I THINK I Can Make This

Started by gitano, February 11, 2023, 03:08:45 PM

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gitano

This thing will be mostly for my grandkids. They'll have to put up with the smoke. Builds character. :D

Paul
Be nicer than necessary.

gitano

I promised pictures of "chips" and here they are:
This is a 1.25" round bar mounted in the lathe and turned to 1.007" to match the breech diameter of the existing "Teutonic" Flobert.


This is the finished (turned) billet parted off and in my hand.


This is what happens when you THINK you have the work-piece held tightly in the soft jaws. No real harm done because damage was in area that is going to be milled away. However, since soft jaws clearly weren't going to work, I had to make some work-holding jaws.


The work-holding jaws being fabricated. They consists of two pieces of 1/2" aluminum clamped in the vise with a 3/4" piece of wood between them. (3/4" will be milled out of the round billet). Using a 1" mill, I milled/drilled down through the wood, but not out the bottom of the aluminum. That left a shelf for the work-piece to register against.


The work-holding jaws made.


Empty jaws before seating work-piece.


The billet in the work-holding jaws.


Milling 0.750x1.600 slot in the billet.


The milling finished.


A square 3/4" billet setting between the "wings" of the breech block.


This is a practice piece. Helps with determining proper order of operations, and things like "can't use soft jaws". Also, I haven't been "on the machines" for a long time, so this practice piece helps get back in the proper mindset for machine work. There's lots left to do with this breech block; drill firing pin hole, drill holes for screwing ears to "action", drill and tap firing pin retaining screw, round sharp edges, and "finish", but this is a pretty good start.


Paul
Be nicer than necessary.

gitano

Got to spend 5 hours at the mill today. Yippee! Worked on the Flobert breech and made a 'blank-seating die' for the Stevens Favorite. I've finished the mill work on the breech. Now it's on to drilling, hand filing, and finishing.

Really glad I made this practice piece. Order of  operations seems straight forward, but there are a couple of places where 'out of order' snuck up on me. Didn't cause me to have to restart, but it did create extra work and some gymnastics.

I didn't get any 'work' pictures, but I'll post pictures of the completed, (for today anyway), pieces when I get them loaded on the computer.


Paul
Be nicer than necessary.

gitano

Here are the promised pictures, but only of the modified .32 S&W Case "primed" by .22 RF blanks, and the die I made to seat the blanks in the modified case. I have to take pictures of the Flobert breech yet.

Here's the modified case from the side.


Here's the head. It's been drilled to accept the blank body, and milled to recess the blank head in the .32 SW head.


These are the blanks I'm using.




Here's the case beside the "blank seating die" I made.


The blank started in the modified case. The blank will not seat with finger pressure.


The blank, in the modified case, in the die.


Die, case, and blank in vise.


The finished, "primed" case.


You might wonder why I didn't just thread the die so it could be used in a press. Fair enough. The answer is that I only have 10 cases. I didn't want to go through the rigmarole of threading the die just for 10 cases.

So...

All the above 'fiddling' got me to thinking. Why not just do the same with the .257 barrel... Using a .25-20 case, there's no need for any mods other than modifying the .25-20 case to take the blank. Here's the big advantage: That blank is the "perfect" charge to keep the velocity down where I want it! You may have noticed, that the box of blanks I bought was for the highest power available. As you can see (if you look at the box), there are 5 levels down in power from these "purple" ones. So, test the purple ones; if the MV is too high, keep dropping back until I find the blank that provides the MV I want. The "four" (yellow) level (the recommended level by the guy that makes the modified cases), gives a MV of 850 to 950 f/s for his 100-grain .312 cal bullets. We'll see what the #6 (purple) blank does with a 72-grain cast bullet or a 60-grain jacketed bullet. The extra capacity of the .25-20 should moderate the MV a little. Like I said, we'll see.

The modified .32 cases cost $3.50 each. I can modify .25-20 cases for free excluding the cost of the cases. Furthermore, if I ever wanted to shoot .25-20 cartridges from the Favorite, (not likely, but possible), all I'd have to do is change the rimfire breech for the centerfire breech. (I have the CF breech, and will shortly have both.)

More when there is more.


Paul

PS -- Looks like no one is using the #2 and #1 blanks, so they're not available. But I ordered a box each of the #5, #4, and #3.

Paul
Be nicer than necessary.

gitano

Here are pictures of the breech of the "Flobert" up to this point. It's still crude, (but not quite as bad as the pictures would indicate), but there's a great deal of "finishing" to do.









