Lock wiring = broken drill bits

tinsfci · Postby **tinsfci** » Sun Nov 20, 2011 9:14 pm

Preparing the new to me race car for next weekend, and needed to drill a diff plug. Bought this http://pitposse.com/posawikit.html , which includes a jig to hold the bolt head while you break a drill off in it. Seriously (insert profanity here) a solid punch in the gentlemens region is slightly less painful than this! Even using the drill press I managed to break drill bits! I finally got it done using a cordless drill freehand.

So, school me on drilling bolt heads... how do you do it without breaking 3 bits for every bolt drilled?

japester · Postby **japester** » Sun Nov 20, 2011 9:32 pm

tinsfci wrote:Preparing the new to me race car for next weekend, and needed to drill a diff plug. Bought this http://pitposse.com/posawikit.html , which includes a jig to hold the bolt head while you break a drill off in it. Seriously (insert profanity here) a solid punch in the gentlemens region is slightly less painful than this! Even using the drill press I managed to break drill bits! I finally got it done using a cordless drill freehand.

So, school me on drilling bolt heads... how do you do it without breaking 3 bits for every bolt drilled?

Can't say about bolts specifically, but for drilling metal, slow, very slow, solid pressure and cutting fluid. WD40 is a reasonable substitute, but any light oil that will transfer heat will do.

What speed were you spinning the drill bits at?

and ...

What on earth is that Pit Posse wire kit? Not being a race guy, I've never seen/heard of them before.

tinsfci · Postby **tinsfci** » Sun Nov 20, 2011 9:41 pm

The kit has lockwire pliers to twist the wire and a couple of jigs, one to hold a bolt head and the other the threaded part of the bolt.

You are probably spot on with not using enough cutting fluid, drill speed was slow enough, but the small bit really grabs. The wire is ~0.8mm, the kit drills are probably just over 1mm and I used 2mm bits for hand drilling. The 2mm bit worked better, but I still managed to break one.

japester · Postby **japester** » Sun Nov 20, 2011 10:58 pm

1mm drill bits are damned fragile!

I've gone through a stack of 1.2-1.6mm bits and I've only been using them in wood, or fibreglass. I'm not surprised you broke a few going into metal.

deviant · Postby **deviant** » Sun Nov 20, 2011 11:28 pm

japester wrote:
What on earth is that Pit Posse wire kit? Not being a race guy, I've never seen/heard of them before.

On a log booked race car you have to secure anything that can vibrate loose and allow fluid out...so sump plug, gearbox drain and fill points and the same for the diff.

'Lockwiring' is an aviation thing. EVERYTHING in aviation is lockwired.

Here is an example, you can see how there is no way you could turn any of those bolts in an anticlockwise direction:

Lockwire pliers are cool things, you grab the two ends of wire in it and lock them shut. Pull the knob out at the end and they spin around and twist the wire up. You then use the pliers to snip off the excess.

Drilling bolts and stuff out is a sh*t of a job. I work in aviation and most fixings can be purchased pre-drilled so we try and avoid doing it ourselves.

You MIGHT find aviation grade stuff in the right size but there are all sorts of sizing differences. I dont know a great deal about it but I dont believe there is a great range of metric stuff so you would need to trawl through the conversion books and look for the closest fit you can.

The lock wire thing will give you the shits once you have done a couple of fluid changes. I always thought you might be able to use these everywhere and weld the suckers in: http://fumoto.com.au/ and then just lock the tap.

tinsfci · Postby **tinsfci** » Mon Nov 21, 2011 1:05 am

It's starting to make sense now. In the pictures Deviant put up the head is drilled from one flat to the opposite. The jig I have drills at an angle in one flat and out the adjoining one, and I was generally breaking drills just as they broke through. I'll guess that the non-parallel edge of the exit hole is enough to make the bit chuck a sad. Mine effort isn't quite as pretty as those pictures, but it does the job.