Making My Own 8mm Jacketed Bullets

[drinksgin (deceased)]

You would not suspect that Corbin was trying to make it as hard as possible to use something HE did not sell you?
Nah, he would not do such a sneaky thing!
;<)

[gitano]

I could understand not using 8-pitch threads because it could be argued that they were too 'coarse' for precise adjustment of the dies. However, that argument obviously fails when considering the MORE COMMON 14-pitch version. The guy makes good stuff, but he's really "a piece of work". I avoid doing business with him if AT ALL possible.

Paul

[gitano]

The issue of the 1-12 bolt for the "locking nut" is easily resolved by not using 12 pitch threaded bolt. DUH. Since I am making the FPH and the INSIDE threads don't have to match anything Corbin-made, I can get a 1-14 tap, (or even 1-8 for that matter), and be 'done with it'.

Still have to deal with the 1.5-12 male thread of the FPH matching the 1.5-12 female thread of the press.  Not too big of a deal as cutting outside threads is a snap.

Paul

[gitano]

Two, 3" long, 1" diameter, 14 pitch, "tap" bolts, ("tap bolt" a is threaded all the way to the cap), cost $17 at Fastenal. A 1-14 tap from EBay, (with shipping), is going to be about $10-$15. I haven't found and priced any local 1.5" steel round stock. I'm hoping I can FIND some locally.

I found it locally - $50 for a 3-foot stick. Ouch!

Paul

[drinksgin (deceased)]

Online Metals, 1 1/2" cold rolled . 10-12" random length, $13.20 plus shipping.

[gitano]

Thanks, Don, but I've tried to do business with them before. They will ONLY use UPS shipping. No exceptions.

I'll just get the $16.33/ft stuff here. I plan on making 3 of them anyway. One each for the Core Swaging die; one for the Core Seating die; and one for the Pointing die. They're going to be 5" to 6" long.

Paul

[j0e_bl0ggs (deceased)]

Pics of swarf making required...

[gitano]

OK.

This morning I'm blacking my friend's son's 1911 knock-off. I'll pick up the 1.5" stock this afternoon.

For future discussions, refer to the following image.



(All measurements in inches unless otherwise noted.)
I think the 'order of operations' for machining the FPH should be:

1) Drill/bore 0.840 hole in FPH body (from 1.5" stock), for floating punch head (0.800 plus 0.040 clearance).
2) Bore secondary diameter to ~0.915 for tapping 14-pitch threads leaving internal shoulder.
3) Tap about half an inch of 14 pitch threads into the ~0.915 bore of the FPH body.
4) Cut 12-pitch threads on outside of body of FPH for at least 4".
5) Part off FPH body.
6) Cut 3", 1-14 "tap" bolt, ("tap" bolt is threaded to cap), to length. (Total length from top of hex head to end of bolt that impinges on the lower edge of punch rim: 0.9" (punch body length) minus about 0.015 yields 0.75.)
7) Bore hole ~0.665 in diameter through bolt for punch (0.625 for punch body plus 0.040 for clearance).
8) Reduce OD of distal quarter inch of threads to ~0.820.
9) Reduce thickness of hex head by half taking excess off of top (the side of the hex head away from threads).
10) Face off the underside, (the side next to threads), of hex head.
11) Texture top of FPH using mill and indexing head.

If anyone thinks they should be otherwise, let me know.

Paul

[j0e_bl0ggs (deceased)]

Looking good Paul!
Just to expand for all in pictures, this is what Paul is attempting to achieve.
I made a few of these for my  Corbin CSP-1 press essentially the same as what he needs. Body here is 7/8x14 UNF.

[gitano]

Good illustrative pictures, "j0e".

With materials in hand, I can see some 'issues'. Not insurmountable, but challenges none-the-less.

The body of the punch is relatively short - ~0.900" - but with a "head" that is 0.800" in diameter. That mean that a hole 0.840" in diameter is required. That diameter in return means that a "large" - 1" - bolt be used for making the 'capture' screw. That in turn means that the length of the capture screw - including the head - will be shorter, (0.900"), than the diameter of the finished screw - 1". Have a look at the attached picture.



Not a lot of threads left there. It's not a strength issue for two reasons. First, there will be no "pull" on the threads of the capture screw. The forces applied to the punch when in use are 'upward' into the body of the FPH. The only "pull" on the threads will be when the punch is extracted from the Core Swaging, Core Seating, or Pointing, dies. Those "pulling" forces SHOULD be small. Second, I will be able to leave more than 3 threads on the shank of the capture screw. THEORETICALLY, 3 threads provide 100% of the rated holding capacity of a screw/bolt.

Paul

upon further reflection... I think I'll make the capture screw a bit longer than 0.90". I think I'll add maybe 0.2". I was corrected: 100% of rated holding capacity is realized with 3 times the bolt DIAMETER. That 'fits' with this bolt, as it is the shortest 1" tap bolt they have and it's three inches long.

Paul

[gitano]

OK... You wanted 'swarf-making' pics? Here they are:



The order of operations had to be modified.  I assumed that the threads would be perpendicular (within a few thousandths) to the head of the bolt. That assumption was false. It was out quite a bit. (I didn't need to measure it to see it was 'way' off.) Since the threads are the critical component, it was necessary to 'clock' (index) off of the threads. SO... I had to mount the bolt as you see above. Since I had to face off some of the profile of the under side of the head, I squared everything up there.

The next operation was to reduce the thickness of the head by an amount that would leave the overall length of the capture nut about 1.2".That meant removing about 0.6" of the 0.8+" of the head. Here's a picture of that operation.



