morning all

Attempted to fit headlights last night on got nowhere fast. The hole on the headlight bar on my Indy is 12.5mm and I need to open it out to 16mm.

Tried using a step drill with oil and it did nothing apart from blueing the drill bit which apparently isn't good.

What type of drill bit/tool would give me the best cutting results using a normal drill or do I need something completely different?

Thanks
Nigel

[Edited on 24/9/07 by jabbahutt]

Cobalt drills seem to manage just about everything

Depends how hard the mounts are (but I don't see why they would be particularly hard ). I would try one of the conical - shaped grinding stones they sell in B&Q etc. Wiggle it about a bit (oooh errr) so as not to wear it down in one place.

HTH

Tapered reamer?

Mine was handy for all that sort of stuff as the chuck in my drill is only 1/2"

Stainless Steel ?
Some stainless steels can be a swine to drill, use a slow rpm and decent quality drill (titanium coated cobalt ot titaanium coated HSS) and lots of soapy water to cool the tip.

Or get a better stepdrill, it really should cope fine with mild steel and stainless if used carefully.

Quality high cobalt drills are a worthwhile investment.

jk

I would guess your drill speed was too high or you used a stepped drill from screwfix.

It doesn't sound like the hole nbeeds to be in a prercise positon so how about using a round file to open the hole out? that is what I do. (sometimes)

Any standard drill should not be used to CORE DRILL, that is in effect what you are trying to do.

Without the chisel point being engaged you are asking for trouble, the drill will jump about and snatch, maybe even break as a result.

It may be done using a pillar drill where you can very gently feed the cutting edges into the workpiece very carefully. Using Cobalt drills is actually a no,no. They are more brittle than standard HSS and will chip the edges off and be even easier to snap.

Use a Standard HSS if need be, drive it slow, feed it slow and make everything as rigid as you can.

Failing that - use a Rat Tail File.

Steve

You could use a hole saw if really stuck by clamping or welding a bit of metal underneath the existing hole to allow the pilot of the hole saw to be located .Then drill at a slow speed with steady pressure
Alternatively a carbide Burr in a die grinder would do the job.
Paul.