Squished's die buildalong: Core Swage die

[squished]

I took a crack at the core swage components recently. Lots of lessons learned I think. I'm hoping for feedback to learn some more.

Here's my core swages set up:

http://i1244.photobucket.com/albums/gg563/picshare771/coreswage01_zps04ab6b09.jpg

I tried what I thought would be a simple, hole through the die with a smaller diameter hole to catch the top punch. Top and bottom punches are .191 with the top punch being .165 as a stopper hole. Simple or so I thought. The threading is pretty rough. I still need to work on that. Also, I'm concentrating on the parts that need machining (function) over prettiness, so yes they look kinda bad.

http://i1244.photobucket.com/albums/gg563/picshare771/corecasting01_zpsa9361ec5.jpg

The core mould is a test piece. I can make it more precise by adding a gate and trimming it down to give a 45-52 grain slug. It's .185 and I thought works OK for test purposes. It's not precise as I said but is a decent test.

I managed to lock up my die on the first test. It seemed to go as planned. I got a squirt out of the squirt hole but then the punches got stuck. I tried everything non destructive before eventually ruining the top punch. Some lessons, I think.

1. Maybe threading the top so it's removable may save the die and top punch better.
2. More polish is probably needed to prevent the lead from acting like epoxy and wedging everything together.
3. Maybe a tighter fit between punches and die bore diameter.
4. Ya gotta heat treat O-1 or it likes to do things you didn't anticipate, like bend or mushroom.

I'm not sure. What do you folks have to say? BTW, feel free with constructive criticism. I'm no machinist and am looking to learn.

[Sitzme]

How about a little more detail?
Are all of the parts O1 and soft?
What kind of finish did you do on the id?
What kind of lead are you using? Pure/Range?
What kind of clearances are you using?

Until you get the hang of threading you can clean up with a die after getting close.
You will pick up strength when hardening but the parts will also become more brittle depending on the alloy and process. Heat treating is another discussion completely but there is probably a thread here.

Keep at it.

[squished]

Thanks for the reply. I'll answer as best as I can.


Are all of the parts O1 and soft? Yes and yes.



What kind of finish did you do on the id? Too rough. I cleaned it up with 150 & 220 grit. I understand I really should be getting to a mirror polish.



What kind of lead are you using? Pure/Range? It was a lead sinker. I believe it was pure lead.


What kind of clearances are you using? I'm not sure how to measure this other than the ID and OD of the parts that fit together. The bore diameter is .191, as was the upper and lower rams.


Until you get the hang of threading you can clean up with a die after getting close.
You will pick up strength when hardening but the parts will also become more brittle depending on the alloy and process. Heat treating is another discussion completely but there is probably a thread here.

Keep at it.

Thanks!

[aaronraad]

What is your standard lube for swaging cores?

Lead sinkers aren't necessarily pure so you should really double check your melt for impurities.

How did the pressure compare on the bleed stroke before the SHTF?

Sounds like you might have had the core bleed past at least one of the punches, which obviously means the clearances weren't close enough to begin with or they expanded under pressure. Did you grind your punches with some relief? This ensures the punch tip is maintaining the correct fit for the length of the die ID and not getting a false fit from the punch at the die end(s).

The die itself has to be perfectly parallel through the section when it starts to load up against the lead slug and where it finishes it's pressure stroke. Before and after these sections the ID can sustain a negative taper or shape of sorts, which obviously assists in reducing pressure on the ejection stroke.

A mirror polish isn't necessary for the core swage but 600 grit would be more appropriate.

[runfiverun]

definitely more polished.
and lube the cores.

the parallel sides where the core is actually being swaged is imperative or you have some lead bleed past the stems and lock everything up.
you might also want to open the hole for the bleed off just a bit and flair the outside of the die around the hole to lower the amount of die body the lead has the squirt through.

[squished]

What is your standard lube for swaging cores?

None. Oopsie! That contributed probably.


Lead sinkers aren't necessarily pure so you should really double check your melt for impurities.

Good to know. Will do.


How did the pressure compare on the bleed stroke before the SHTF?

Noticibly easier around the time the squirting started.


Sounds like you might have had the core bleed past at least one of the punches, which obviously means the clearances weren't close enough to begin with or they expanded under pressure. Did you grind your punches with some relief? This ensures the punch tip is maintaining the correct fit for the length of the die ID and not getting a false fit from the punch at the die end(s).

