Hopkins & Allen?

Davenport?

Bill Lawrence

Bill, nope.

Bob,
Nice job of graying out the name on the block and hammer.  Anxious to see the progress of your build.

For others, here is a pic of the patent drawing.  I have a kit from Rodney that I'd like to modify the workings to resemble this design.

Greg

Bob, where’d you find it. What makes it a project?

rkba2nd, thank you for the kind words.

rifleman, the gun shown, is not the project.  This gun is one, of only two  known guns in this configuration.

The current owner has graciously allowed me to study the features of this action. With this information, and the patent drawings, I should be able to build one.  Greg (gt), his son and I will be working through the issues in machining the parts, especially in a tough spot inside the frame.  Luckily, and I just found out today, those two have been studying and discussing how to machine this area.  So, yes, all the parts will need drawings and then will be machined from solid 8620 steel stock.  Once I know the action will function with a barrel, and test fired, it will get wood added from blanks of English walnut.
Hope this helps to clarify what I am doing.
Bob

Rights side view.

Again, note the screws.  And, of course, the levers are the big thing here.  The standard Hepburn has the side lever to lower the Breech block.  The others use the lower finger lever.

Bob

Bob, now I understand….it will be exciting to see your progress. Thanks for clarifying.

Bob, I'm sure that your action will be a masterpiece and you may also then know why the Hepburn/Walker Hepburns ended up the way they did instead of like the Patent;-)

As I said earlier there are only 2 known guns of this style.  First one Tom Rowe calls a Short Range Creedmoor in the Hepburn Book.  The other is a military style gun.  The one I am basing this gun on is the Military gun.  Looking at the different parts in this gun compared to the Creedmore, and the patent drawings, this gun is probably the more advanced.  The Breech Blocks and trigger frames are different designs. 

Here are a couple pictures of this guns trigger frame.  I have arrows pointing to a piece of steel dovetailed into the base frame and then pinned into place from the top.  This dovetailing is done on both side of the frame and I believe it was done to modify an existing frame in order to add the bump, and valley in front of the bump.  It appears this valley is the bearing surface for a mating radius on the breech block that captures the breech block.  The breech block rotate after lowering enough to clear the square thrust shoulders of the Breech Block and contacting this valley.  These picture help to understand this.

Because I am just getting started, this is all casual observations at this point and I will correct it later if I find out this works differently than I believe at this point.
Bob

steel-pounder, if I understand what you are asking, you are referring to the lower case “a” rail in the breech block, shown in the patent drawing.  If so, I believe what you are saying is correct.

Neither of the two actual examples have that rail.  The Short range version has a cam that appears to be activated by the lever and the cam then tips the breech block.  The military version has this valley and bump that the breech block drops into and is then tipped by the link and the finger lever is opened.  This is hard to see when the parts are installed in the frame, but am fairly certain I am correct on this.  I will understand more as I get deeper into my drawing, seeing dimensions and understand what is going on inside this action.
Bob

Ya, this could get really confusing looking at the different configurations.

On the surface, this version appears to be the most simple and robust. Being a military version, I believe, is the reason for this.  So it is what I am concentrating on, but we will see.  I just about have the first drawing done.  It’s a side view of the frame and hole locations.
Bob

Yes, bobw! Interesting machining challenge cutting that "red arrow" internal radius - on both sides of the internal receiver.

Thanks for sharing... Looking forward to seeing more  

Jeff P

Amoretti wrote on Oct 29^th, 2024 at 5:23pm:


Actually 3.

steel-pounder wrote on Oct 29^th, 2024 at 7:47pm:


Yes, it’s the track for the breech block.  The issue is, the barrel receiving block of the frame is in the way of any normal cutter.

The other 2 can be machined using conventional methods, there’s plenty of room.

An updated picture pointing out all 3 tracks.
Bob

steel-pounder wrote on Oct 29^th, 2024 at 8:57pm:


If I understood Greg correctly, this is exactly what they came up with.  In the original frame it looks to be just enough clearance to complete the arc and miss the barrel section of the frame.  It will need to be a long end mill.  Not sure how large will work but my guess it will need to be small, 1/4 but hopefully 3/8.
Bob

"Question Bob, I think I understand what you are purposing but to clarify for me, are you saying the centerline of the long endmill would be perpendicular to the radius you are cutting? And that same centerline would pass through the axis of rotation of the rotary table? Or the edge of the cutter would be a lined with the axis and perpendicular to the radius?"

