Material suggestions?

[Highpower]

OK all you engineers out there!   

I want to make a new ratchet collar for my arbor press. The original is a porous casting with obvious voids in it and I just don't trust it. I'm sure it will end up failing on me at the worst possible time. So what's the group's general consensus on what the best material to use would be? I don't happen to have any steel in that diameter sitting around, so I will have to purchase something specifically for this job no matter what. So what material do you recommend I buy? 

p.s.
It is a 3-1/2 ton press if that matters.

   

[Dr Stan]

Highpower,

Are you referring to the ratchet itself, or the arm that acts as both a collar and to hold the handle? I'm a bit confused because of your references to "diameter" and "casting".

If its the arm I'd go with a weldament out of 1018 cold rolled or hot rolled. Machine as necessary.

If its the ratchet it would depend on what if any heat treating equipment is available. I'd probably go with 1018 also, but case harden the teeth and keep the core relatively soft to reduce the chance of breaking the teeth.

Stan

[PixMan]

I would use 4140PHT, no question. No further heat treatment required.

[f350ca]

I'd probably make it from the best mystery metal I could find at the dump. 4140 as Ken suggested would be my choice, even in the annealed state, easier to machine and face it we shouldn't be buying green bananas, you'll never wear it out.

[Highpower]

(03-31-2015, 10:48 PM)Dr Stan Wrote: Highpower,

Are you referring to the ratchet itself, or the arm that acts as both a collar and to hold the handle?  I'm a bit confused because of your references to "diameter" and "casting".

Stan

Sorry Stan. I'm referring to the ratchet collar or 'wheel' with the teeth going around it. (The rusty part showing.) Moisture collects in the voids and well, you know...

By diameter I meant the size of the round stock I will need to make the new part. Approx 3-1/2" diameter.

I don't know if the original is cast steel or cast iron. But it certainly wasn't machined from solid bar stock. 

Ken, I'll have to check with the local metal supply. (Shapiro) I think they have 4130, but I'm not sure if they have 4140. 

[Highpower]

(03-31-2015, 11:38 PM)f350ca Wrote: ... and face it we shouldn't be buying green bananas, you'll never wear it out.

Point taken Greg.     

[Highpower]

Well, Shapiro doesn't have any 4140 so local pick-up is out. A few places I checked only have round stock up to 1-3/4". So I went to Speedy Metals web site to have a look. They have plenty of it in the larger diameters.

But now I'm faced with too many choices. 

4140 hot rolled - annealed
4140 hot rolled - hardened
4140 cold rolled - annealed
4140 cold rolled - hardened
And just for good measure, let's throw in some 41L40 as well.   

Mystery metal is sounding better all the time!   

[dallen]

Willie
have you pulled the pinon out of the press yet, some of those are made all in one piece

DA

[Highpower]

David,
Yes I did several years ago when I bought it. I tore it apart to clean and lube everything, but mostly to try and shed as much weight as I could so we could lift it up onto my workbench. The legs of my engine hoist don't fit under the bench and it is one heavy son-of-a-gun.

It's one of those projects that I have just put off for too long. The ratchet slides off of the pinion but now that you mention it, I don't remember if it is keyed or splined to the pinion. I THINK it just keyed though. Will have to look at that again.

[Vinny]

I'm wondering how well 1144 Stressproof would work.