Hot Rods Drilling help needed.

What is the best way to drill a small hole in sheet stainless to use self tapping screws?

 

I've never drilled a hole for a self tapping screw but I would think a small bit if you must. HRP

 

Some types of SS are very hard,beside center punching to have a spot so drill dose not scrach up all around were your trying to drill,you need a very good carbid drill bit that is sharp. If it really hard SS just the screw will never make it's own hole.

 

+ lots of lube and slowest speed

 

Use a sharp pointed punch and punch a hole. This will turn the edges in, and the screw will have more than twice the grip. Faster too.

 

Doh,I totally missed the stainless steel...disregard my first reply. HRP

 

Thanks for the tips, I am out of town and have tried all the bits I have and none are doing more than scratching it!

 

If your holes are to the edge of a panel and your putting two panels together, I use a whitney punch.
Works great , use a quality screw from the likes of grabber.

 

Buy yourself a good bit, or set of bits, drill the hole and forget the self-tapping screw, unless you really need or
want it. Drill at slowest speed possible while applying pressure and lots of lubricant.

 

The self tapper's are required. I now have better bits and will try again in the morning.

 

it's already mentioned Lots of lube slow speed.Never generate heat on the bit or you'll burn the tip in an instant.

 

Agree re speed etc. I measure the size of the pilot point on the screw and use a drill just a bit smaller.

Pete

 

use carbide bits about the size of the screw shank. That's the dia. of the screw body minus the threads. If you're using a high speed drill, use the trigger on trigger off meathod of drilling.

 

I find a step drill works best on stainless, try one, a good quality one.

 

I have read that the problem with cutting/drilling stainless is not that is harder....but just the opposite.
It is softer than mild steel and rather than the tooling removing material as desired, it tends to tear, or maybe even 'smear', and does not lend itself to a clean cut.

Any professional metallurgists out there that can shed some light on this notion?

Ray

 

Using drill bits with split point works the best for drilling, the point doesn't wander and it starts much better, for sure run slow drill speed to insure you do not burn it and work harden the material. Carbide isn't necessary to drill SS, but a sharp bit with split point and slow drill speed is a must. During my working days, I was in charge of the sharpening of drill bits for production and they drill a lot of SS, we used 135 degree split point bits and they worked good, even without lube, no carbide just HSS

 

Might want to consider buying an "automatic punch" for this kind of work.
They're relatively inexpensive for what they do; which is get a small dent into the material so that a drill-point doesn't wander around and scratch every place you don't want it to. You can also make the divot deeper with a standard center punch if need be.
Prices vary according to brand.
Starrett probably the most expensive, Facom & General are some others, all the way down to HF.

Just do a google search or go to McMaster-Carr or MSC and type in automatic punch.

 

Rusty is correct, a punched hole is the way to go. That's why OEM sheet metal is pin punched, to provide a larger length of thread engagement and ease of production.

 

Use a #00 or #0 Center drill (cobalt) maybe HSS if you don't have a lot to do. If you have a steady hand you can drill them without center punching

 

Getcha self some of dis. This stuff makes stainless its bitch.

 

Just did this myself last weekend. Three holes, .093" dia.
"Slow" drill rpm, lots of pressure and lots of lube.
I used a new high speed drill, but cobalt would be better.

Mike

 

I use the Boelube with holesaws for stainless (11ga) and I get 2-3 1 1/2" holes out of 1 hole saw. Impressive stuff!!

 

Cobalt drills will do the trick.

 

I use an automatic punch 1st then take a small piece of hard wood as a drill guide. Drill the hole in the drill guide locate over punch mark add lube and drill slowly.

 

2nd cobalt bits from most hardware stores will work great

 

The problem with stainless is that it gets hot and once it gets hot it is slippery, slippery enough that the bit doesn't want to take a bite. low speed and lots of lube, a well sharpened bit and if you cant sharpen a bit then lots of bits cause once the bit gets dull it is useless.

 

Thanks for all the advise, Got it done. The ONLY thing I found to work was a Carbide bit at low speed with lots of pressure! This job was a nightmare because of not only the stainless but the amount of space I had to work which made keeping pressure on it near impossible. Used a 1/8th Carbide for the initial hole, then I used a titanium bit to get to the desired size. The self tappers that were available to me were stainless phillips head. I had to drill the holes to the exact size of the shank because they would not cut at all on their own. I even broke a phillips head bit in 2 trying. Took a total of 3 hours to drill the 8 holes and install 3 screws! Was a nightmare!

 

I was out of town with limited tools is what made this so hard to get accomplished!