Date: Fri, 8 Jul 2011 00:37:08 -0400
Reply-To: Kim Brennan <kimbrennan@MAC.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Kim Brennan <kimbrennan@MAC.COM>
Subject: Re: [Friday] Bolts -- Rockwell hardness translate to grade?
In-Reply-To: <1310098443.12454.65.camel@TheJackUbuntuNetbook>
Content-type: text/plain; charset=windows-1252
www.mcmaster.com
Get the right stuff. If you choose the military grade stainless, it will most likely be more than enough.
On Jul 8, 2011, at 12:14 AM, Rocket J Squirrel wrote:
> Hi all (jumping the gun a bit on that Friday thing . . . )
>
> I bought a Hi Lift jack from Al "Pensioner" Knoll earlier this year.
> It's a vintage piece. Very cool.
>
> I just went to refresh the critical parts on the jack with ones from Hi
> Lift's jack rebuild kit, but the shear bolt and the climbing pins in the
> kit don't fit.
>
> Puzzled, I contacted Hi Lift and described what I was looking at and the
> fellow there said that the jack was made prior to 1960 (!) and they
> don't have parts for it.
>
> While the original climbing pins are in good shape, the original shear
> bolt is bent a bit. Needs replacing. I asked Hi Lift what grade of bolt
> I could use there and the nice man wrote back to say:
>
> "I’ve been a couple of days trying to get you an answer, but with little
> success. Our shear bolts are specially made and heat treated for us.
> The Rockwell hardness scale on these bolts ranges from B85-95, with most
> testing to B89-90. I’ve been trying to find out what bolt that compares
> to but have failed to find any comparison."
>
> So I looked at some charts this morning and, if using tensile strength
> is any indication, this Rockwell hardness translates to something like
> 88,000 psi. Grade 2 bolts come in at around 74,000 and Grade 3 (a
> rarity, I think) are more like 110,000. It's a 1/4'' bolt.
>
> Did I count on my fingers and toes good enough?
>
> The fellow went on to add that,
>
> "I know my dad would break his shear bolt and just stick another bolt
> into it, but that is not a recommended safe practice. I wish I could
> just send you a shear bolt, but we’ve checked and don’t have any laying
> around after all of these years."
>
> Fair enough.
>
> So I got four choices here: re-assemble the jack and sell it on
> craigslist with a caveat and buy a new jack, re-assemble this one with
> the deformed shear bolt and see if it holds when I need it (not so
> smart), or bang in some Grade 1 or 2 bolt* from the hardware store
> (unknown degree of smartness).
>
> Ideas?
>
> =============
> * There does not seem to be any way to determine whether a bolt is Grade
> 1 or 2, as neither have marks on the head. So what's my Ace Hardware
> store gonna stock? It is a mystery!
>
> --
> Rocky J Squirrel (Jack Elliott)
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