[Drill Bit]

I need to drill some stainless steel and not having much luck.
I have seem great testimonials on TTP HARD drill bits which seem to be for harder metals - has anyone used them ?

 

[MushCreek]

Stainless steel (depending upon the grade) isn't necessarily harder, but it is tougher. LOW RPM and high pressure, and cutting oil of some kind. I like TIN coated 135 degree split point bits for tough materials. Stainless will also work harden, especially if you go at it with too high an RPM. What grade of SS are you drilling, and what is the drill bit diameter?

 

[Drill Bit]

Great thanks for that advice, not sure of the grade os SS.
May try the TTP HARD bits they are are 135 degree split point - they recommend a lubricant also and sell a paste.
Need to drill 8mm so thought I would graduate - do 4mm first.

Thanks again

 

[SeniorSitizen]

If you are inclined to do graduate drilling, the first hole and or consecutive graduated holes need to be smaller diameter than the distance across the web of the next size up.

I've never found it necessary when a good HSS bit is used. To each his own.:biggrin2:

 

[Bondo]

Stainless steel (depending upon the grade) isn't necessarily harder, but it is tougher. LOW RPM and high pressure, and cutting oil of some kind. I like TIN coated 135 degree split point bits for tough materials. Stainless will also work harden, especially if you go at it with too high an RPM. What grade of SS are you drilling, and what is the drill bit diameter?

Ayuh,.... Agreed,.... for 5/16", I wouldn't pilot-hole it,....

Probably try a carbide bit, 'n lotsa oil,....usually Atf,...

The work-hardenin' can ruin a hole,...
If yer bit ain't cuttin',... Quit,....
Get another bit, resharpen, whatever, 'n pray it'll pop through the hard area,...

Lotsa oil, slow speeds, 'n steady chips,...