We haven't had time to dabble in this yet, but thoughts are that it will be lining up with the center of the cutter, and initially the thoughts are a larger diameter tool so the dish is less pronounced  = less file, gage and blueing work... The hangup will be what diameter tool fits between the cut we have to make and the rest of the action.  Without working a percentage of the radius of the tool in to our offset, it will be a sneak up to finish dimensions.  We'll model it in our software so we have a close idea - probably closer than we'd be able to measure...

Bob,
I'm not going to dovetail the lower lumps into my bottom metal, I had to weld some portions of the bottom metal already so now I'm making lumps and front lugs to weld into the casting before I machine it...  I'm also adding a lump to the rear of the bottom metal so the spring has less arc in its design and clears triggers a little easier.
G

Lynn, you brought up a good question.  I didn’t respond because Greg has a better handle on the answer than I do.  After all, I’m not an Engineering or machinist, just a knot-head hobbyist trying to figure this stuff out.

Thinking out loud about this radius, and I’m not trying to minimize it’s importance, but here’s my take on the operation of the breech block.  On opening, the bb drops until it clears the front nose of this radius.  At that point it can start tipping but really nothing forces it to tip until it hits the valley in the trigger guard.  At that point it is force to tip.  This being said, the link has a ledge that engages the bottom of the bb so it can’t try to straighten back up, it will also follow the bb as the lever is opened.  See the disassembled picture, this picture shows the configuration of how it came apart.  So on opening, this radius does very little, other than not letting the bb tip too far.

On closing, when the finger lever is moved to closing, the bb comes free from the trigger guard and raises until it contacts our radius which then forces it to start the closing operation.  Looking at my drawing you will see the front nose of this radius is just below the bore centerline.  So as the bb closes, and a shell is in the chamber, the bb will come up hard into this radius and cam a tight shell into the chamber.  Once past the radius nose the bb can raise and close completely.   

This may seem simple, and if I’m correct, also shows the importance of the radius is in the last stage of closing only and only a loose guide for the rest of the operation.

Please correct me if I’m off on these assumptions.
Bob

Bob, 
from our modeling, you are correct.  There's not much to do with this arc, but some form of it has to exist to get things started.  A slight curve in the arc face from a mill has little effect except for the wear factor.   If parts are hardened correctly, it's mute - serves as a lube and crud reservoir. 
Yes, to mass produce these the effort would have been a considerable expense, even adding the lever feature to the Hepburn was an expense outside of normal production, probably the reason only 24 were made...    ( I know there's 23 listed) plus a few patent models like this one...
One of the curious features that has my mind wandering astray is including a curved transfer bar in the breech block... Have the sketch muddled through.  Not enough hours in a day...
G

Amoretti wrote on Oct 31^st, 2024 at 1:52pm:

From the drawing, the top of the ramps form the recoil lug shoulders for the BB when firing the rifle. I would think not and still keep with the concept of a reproduction of the original.

LRF wrote on Oct 31^st, 2024 at 2:02pm:


Lynn is correct on the lug shoulders.  Before I went that route I would probably check out EDM.
Bob

Greg,
One of my hand drawing of this breech block.  (By the way, I think of my drawing being equal to your stock work)     

Another steep 25 degree firing pin. 

Maybe this will help with your transfer bar thinking.
Bob

steel-pounder wrote on Oct 31^st, 2024 at 7:10pm:


I agree with what you say about the pictured version.  I expected to see this in the gun I am working with, but was pleasantly surprised with what I found when it was disassembled.
Bob

rodneys wrote on Oct 31^st, 2024 at 10:03pm:


Rodney, that’s an interest solution, but my initial thought is that it wouldn’t work.  I believe a straight taper would interfere with the rotation of the breech block, especially at the top.
Bob

Wasn’t sure how I was going to measuring all the humps and valleys of the trigger guard.  This is what I decided to try.  Might be considered a little bit farmerizing!   Very close vertically, not super accurate on the horizontal, but should be close enough.  I figure ( + or - ) around .005, but even that’s a moving target depending on what is being measured.
Bob

Bob, I did not mean to sound like I was telling you what to do I was just brainstorming. I’m going to try it if nothing else will get most of the material out of the way, and then I can hand chisel the radius in. That is what Farrow did, according to the receivers that I have examined when I was making molds  of them. I watched a video years ago of a fellow from England that was building Gibbs muzzleloaders from scratch. He chiseled out the Rigby Flats, the snail around a percussion nipple. He was using high speed, steel inserted into a steel handle. You sharpen it with a small flat on the bottom like an engraving tool. So you can control the depth of cut and use just a little bit of cutting oil. It’s amazing how much you can do with it. Just have to keep it sharp.

