yampug wrote:yep i think i might splash out on a posh bit, don't fancy a cheapo hss snapping off in the hole.
remember to keep the speed down and use a cutting fluid to help stop the bit from overheating. If the bit does have the cheek to snap, you can usually break them out with a hard hole punch or twist them in reverse with long nose pliers if the bit size is large enough to allow
FOR WHAT ITS WORTH , heat it cherry red and let it cool , the bolts will become brittle and should be eaiser to get out , last one i did i ground off the heads and witha center punch and decent HSS left handed drill bit drilled em out in reverse ...... yes it workd for me but all euxps are deffo not the same
***** TIME TO RIDE TIME TO DIE FASTER FASTER I HEAR YOU CRY ***** life is all about choice
As other people have said invest in a good drill bit, i used a 3 m/m then a 5.5 tungsten carbide drill bit and rocol cutting fluid to do mine. try and keep the drill nice and square to the valve and dont try and drill it too fast.
Tungsten carbide bits are more brittle than normal HSS bits so the key really is nice and easy, after drilling with the 5.5 i ran through with a 6m/m tap one turn forward the half a turn back and take the tap out every 3 turns in and clean it, again do it using a good cutting fluid
Best of luck mate