Date:         Tue, 15 Jun 2010 07:39:02 -0600
Reply-To:     Bob Johnson <b.johnson1950.2010@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Bob Johnson <b.johnson1950.2010@GMAIL.COM>
Subject:      Re: noise SOLVED. Now need to Heli-Coil?
In-Reply-To:  <4c16e641.d7b4e50a.277e.ffff8e23@mx.google.com>
Content-Type: text/plain; charset=ISO-8859-1

Absolutely true!
One of the biggest mistakes in drilling a hole is not enough pressure!
Especially on the larger diameters!

That said, there is machine drilling and there is hand drilling!
I have actually dulled a drill bit so that it doesn't grab!
Especially with some of the softer metals.
Brass, Copper, Aluminum

It's better and safer when drilling by hand to not have the drill bit too
sharp.
Again especially on a pre-drilled hole.
They tend to want to grab most !
No fun to be spinning around with a big 1/2" drill motor in your hands!

Reach a balance where you are producing a chip
but not burnishing up the hole !
(heat treating)  ;o)




On Mon, Jun 14, 2010 at 8:26 PM, David Beierl <dbeierl@attglobal.net> wrote:

> At 09:55 PM 6/14/2010, pickle vanagon wrote:
>
>> But I think I'm going to try the helicoil repair this weekend.  I don't
>> want
>> to run 3 bolts long term.  Is the insert really that hard to install?  I
>> figure, after I drill and tap, that the insert must be pretty easy to get
>> in.  And, where I'm' doing it, I'll have easy access.  Not like doing this
>> in an engine compartment.
>>
>
> The hardest part is getting the tap to go in straight.  Compared to
> that, most everything else is dead easy.  If you're not used to
> drilling in steel -- use a drill containing cobalt if possible, use
> cutting fluid (Tap Magic, lard, whatever you're going to use for
> tapping).  Keep the drill speed way down (for this size I'd stay
> below 700 rpm)  and use *heavy* feed pressure.  You want the tool to
> cut and not rub.  Watch out -- if the drill snatches as it breaks
> through, it will snatch your wrist if you let it.  If the drill
> dulls, sharpen or replace it, then turn slower and push harder.  But
> take great care that the tool is always cutting.  If it rubs it may
> work-harden the steel and then you'll have a much more difficult time.
>
> Yours,
> David
>