I will dig out my chisels and take a picture of them and also how they can Cut. We have the Tulsa show coming up this weekend. I’m not setting up but I will go up for a day. Bruce has something he wants to show me. Anyway, I hope you can make it out one day and if you do plan to stop by I’m just a couple miles off I-40 just east of OKC.

Rodney,  Thanks, always wondered how Farrow make that cut. Now, back to Bob's most interesting discussion.
Chuck

Thanks for sharing those chisel picts Rodney... been meaning to make some up. Got a few 8% Co HSS bits... was just wondering what's a good length to make the handles? Looks like you might have one silver soldered in place?
Looks like something that the MagnaGraverII I recently picked up might help with?
Cheers!
Jeff P

Jeff the handles are 4 to 5” long I drill a hole in the handle, slightly bigger than the flats on the tool and grind the corners off the tool tapering to the end and drive it on seems to work pretty good. Use mild or leaded steel. I use a medium ball peen hammer and just tap, tap, tap. And practice.
Bob I think you are correct about making a special tool to do the complete radius. I have a idea I will see if I can get it built and try it out and post.

here you guys are talking about chiseling out arcs in the reciever with a look to function. C'mon, I can't even figure out how to scratch the lines in there, far less remove unneeded material. 
Y'all are on a plane far above me. And I really enjoy seeing all this. Thanks.

Bob very clever idea of using a hardened guide. Why did I not think of it. L O L yes and I think I do need to shorten up the heel  the last part of the radius what is giving me trouble. What I did there was one eight inch deep.

ssdave wrote on Nov 5^th, 2024 at 10:47pm:


Dave, you are right about this radius if it was out where access was easy.  And I believe a mill may still work, using a rotary table and a long end mill, to at least rough out the arc.   

Here’s a refresher on the radius and where it is, along with the obstacles.

The front radius, marked in red, is where the problem is.  The portion of the frame that the barrel threads into is an obstacle to full access, also in red in both pictures.
Bob

Bob, I believe you could make a cutter that the depth of cut can be done with the knee of your mill. To simulate I made a 3d model using your drawing for dimensions. The tool is a scraper cutter that pivots and is feed down into the action body by raising the knee. You would put a long handle on the cutter so you could pivot it. The arc appears to be about 61 degrees. Here are a couple pics and a short video if it works.

Also, of course the views are section views. The cutter would span the whole width and actually I think it could be built to use carbide inserts as the scraper blade.

Now when reviewing my concept you need to keep in mind that the original's were started as net shape forging and this cutter would only be finishing the the radius surfaces.

Bob if you agree this cutter/scraper would work then in my opinion you can show how Remington did the job, so now go ahead and EDM those surfaces and get on with the build. You get to choose.....and we are waiting to see the results of your craftsmanship.

bobw wrote on Nov 6^th, 2024 at 12:06pm:


Bob, if youre using modern methods for machining why not a sinker edm with the arcs cut into the carbon blocks?

LRF wrote on Nov 6^th, 2024 at 1:20pm:



Yes, got it Lynn.  Haven’t had a chance to look at it yet. Thanks

bobw wrote on Nov 6^th, 2024 at 4:09pm:


Lynn, I have now looked at the video and there’s a probability that this is what I will try if, like you say, I can get it roughed out first.

Thanks to you, and everyone, that have, and will, comment on this project.  I have 4 screws and a lever spring to get on paper yet….then the interesting stuff can start happening.
Bob

LRF, I really like that cutter! Would you make it just for that diameter cut? I would! It could be used to cut both sides with a little dinking!

AJ now that is using your thinking ability.I will have to try that.

From the bottom angle picture, the internal radius pieces almost look like they are made separately from the action housing and then installed…..

Tom Klinger

LRF wrote on Nov 6^th, 2024 at 10:50pm:


Thanks Lynn but the modeling won’t do me much good, I don’t have CAD software.  Wouldn’t mind learning it but have tried online programs and find the process really boring.  I would do much better, at least in getting the basics, in a physical classroom setting.   

Nothing around here that has this training though.  Been a few years since I tried online so maybe I should give it another chance.   

Anyone have a good experience/advice online and can recommend a software brand?
Bob

LRF wrote on Nov 7^th, 2024 at 5:56am:


I think the key to using this method is removing the bulk of the metal using a different method.  Lynn, you had also mentioned this earlier.   

I do like the rotary table thinking, even though it would be very tedious.  I would be using the rotary table, with an end mill, to remove the excess metal so the frame would already be on the table.  I think the biggest challenge using the table will be clearance past the table for the mill ram and still keeping everything rigid. 

