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rolland
11-03-2009, 10:20 PM
I have built a gatling gun .22 caliber and am in need of some expert help. I made the extractors from ground flat stock 1018 and case hardened them according to the plans, but they are not working out. I can not get the case hardening deep enough to do any good and they wear very fast.
I was wanting to find a more suitable material, I was hoping someone might have had some idea what would be a better material. I was thinking of 4140 or O-1 flat stock but having not worked with either one I am not sure if they would work.
Any ideas?

dp
11-03-2009, 10:52 PM
I can't help (also have had no luck treating 1018) but I'd love to know more about the gun.

JCHannum
11-03-2009, 10:59 PM
Pictures are definitley in order. Who's plans did you use?

Either 4140 or O1 would be suitable. The O1 would be simpler to harden and draw. I am surprised that case hardening is wearing on the 1018 though. What method are you using?

motorcyclemac
11-03-2009, 11:27 PM
As Jim said...4140 or O1... I would use 4140 myself...but it is what I have.

I am a bit concerned about your case hardening process. It SHOULD be doing the trick.

What kind are you using...and are you getting it hot enough...and are you using a slightly carburizing flame?

Cheers
Mac.

38_Cal
11-04-2009, 12:24 AM
Since many extractors are springs, I use either 1075 or 1095 from the Brownells kits. Even on those that don't need to be a spring, I heat treat them as though they are, and (knock wood) have never had one fail. Heat to cherry red, oil quench, polish and draw to peacock blue.

daveo
11-04-2009, 07:31 AM
I had mine edm machined out of A-2 air hardening tool steel. Made a very hard , springy extractor

http://i297.photobucket.com/albums/mm234/daveo11/Picture020.jpg

rolland
11-04-2009, 12:40 PM
for those that ask here are the photos. These were taken a few months ago. Most every thing is done now just need to sort out the extractors. http://i291.photobucket.com/albums/ll291/rgh25/gatling%20gun/100_0702.jpg

Bill Pace
11-04-2009, 12:52 PM
Most every thing is done now just need to sort out the extractors.

VERY NICE!!

Did you keep track of your hours?

I have debated, argued with my self, made excuses, etc, etc about tackling a Gatling -- the scope of it just sorta overwhelms me... then when brass went outa sight in cost a while back ... well, it still aint been done.

I've done the 3 brownings from Coffee cup and the German MG-42 based on the Ruger 10-22 and enjoyed them immensley.

rolland
11-04-2009, 12:55 PM
Bill
I started July of 2008, and am still working out the bugs.

Bill Pace
11-04-2009, 01:07 PM
Bill
I started July of 2008, and am still working out the bugs.

So your'e at about 15-16 months? -- thats not so bad.. How do you do your work - are you still actively employed and do it on wkends, etc, --retired and can put in lots of time?

I am retired and do have plenty of availiable time -- heh, in fact thats some what part of of my delimna, I'm 70 yrs, and I can feel my ole bod slowly (so far!) deteriorating on me, and have to wonder if I want to dedicate myself to that extensive a project at the expense of other things I enjoy -- I tell ya, getting old SUCKS!!

daveo
11-04-2009, 03:48 PM
I polished mine to get me motivated to work on it!!! The drum mag is functional but is just for looks. I quit counting my hours at 350 or so..... Then again this is my first machining project. Besides little stuff.

I figured the extractors would fail so I had those made as well as the firing pins.

http://i297.photobucket.com/albums/mm234/daveo11/Picture014.jpg

rolland
11-04-2009, 04:21 PM
Bill
I retired about five years ago and went back to work doing hobbies, and gunsmithing. I have built the three coffee cup guns and they are a breeze compaired to the gatling gun.
Dave
That looks really good, I thought I would polish mine after it is fully functional.

This is the carriage I have it completed now. This photo was taken earlier this year.
http://i291.photobucket.com/albums/ll291/rgh25/gatling%20gun/100_0713.jpg

JCHannum
11-04-2009, 05:34 PM
Nice job, both of you. I especially like the artillery carriage.

Like Bill, I have had the Gatling gun on the back burner for several years now. In fact I have accumulated most of the brass needed and plenty of barrels, so my excuse for not starting is weaker.

How are the extractors wearing? It sounds kind of strange. I had forgotten the form of the extractor, and was thinking about a different type. The thin section could present problems in case hardening, but I would suspect them to be more prone to breaking than wear.

While 38_Cal's suggestion of spring steel is a good one, I would be tempted myself to use O1 unhardened. If using mild steel, I would just case the hook area to prevent wear there and leave the balance untreated.

A tip, when drawing small parts to a color as 38_Cal suggests, I use a pan of brass chips on the kitchen stove to heat the part. It is easier to control the heat and watch the color change. Just put the pan of chips on the burner, lay the part on top and turn on the heat.

rolland
11-04-2009, 06:15 PM
I am going to recut some extractors and try the methods suggested. I "think" I did not get enough heat when I first tried the case hardening compound. I used a oxy/ace torch with a low flame.
Thanks for the advise I shall muddle on.

Had I known then what I know now I doubt I would have started the project I is really time consuming. Altho it will make a nice addition to the living room

hitnmiss
11-05-2009, 09:04 AM
Those are gorgeous!

I'd love to make one someday.

Ken_Shea
11-05-2009, 10:51 AM
Beautiful work guys, it takes a dedicated kind person to build something that complicated and extensive.
Rolland
"Had I known then what I know now I doubt I would have started the project "

you didn't quit though !

Have done some case hardening but have read that the process can be repeated for additional depth, true or not, not sure!

50BMGBOB
11-06-2009, 04:12 AM
Looks great. I'm just getting started on building one. I figure 2-3 years as I'm not retired. I'm cheating and bought the carrier block and rifle plates from RG-G. I'm new to machining and figured that would save me time and tooling ($$).

38_Cal
11-06-2009, 10:19 AM
I am going to recut some extractors and try the methods suggested. I "think" I did not get enough heat when I first tried the case hardening compound. I used a oxy/ace torch with a low flame.
Thanks for the advise I shall muddle on.

Had I known then what I know now I doubt I would have started the project I is really time consuming. Altho it will make a nice addition to the living room

For case hardening, with Kasenit, I run the parts at a bright cherry red, with just overhead lighting in the shop, not the swing arm bench lights. I also quench by dropping/plunging the still red parts from about 2" above the oil...keeping them red right up to that point. If you take off the heat and have to move more than that, they start to cool, and may well be too cold to harden. HTH!

clutch
11-06-2009, 06:27 PM
Looking at my RG-G plans, I see ground flat stock in the materials list for the extractor. Then I see a note about using key stock included in the kit they sell.

I could have sworn they called out O1 but I can't find that. Still, ground flat stock to me, means tool steel and O1 is what I bought.

My build hasn't started yet, I'm putting the finishing touches on my machine room that is going to be my man cave this winter.

I have the stock and tooling, but I'm having a hard time the time this year to do anything other than work this year. I've worked more OT this year than I have in over a decade. Not complaining given how the Michigan economy is at the moment.

Clutch