Next was drilling and boring the through-hole for the body of the punch. J0ebl0ggs had already determined that the 'slop' needed for the punch head to 'float' in was 0.040". There was no reason to have less play in the body of the punch, so the diameter of the hole would be the body diameter (0.625") plus 0.040", or 0.665". First I drilled the through-hole into the bolt 1.5" using a 3/32nds drill bit. Then increasing in 16ths, I enlarged the hole up through 0.500". From that point I could use a boring bar to enlarge the hole to the necessary 0.665".

Here's a picture about mid-way through the drilling.


That's it for 'swarf-making' pictures. It took me 3.5 hours and I only took those three pictures. There wasn't too much else to see except reducing the terminal end of the capture nut to 0.815" and then parting it off. The 0.815" dimension was determined by the diameter of the head of the punch (0.800") and adding a "little bit" to it but keeping it smaller than the 0.840" of the bore for the head that will be coming when I make the FPH body. I figured 0.815" would be wide enough to 'capture' the head of the punch, and small enough to slip into the 0.840" FPH bore easily.

So here are pictures of the 'beast' with the punch and the die into which the punch will be pressed. In this case it's the Core Seating die.

This is a picture of the three pieces so far. On the left is the Core Seating die that will be screwed into the ram. In the middle is the punch Capture Nut, and on the right is the punch.


This is a picture of the Capture Nut on the punch as it will rest when inserted in the FPH die body.


This is a picture of the three pieces as they will be oriented (except the die will be "down" and the punch "up").


And here is a picture with the three pieces on their sides so you can see the relationship between the Capture Nut and the other two pieces.


Paul

[drinksgin (deceased)]

If you don't quit that, I shall have to go make a mess in the shop, too.

[gitano]

Fudge. I have just found ANOTHER problem with the press.

The 'way things work' is that there is a "top" punch (in this case that's the "Floating" punch), and there is a "bottom" punch. The top punch sits inside the Floating Punch Holder. The bottom punch sits inside the ram beneath the seated die.

For example:
When everything is in place, the FPH (top punch) is screwed into the top plate of the press. The body of the bottom punch sits inside a recess bored for it in the ram and the die (in this case the Core Seating die) is screwed into the bottom plate of the press with the shaft of the bottom punch sitting inside the die.

To seat a core in a jacket, one drops a sized core into a jacket then starts the jacket into the Core Seating die and raises the ram. As the ram moves up, the top punch slips inside the jacket and pushes the core into the jacket. As the ram is raised, the core (and jacket) are pushed farther and farther into the die. At some point, the bottom of the jacket engages the top of the bottom punch. As the ram continues to raise, the core is SWAGED into the jacket and the jacket expands to fill the inside of the Core Seating die. As the ram is lowered at the end of the core seating stroke, the bottom punch is forced upward into the die thereby pushing out the finished, cored jacket.

Here's the problem. The ram isn't bored out to the right size for my bottom die. This press clearly wasn't made for Corbin's "H" series dies.

This is a REAL problem. The diameter of the body of the bottom punch is 0.873"  (2 thou smaller than 7/8ths). Not only do I not have a 7/8th drill, I don't have anything that will hold a 7/8ths drill. Furthermore, I can't bore the hole larger as the depth is WAY longer than any borer I have. I'm not sure what the depth needs to be, but it needs to be AT LEAST three inches deepER than it is now, making it probably a total of 7".

Once I find out the max depth, MAYBE I can get the local machine shop to bore it out for me. If not, I'm "up the creek..."

Very disappointing.

Paul

[j0e_bl0ggs (deceased)]

Marathon cross planetary 'paper whipping' and have calculated working distance for the die set... (5 1/4")
Now needed a 57/64 bottom cutting multi lobe drill or reamer.... sheesh!

[gitano]

I received the 1-14 tap for threading the inside of the Floating Punch Holder (FPH) earlier in the week and was able to get some time in the shop on Friday to work on the FPH.

Here's a brief photo-essay on it's fabrication. Three things to note: First, photography isn't the first thing on my mind as I fabricate things on my metal-working machines. Keep in mind that I have no 'formal' training, and keeping my mind on task is very important to successful results. Second, lighting in my shop is "task-lighting", not "photographic" lighting. And finally, these pictures were taken with my cell phone so in some the focus isn't razor sharp. With those qualifiers;

Here is the 1.5" stock loaded in the lathe, trued to 1.491", and the internal hole bored for the head of the floating punch and the body of the punch capture screw.

and


Next you can see the internal threads cut for the capture screw.
]

This turned out to have its challenges. The tap I got off of EBay was a "plug" tap, meaning that it has a long, gradual lead to the cutting threads meant for cutting threads in a through-hole, or for starting threads in a deep hole. The hole in the FPH is neither "through" or "deep". However, I was able to get a good, straight start on the threads. Unfortunately, I was not able to even get close to cutting the necessary threads for the capture screw. What I needed was a "bottom" tap, which is designed to cut threads to the bottom of blind holes like the one in the FPH. So "Why didn't you get a bottoming tap, Paul?" Because there weren't any available on EBay for even close to the price of the plug tap. So... I had to turn the plug tap into a bottoming tap. Took about an hour on the grinder to grind off about half an inch. Thereafter, it worked like a champ.

And here is the 'proof of the pudding'.


Next cam outside threads. Pretty boring really.


And here is the finished outside threads.


Parting off a piece of 1.5"diameter stock is a chore.

I still don't have a knurling tool, but I wanted to texture the top of the FPH both for practical reasons as well as cosmetic. I chucked it in the dividing head on my mill, inserted a 1/4" round-nosed mill cutter in the head and cut grooves every 12 degrees (30 of them) around the top of the piece.


And


And here's the finished product with the capture screw and floating punch installed.


Here's what it looks like in the press:


And


And here's what it looks like in the press after blacking.


Still one more major machining operation to perform before I can start making bullets.

Paul