Date: Wed, 26 Mar 2003 15:22:31 -0600
Reply-To: John Rodgers <j_rodgers@CHARTER.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: John Rodgers <j_rodgers@CHARTER.NET>
Subject: Re: 250 ft-lb torque wrench?
Content-Type: text/plain; charset=us-ascii; format=flowed
A breaker bar (at least 1/2 in. drive) an appropriate sized socket, and
a piee of pipe will do the job.
The formula to calculate the FT/lbs is to multiply the length of the arm
times the force applied. For example, if you slipped a 4 foot pipe down
on the braker bar all the way down to the socket (that half inch or so
off the center won matter for this calculation), then hang a 180 lb man
on the other end of the bar, you will have applied 720 ft/lbs to the
bolt or nut. If the pipe is 2 ft long you will have to double the weight
of the man to still get 720 ft/lbs. Or if you use a 12 foot pipe you
could use a 60 lb kid to apply the force. The point is that by juggling
the weight at the end of the bar and the length of the bar you can come
up with all kinds of combinations of bar length and weight that will
give the same # of ft/lbs.
Trick here in your case is to find a bar of a workable length for your
application and then figure out what weight will work to give you the
required 240 foot/lbs.
One thing, some of the mechanical pointer type torque wrenches have
instructions to tell you how to multiply the torque and still measure it
on the gage mounted on the torque wrench. It is something to look for.
None of the break-over type torque wrenches that I have seen can do
this, though there may be some out there somewhere.
John Rodgers
88 GL Driver
Craig Oda wrote:
> The pulley bolt on my 83 waterboxer will need to be tightened to around
> 240 ft-lb when I reassemble the engine. I'm thinking of buying a 250
> ft-lb torque wrench from HarborFreight. It's like $70 bucks plus tax
> and shipping. (I am a CA resident :-(
>
> The Bentley says that there is some type of tool like a extension that
> can increase the torque of my existing 3/8" 75 ft-lb wrench. I went on
> the Internet and was not able to find this type of extension for a cheap
> price.
>
> What does everyone else do when then torque down bolts like the pulley
> bolt? Do you have a 250 ft-lb torque wrench and just tighten it with an
> cheater bar?
>
> My other option is to buy an impact wrench and air-compressor, which I
> kind of want anyway, but that is more cash :-( and I don't want to
> spend the cash this month. I've never used an impact wrench before, can
> the wrench be set to apply a maxium torque to bolts when tightening the
> bolts?
>
> -- Craig
>
> --
> ------
> Craig Oda's Personal Email
> Living and Working in the SF Bay Area
> Automobiles: '83 VW Westy (watercooled); '77 VW Bay Window
> Other Info: http://communitybuilders.info/~craigoda/
>