I agree. I saw some on the bottom punch once I extracted it. How is the relief ground? Like a chamfer?


The die itself has to be perfectly parallel through the section when it starts to load up against the lead slug and where it finishes it's pressure stroke. Before and after these sections the ID can sustain a negative taper or shape of sorts, which obviously assists in reducing pressure on the ejection stroke.

I may try that. Good suggestion.


A mirror polish isn't necessary for the core swage but 600 grit would be more appropriate.

Thanks for the help!

[squished]

definitely more polished.
and lube the cores.

the parallel sides where the core is actually being swaged is imperative or you have some lead bleed past the stems and lock everything up.

Good tip. Thanks!


you might also want to open the hole for the bleed off just a bit and flair the outside of the die around the hole to lower the amount of die body the lead has the squirt through.

This makes total sense. Thanks for the tip.

[clodhopper]

Thanks for starting this thread, squished.
I am planning to make some core swage dies soon. First one will be .250, I already have a .188 from Lafaun.
Tomorrow, I start a two semester CNC machining class, will have access to top grade lathes and milling machines.
already have 6' of 1" O-1 drill rod, and some 1144 punch material.

I'm wondering if you used O-1 for your punches?
Ted Smith's book says that "stressproof" was his favorite material for punches. After some searching of the web I discovered that 1144 was stressproof, Mcmaster-Carr has some.
If in the US, PM your address and I will send a couple peices of 1/4" in a a padded envolope.

[squished]

That's very generous, clodhopper. Thanks! I have Ted Smith's book but neglected to read it obviously. That's another good tip.

[squished]

Here's the updated core mold.

I added pins temporarily while I fabricated a quick and dirty handle out of CRS. And I made a gate with some countersunk holes to help pouring the lead. Then I turned down the screws that held it to the handle to act as the pins.

http://i1244.photobucket.com/albums/gg563/picshare771/cores_zps1619e83c.jpg

It works better than the previous iteration but there's still plenty of work to do for tuning. The gate needs to be reduced in width so it shears before it reaches the side of the mold if that makes any sense. And the handle is somewhat rattly so I get some separation in the lead poured into some pieces.

I can see the advantage to repurposing an old bullet mold as alot of the alignment is already done for you. These cores probably weigh in the 55 grain range so the mold needs to be trimmed some.

As always, comments about function are welcome.

[clodhopper]

Learned in machining class that 1144 stressproof's value as punch material comes from heat treating that relives internal stress in the material.
It wants to remain straight as you machine some off.

[Cane_man]

1144 machines very well and you dont have to heat treat it, really good stuff... as has been pointed out McMaster has gobs of it

[squished]

Good stuff. I hope to work on the squirt die later this month as time permits. Thanks for the tips.

[Larrypeterson]

If I may,

You mentioned that O-1 can deform when heat treating. I have been swaging for a while now, but I have been a knife maker for the past 56 years. IMO, O-1 is one of the easiest and most forgiving tool steels to heat treat. I want to share one observation about the quench. If a knife blade is held at even a small angle as it plunges into the oil, it will warp or twist. One side gets quenched an instant before the other. When plunging the die into the quenching oil, use every effort to push it in straight and even. Do not move it back and forth until the quench has taken place.

In 1960, the Greyhound Buss company produced a training film about the heat range for heat treating axels. They had experienced axel failure on their buss's and found that the culprit was too much heat before hardening or quenching. They indicated that the grain size was course if you used too much heat and they were also to course if too little heat was used. This weakened the metal and caused fatigue. The ideal heat for O-1 tool steel is when it reaches "dull cherry red." Some folks use a magnet and as soon as the heated metal looses magnetic attraction it is ready to quench. After the part is cooled, I personally buff of the black oxide and slowly re-heat the part to where the metal has passed the yellow color and is a mottled red, but not completely blue. On a knife this will provide a "Rockwell C scale" 56 to 58 hardness. I make my dies the same hardness.

As a post thought, I might add that a mild steel can be "Case Hardened" by heating it to a cherry red and covered with Kasenite or red cherry hardening compound. I usually keep the flame on it for several minutes and quench in water. The mild steel is tough and the hardened surface will make for a rigid and easy to polish surface. It will be good for at least .010 hard surface. By the time it wears out, you will have trashed it.

I wish you well. LP

[squished]

Thanks! I haven't had time to work on these again but I'll give that a whirl next time. I tried knifemaking years back - all kinds of fun! Especially heat treating.