Drilling stainless steel

[Robin427]

The GD fuel tank seems to be made of the same alloy that the Terminator was made from - some sort of futuristic armour plate. I need to drill 6 holes in it to fit the fuel sender but I've already snapped one (new, quality HSS) drill bit and I think I've burnt out another bit already. Should I be using carbide bits or some sort of laser device?

[Kevin W]

I doubt its made from anything esoteric. My suggestions for drilling stainless (obtained from many attempts at doing it wrong) are:

Don;t hit the hole punch too hard - just a little nick in the surface is all thats needed to locate the drill bit - an almightly dent will make drilling very difficult.

Drill a small pilot hole (1-2mm to start with), then drill the larger hole that you require.

When drilling the larger hole, use a slower drill speed, be patient, and ensure the tip doesnt get hot. Use a light oil to cool the tip. I have also used cutting compund to help along drill bits which are getting blunt...

and so lastly, and probably most important, ensure drill bits are sharp, and don;t drill fibreglass with the high quality drill bits used for drilling stainless/mild steel.

HTH

Kevin

[Robin427]

Already snapped my 2mm drill bit. Think I might drive up the road and buy a big pack of 4.2mm HSS bits. I'll try using a lower speed - I assume WD40 will be OK for lubrication?

[Robin427]

OK... that's the 1.5 bit snapped

[Cabo]

Get hold of a set of cobalt bits such as these :-

http://www.screwfix.com/app/sfd/cat/...10331&ts=29039

If those dont do the job then superglue might be the next resort

[BenBaron]

you wanna see how many drill bits I got through drilling holes through my stainless engine bay cladding....I riveted every inch!!! think I went through about 200 rivets or more, probably 15 drill bits.... was sulking afterwards, during and before....

[Robin427]

God knows how GD originally drilled the large hole for the fuel sender - I'm going to head up the road to the drill bit shop...

[craigh]

get some stainless steel drill bits and use some form of cooling agent, its tough stuff ,i used a squirt of wd40 now and again to help things out

[Robin427]

Blimey, they don't give away those Cobalt bits, do they? Had to buy a ten pack of normal 4.2mm bits as well as the cobalt ones only do half mil sizes

[Robin427]

WOW! They go through it like butter!!!