Strongest rod available

[Froneck]

ARP has a really good practical overview of high strength steels used in their fasteners.
If you are thinking of using a bolt for a source of material...………

The Official ARP Web Site | Technical Information

I looked at this sight, they have torque specs for 200,000. Looking at their various bolts and nuts I see Chrome Moly listed as 180,000/210,000 No others am I to assume the Chrom Moly bolts can be torqued to the 200,000 spec? Not interested in torque rating since the item will not be used as a bolt.

 

[Dan from Oakland]

I found the "ARP Materials" tab pretty informative regarding material strength info.

 

[Illinoyance]

OP's Rc40 pretty well defines the strength. Rc relates to strength.

 

[Froneck]

I understand hardening and strength. A simple explanation would be hardening will bring Tensile and yield strength closer together. Not perfect but simple. I want something tough, If anyone remembers the old jack handle/wheel nut wrench, it was only 5/8" in diameter but almost impossible to bend by hand. However I have seen bent jack handles so they were not very hard. If can find some of them I would turn them down! I want hardness but I want to tap it too so I'm looking for the highest strength at a hardness I can tap. I have tapped material in the RC 40s but don't remember trying in something RC 50

 

[Matt_Maguire]

I understand hardening and strength. A simple explanation would be hardening will bring Tensile and yield strength closer together. Not perfect but simple. I want something tough, (snip) I'm looking for the highest strength at a hardness I can tap. I have tapped material in the RC 40s but don't remember trying in something RC 50

You’re paddling your canoe in a circle here… Carbon has the largest effect on how hard/strong a steel can get. For tough you add nickel. Moly is a carbide former & helps with strength at higher temps. The salad is endless…

I’ll attach some stuff… Good luck with your tap @ 50Rc. Also a good heat treat guy is going to caution you (NO GUARANTEE)in that part he'll temper @ 600°F to get that hardness. It drops the impact (IZOD) to 5-6 Ft/Lbs where @ 40Rc it's 30+. Go back & look at the 4142 chart J Oder posted, it's the little curvy line on the bottom getting close to the 600F temper#.

Good luck,
Matt

 

[JST]

The original request for "the strongest rod available" sounds like a code phrase for "I dunno exactly what I want, and there are no specs, but I want it real strong". That sounds bad, and not thought through well, but it may reflect a real situation in which much of the info one might want is just not available.

Usually, when you dig into the back story, you find out that the "rod" is probably not gonna be the limitation. Some other part is really the problem, and the idea behind the "ask" is to shift the failure onto a particular part.

But that may not be the way to do it, because often "very strong" goes along with "breaks right above that stress". The "strongest" part "for the application" may not be the one with the highest ultimate tensile strength, or the one with the highest yield point.

Even 4140 can be quenched and tempered to be over 200,000psi in yield, and at about 250,000 psi ultimate tensile strength. At least my Bethlehem steel book shows that. A 400F temper is given for those results, with just over 1550F as the temp it is quenched from, in oil.

This is the point that the usual question is "Just what do these pins need to do in the assembly? And how do high strength pins help the larger assembly be stronger?"

Those answers may not be available, for various reasons from NDAs to lack of data.

"Pins" typically are used in shear, which can be assumed to be about 40% to 60% of the tensile strength. So presumably the 4140 could be 120k psi in shear, or at 0.0314 sq inch, about 3000 to 3700 lb ultimate in single shear.

Most likely, a person will not do a lot better than that, so that's probably a good maximum design point.

 

[Froneck]

Nothing has broken nor has any other part failed, I didn't make it yet. I don't want to heat treat, looking for the highest yield strength from off the shelf metal. I must drill and tap a hole in the center of a 1" X .205" diameter pin. Not in the end, into the side so that at the center the thickness of the pin will be reduced by the hole diameter. Center being 1/2" from either end. Currently I have a 17-4ph and 15-5ph 1/4" rod from McMaster. I'm going to drill, tap and test the strength. Corrosion resistance is not important, I want the highest yield strength and looking for suggestions to add to the test. I'm thinking AR500 turned round.

 

[magneticanomaly]

Transverse tapped hole in skinny rod that has to be very strong. Huge reduction in cross-section at point of max stress. Any chance oif leaving the ends (trunnions?) .201" and fattening the middle where the hole has to be?

