Drill Bits - Need some help and advice

[BukitCase]

Mudd, if the "big bit" comment was aimed at me you should re-read - I specifically was referring to ANNULAR cutters, not big twist drills - I also have an inexpensive Taiwanese drill press and have drilled hundreds of holes (up to 1")using the cheapo HF "silver & Deming" bits as well as up to 3" holes using hole saws - they seem to hold up pretty well even when I just use compressed air cooling... Steve

 

[the old grind]

Annular cutters and carbide (or carbide-tipped) drills need a rigid (stable) spindle. Hand drilling with either is a recipe for chipped corners and loss of cutting action/chip formation. 'Short molecular chain' animal fats lube chips in the flutes, but also allow the cutting edge to bite in. Lube oils (long chain) work in the flutes but deter the cutting edge from biting in. Windex, water beat lube oils as a drilling aid.

btw, I googled 'lard oil' and discovered a cooking trend of using 'good old-fashioned lard' like Grandma always did. Lucked into a few how-to's to render and bottle lard oil for the mills & lathes. (filtered bacon grease works great, smells like breakfast :licking

Thread tapping is where you really see what works best and what falls short.

 

[BukitCase]

"filtered bacon grease works great" - bet that's where the expression "hogging out a hole" comes from :laughing:

TOG, seriously though - good info, that's the gist of what I found researching these cutters - so far I've only used a couple different sizes and only on my new mill. amazing how quick and clean a large hole can happen :thumbsup: ...Steve

 

[CNC Dan]

Annular cutters and carbide (or carbide-tipped) drills need a rigid (stable) spindle. Hand drilling with either is a recipe for chipped corners and loss of cutting action/chip formation. 'Short molecular chain' animal fats lube chips in the flutes, but also allow the cutting edge to bite in. Lube oils (long chain) work in the flutes but deter the cutting edge from biting in. Windex, water beat lube oils as a drilling aid.

btw, I googled 'lard oil' and discovered a cooking trend of using 'good old-fashioned lard' like Grandma always did. Lucked into a few how-to's to render and bottle lard oil for the mills & lathes. (filtered bacon grease works great, smells like breakfast :licking

Thread tapping is where you really see what works best and what falls short.

Yup.

Lubricating oils are intended to prevent metal to metal wear, just what you don't want when you're trying to cut metal, with metal.

 

[downsizingnow48]

For general cutting and drilling I use black cutting fluid from Enco, same thing as plumbers use to cut threads. For a bit better finish sometimes I use lard oil that I got from McMaster Carr. For thread cutting I use TapMagic. For aluminum, WD40. And now I am gonna have to get a bottle of Windex and give that a try too.

 

[muddstopper]

Mudd, if the "big bit" comment was aimed at me you should re-read - I specifically was referring to ANNULAR cutters, not big twist drills - I also have an inexpensive Taiwanese drill press and have drilled hundreds of holes (up to 1")using the cheapo HF "silver & Deming" bits as well as up to 3" holes using hole saws - they seem to hold up pretty well even when I just use compressed air cooling... Steve

Wasnt directed at anybody in particular. I just saw it several times, and I dont think it was just in this thread, that the small machines wont drill big holes because of speed and HP. Admittedly, its hard to beat speed reduction and hp when drilling big holes, but a quality oil will help if you dont have the big machines. I dont subscribe to the theory that water or transmission fluid, WD40 etc, works better than the right oil because I have proven it to myself that that isnt true. And I had a old time machinist tell me many years ago that water was best, but I lost faith in that advice as soon as I found out what the correct oil would do.

And I believe the HF SD drill bits are made by the same chinese company the Northern tools are made by. Box and packaging looks the same anyways. Funny thing is, you can buy the 8 bit set for about the same price of just buying the single 1in drill. For what I do, those cheap bits get the job done.

 

[Big Barn]

Water and water soluble coolants work well, but I don't use them on my mill or drill press because of the rust factor. Pretty much use the same as downsizingnow48. Terry

 

[CNC Dan]

...And I had a old time machinist tell me many years ago that water was best, but I lost faith in that advice as soon as I found out what the correct oil would

As a COOLANT only, water is better. But as a CUTTING fluid, oils made for cutting are much better.

 

[muddstopper]

I tried windex, well it was the cheaper blue cleaner off brand, didnt like it. Just saying.
Have been doing a little reading about Lard. I had never heard of using animal fat before.
Dont know that I will ever try it because all my cooking grease turns into gravy and gets poured over my biscuits. I do wonder how much salt might be in the grease and what kind of effect that would have on a piece of machinery.

 

[muddstopper]

As a COOLANT only, water is better. But as a CUTTING fluid, oils made for cutting are much better.

I'll agree with that