Here is the breech block for the Stevens Favorite. It started out as the breech for a .32 caliber RIMFIRE rifle. It was modified to CENTERFIRE. I am not going to change it back to RF. Instead, I am going to try to make a replicate, but in RF configuration. Since I don't have any steel plate that is 0.543" thick, (the thickness of the existing breech), I am going to use some 4140, 2" round stock I have. I had to use a grinder and cutoff wheel to take an inch off of the round billet. Since I will be milling this, and 4140 usually comes heat treated, I decided to anneal the workpiece first in a programmable kiln I have. I heated the piece to 1600F and held it there for an hour. Then, fairly quickly, (opened the kiln door), dropped the temperature to 1390F. Then programmed the kiln to lower the temperature to 1260F at a rate of 25 degrees per hour. (About 5 hours and 20 minutes). Then let it cool to room temperature over night. When I took it from the kiln, it was "softer". When I finish shaping it, I'll temper it by
1) reheating it to 1550F;
2) quench in oil;
3) then heat up to 400F;
4) hold it there for an hour;
5) then let it cool to room temp.

Here are annotated pictures of the existing breech.








The "chunk" in the kiln, but after annealing.


In the dividing head in vertical orientation. (It would be on a rotation table if I had one.)


You can see the scale on the "chunk". I got most of it off with a wire brush, but some of it was too stubborn. It doesn't matter because it's all going to be milled off anyway.


Paul
Be nicer than necessary.

gitano

Work continues on two fronts: Flobert and Favorite. Here are some pictures of milling the replacement, rimfire, breech block on the Stevens Favorite.

This first picture is the 'chunk' clamped in the milling vise and milling off the first flat, (the top of the breech). Subsequent pictures will clarify.


This is the piece after that first milling, with the pattern I used on top so you can better see how the milling will proceed. The next picture will show the next flat to be cut.


This shows the next flat that will be cut. Once this flat is cut there are no more straight cuts. All subsequent milling will be performed with the piece in the dividing head so I can rotate the piece as needed.


There are four holes that will be drilled after the entire profile of the breech block has been milled:
1) Firing pin - not terribly critical in terms of positioning since nothing of the action will be rotating around the firing pin, and firing pin strike has a certain 'flexibility' regardless of centerfire or rimfire ignition.
2) Firing pin retaining pin - wide "room for error" in this hole.
3) Lever linkage pin - VERY critical placement relative to several faces of the breech block. Almost no room for error.
4) Extractor pin - VERY critical placement relative to several faces of the breech block. Almost no room for error.

I will use the existing breech block as the pattern for locating the critical holes.

I have a feeling that there will be more hand filing on this thing than I want there to be. That's another reason why I annealed it. Speaking of which, it ain't THAT soft even now!



Paul
Be nicer than necessary.

gitano

In this installment, I have finished with the "flats". All of the rest of the surfaces are curved.



Here is the original breech block on the workpiece showing the relationships between the  faces that have been milled and those yet to be milled, as well as the holes.



Paul
Be nicer than necessary.

Jamie.270

Too bad they don't make a pantograph work holder for a vertical mill!
QuoteRestrictive gun laws that leave good people helpless, don\'t have the power to render bad people harmless.

To believe otherwise is folly. --  Me

gitano

Next installment of "making chips":

Getting started.




Getting finished.






Starting to resemble the original.


Paul
Be nicer than necessary.

gitano

The profiling performed on the mill is complete.



I'll finish the profiling at the grinder.


Got the important holes drilled "to spec".


Here's the original on top of the new one positioned with pins in the holes to align them.


I still have to mill the groove, but that requires taking the workpiece out of the dividing head and positioning vertically in the vise. (Pictures will clarify.) Once the groove is milled, I'll drill the firing pin hole(s). Plural because there are two diameter holes; one for the pin itself, and one for the body of the firing pin captured inside the breechblock.

More later.


Paul
Be nicer than necessary.

gitano

#40
Next installment.

I started today by removing the excess metal that I used to hold the workpiece in the vise. This took a while.






Here's what it looked like coming off the mill and compared to the original.


The below picture is after a few minutes on the grinder. (The workpiece is adjacent to another breech block I got from Numrich.) I'm not finished on the grinder by a long shot, but the "rough edges" are ground off.


I can't decide, (don't know), whether to harden/temper before I mill the groove. If I harden first, I may have a difficult time milling. If I harden last, the "ears", (only an eighth of an inch thick and with a hole in the middle), may warp when I heat to 1600F and quench. (Then temper at 400 for a couple of hours, for a hardness of 55-60 Rockwell.) My "go to machinist guys", Jay Edwards, drinksgin, and j0e_bl0ggs, are gone. The only one left is Paul Hoskins.


