Page 2 of 4

Re: OFCC University - Metallurgy 101

Posted: Fri Dec 19, 2008 4:53 pm
by Mr. Glock
curmudgeon3 wrote:It would be nice if someone could now post a treatise on the chemical structure and content of plastic/polymers so the Glock worshippers don't feel slighted.
I'll handle that one...it comes from God and is thus perfect. :twisted:

Re: OFCC University - Metallurgy 101

Posted: Fri Dec 19, 2008 4:53 pm
by farblue
TL;DR...

Pull trigger = Go bang, yes?

Re: OFCC University - Metallurgy 101

Posted: Fri Dec 19, 2008 5:40 pm
by Newcomer
Wow Morne - you'd have done my father proud - he was a metallurgist for Republic Steel - worked there 45 yrs. Good job.

Re: OFCC University - Metallurgy 101

Posted: Fri Dec 19, 2008 5:45 pm
by willbird
Morne wrote:
willbird wrote:The "non magnetic" stainless steels have iron in them ??
Yeppity skippity.

The 300-series of "Austenitic" stainless steels are the famed "non-magnetic" stainless steels - at least when they are ANNEALED (in their softest condition). These have been so heavily alloyed with other stuff that they are actually in the FCC (austenite - and hence the name) crystalline structure AT ROOM TEMPERATURE. These steels cannot thus be heat treated in the conventional sense but instead can be work-hardened (usually on rolling mills) to achieve higher strength. That same work-hardening phenomenon can be a real headache to machinists, too.

Iron is only magnetic when it is in a body-centered crystal structure - either cubic or tetragonal. That's actually one way to test the effectiveness of quench oil - take a steel sphere suspended from a steel wire (all at about 1600 F) and dump it into a cup of quench oil with a strong electromagnet at one side. You measure the time from immersion until you hear the "TINK" indicating that the sphere has finally been swung over to hit the cup wall. Weird, huh?
I am a machinist by trade meself Morne ;-), yes those work hardened alloys are terrible to machine at least on manual machines.

But yes the Austenite deal makes sense then, because when a steel is heated to it's critical temperature it is no longer magnetic, I have read that uber fancy heat treat furnaces measure this effect to determine when you have reached critical temperature rather than less precise methods.

Bill

Re: OFCC University - Metallurgy 101

Posted: Fri Dec 19, 2008 5:48 pm
by curmudgeon3
Mr. Glock wrote:
curmudgeon3 wrote:It would be nice if someone could now post a treatise on the chemical structure and content of plastic/polymers so the Glock worshippers don't feel slighted.
I'll handle that one...it comes from God and is thus perfect. :twisted:
"Thou shalt not worship false gods". (Like Gaston.) :P

Re: OFCC University - Metallurgy 101

Posted: Fri Dec 19, 2008 6:06 pm
by SMMAssociates
curmudgeon3:

It's a polymer of some kind.... Can't recall what.... Odds are the weatherstripping around your storm windows is vinyl. I was in the vinyl extrusion business (i.e., making that stuff) for about 30 years. We also made siding and window frame components that are a harder vinyl, but essentially the same stuff. All of these are roughly similar in most characteristics to the polystyrene that your favorite model aircraft (and boats) were made of. (Vinyls tend to be more substantial.)

The Tuppergun polymers are closer to Nylon (pocket combs used to be made out of that - really tough material). They're also often called "Engineering Plastics", and many are tougher than their weight in steel or aluminum, but with some manufacturing restrictions (real thin parts, for example, tend to be very flexible).

If the designer knows what he's doing, a good deal of the parts in your gun could be made of the right polymer and you might never find out. However, Glock (and others) use a better system whereby the really critical parts tend to be made of steel and supported by steel, with that set into a polymer grip frame. Steel and alloy slides are generally the norm anyway....

Regards,

Re: OFCC University - Metallurgy 101

Posted: Fri Dec 19, 2008 6:30 pm
by curmudgeon3
Stu,
Don't tell me ........ you broke down and bought a Glock?

Re: OFCC University - Metallurgy 101

Posted: Fri Dec 19, 2008 7:44 pm
by Mr. Glock
Stu just recently moved up from the Arcabus....

Re: OFCC University - Metallurgy 101

Posted: Fri Dec 19, 2008 8:26 pm
by SMMAssociates
curmudgeon3:

No Glocks here, but I've got an XD and an M&P :) ....

Mr. Glock:

Got rid of the arquebus - too much trouble to wind it's wheellock. Matchlocks are so much much simpler. :mrgreen:

There are holstering issues, though.... :twisted:

Regards,

Re: OFCC University - Metallurgy 101

Posted: Fri Dec 19, 2008 9:45 pm
by Strider
:roll:
Forgive them Gaston, they know not what they say....

Morne : would now be a good time for a knife question? I've been trying to research field/bush/camping knife selections. I keep reading suggestions for a "high carbon" blade. Can you define what % makes a high carbon steel?

Re: OFCC University - Metallurgy 101

Posted: Fri Dec 19, 2008 10:27 pm
by Morne
Mr. Glock wrote:Cool...good work...some follow up from the class on Lesson 1.

1. Late 1800's Blackpowder Rifles (like the early Winchester lever actions)..what type of steel in the barrel?

2. When smokeless powder came out, Winchester went to Nickel Steel (as marked on the barrel) to differentiate from the older guns...which is that one(s) on your chart?

3. Ruger Hammer-Forges barrels around a mandrel to create rifling (as opposed to gun drilling them), does this process impact the type of steel used?
1 - Probably either damascus steel (especially european and custom guns) or plain carbon steel (especially mass-produced domestics).

2 - That would be the 23XX and 25XX series of low-alloy steels.

