personally, other than for my own use, I am not going to lay in some AISI 1095 spring steel, make a spring, finish and temper it for any $21 each and that is for certain.

I also bought a Lewis patent ejector for end metal. It is not for an LC Smith, of that I am sure to about 9 decimal places. All the various parts and pieces look to be intact though. This gives me an opportunity for a hands on look at the proper ejector system. Once I understand it I can set about working up a copy with correct dimensions to work with the LC Smith. When I have figured out exactly what it fits after I have copied it, I can always set it right later, list it for the correct shotgun, and resell it. I expect this ejector project to be the other part of the build that will rival the rotary bolt for sheer orneryness, perhaps even exceed it. Before I can tackle the monoblock, I have to know where I am going with the ejectors in order for everything to work together. For now though I need only concentrate on getting the top snap assembly properly sprung and working smoothy. Then I can make and fit the buttstock some sixteenth of an inch or so larger all around, to provide a handle to assist with jointing the monoblock/barrel assembly.

I do love getting stuff in the mail. I am like a kid at Christmas waiting on parts. This is just some of the fun stuff that comes with a build.

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Old 08-19-2020, 06:12 AM   #39
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LC Cmith Project--TIG Repair of the Triggerplate

Hey all
We addressed the TIG welding of the triggerplate yesterday morning. I got back some responses to my case coloring questions on the Practical Machinist Forum. The process involves heating the parts inside a carburizing box to critical temperature, so any annealing needed is built in. Also it does no harm to anneal a part to repair it before the process takes place. That being said we went ahead and took the trigger plate up to a bright orange color with the torch, and stuck it in the lime box to cool it slowly as possible. Then the welding was done on the annealed part. It is now much softer and easier to work, A lesson was learned. We stayed just a tad too long with the torch on the very thin web around the hole at the top of the safety block, and we burned a bit of material away. If you would attempt to anneal such small parts with a torch, I think better to place them on a small scrap of metal plate and run the torch on the plate instead to bring them up to heat. In Pictures #1 and #2 the kid has placed a bit of TIG weld around the hole to build up and replace the metal we burned away. Pictures #3 and #4 show two views of the mild steel plug welded into the drilled hole. After dressing out this weld, I wound up with a very small surface void. Picture #5. It would not show, the exposed side of the trigger plate cleaned up very well indeed, but we will put a tiny spot of weld there this morning to fix the void. The goal, of course, is to wind up with a part that you cannot tell was repaired but you do have to stay with them awhile till you get there.

Next up touch up weld, dress the welds out, and begin the fitting up of the trigger plate. . .
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LC Smith Project Gun Starting From Scratch-dsc03539.jpg   LC Smith Project Gun Starting From Scratch-dsc03538.jpg   LC Smith Project Gun Starting From Scratch-dsc03537.jpg   LC Smith Project Gun Starting From Scratch-dsc03536.jpg   LC Smith Project Gun Starting From Scratch-dsc03540.jpg  

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Old 08-23-2020, 01:31 AM   #40
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LC Smith Project--Weekend Post--Ejector Plans and Such

Hey All
The welder kid at work has been out on the portables all week, I've been busy trying to drill and fit parts for him for assemblies I don't get to see. There was no chance to touch up the TIG welds on the LC trigger plate at any rate. I did get soft hardware screws fitted up properly to the LC frame to hold everything in place during the process, but I cannot go forward with assembly until the trigger plate welds are touched up to my satisfaction.

The mail lady showed up right on time Saturday with my ejector fore end metal though, so this evening I spent measuring, checking and seeing what I can come up with for an ejector assembly. I was not sure what I was looking at exactly in the pictures of the fore end iron, I was leaning heavily toward an Ithaca or perhaps a Fox ejector grade. I got a very pleasant surprise, once I got it in my hands. It is a late Syracuse Arms iron for an ejector 12 gauge patented by one George A. Horne in Oct 1896. Missing is the fore end catch, and the external mechanism for turning the ejectors off and on, a nice touch unique to Mr. Horne although Uncle Dan LeFever had his version of the same. The part is in the white, and appears unused. The high serial number may indicate it was an inventory part left over from the sale of the company in 1905 and the not too distant subsequent closure.

The only Syracuse shotgun I have on hand is a damascus 10 bore Hollenbeck gun, very early Syracuse serial 3xxx.

In Picture # 1 is the 12 gauge LC Featherweight on the left, and the 10 gauge Hollenbeck on the right. Notice the size difference!

Picture #2 shows the real difference between the two guns, as far as ejector mechanisms go. The LC uses a separate hinged part in the fore end iron to activate the extractors, and the Hollenbeck uses the solid round pin dead center in front to activate them. This Hollenbeck is an extractor gun, picture #3 shows the difference between the for end irons, the extractor metal on the left, the ejector on the right. The ejector frame would have hammer links installed in holes drilled front to back through the frame so the fired hammer would push a stem out into the hinge joint and into the for end iron cutout(s) to activate the ejector sear(s) of the fired barrel(s) only. Picture #4 are the sears that hold and release the ejector strikers Picture #5. Notice the space between the strikers, this is where a thinned version of the solid pin from Picture #2 protrudes between them to extract and lift the shell(s) in the unfired barrel.

These early ejector systems have their faults. Probably the worst feature is that the ejectors are "cocked" by the standing breech pressing the ejector\extractors into their seats as the gun is closed. This limits travel of the extracting mechanism to not really enough, and makes the shotgun harder to close.

Here is my preliminary plan, subject to many refinements. I would space the ejectors in my mono block to approximately match either side of the LC barrel lug. This gets each of them working in its own hole, like a modern over/under rather than using a split extractor system. Dragging against one another is inevitable in the split system. I would utilize the crank lever cocking arrangement of the LC system to cock the ejectors, possibly by riding down an integral angled surface on the ejector strikers during the crank lever's swinging travel. Lastly, I would use some form of a projection activated by a crank lever in the fired position to trip the sear of the ejector of the fired barrel only, something George O. Lewis already worked out on the somewhat later LC ejector guns. The hinged extractor activation lever in the LC for end iron would be retained, but made t-shaped to bridge the ends of the wider spaced extractor stems. I'll be tinkering, and thinking this out til such time comes to begin construction of the monoblock, perhaps mocking up a mild steel model or two.
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LC Smith Project Gun Starting From Scratch-dsc03544.jpg   LC Smith Project Gun Starting From Scratch-dsc03546.jpg   LC Smith Project Gun Starting From Scratch-dsc03548.jpg   LC Smith Project Gun Starting From Scratch-dsc03549.jpg   LC Smith Project Gun Starting From Scratch-dsc03551.jpg  


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