Backplate?

[cool_hardware52]

Much good info here already.

If I need to drill 300 seires SS I use:


135 degree spilt point drill, cobalt if available. When your buying drills consider a counter sink to champher the holes after you drill them.

Cutting oil, not lubricating oil. (Hardware stores usually have small cans of "Tapping fluid")

Center punch the center of the hole

Use a slow speed, 3/8 hole ~700-800 rpm (this may be hard to achieve with a hand drill motor)

Feed the bit without dwelling, i.e. with out stopping. If you need to withdraw the drill for more cutting oil do so quickly without dwell. SS will "work harden" if you stop. If you work harden you are in trouble.

Use a drill press if at all possible, easier to feed without stopping.

If you have no drill press start with a smaller pilot drill, ~3/16.

Don't use too large a pilot drill or your finish drill will just cut "threads"

A word of caution: anytime your drilling thin materials, i.e. where the thickness is less than about 1/2 the drill diameter, there is a very good chance that the drill will "catch" as it breaks thru the back. The material can then spin. If your using a drill press think about where you hand is and where the spinning material will go. Best to clamp if you can.

If your using a a hand drill, clamp down the material.

Good luck, be careful



Tobin

 

[divad]

Much good info here already.

If I need to drill 300 seires SS I use:


135 degree spilt point drill, cobalt if available. When your buying drills consider a counter sink to champher the holes after you drill them.

Cutting oil, not lubricating oil. (Hardware stores usually have small cans of "Tapping fluid")

Center punch the center of the hole

Use a slow speed, 3/8 hole ~700-800 rpm (this may be hard to achieve with a hand drill motor)

Feed the bit without dwelling, i.e. with out stopping. If you need to withdraw the drill for more cutting oil do so quickly without dwell. SS will "work harden" if you stop. If you work harden you are in trouble.

Use a drill press if at all possible, easier to feed without stopping.

If you have no drill press start with a smaller pilot drill, ~3/16.

Don't use too large a pilot drill or your finish drill will just cut "threads"

A word of caution: anytime your drilling thin materials, i.e. where the thickness is less than about 1/2 the drill diameter, there is a very good chance that the drill will "catch" as it breaks thru the back. The material can then spin. If your using a drill press think about where you hand is and where the spinning material will go. Best to clamp if you can.

If your using a a hand drill, clamp down the material.

Good luck, be careful



Tobin[/QUOTE




Thanks for the thorough description. I think I have experienced "work-hardening." I didn't like it.

 

[cool_hardware52]

Thanks for the thorough description. I think I have experienced "work-hardening." I didn't like it.

I've experience both work-hardening and plan old hard work, I didn't like either



Tobin

 

[deadend]

What fun is it though if you can't wrap the drill up in it's own cord when it catches and skin a few knuckles? It takes blood, sweat, and beers to get any work done.

 

[cool_hardware52]

What fun is it though if you can't wrap the drill up in it's own cord when it catches and skin a few knuckles? It takes blood, sweat, and beers to get any work done.

Deadend,


I'm with ya there, and have the scars to prove it. That's why I don't like twist lock cords, they don't "self disconnect" when wrapping up.


Tobin