As is often said here, more description of trhe appplication might yield better advice.

 

[Froneck]

I'm limited to what can go thru a .205 hole. What I'm doing is making a better .22 conversion for the 1911 Colt Pistol. Frame is about 3/4" wide, support for the pin is .205" hole. (actual hole could vary from .201" to .205 I have a .205" reamer).190" long on each side with a .375" gap in the middle. I want to push the barrel back not push the barrel forward as is currently done.

 

[Matt_Maguire]

Putting a hole in a rod used to push or pull sideways creates what engineers call a “notch” (they hate notches)… It will significantly reduce the safe load allowed.

You are also not gonna tap AR-500, AR-400 is a chrome moly boron steel that’s pretty much the limit for tapping in a normal world.

Good luck,
Matt

 

[Froneck]

Those in the competitive group refer to all the Colt 1911A1 as simply the 1911! No other gun being made has a similar number but numerous copies by Ruger, Kimber, S&W, Springfield as well as Action X Rock Island and others. (all are refer to as the 1911)
The bottom of the barrel Ruger MK3 is no match to those being made by Hammerli, Walther, Pardini, Matchguns, Feinwerkbau, Baikal and others! No top competitor I know of is using the Ruger.22! I have the Hammerli 208s and 215, Feinwerkbau AW93, Matchgun MK2 and Baikal IZH-35.
My son is one of the top Pistol shooters in the USA and has broken a few shooting records.
.22 conversion for the "1911" is being built by Marvel and Nelson both are being used by top competitors that all have a few guns I mentioned above. My son has purchased the Nelson version that has a cost greater than a New Ruger MK3 and intends to try it though he has the Hammerli 208s and 215s .22 Pistols.
I have built quite a few "1911" target pistols simply because any of the "1911" pistols out of the box from Ruger, Kimber, Springfield and S&W will not shoot accurately at 50 yards!
Further more I might remind you that the pin that holds the link in the "1911" is .155" in diameter and is enough for 230gr. Military Ball ammo. The "1911" barrel moves, the .22 conversion barrels do not.
I simply want to test my idea of making the .22 conversion and only change is how the .22 barrel is held in place! Both the Nelson and Marvel have barrels that are threaded into a block that holds it in the "1911". The barrel is threaded 3/8" X 40TPI LH. So .375 - .223 =.152 gives .076" wall thickness. No barrels I know of have broken! There will be less stress on my pin!

 

[DDoug]

.22 conversion.....

Some folk would put pallet-jack wheels on a John Deere tractor...

Or ask about firing pin materials/construction in the antique machinery section.....

 

[Froneck]

The idea and why most of the top shooter are using the conversion to stay with the "One" gun. Over the years .22s by Hi Standard, Ruger and S&W made .22 pistols that were similar to "1911".
Prior to Covid I did get out but after many ranges didn't shoot. Camp Pery didn't shoot in 2020. Prior to that I had 38 consecutive years I shot at the National Matches at Camp Perry so I have been getting out. Grips for the Hammerli, Pardini and Feinwerkbau pistols are made to have the same grips as the "1911" Most of the Top Shooters will shoot he "1911" 45ACP in both Centerfire and .45 match and want a similar gun for the .22. My son being a member of the Army AMU shooting team, the best pistol shooters in the country are supported by an Army budget so the best is what they have! They too are shooting the .22 conversion! He has retired after 22 years.
Shooter like my son are offered the best to shoot at no charge and is getting Pistols from Accuracy X to shoot on their team. Accuracy X 1911 .45ACP sells for $5000+ for the top model! He has 2 "1911" chambered for 9mm to shoot Bianchi Cup. If anyone is interested see Shooting Sports USA - July 2018. It's online magazine click on the > (right side of the page) to turn the page to the article.
Simply put I will build my conversion. Currently I make what's considered the best trigger shoe for the 1911 and best trigger available for the Pardini. I have a Hut already reserved at Camp Perry so I'll be there in July!
I never asked about firing pin material selection. I'm only requesting material that has the strongest yield strength available. Here because I find the best minds in the forum! I included the function because I was asked, now you see why I didn't at the start!

