Home Forums Hunting & Shooting Hunter's Campfire Drill Bits

I didn't expect Horror Freight drill bits to be anything other than MIC crap. But they're ok for wood, aluminum and maybe mild steel.

Speed and feed

210÷ the decimal equivalent of the drills diameter

For instance.....simple two flute HSS formula that I use daily

250 ÷ .250 = 840

Most people run a drill to fast

Learn how to sharpen a drill because when a drill becomes dull it's far from dead.

Ti coatings have sold more drills then a 25% sale has.......eye candy

Notice I didn't mention what goes inside a horse's mouth......a bit

It isn't pure water. It's either has water soluble oil added to it or water with a synthetic lube added. Great for cooling but depending on the material being drilled it might not have the proper lubricity. As B said, resulfurized oil (RIGID pipe threading oil) works well, have also used tap magic. The lubricity of either reduces heat build up.

Coolant

It's called coolant

Are you using oil when you drill?

Yes, I use oil.

For a lot of applications oil is ok

Union Butterfield makes a fantastic thick cutting fluid we use by the case.

But mostly we use water soluble coolants of varying types for most of our machining

Stainless is very tough on bits, lucky to get 6 holes out of a bit.

What size drill and how deep are these holes?

All the answers are here, Slow, steady pressure, lubricate, and use the right drill bit which is a Marginless bit.

If you are stuck on using standard Margin bits well wrong tool for the job.

Thanks AJ,

HS shop was a long time ago...

Hanco,

I always forget, is stainless soft or brittle?
I just recall problems with previous owner aftermarket hardware kits...fully believe hex key ones are better than Phillips or slotted (more surface area)

Never realized Stainless work hardened. It explains a few things though..

There are all sorts of alloys called "stainless" with different machining characteristics. Some are "hard", while others are "tough". There is a difference when drilling or machining is concerned, and different lubricants and procedures need to be used. Some chrome-moly steels are actually harder to machine than stainless. I've even worked on Hypereutectic alloy aluminum racing engine pistons that would dull a high speed steel lathe cutter bit. Had to use a carbide-tipped bit!
Jerry

Some stainless will work harden to the point you better have carbide to drill the hole afterwards. Like glass.

I like soluble oil better than cutting oil not only for cooling......but on a drill press or a lathe you can keep it on the cutting edge. It is so much thinner it runs down easier.

Sometimes I’ll evaporate 5 gallons of water out of the soluble oil in a shift. The oil doesn’t evaporate.
If you keep adding a mixed coolant it get thicker and thicker.
Big holes and a 60 hp lathe. Steam all over the place.

For a regular cutting fluid......Boelube......yup Boeing. Developed it. A 747 has something like 4,000,000 rivets. They know about drilling. Using it on a Gemcor riveting machine drilling Titanium we put some in the lid of the bottle and dipped the drill in it every third piece. Maybe 1/4” thick.
After that it would heat up. Boelube Coates like nothing I’ve ever used. And I’ve done a lot of exotics.

You can buy it most places. Great stuff. I’ve drilled from .003 to 3” holes. Screwed up a lot years back, less now. I’m lazy. Don’t wanna fix my mistakes anymore.
If you learn from your mistakes........I’m a frickin genius.

Stainless machinability is all over the place. Some cuts like butter. 416 is a joy.

Some take a good bit of pressure to keep the chip.

Some cast really sucks........

For home or most industries a margin less drill isn’t needed.
Drags the hole, creates more heat in a home drill press

Don’t have the rigidity and straightness of a CNC.

Larger drills all have margins. Drag and lock a lot easier with out the margin.

Thanks HRL and 257x
I was forgetting about grade(?) Formulation numbers

Cr-steell vs.stainless makes sense ... wait, crap, I thought stainless had chromium in it...
I swear, I hate it when my brain leaks data. I'm gonna have to look it up now...

I ran into a piece of Inconel the other day. Had to break through it with carbide. Ordered a new piece to replace the bad one. No pecking around on that stuff....

Try 16” diameter.......cast.......interrupted cut......lol......getting thru the scale eats so many inserts.

Or cutting out a Stelite bearing.

Or Super Duplex Stainless.

Repair parts are always a challenge.

But watching the CNC boys tapping 60 RC material......wow.

I've been machining a forged steel 1956 Chevy 6 cylinder crankshaft recently, reducing the radius of the counterweights about 1/2" so it can turn inside a different engine block. That sucker is hard as woodpecker lips! The chips come off the cutting tool BLACK, and hot enough to cauterize the cut if one gets imbedded in my forearm. Since it's an interrupted cut, the only way to do it and get a smooth finish is at about 450 RPM and take very light cuts. Getting a 100-lb. chunk of metal 3 feet long turning that fast is an adventure- - - - -I'm glad inline six crankshafts don't need bobweights to keep them from vibrating!
Jerry

Try a zero radius tool and slow it down. The zero radius keeps the tool from pushing away.

Steadyrest at the middle. That's how 305/350 chevy cranks were "topped" in production, two at a time.