Re: Having a ball with a joint....

[Sam Letzring <slet@ftp.lle.rochester.edu>]

>X-Authentication-Warning: coimbra.ans.net: majordom set sender to
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>Date: Fri, 21 Jun 1996 15:42:23 -0500 (CDT)
>From: Jeremy R King <kingjer@eng.auburn.edu>
>To: Michael Spiers <mikes@specnet.com>
>Cc: rao@pixar.com, quattro@coimbra.ans.net
>Subject: Re: Having a ball with a joint....
>Sender: owner-quattro@coimbra.ans.net
>

_________________________________________________

On the subject of bolts- 

According to my info - and this comes from the McMaster-Carr catalog- my
bible for all such info and a good way to find obscure mechanical hardware:

Metric Cap Screws- Grade 8.8 ( marked as such on the head) Are comparable to
SAE Grade 5- up to 16 mm dia. minimum tensile strength is 116,000 psi. These
are sometimes available in hardware stores.

Metric Cap Screws- Grade 10.9 are the high strength bolts comparable to SAE
grade 8.  Minimum tensile strength is 150,00 psi.

Stainlees Steel Metric cap screws- 18-8 Stainless steel have only a minimum
tensile strength of 100,000 psi.- so don't be tempted to use these for
automotive applocations. These screws I know are usually available in small
hardware stores.

Metric Socket Head screws ( hex allen head) are usually availble in DIN 912
class 12.9 with a minimum tensile strength of 176,900 psi which exceeds SAE
grade 8 specifications 

Pep Boys carries the best selection of 8.8 and 10.9 grade metric hardware I
have found- complete with all the nuts and washers.

SAE Grade 5 bolts have three radial raised lines on the head of the bolt and
have a minimu tensile strength of 120,000 psi up through 1" dia.and grade 8
bolts have 6 radial raised lines on the head and have a minimum tensile
strength of 150,00 psi.

Din 931/933 Spec. bolts have the grade 8.8 or 10.9 raised on the head of the
bolt.

Hope this continues to clarify the strength question. It is not really the
"hardness" of the bolt, but rather the tensile strength of the bolt- i.e the
force required to "stretch" the bolt.


Sam
______________________________________________________



>Yes.  The 8.8 means "grade 8".  If they're not at the local hardware, try
>a fastener store.  There are two such stores here in Auburn (small town)
>so there should be one near you.  Opelika Bolt and Screw (shouldn't the
>order be reversed?) even sponsored our Formula SAE racer.
>
>---------------------------------------------------
>Jeremy R. King	    Auburn University, Alabama, USA
>///////////     '86 VW Quantum GL5     \\\\\\\\\\\\
> Rear Dynomax Glasspak, Hollow cat, Drilled Airbox
>   Sach's / KYB struts, Round 55W Driving Lights
>\\\\\\\\\\\  Still Slower'n Christmas  ////////////
>---------------------------------------------------
>On Fri, 21 Jun 1996, Michael Spiers wrote:
>
>> > >  Get new ball joint bolts too, torque to spec....
>> >
>> >
>> > 	Yes, and note that they have a particularly high hardness
>> > 	grade (10.3, I think).
>> 
>> The pretty green-tinged jobs I've got in front of me say 10.9.  Cool.
HBL Audi
>> had 'em on the shelf (at a bargain price of $2.51 each no less.)  The other
>> bolts I need to replace are the inner control arm bolts, tehy have 8.8 on
'em.
>>  Any local hardware store should have those right?  (HBL didn't have
these, nor
>> the nutz for the ball-joint bolt.)
>> 
>> -- 
>> -Mike
>> mikes@specnet.com
>> mks107@psuvm.psu.edu
>> 87 5000CS TQ - Metropolitan Washington, D.C. (but not for long...)
>> 84 5000S - Boulder, Colorado
>> 90 80 - Bethesda, Maryland
>> (hunting for the elusive Lago Blue '91 200Q)
>> 
>
>
>
Samuel A. Letzring
Senior Scientist
Laboratory for Laser Energetics
University of Rochester
Rochester, NY. 14623
716-275-5659
FAX 275-5960