[DeTomaso] drilled bolts for brake calipers

[boyd casey]

I have never worked with saftey wire unless the connection in question was
slready saftey wired. So this probably falls into the category of a "stupid
question" But it is mt belief that the only really stupid question s are
 the one's you don't ask, So here is my stupid question: I suppose that
aircraft grade hahardware  (nuts and bolts) that are pre drilled are
probably prohibitively expensive   and harder to get ( You can't just run up
to the local hardware  store)   On a side note Harbor freight has a safety
wire tool on sale in the current ad and they have the wire on sale too. I
have never been great at precision drilling or cutting so the  idea of a
drill press and a jig sounds like a great idea if available. Also this is an
area where it definitely pays to get quality drill bits and but bits from a
reputable source ( as you said once the hardware is out of the box you don't
know what you have), Thanks for sharing the benefits of your advice.

Boyd

On Fri, Aug 7, 2009 at 3:11 AM, <JDeRyke at aol.com> wrote:

> In a message dated 8/6/09 11:0





> 2:02 AM, kenn_green at yahoo.com writes:
> snip....
> > is 1/16 (0.0625") OK for safety wire?  Seems like cobalt drills would be
> > a good choice.  But I thought that cap head screws were usually grade 8.
> >
> As long as the bolt head is big enough to safely accept it. The
> aircraft-grade safety wire of choice is 0.032" dia, so drilling an 0.060"
> hole is far
> bigger than necessary, but in these bolts it should work OK. An 0.060"
> drill
> is maybe slightly less prone to break than an 0.048", I guess. Stock
> caliper
> bolts are metric gr 8.9, roughly equivalent to our SAE gr-5, so no problem
> drilling them.
>
> High-carbon bolts (gr 5 or 8) drill fine as long as -A- the drill is sharp,
> -B- you use lots of lube and -C-use the right drill speed. Too fast is
> worse than too slow 'cause it builds heat. Once the drill bit gets hot or
> dull-
> which happens pretty quickly, the bottom of the hole will overheat and that
> hardens the steel in & around the partial hole. Then, you've really got a
> problem finishing up that hole, even with a new bit and the hole full of
> oil.
> Sometimes, its better to start over on a different flat with a new drill
> bit. As I said, have a pocketful of new bits close by when you start such a
> project drilling many bolts and don't try stretching a worn bit for 'one
> more
> hole', which will only end in tears...
>
> You guys know not to drill straight thru a hex-bolt head.... the technique
> is, you start in the middle of a flat, drill in a very short distance,
> rotate the bolt head so the drill is now angled to the surface and drill in
> a
> little more, using the initial hole to catch the bit so it doesn't slide
> off.
> Then rotate the bolt still more & continue.... if done right, the hole will
> go in one flat and out the next one, not clear across the head. All this is
> slow & tedious and is why people sell drill guides, but it can be done
> satisfactorily either way.
>
> With allen bolts, you drill one hole straight through one side into the
> center hex hole, again not all the way across and try to not hit a corner
> of
> the internal hex. If you do, you may have to pound a hex-driver in the
> hex-hole (before adding the wire) to deburr it enough to tighten it.
> Normally,
> they're much simpler than drilling hex bolts, even though black-oxide
> allens are
> almost always gr-8. But there are so many chinese-copies floating
> around..... Stainless ones can be almost any grade and are not often
> marked, so out
> of the box, you never know for sure.   Good luck- J Deryke
> _______________________________________________
>
> Detomaso Forum Managed by POCA
>
> Archive Search Engine Now Available at http://www.realbig.com/detomaso/
>
> DeTomaso mailing list
> DeTomaso at list.realbig.com
> http://list.realbig.com/mailman/listinfo/detomaso
>