Drilling pilot holes in stainless steel enclosures

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automate0042

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Periodically I need to drill a pilot hole in a ss enclosure- grab the drill bit set and fight it tooth and nail. What's the best type of drill bit to use in ss?
 
I usually start with my smallest drill bit (e.g. 1/32") and then step up in 1/8", or so, increments. More bit swapping but overall it is pretty painless.
And don't forget plenty of lubrication (for the drill, not you).
 
automate0042 said:
Periodically I need to drill a pilot hole in a ss enclosure- grab the drill bit set and fight it tooth and nail. What's the best type of drill bit to use in ss?
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More pressure, less speed. Not the other way around. That's what will destroy your drill bit. I've seen too many good drill bits burned up because everybody wants to drill on the fastest speed possible. Slow it down so you produce one long shaving.
 
Thanks for the responses. That's why my index is usually shy the little ones- easy to get in a bind! I was going to refill my index and realize that there are different types i.e. cobalt, 135 deg. angle, etc. etc .
 
I did a quick search on this topic and ended up on a machinists' forum and learned of the existence of Type C aircraft drills. Not sure if these would be helpful, but it might be worth checking out.
 
automate0042 said:
Thanks for the responses. That's why my index is usually shy the little ones- easy to get in a bind! I was going to refill my index and realize that there are different types i.e. cobalt, 135 deg. angle, etc. etc .
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I have a true cobalt set of drills not cheap ones that claim they are cobalt as many you find in the big box stores are, yes they are very pricey but worth the price if you drill hardened steel or SS often, just watch out for sales gimmicks as there are many who use the word cobalt as a trade name or other method of deception such as having a low amount of cobalt like only 3% and are not true cobalt drills, also the set of carbide quick change hole saws I use will also drill SS and have true M42 cobalt pilot center bits, it is always best to not over heat a drill bit when drilling any metal as the bit will loose its temper and not hold its edge.

Avoid any drill bits that are coated as if you intend to resharpen them the coating is lost, cobalt drills come in two grades M35 (5% cobalt/hardend tool steel) and M42 (8% cobalt/hardend tool steel) the latter being better for more harder metals such as SS, while titanium drill bits are alittle harder but they only are coated and will loose there hardness when they are resharpened while a true cobalt can be resharpened the life of the bit.
 
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hurk27 said:
I have a true cobalt set of drills not cheap ones that claim they are cobalt as many you find in the big box stores are, yes they are very pricey but worth the price if you drill hardened steel or SS often, just watch out for sales gimmicks as there are many who use the word cobalt as a trade name or other method of deception such as having a low amount of cobalt like only 3% and are not true cobalt drills, also the set of carbide quick change hole saws I use will also drill SS and have true M42 cobalt pilot center bits, it is always best to not over heat a drill bit when drilling any metal as the bit will loose its temper and not hold its edge.

Avoid any drill bits that are coated as if you intend to resharpen them the coating is lost, cobalt drills come in two grades M35 (5% cobalt/hardend tool steel) and M42 (8% cobalt/hardend tool steel) the latter being better for more harder metals such as SS, while titanium drill bits are alittle harder but they only are coated and will loose there hardness when they are resharpened while a true cobalt can be resharpened the life of the bit.
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WOW!!!! Excellent information. Thanks! To the point the good tools aren't cheep up front but they payback in the long run.
 
hurk27 said:
I have a true cobalt set of drills not cheap ones that claim they are cobalt as many you find in the big box stores are, yes they are very pricey but worth the price if you drill hardened steel or SS often, just watch out for sales gimmicks as there are many who use the word cobalt as a trade name or other method of deception such as having a low amount of cobalt like only 3% and are not true cobalt drills, also the set of carbide quick change hole saws I use will also drill SS and have true M42 cobalt pilot center bits, it is always best to not over heat a drill bit when drilling any metal as the bit will loose its temper and not hold its edge.

Avoid any drill bits that are coated as if you intend to resharpen them the coating is lost, cobalt drills come in two grades M35 (5% cobalt/hardend tool steel) and M42 (8% cobalt/hardend tool steel) the latter being better for more harder metals such as SS, while titanium drill bits are alittle harder but they only are coated and will loose there hardness when they are resharpened while a true cobalt can be resharpened the life of the bit.
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Very well said. I only buy and use cobalt alloy drill bits. They are are cheaper in the long run by lasting longer and getting the job done with less labor. I will add to what was said above, one of the objectives with drilling metal is to hit the optimum cutting temperature. In mild steel, this is high speed and high pressure, but in stainless this is lower speed and high pressure. Using high speed in stainless, the bit overheats and will loose its hardness quality.
 
Cobalt

Cobalt

I use a titanium cobalt jobber set made by " Westward " available from Grainger. They are not overly expensive and will last a good while if run correctly.
A Master Electrician I work with sometimes has a nice set of Cobalt step bits which are also very useful.
One thing many people in the field are never taught and for some odd reason do not seem to practice is most metals need to be cut at lower RPM.
There are some rare exceptions to this rule involving uncommon metals and exotic drill bits and cutting lubes.
Its rare indeed to ever hear a sawzall run at moderate speed, but the trigger happy thing actually works against in most cases.

All the best.
 
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