As far as setup goes, my thoughts are to doing this against the outside of the frame and then moving it to the inside.  I don’t think it would be to tough this way once once the numbers are found.

Funny, though these conversations, how thinking has changes in how to do this.
Bob

I have used carbide inserts for broaching with a mill.  Warning: retract the cutter away from the work before backing it up or it will chip badly.  Other than that, they work great.

Hi Bob,I’ve been following this thread and it sure is a head scratcher. I like the idea for doing everything ‘in house’ but this is one scenario that might be best served by going outside and have it EDM’ed, no harm no foul. If you want to try it yourself AJ and LRF with there carbide insert using the vertical RT I think may be your best bet. Light cuts with a positive rake carbide insert with AJ’s warning may just do the job and leave a nice finish. I’m sure you will set up some ‘proof of concept’ parts first. What ever way you go I’m sure it will be first class work.
Cheers Richard

There must be days when you just sit back and smile. Thanks for including us.

Looking forward to this build journey Bob!
Jeff P

I spend lots of time checking and double checking my numbers, and thinking through the steps to machine a frame like this.  So for now I am just opening up the frame to within around .015 per edge of the final size of all the openings.  When fully opened up it will then be similar to machining a casting set to get to the final finish to size. 

In these two pictures I am machine very deep into the steel blank in order to get below some of the features inside the final frame.  I first drilled 1/4 inch holes over 2 inches deep, staying inside my layout lines, this save some work with an end mill.  As can be seen in the first picture (larger hole at the front) I tried drilling the front area of the breech block, knowing the risk involved because of the barrel shank hole intersecting this area, it didn't go well, but no harm done.  I ended up just picked away at this area with the end mill, it needed to be below 1.310 inches from the top of the frame.

Once the holes were drilled I continued picked away at it with a 1/4 inch end mill, the largest I can use in this area.  I was milling over an 1 1/2 deep at some points which stretched the ability of the end mill I was using.  Since I was rough out the holes I wasn't overly concerned about side straightness, I have a slight taper on all side currently. If I was machining to my final sizing I would have taken the time to grind the shank of the end mill, in order to gain clearance, as I went deeper past the cutting flutes.  Being carbide end mills, grinding the shank isn't as easy as walking over to a grinder. It takes special grinding wheels, diamond in my case, that I only have on my tool grinder.

This first picture shows the roughing out after drilling.  You can still see where the drill went through in the side of the opening.

This second picture is what things looks like after machine to final rough opening size.  These two larger front tracks or openings are where the breech block moves. The rear, longer cut, is the hammer path.  These round corners will need to be removed later.  Once the frame is opened up and the profile is closer to final size there will be much less material and depth to work with and I will use a smaller diameter end mill in order to reduce the size of the corner radius so the final truing up is easier.  The final truing up will be done, as a few of us have shown here in the past, by using a scraper to square the corner and sides for the breech block.

Bob

It would drive me bonkers if I lost my DRO. A tip o’ the hat to you Bob.
Cheers Richard

Understand, my DRO just quit on me. Can't argue, 1977 model.
Helpless without it. In the process of replacing it.
Chuck

bobw wrote on Nov 22^nd, 2024 at 7:50pm:

Yes they are.
A short story if I may concerning the lines. When I was a toolmaker back 40 years ago or so, working in a mold shop we had a dedicated bridgeport with an Advance Rotary Table on it. If I may brag, there were and are few people in the world who are as good as I was on that table (we don't need no stinking CNC). And the bridgeport table dials were marked and the dial locks locked on zero, clockwise turning direction (so the backlash was taken up correctly) and X was on the left table dial, so you knew where the center of the Advance table was. It was a crime for anyone to adjust those zero's or table marks. Then we got a new hire and he, maybe not experienced, changed them. OMG the boss went off on him like no ones business. So those marks are most important, I know where you are coming from.  

I'm not a Hepburn expert, but am learning, and I understand the standard version has a rebounding hammer.  I did not check this action before it was disassembled but I am assuming it also has the rebounding hammer.  I say this because it has the same screw, all the other versions have, above the back trigger assembly screw, which on the surface looks to do absolutely nothing.  See the yellow arrow in the picture of the Walker.  I assume this screw has something to do with the rebounding of the main spring, maybe someone can verify this for me.  

Anyway, when I removed this screw it was bent, as seen in the second picture.  I installed this screw and the hammer and found the hammer has definitely hit the screw, the marks line up with the hammer as shown on the last picture.  But, the only way this can happen is with the breech block removed letting the hammer fall past the normal stopping point against the breech block.  This must have happened several time in order to bend this screw this much.
Bob