Taps that are used on a freshly drilled hole have a taper to get them
started. If you're tapping a blind hole, the taper hits the bottom well
before the threads get cut all the way to the bottom. In a really good tap
set designed for blind holes, there's a starting tap, that has the usual
amount of starting taper, a second tap with a shorter taper to get you
close to the bottom, and a bottoming tap with no taper that gets the
threads all the way to the bottom of the hole.
You only need bottoming taps when you want the threads to go all the way
to the bottom of a blind hole (like the head stud holes in a block), which
not only makes the stud less likely to pull out because more threads are
engaged, but is always a good idea, because a blind hole with tapered
threads will put a lot of sideways pressure on the bottom of the hole and
will tend to jam the stud. Of course you don't need them at all when the
hole you're tapping goes all the way through.
In the case of the ARP studs, the threads on the ones that Greg gets are
longer. The hole is already tapped, so no taper is necessary. The
procedure is to drill a little deeper into the block with exactly the
right size drill--which doesn't touch the existing threads--and then
thread the bottoming tap in and extend the threads to the bottom of the
hole.
-----Original Message-----
From: Rob Dardano [mailto:19to1tr6@mediaone.net]
Sent: Wednesday, February 06, 2002 7:26 PM
To: Bill Babcock
Subject: Re: bottoming tap
Hi Bill read the e-m on ARP studds and need to ask. What is the
differance
between a tap and a bottoming tap. does it flatten the bottom of the hole
some how . And is it the right tool to use or do taps do just about the
same thing. Or a simpler ques. would be do you have to use a bottoming
tap
in this sittuation ?If so were else is it ness. when you are tapping a
hole?
Thanks Bill just tryen to get learnered I should start with spelling, and
grammer NAH// rob
----- Original Message -----
From: "Bill Babcock" <BillB@bnj.com>
To: "'Joe Curry'" <spitlist@gte.net>
Cc: <fot@autox.team.net>
Sent: Wednesday, February 06, 2002 8:13 PM
Subject: RE: Rear Wheel lift
> Replace your Quaife with an ATX and you won't care so much if you lift a
> wheel. Quaife's are torque-biasing diffs, ATX's are true limited slips.
>
> I think the main reason LBCs lift wheels is that the roll center of the
> front is different than the roll center of the back. Real suspension
gurus
> might be shaking their heads at such twaddle, but I think it's true.
> Usually that means bringing the front roll center up, though with your
> rotoflex rear suspension you might be able to bring the rear lower. I
> don't know much about them. Theoretically a heavier rear sway bar will
> force the outside wheel down, but in practice, that much force will
> increase the rear end steer, make the car too tight and will probably
> screw up the turn in. Not what you have in mind for autoX.
>
> You could also get a passenger to hang their ass out like a sidehack.
>
> -----Original Message-----
> From: Joe Curry [mailto:spitlist@gte.net]
> Sent: Wednesday, February 06, 2002 2:25 PM
> To: Friends of Triumph
> Subject: Rear Wheel lift
>
>
> Hey Guys and Gals,
>
> I have been having a ball figuring out the limits of Tiny Tim (the
> Autocross Spit) now that I have the S2000 engine performing as it is
> supposed to.
>
> My most immediate problem is that on a hard corner, I am lifting one of
> the rear wheels.
>
> Bear in mind that I have a Rotoflex rear suspension and a Quaife LSD.
> What recommendations do you have about how to keep all four tires firmly
> planted on the pavement?
>
> I eagerly anticipate all the learned replies!
>
> Regards,
> Joe (C)
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