drill bit suggestions

[chineshop_guy]

as title says, got a job for home shop, i've done similar parts before and had issues.
machine is tree j325, mist coolant. material s7 tool steel. something like a hundred
14mm holes thru 2.75 inches.
the last time part was quite a bit larger had more like 250 12mm holes, after about maybe 30 holes
tool would dull out, sharpen go again.
iwas using cobalt 135 degree split points, i believe came from kodiak cutting tools. don't remember
exact parameters off top of my head. told myself i wasn't gonna do anymore of these, guess i didn't raise the price high enough damn it
anyway, suggestions

 

[DMF_TomB]

as title says, got a job for home shop, i've done similar parts before and had issues.
machine is tree j325, mist coolant. material s7 tool steel. something like a hundred
14mm holes thru 2.75 inches.
the last time part was quite a bit larger had more like 250 12mm holes, after about maybe 30 holes
tool would dull out, sharpen go again.
iwas using cobalt 135 degree split points, i believe came from kodiak cutting tools. don't remember
exact parameters off top of my head. told myself i wasn't gonna do anymore of these, guess i didn't raise the price high enough damn it
anyway, suggestions

.
feed and speed parameter changes and using cutting oil instead of coolant and trying pecking might help BUT some steels are just plain abrasive and machining them will cause short tool life.
.
for example machining annealed m2 steel i am lucky to get 20 minute tool life. some steel types even in soft condition are abrasive to tools

 

[Rstewart]

There's lost of manufactures that make powdered metal drills that are coated. OSG would be my favorite, I'm not sure carbide would be your best bet.
Mist coolant Ain't gonna cut it!

 

[Mtndew]

There's lost of manufactures that make powdered metal drills that are coated. OSG would be my favorite, I'm not sure carbide would be your best bet.
Mist coolant Ain't gonna cut it!

I agree,OSG makes some really good powdered metal drills.
But if your machine can handle a solid carbide drill, you want Guhring. Better price, MUCH better quality. And usually in stock at MSC.
Guhring, Inc. - RT100

 

[HuFlungDung]

It might be worth your while to get a spade drill with a coolant inducer so you can pipe some coolant down the hole. You'd just have to rig it temporary for this tool's use. A Little Giant submersible pump in a bucket, and a hose if you have no flood available. Oh, and a raincoat

 

[Cheshire]

I agree, nothing against OSG, but if I'm drilling into the medium to "why me" steels; Guhring is what you want.

 

[tc227]

as title says, got a job for home shop, i've done similar parts before and had issues.
machine is tree j325, mist coolant. material s7 tool steel. something like a hundred
14mm holes thru 2.75 inches.
the last time part was quite a bit larger had more like 250 12mm holes, after about maybe 30 holes
tool would dull out, sharpen go again.
iwas using cobalt 135 degree split points, i believe came from kodiak cutting tools. don't remember
exact parameters off top of my head. told myself i wasn't gonna do anymore of these, guess i didn't raise the price high enough damn it
anyway, suggestions

If 9/16 works try a Drill Hog in cobalt.
Not a Milwaukee drill hawg.

 

[D Nelson]

If 9/16 works try a Drill Hog in cobalt.
Not a Milwaukee drill hawg.

Try YG gold p drills not too expensive and really drill well
Don

 

[memphisjed]

Drillco or Viking.
If using a hand drill the Milwaukee red helix are good. They can take a beating.

 

[CarbideBob]

If you want to go into this hole of how and why I recommenced this.
https://www.amazon.com/Drills-Technology-Advanced-Operations-Manufacturing-ebook/dp/B00IZL9NMC
Not light reading at all and and if a mere mortal like me you have to go through it four or five times.
Drills seem like simple cutting tools... they are not. There is so much going on at one time.