Any Tips For Drilling A 1mm Hole In A Grubscrew?

[innovator]

As the title says, anyone got any tips for drilling a 1mm hole through a grubscrew? The only grubscrews I can find are hardened and are bloody tough to drill through - using a 1mm drill isn't helping, just keep snapping them off.

I have made a tool that the grubscrew screws into wihch then slots into another piece on the benchdrill, so it is dead centre and not moving at all.

Have also tried heating them up and then chucking them in a bucket of water which made it a little easier, but still hard.

Any hints greatly appreciated.

Cheers

Hi,I`m a newby and an old grey beard at that ,but I do have some suggestions that may help you .Firstly do you have to use grub screws because they are very hard (they are used to fasten pullys etc to shafts and need to dig into the shaft) There are other screws available with socket heads (allen keyed) that are only high tensile and that is easily workable .Nextly if you really need to use the grub screw then you will have to soften it as much as possible .This is done by heating to a bright red and then placing in deep hot sand and allowing it to cool for as long as it takes (overnight) It will probably still retain some hardness due to to the actual carbon content . Before attempting to drill it, slowly file or grind a very small flat on the section of thread where you want the hole(with the edge of a file would be good) other wise when the drill bit engages the thread it will break nearly every time .Center punch and try.If it is still very hard you need to harden a tool steel drill bit (good quality) Do this by heating the drill bit to cherry red (carefully) and then quenching it in mercury .Drills treated thus can drill glass.Sorry this is so long .Hope it helps .

[Duncan]

well.....1 post grey beard and it was a beauty!

[FLN75S]

You could just buy a Flow control and screw that straight into the 3/8 thread you tapped. Thats what i do PM me if your interested i sell them all the time at work.

[stolly]

Thanks for all the suggestions everyone. Greybeard, tried all those things which helped a bit especially cooling the grubscrews slowly rather than quickly. Tried centredrilling them in a lathe but still found it f'ing hard to drill them without snapping drillbits.

In the end got some stainless grubscrews, slow speed on the drill press with plenty of rocol and went through them piece of piss.

[stolly]

You could just buy a Flow control and screw that straight into the 3/8 thread you tapped. Thats what i do PM me if your interested i sell them all the time at work.

-Thanks, by flow control do you mean something like a needle valve? I'm trying to set it up in a way so that once set, the flow (and therefore the speed of the cylinder) can't be altered

[r33_racer]

Good that you got it sorted.

I was going to suggest a carbide drill.

[FLN75S]

-Thanks, by flow control do you mean something like a needle valve? I'm trying to set it up in a way so that once set, the flow (and therefore the speed of the cylinder) can't be altered

Bit late but no not needle valve as they can be altered, the flow control i was talking about is screwed into the line and is set with a certain flow rate like say 1,2 or 3 litres a minute whatever you want pretty much. It can't be altered its a pre set thing.