Recently i have been thinking there has to be some easier methods for drilling ss304 material for 02 sensor bungs. I generally do not want to work harden the material so i try and keep the piece cool and drill at low speed.

My current method is a drill press using a stepped drill bit.

I am curious to know your methods and if you have any specific tools or bits that might make the job easier?

 

Try using some Castrol Moly Dee fluid...It works wonders on tough stuff like stainless. Those step bits work pretty well if you have the cobalt version of it. Make sure your cutting edge is SHARP.

 

just use the proper size drill alan. the step drill takes too long to get the proper size which creates more heat. also use some coolant if you aren't already. or you could plasma the hole, but that might require more tidy up before welding the bung.

 

I use a hole saw. Fastest with least heat. I use the good Morse red ones. Last forever.

 

Use lots of coolant or if you can get some jokish that stuff is great. Use a 1/8th bit to start it off, step it up to about half your actual size then the third bit is your actual size. Keep your speed around 350-400rpm for the 1/8th, step it down accordingly for the next bit. Make sure your bits are sharp otherwise you may be there for a while.

 

I use a rotabroach, they are super tough and real precise.

 

Those annular cutters are fantastic

 

yeah, they make it so easy.

 

Most of the time I use a sharp stepbit and drill press. But I am sure there are better ways.

 

Same, also use a few different sized hole saws with carbide teeth. So far I have yet to see one fail.

 

Hole saws work great on the thick sch10/40 304

But if its in a down pipe, just blow a hole in it with the tig torch..

 

this is what I do