Drilling Stainless Steel

[thaeni]

I'm installing a tank monitor for my holding tank and it requires a
1" diameter hole. I can't seem to find a drill bit that will penetrate
the stainless tank. I tried Cobalt and Titanium with no luck. Any
suggestions would be appreciated.

 

[jimmyb]

I'm installing a tank monitor for my holding tank and it requires a
1" diameter hole. I can't seem to find a drill bit that will penetrate
the stainless tank. I tried Cobalt and Titanium with no luck. Any
suggestions would be appreciated.

make sure your drill speed is very low. when drilling steel the larger the dia drill the slower speeds are needed. stainless is harder on drills than mild steel and requires slower speeds and plenty of lubrication. it may not be your bit but your technique. be sure your bits are sharpened and cutting a nice chip.

jimmyb

 

[Steve Dion]

Doesn't your tank have a manual guage in it?

If it does, the new one can be mounted in the same place.

 

[mel22]

Follow the slow speed advice and if you can find a product called Tap Free, use that as a lubricant. You may want to start with a small bit first and when you get a pilot hile through then use the larger bit. But slow speed and lubricant is your best friend. Tap Free is used for tapping threads in is probabley the product you can use. Look for it at best auto supply stores or if you have a machine shop supply local they should have it.

 

[Johnb]

Whether you are drilling or hacksawing stainless you need to make sure that you are always removing material or it work hardens and become all but impossible to penetrate. Start with a good sharp bit. Drill a pilot hole first. (The smaller drill means the force you put on it is on a smaller area so the force per area under the bit is higher so its keeps cutting). Lubricate the bit, that will ensure it does not overheat, get blunt and work harden the steel. Back off and add oil if it starts to smoke. Use a low speed so you don't overheat it so easily. The stainless will then dirll like butter.

 

[Bill Roosa]

Alternate solution
mark a 1" circle and drill numerous almost connecting small (1/8") holes then hack saw through what is left. Finish off with a rat tail or half round file. I have found that large diameter holes in genaral are difficult to acomplish. Add SS to the mix and you have a project that no beginner should touch.

 

[sesmith]

A step drill works well for large holes in relatively thin metal. I have not drilled stainless with a step drill, but a good sharp step drill with lubrication and a relatively slow speed should do it.

Scott