 

[magneticanomaly]

If I understand correctly the pin OAL is 1-1/8" the "trunnions" are 3/16 long, the gap between supports is 3/4". I think this would allow making the pin in two halves, to be inserted from the middle. If the only attachment required to the middle of the pin is a stud of some kind threaded in, the inner portions of the half-pins could be arbitrarily fat, and split along the axis and joined by the stud.

But I do not pretend to understand the function of the pin.

 

[Froneck]

Pin is about 1" long, 3/4" is in the frame, about 1/4" protrudes out of the frame and is used for another function unrelated to the pin function. 3/16" of the pin is supported by .205" hole on each side of a 3/8" gap in the middle. In the gap is a steel 3/8" wide tab with a .205" wide slot 7/16" long at a 5ish° angle. Access to the 3/8" wide tab is available on one side only. Currently the tab is threaded and the screw pushes on the .205" pin which can't move being supported on both sides by the 3/16" long holes. Therefore the tab must move forward. The movement within the angled slot causes downward movement. I do not want forward movement, I want movement rearward so the angle must be reversed. A hole in the tab for a screw threaded into the .205 diameter pin will push against the back of the slot causing the tab to move rearward and with the 5ish° angle reversed will cause the same downward movement.
I can't determine any other way to cause rearward movement.

 

[Froneck]

The "1911", I use the "" to avoid having to use the exact designation but if checking any gun forum or makers sites like Accuracy X the pistol is called the 1911 so from now on I will remove the ""! The 1911 has a locked breach, unlocked via recoil, slide moves to the rear due to inertia and blow-back. Most .22s are Blow-back only. First was the Colt Ace and the Ace .22 conversion for the 1911 made by Colt. The Kart .22 conversion made by the well known 1911 barrel maker Fred Kart. Another similar .22 conversion was the Day conversion, made by Bob Day. Currently makers like Marvel and Nelson as well as a few imports use the same principle. The .22 barrel is fixed on to the frame and does not move. ALL have used the pin (known as the slide stop pin) to anchor the .22 barrel to the frame. I'm changing nothing except in locking the barrel using a downward force as described created by the angle of the slot when the barrel is pushed forward by the screw pushing on the pin. I want to push it backwards.
Competition shooters shoot a lot of ammo, when my son was home I would purchase 3 cases of .22 ammo (5000 rounds/case) which would last for a year. How many times per year will the pin have to be changed? The .22 phase of a pistol match is 90 rounds fired. Can be more but only 90 are scored. Change the pin before each match?
I will test what ever material I use but want to start with the strongest available.

 

[Paolo_MD]

Maybe I am guessing wrong and, of course, I don't have any clue about how much free space you have around the pin inside the receiver. However, if spatially possible, my solution would be to have a tight clearance hole in your pin and have the pin passing through a bushing which has a threaded cross hole aligned with the one in the pin.
The bushing doesn't need to be hardened (or, at least, not as much as the pin) and its outside can be machined down in places that would otherwise interfere with other components of the gun.
If there is a "tight slip fit" between pin and bushing, the bushing would contribute in increasing the strength of the assembly and a smooth hole with a nice finish (don't you also have a jig grinder?) crossing the pin does have fewer stress risers than a threaded one even if you have slightly less material left.

Paolo

 

[Froneck]

Paolo: there is very little room! In the 1911 .45ACP the lower lug of the barrel would slide on top of the pin to push the barrel into the locking lugs. The pin would fit thru the link that has an outside radius of .184" with just enough clearance for it to pivot. A slot is cut under the pin slightly wider than the .136" width of the link for clearance so there is very little room for a bushing. There very little room to do anything and only way I can think of is to thread the pin.

 

[kenton]

After reading what you want to do I would give 1144 a try. Pretty good mechanical properties and very easy to machine. Buy a 3 foot piece and make a few dozen pins and replace them when they wear out.

Object moved

Edit: it drives me nuts the mcmaster links always change to "Object Moved" but the link still works.

 

[Froneck]

I will order a 3' length of 1144 from MMC tomorrow, I thought about it. It is quite tough I purchase a piece of 3" round for another project. Does anyone know if AR500 is available in rod? Might try AR400. I have a piece of AR500 3/8" plate I got for another project, little bigger than needed so I might shave off a sliver and turn it round.