Hi Jeff
Whilst we're on the subject of taps here's a tip, and possibly the reason
your tap broke, always ensure that none of the original bolt is left in the
hole you are going to re-tap, if some is left as you tap the thread the
piece of old bolt will often come loose and act as a wedge, (it gets pulled
round rather than have a new thread cut in it!) jamming the tap solid. I am
a toolmaker and spend a good proportion of my time repairing steel dies for
casting aluminium, these take a pounding and often screws holding the
handles etc break. I have been where you were several times and have found
this to be a big cause of broken taps, of course they will also break all of
their own accord! I hope this can ease your troubles in future.
Graham.
----- Original Message -----
From: Jeff McNeal <jmcneal@ohms.com>
To: Graham Stretch <technical@iwnet.screaming.net>
Cc: List Spitfires <spitfires@autox.team.net>
Sent: Tuesday, March 07, 2000 3:15 AM
Subject: Re: screwed... My solution
>
> Well, you guys were right. The Cobalt bit didn't even make a dent! But
my
> die grinder sure did! Sparks were flying as I ground down the welded-on
nut
> into oblivion and with it, that darned broken tap. For now, I just have a
> large fender washer doing the honors with a nut and locknut. It'll do
until
> I can teach myself how to weld -- or not.
>
> Thanks to all who offered suggestions.
>
> Got a new problem though... A couple actually. I'll save it for another
> thread.
>
> Jeff
> ----- Original Message -----
> From: Graham Stretch <technical@iwnet.screaming.net>
> To: Jeff McNeal <jmcneal@ohms.com>
> Cc: List Spitfires <spitfires@autox.team.net>
> Sent: Monday, March 06, 2000 12:29 PM
> Subject: Re: screwed...
>
>
> > Hi Jeff
> > I doubt that the Cobalt drill will touch it either, for the jig try a
> piece
> > of flat steel stock with a hole the right size drilled in it, try the
back
> > door of a local machine shop with enough Dollars for a drink! They will
> > probably have some scrap around big enough for your needs (1"x1"x6"
should
> > do) cramp this to the floor and drill down the hole. Alternatively I
think
> > these cars use a nut welded to the floor from underneath why not just
> remove
> > it and weld a new one in place.
> >
> > Graham.
> >
> > ----- Original Message -----
> > From: Jeff McNeal <jmcneal@ohms.com>
> > To: Spitfire List <spitfires@autox.team.net>
> > Sent: Monday, March 06, 2000 4:50 AM
> > Subject: screwed...
> >
> >
> > >
> > > Pardon the abrasive header of this message, but it seems like the most
> > > concise way to describe my situation. When replacing my seat rails
> > > yesterday, I noticed that the PO had drilled an alternate hole in the
> seat
> > > track because he busted one of the 1/4" mounting bolts in the original
> > hole.
> > > Up for the challenge, I sawed off the nub sticking up so I would have
a
> > > nice, flat surface to drill through, which I did with a 7/32" bit,
> > drilling
> > > through the old bolt. So far, so good.
> > >
> > > Next, I borrowed a buddies tap and die set and proceeded to tap a new
> 1/4"
> > x
> > > 28 thread. Then, SNAP! The tap busted off inside the hole, with no
way
> > to
> > > get it out. I killed two perfectly good drill bits trying. Someone
> > > suggested a cobalt drill bit to slice through the hardened steel of
the
> > tap.
> > > Now, the thing is a real mess and I'm trying to figure out the best
way
> to
> > > drill back through and retry with a new tap.
> > >
> > > I wish there were some kind of jig I could create that gave me the
> > stability
> > > and precision of a drill press. Right now, there's no way I can get
the
> > bit
> > > started straight on because of the way the tap broke off. My plan at
> the
> > > moment is to attack the problem from the bottom side this time, using
a
> > die
> > > grinder to flatten off the bottom, before drilling up and through.
> Before
> > I
> > > attempt this, is the broken tap going to be too much for my grinding
> > wheel?
> > > IS there a simple, clever way to rig up a portable drill press so I
can
> > > drill straight down without worring about drilling crooked? Or should
I
> > > just say "screw it" and use the alternate hole that the PO drilled,
even
> > > though it interferes with the travel of the sliders?
> > >
> > > Thanks!
> > >
> > > Jeff in San Diego
> > > 67 RHD Spitfire Mk3 aka Mrs. Jones
> > > www.ohms.com/spitfire/spitfire.shtml
> > >
> > >
> >
>
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