Paul
Be nicer than necessary.

gitano

In order to determine whether I should temper first then mill, (to prevent warping), or mill first then temper, (because breech would be too hard to mill after tempering), I took a piece of scrap from removing the breech from the workpiece, (see post number 41, third picture), and hardened/tempered it.

Into the kiln at 1600 degrees Fahrenheit, soak for 30 minutes, (1 hour per inch of thickness),  then quench in oil, then back in kiln to 450 degrees for two hours, then allow to cool to ambient in kiln overnight. Expected Rockwell hardness of 55-60.

Here's a picture of the kiln.


The "chunk" at 1600F.

Notice how you can see the heating element in the left wall of the kiln. You can't see that with your naked eye. That's because the sensor in the camera is sensitive to infra red. Lots of people don't realize that you can take "heat" images with most cell phone cameras.

After quenching.


It looks exactly the same after tempering, so no picture of that. I don't have a way to measure hardness, but this piece is "too hard" for my mill cutters. Which answers the question of "order of operations" with respect to milling and tempering.

I thought I MIGHT mill the groove, and then insert a piece of 0.250" bar in between the "ears", and then clamp them to the bar, but I don't have a clamp suitable for that, and I don't really want to try to make one. I'll just temper and hope for the best. After the groove is milled, the "ears" are only 1/8" thick. :sweatdrop:

So, left 'to do' are:
1) Mill "the groove",
2) Drill the holes (3 of them) for the firing pin,
3) Sand to final thickness,
4) Make firing pin and retaining pin
5) Harden then temper breech, firing pin, and firing pin retaining pin,
6) Grind breech to final shape.

While I was looking this post, it occurred to me that what I MIGHT do is get the 1/4" bar to put in the milled groove, drill holes in it to match the holes in the breech block, then use bolts and nuts through those holes to "clamp" the breech block ears to the 1/4" insert. That should/might prevent the ears from warping.

News at 11.


Paul
Be nicer than necessary.

gitano

Apparently, the "purple pills" are too strong! :stars:




Here's the loaded round. Looks like I'll have to use the lower powered yellow or green versions of the .22 blanks. My breechblock actually fits the breech a bit tighter than the original, so it would have been a bit uglier yet with the original. Neither are "tight" against the breech. The issue isn't the breech block, as it has fairly tight tolerances on shape and size. The issue is the barrel breech. I could be back another 50 thousandths.


The loaded cartridge.


Comparison between my breech block and the original.








I thought I would be sanding for the final finish, but when I took it out of the kiln it had a very nice 'case coloring' and I didn't want to remove that. Therefore, mine is a bit 'scratchy'. I don't really care because I know what I could make it look like because I've done it before. I'm "happy" with this. It was A LOT of work! But then, making "one-off" items usually is.

It works and looks as good as the original. Not much I would change in the process. If I were to consider making more of them, I MIGHT ask a local CNC shop to shape the basic shape, and I would mill grooves, drill holes, and make the firing pin. The real time consumer and 'pain' was getting the fundamental shape milled.

I can't get my hands on the weaker .22 blanks until mid June.


Paul
Be nicer than necessary.

Jamie.270

:huh2:
I'm trying to figure out how that case head ended up torn all to he!! and wadded up like that.



bummer. :Banghead:


Are you sure the bore isn't undersize somehow?
QuoteRestrictive gun laws that leave good people helpless, don\'t have the power to render bad people harmless.

To believe otherwise is folly. --  Me

gitano

Sorry about the tardy response. Only excuse is "It's Springtime in Alaska!"

Re bore/chamber size:
Nah. I checked, (mic'd), before test-firing.

I think the 'purple' blanks are not for using in firearm. By that I mean that I know they are made for "nail guns", but they are really not intended for use in firearms. Why would you need a 'muscular' blank?

They MAY 'work' in the "Flobert" I'm making. (Yes, I'm still making that.) Given the potential cases I intend to use, maybe the extra case capacity will render the purple blanks useful.

I THINK I'm going to make my own .25-20 cases for the purpose of using the nail-gun blanks. The combination of larger case capacity, completely enclosing the blank in a close-fitting "chamber" within the fabricated .25-20 case MAY allow them to be used. One issue remaining is "headspace" - the fit of the breechblock to the breech. The "Flobert's" design does not ensure a tight headspace. The greater the headspace, the greater the chance that the purple blanks won't be able to be used. Just too powerful. Furthermore, the strength of the purple blanks may obviate their use because they propel the bullet faster than I want (subsonic). Time will tell.


Paul
Be nicer than necessary.

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