Tool steel for hammer screw
 

I am having continuing problems with a hammer screw for an O frame 16 hammergun. I have had two replacements break,head breaks off, in the past 18 mo. I am considering having the hole tapped to a larger diameter and a new screw made. I want to use a good steel but do not know what to use. Anyone knowledgeable on steels ?
David

if the tool steel is breaking from shooting the gun then the problem is that the steel being used is to hard..you need steel with less harding in it...to brittle or hard steel breaks very eaisly...you nned a softer screw in my opinion....charlie

Charlie
That screw is really small. # 4, I think, and with very little presure the head just rings off. I have some offset hammer firing pins Dave Purnell made out of a very tough steel, Maybe something like that.
David

Ooops- Charlie- perhaps you mean firing pins here
 

-- I like O2 drill rod for firing pins, but most machine screws found in older "double hardened and fitted" side-by-sides (M21 Winchester the exception) are machine from 1018 low carbon no alloyed mild steel- later machine screws produced on Acme and other makes of automatic screw machines might use 12L14 (greater machinability)-- If you want to shoot this hammer gun, and have it function, I would suggest drilling out and re-tapping the threaded hole and using a new configured machine screw with matching threads of course-I also have some firing pins I turned on my South Bend lathe from O2- need to see the entire broken one first before I can possibly match it-- Charlie- I hope you "Hit for the cycle" on your Tom Turkeys- MI does not yet have a minimum beard length for the spring season- the Fall season here- you can take either a Tom or a Hen-I like the chests marinated in Jack Daniels and grilled over hardwood with JD barbeque sauce- that way, if you overcook the bird, you can always drink the gravy- straight up on on the rocks- your call!:bigbye::bigbye::bigbye:

Dave, I would use A2 or D2 air hardening tool steel. After hardening I would draw the screw down to Rc 28-32 You want the screw to be tough but not brittle. I would also check the fit of the hammer to the spindle it should fit fairly snug so that the screw is doing minimal work. Something is side loading that screw. As you know those screws are not that strong so any side load will just pop the heads off.

Dave
Thanks, I used to do some blacksmithing and made tools with both D2 & D3. Really tough steel. Will get some D2 rod.
David

I've had good luck turning things on a lathe from grade 8 Cat bolts. They are extremely tough. Caterpillar pad bolts are the toughest steel I've encountered. Don't know what kind of steel they are exactly but they are tough... I've never understood why the shank on a hammer screw was made so small. There's enough metal in the shaft for a larger screw.

Ill give it a "SWAG" Richard
 

--I've had similar experiences with Grade 8 bolts on John Deere and other quality made American products- my guess- as welding involves knowledge of parent and filler metals and some basics in metallurgy- for both ferrous and non-ferrous- Cobalt is the additional alloying element-to medium range carbon and also nickel, chromium and molybdenum most likely will be present- have you ever spark tested one of these bolts?:bigbye:

Hi guys,

I'm going to move this into the proper forum in a few, OK?

Best to all,

John

That's why you be our "Head Fred" John
 

= What new area- lots to learn as always, even Met 101!:bigbye: