clarke5700

Hello i need to open up two 13mm holes to 19mm i ran the part over to the machine shop as i dont have a 19mm bit and thay had ago but said they could not do it due to it being hardened steal any idears?? Or links to a special drill bit i could buy?? Gessing it will have to be a diamond bit??

stucos71

Drill bits for stainless steel usually cope with hardened steel, as they dont burn out like ordinary bits.
Ive got a few, and they have never failed yet

rst in breaking

iTrader: (2)

i have a few 19mm bits clarke used for drilling breathers if any use?

LukeDaisley

iTrader: (1)

i had to drill a hole in a old WW2 tank last Christmas ended up using masonry bits in the end.

Ginge !

dont you aneal metal when its heat treated ?

ajamesc

cobalt drill bits are good and go up in stages not just 13 to 19 also dont drill to fast

SteveB

iTrader: (3)

Drill it very slowly and use plenty of lube....

Ginge !

you are talking about the same thing aint you steve,,,,,, kids also use this site too pmsl

jamesXXX

Cobalt bits, nice and slow, will get through most things

chaffe

feeds and speeds

clarke5700

Hmmm im gonna have to get looking for some drill bits

stevieturbo

Cobalt bits will go through it no problem.

I had to drill my crank. With normal HSS bits, it barely made a mark. Even with a cheapy cobalt bit off egay, it drilled no problem. I was quite amazed.

What exactly is it you need done though ? Could somewhere with a laser or waterjet machine open them up ?

Mark V8

iTrader: (2)

Tungsten carbide would do the job, if the part will fit on a milling machine any engineering shop with a carbide tipped boring bar or a CNC mill and a carbide milling cutter could do it.

If it's crazy hard then you could get it spark eroded.

Mark

cabriolet

used masonry bits on hardened steel before to good effect

zippyobrien

iTrader: (2)

Cobalt as said. But is go with tungsten carbide. Half the usual speed bit with an agressive feed. Probably find its only case hardened any way

The reason you agressive feed it is to stop it getting a chance the heat up and further harden it.

Assume your using a pillar drill as a minimum, not trying to pistol drill it lol

clarke5700

Lol yea got a piller drill. Its like to washers they are only 3mm thick with 13mm holes in them all ready just need opening up to 19mm i think ill have to buy a bit and give it ago.

stevieturbo

If it's just a washer, wouldnt it be easier just to buy bigger ones ? Can they be held securely to run a drill bit through them to enlarge ?

Might be as handy with a die grinder and carbide burr to open them up.

clarke5700

Its LIKE a washer. But curved shape to it and an indent ectect not an off the shelf washer

chaffe

washers! bore them out on a lathe! with carbide tipped tooling

SteveB

iTrader: (3)

How about a dremel type tool with a grinding stone???

chaffe

chaffe

how about this

SteveB

iTrader: (3)

Care to share the joke???

chaffe

i was crying not joking

zippyobrien

iTrader: (2)

A lathe would be preferable. If ur not in a desperate rush. Post me them, ill machine them and post them back mate.

tabetha

I've got cobalt and carbide bits up to 28mm, and a lathe/pillock drill if you need some help, use heat soak grease for cooling that's what I use, all my bits are shanked to 13mm so fit in a ordinary drill as well, just go up in 0.5mm or 1mm increments at a time will be no problem.
tabetha

wilky

iTrader: (1)

i run my carbide 6mm slot drill at 800rpm to take out stainless boltes[turbine housings]