Stainless Drilling

[pneumatic]

I am repairing the valve leakage on the gland packing,material valve is stainless steel. I have to make hole on the neck for injection sealing, so I have to drill the stainless steel material. The problem is stainless steel is very hard stuf. How do I drill stainless steel? what material for drill bit? and drill speed (I used air pneumatic drill, couldn't adjust the speed)?

 

[Rjeffery]

Try step drilling it. start with 1/8 ot 3/32 inch and continue to increase in size by 1/8 inch steps until you get to the size hole you need. SS is not that hard...

 

[MASSEY]

I concur that SS is not that hard, but it will 'burn' up your bits if you drill too fast.

Most pnuematic drills can be slowed in one of several ways:

1. Adjust integral flow control mounted on drill.

2. Or purchase a flow control and place it in line.

3. Or decrease air flow in line via air supply regulator at source.

4. Or, if all else fails, reduce volume of air supplied to drill by 'crimping' air supply line with hands or stepping on the hose.

This last option is not recommended - but it will work.

Also use lots of lube or cutting oil.

 

[pneumatic]

further information material valve is SS 304 and i have tried drilling, using HSS drill bit and drill bit quickly dull, it is long time and need many drill bit for one hole.Is there material dril bit for avoid this? (long time drilling and quickly dull) thanks for all

 

[MASSEY]

Try a TIN coated bit with lots of feed pressure and slow speed.

It is important to not let the bit spin on the SS material without cutting it. Once it's brandished it's too late.

Good Luck!

 

[TVP]

M1, M7, & M10 tool steels are recommended. As others have already mentioned, you must use copious amounts of cutting fluid (sulfochlorinated petroleum oil), and do not allow the tool to dwell. Tool must be kept sharp. TiN coating helps. Slow speeds, ~ 15 m/min (50 sfpm), work best.

 

[scmtnrider]

You might try a carbide bit and try using a center punch to hold the bit in place. Stepping up from smaller diameters is also a good method. Different types of stainless have different hardnesses. Also, stainless steel can be purchased with different hardnesses on the same type of material i.e. full, half and quarter hard.