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:

What the heck is Met 101¿ I mean Met 101? ;)

So much to learn, so little time..?

Best to ya', Francis!

John

Mr. Dwyer,

Call me and check your PMs

John Truitt

All relative to your location and occupation, John
 

[quote=John Dunkle;43460]What the heck is Met 101¿ I mean Met 101? ;)

So much to learn, so little time..?

Best to ya', Francis!-- If you live in New York City, and are a National League Fan- could mean the hapless Mets (sorta like the Cubbies, but not in Chi-Town, but the Big Apple-- If you were the late Maria Callas, or my favorite- Beverly Sills (aka- Bubbles, einen zaftig Frau, Ja!!)- the NY Metropolitan Opera- but for us lads who learned to spark test metals and went into the fabrication/repair/pressure code areas of welding- Met 101 is the basic of metallurgy, identifying ferrous metals, the difference between surface hardness and through hardness, Air, Oil and Water hardening alloyed tool steels- goes with the old adage- 95% of a good weld joint is in the preparation and knowledge of the parent metals and filler rods/wire and processes to be used-

Then there is the "down-to-earth" get it fixed and back into the field ASAP welding I help my farmer friends with- have a Lincoln 250 AC-DC portable welder/generator (Onan engine, battery start) on a trailer-- also a Senco gas engine dual tank air compressor, torch set (propane- heat and cut only, no brazing)- extra long leads, and my basic rods for quick repair of farm machinery, where rust, paint, grease, mud and cow poop are part of the program- 1/8" and 5/32" Lincoln 6011- run on AC (no magnetic arc blow- most welds are run "out of position"-- If any PGCA members who do similar work are reading, be advised- FYI- Acetylene has tripled in price since the big Union Carbide plant in TX blew up-and many welding supply distributors who handle cylinder gases are on an "allotment" -- I do 95% of my metal cutting with either a Lincoln Plasma torch (uses air pressure- 120 PSI) or with abrasive wheel cut-off or in-shop band saws-

I was fortunate, in that my boss at the Boiler Shop- as a "reward" for passing API and ASTM code tests with SMAW (stick rod welding) and TIG (aka- Heli-Arc) enrolled us in the AWS- so we got the monthly news letters/magazines, plus the Lincoln welding journals- there was good method in his doing this- the knowledge was there for the reading, and we got quarterly bonus checks for the jobs we ran that passed first time in and came in on time or ahead of estimate-

I thank my maternal grandfather and my father for instilling in me a deep desire to learn-something new every day-

I had to replace a firing pin a few years back, and the gunsmith recommended a type of steel called" S-5, I think. Supposed to be very good at withstanding trauma. Anyone heard of it?

Todd, S-5 is a tool steel alloy used for making punches,chisels etc. It has the ability to withstand repeated blows without failure. Very good for the firing pin application.

David,

I make the offset firing pins for early underlifters from "fatigue proof" steel rods I purchase from Brownells. In their catalog it is listed as "superior quality, high density, very machineable and tough, without brittleness, due to a high ratio of manganese to carbon. Does not require heat treating like low density mild steel-perfect for spring guides, screws, firing pins, any parts that will be subject to shock or repeated stress."

I just purchased a small thread cutting lathe and am still in the process of setting up a workshop. I'm not a trained machinist, but as I started making offset firing pins to keep my underlifters in the field, I'd like to try making hammer screws also, for the same reason. It's just going to take a while to get up to speed.

Dave

John
Sorry-move it where you feel it belongs.
David