Question about through-coolant drill and mill bits

[Stacy E. Apelt - Bladesmith]

Question for the machinists here:
I have a good number of brand-new carbide through-coolant drills and milling tools. It there any reason they can't be used like regular bits with a coolant flow aimed at the drill end. Most I am interested in using are between 1/4" and 1/2".

The thought came to me the other day when I was looking for a bit in my carbide drill box, and thinking that all these expensive tools were being wasted if I can't/don't use them.
Several years back I bought many assorted lots of new carbide tooling and drill bits at auction from an aerospace company that closed. They were stupid cheap, something like $1 each for 1/4 to 3/4" carbide drill bits. There were also bits with CBN tips and boxes of carbide and CBN cutters plus milling and boring heads for the cutters in the lot.

 

[navman]

Honestly, I don't see why they wouldn't work with normal flood coolant.

 

[Stacy E. Apelt - Bladesmith]

Thanks, I will give one a try next time I have the flood coolant set up. I might try one with no coolant just for fun.


BTW, I took the three-sided and four-sided cutter inserts for the various milling heads and made wood turning tools from them. It is pretty much exactly what the expensive turning tools use.

 

[Contender Machine]

Thru coolant carbide drills offer 2 main advantages. The drill is cooled right at the tip where the heat is being generated and the chips are being forced back up out of the hole by the coolant. This allows you to drill very deep and fast without pecking the drill. So if you don’t have thru spindle coolant just make sure you peck and don’t run them at Mach 1 and you’ll be fine.

I always say that thru coolant drills are the 8th wonder of the world. It’s amazing how much material you can remove with one in a proper setting.

 

[Stacy E. Apelt - Bladesmith]

Thanks Contender. I had read that they are amazing at fast drilling deep holes. I am sure in a large machine shop they get a lot of use.

I looked around and found adapters for drill presses and mills that allow a through-coolant drill to be used, but they seem very specific as to drill bit size or require an adapter to fit each drill bit. It probably wouldn't be worth it to put that kind of money into these bits I have. I don't drill deep holes often, either.

Another thought would be to sell cheap them to a machine shop or put them in The Exchange.

 

[Contender Machine]

They are wonderful in a production setting in a machine shop but they require a rigid machine and typically are used with no less than 300 psi coolant pressure. It’s not uncommon for cnc mills to have 1000 psi thru spindle coolant pumps.

It’s not worth it unless you have a proper set up with a lot of holes to drill.

You definitely got a good deal. Depending on the brand of drill it’s pretty easy to spend $100+ on a single 1/2 inch diameter solid carbide drill.

 

[Stacy E. Apelt - Bladesmith]

Thanks guys. I am going to close this thread now.