3 - No, it doesn't affect the chemistry of the steel. Some folks like forged parts better than barstock due to the grain (yes, steel has grain much like wood) flowing in the direction where strength is needed. I'll get into this more in the last chapter - castings versus forgings.
Strider wrote:Morne : would now be a good time for a knife question? I've been trying to research field/bush/camping knife selections. I keep reading suggestions for a "high carbon" blade. Can you define what % makes a high carbon steel?
GREAT QUESTION!

Steel has a eutectic (fancy word for ideal mixture) point at 0.77% Carbon content. Any steel with less than that amount is commonly referred to as being low-carbon (technically, hypoeutectoid) and any steel with more is called high-carbon (technically, hypereutectoid). The most common for knives, 1095, is a high-carbon steel by virtue of its 0.95% Carbon content. Some folks call anything within about 0.10% or so of the eutectic (thus, 0.67%-0.87%) medium-carbon steel but that is not universally accepted. I've heard people call 4150 a medium-carbon steel before - I just roll my eyes. :roll:

A quick aside into polymers - Glocks are made from unreinforced Nylon (I believe 6/6). There are currently better polymers out there for this application. Also, some folks, like Cavalry Arms, have chosen to keep the Nylon matrix but add a fiber-reinforcing component. Glock might have been early in the field but others have taken their art form and raised the bar. The Heresy of Gaston has yet to answer.

Re: OFCC University - Metallurgy 101

Posted: Fri Dec 19, 2008 10:41 pm
by Johnny45
Wow Morne, you sure disturbed a lot of cobwebs in my brain. Some of it is coming back now. I Can Can See Betty Talking Naked. My trick for remembering carbide formers. Thanks! :D

Re: OFCC University - Metallurgy 101

Posted: Fri Dec 19, 2008 11:57 pm
by Mr. Glock
Morne:

As for the polymers, Glocks were designed to flex in the frame during firing. Some of the new polymer pistols have reinforced their frames by joining the front and rear sections of the drop-in parts (front locking block/slide rails and rear slide rails/striker trigger). They had to be different...not necessarily better. Glocks aren't known to break frames...other things maybe (being first you know...you've heard of the Colt 1905?), but not that.

PS Don't pick up that "next best thing" argument, as you know my next statement will be (HInt: the 1911 is old..... :P )

Love the topic though.

And, did steel progression over time move up the chart? ie blackpowder was low-carbon, then nickel steel, then x, then y and the top of chart was most recent?

Re: OFCC University - Metallurgy 101

Posted: Sat Dec 20, 2008 1:22 am
by SMMAssociates
Mr. Glock:

Given the proliferation of mini-magnums - for example, the S&W M19 of the 60's is essentially a .38Spl with one heck of a cylinder upgrade (and they didn't really bother to change much else - the forcing cone is shortened to allow for the longer cylinder!) - my guess is that the steels are incrementally getting better over time. You can make 'em lighter that way, too, without necessarily getting into exotic metals and difficult machining issues.

The plastic folks, IMHO, are moving the same way, but I don't think that there have been materials changes over the short term to match what's happened to steels since say 1900....

ALSO, somebody mentioned that "Glock hasn't kept up" or something like that. A mold for a grip,for example, could cost way over $30,000, and once you get one that is tuned to work with the plastic you've chosen to use, odds are that the next choice in plastic will NOT flow the same way, or otherwise "work" in the existing mold. There's little incentive to re-do a mold until the old one works out.

However, mold design is a bit of a black art (I worked for a plastics plant for more than 30 years - mostly in the office, but picked up a lot by osmosis), and it's possible that the existing molds were created by CNC milling machines, and cutting a new one from the existing program (and then letting a skilled mold maker tune it) would be a lot cheaper than making a new mold for a different material. If the whole job was done by hand (not unusual when I was in the business), the cost would be easily a LOT more, new material or not.... They'll wait for the "(M)" version :)....

My "history" is kind of eclectic. Mom's brothers owned a plastics extrusion plant and a molding plant. We later added a pile weatherstrip plant in SC. I started in Shipping at the extrusion plant, moved into the office, did QC and design work for a couple years, and then got into computers. I got into the rent-a-cop business about the same time, as well as telcom. Doing the design work, way back when, I learned a lot about how to design extrusion dies and molds for injection work. Extruding plastics are a lot like the way toothpaste comes out of a tube - but you'll note that the glob coming out often is slightly larger than the hole. That's called "swell", and figuring it depends on the material, molding or extrusion temperatures, and a few other things. It's pretty much a black art, as I said before. Extrusions are easy, btw. I designed more than a few, but we had die makers who knew how to take my figures and make things work. Nobody ever complained.... I did mention being armed? :) Anyway, the Glock folks probably won't muck with what's working right now.

Sorry to write my usual novel :D.... BTW, with one exception, if you're concerned about MIM issues, the process is exactly the same - including the "swell" and other things. MIM parts are cooked after molding, which causes the metal in the mix to come together and burn off the "matrix" - some plastic. Since you can do all kinds of magic when molding plastics, most of that is also possible with MIM. Calculating what'll happen by the time the parts are ready to paint has to be right up there with predicting the weather....

I now yield the floor to the guys who are young enough to remember this stuff.... :mrgreen:

Regards,

Re: OFCC University - Metallurgy 101

Posted: Sat Dec 20, 2008 2:19 am
by tjeffries
What you can't learn from a bunch of gun nuts :shock: Thanks Morne :lol:

I used to set-up/troubleshoot rubber injection molding machines with mold temps ranging from 290-370 degrees F. Every time I'd use one of my nice telescoping magnets to pick up a metal blank from a hot mold, the heat turned it into an expensive pointer. The tool room no longer lets me anywhere near their magnets :lol: