Grade of Stainless for Hinge Pins

[Flash Gordon]

Customer wants me to make some replacement 1/2” diameter hinge pins for heavy architectural doors out of SS.
He thinks the originals were chrome plated brass. Any suggestions on alloy selection?
I was thinking about something stronger than 304.
Thanks

 

[rklopp]

What do the pins turn against? For example, stainless on stainless could lead to galling. Are they interior or exterior? My favorites would be 303 or 17-4 H900 after machining in condition A, but those might not work against whatever hinge knuckle material you've got.

 

[Flash Gordon]

The hinge plates are chrome plated brass. Galling was one of the concerns I had also.
I’m looking for something that I can get from McMaster since I will only need a 3 foot stick.

 

[implmex]

Hi Flash Gordon:
If you really want to go to town and have hinge pins that will last forever, then hardened 420 would be my first choice because it's tough too and will go up to about 52-54 RC.
Those hinges will wear out a century before the pins show any wear at all.

Next on the list would probably be 17-4 PH condition H900 as rklopp has recommended.
Not so gall resistant but still pretty good at 44 RC and easily machinable in the hardened state (except drilling tapping and reaming).
High strength stuff 170,000 PSI yield strength vs 30,000 PSI for 303.
McMaster sells it but it's expensive.

Other exotic grades like Duplex 2205 don't get much harder than 303 does and their use is mostly in very corrosive environments...pointless for hinge pins on doors.

Nitronic 60 doesn't gain you anything either.

I've been disappointed with 303 for things that wear, but no more so than with 304 or 316, and 303 is much nicer to machine.

Those are probably the most common choices available to you, and if the originals were chromed brass, I'd say fukit and make them out of 303, maybe with grease nipples on them so when they never lube them you can point to the grease nipples and claim they didn't maintain them properly.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com

 

[Murf]

Are you sure you want the hinges to wear prior to the pins (cheaper and more easily replaced)?

Murf

 

[plastikdreams]

I like the 17-4 and 420 suggestions...but why limit yourself to stainless when you can get some 625 or 718 inconel? Then of course one could grab some Ti6Al4V...personally I'd go with the 17-4, but I'm a big fan of the stuff.

 

[LOTT]

You can buy hardened and ground 17-4 H900 from McMaster, cut it to length and TIG weld a washer on top. Ten minutes from start to finish.

 

[Triaged]

17-4 H900 is a great choice for stainless but why not chrome plated steel?

 

[implmex]

Hi Triaged:
I've found that by the time you've screwed around with a plater for just a few pieces, you're way better off financially to just buy the more expensive stainless and avoid the whole chrome plating thing.

Sometimes you just can't get the perfect match to something that's already chromed by having even a polished piece of stainless next to it but for something like these hinge pins, I wouldn't personally strain myself.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com

 

[Triaged]

You're right, if I was going to pay the min lot charge for chrome I'd make it out of a better material! Maybe I should have been more specific... McMaster sells chrome plated shafts that could make a good hinge pin. https://www.mcmaster.com/product/5947K13

 

[Flash Gordon]

Thank you to everyone for their suggestions. I will go with the 17-4 PH.
These pins are not shaped like the ones for a normal door. They’re only about 1” long and the head of the pin is in the center. Picture a 1” diameter washer with a 1/2” diameter shaft sticking out from each face of the washer.

 

[Rob F.]

Do you need to add a zirc fitting and grease passages so this wont happen again anytime soon?

 

[plastikdreams]

Well I mean...there's always Thompson rod.