Looking for Tier 1 Drill Bit Suggestions

[dogdog]

-That's not quite true. I've had to sharpen many a punch for stamping dies that was coated (several types) as well as a few drills someone had. The coatings will erode a grinding wheel but they can be sharpened once you grind below the coating. I wouldn't bother trying to remove the coating from the outside or the flutes, it can still provide less rubbing/friction between the drill body as well as aiding in the evacuation of chips from the flutes. I still believe that many of the cheaper drills that are coated are not made from HSS unless it expressly states it is.

Any type of carbide cutting tool (drill, end mill, etc.) should not be sharpened with the usual grinding wheels (AlOx, carborundum, etc.) and require a diamond wheel (expensive) for this. Yes you can use a Silicon Carbide (usually green) wheel but it leaves a rather rough cutting edge and may induce thermal micro-cracking if not careful. Not having a diamond wheel (which should always remained mounted on the hub once it's been "trued"), that's what I use but it's not recommended. For that reason I try not to use any of my carbide tooling. HSS works for most any situation/material and sharpening is far easier if I dull it on heat treated (below Rc 52) or welded material.

For the occasional drilling tasks, use whatever suits your budget. Not much point in expense without benefit. Ganbatte.

It is true the drill bit is still some what usable.... dependent on the parent material, but the coating supposedly makes the underlying metal harder only on the few thousandths of an inch on the surface "supposedly". You might still get a usable bit after grinding, but.... Not that it is always the case, they used the coating because they don't want to used the expensive HSS alloy/metal in the whole drill bit... so is it still "drillable" after sharpening yes. It will probably not be the same. That was what I was "told" 30 years ago. probably still true today with more marketing wanks.

Better to invest in drilling techniques than kept buying more expensive consumables. Yes drill bits are consumables likes it was mentioned few posts back already..

 

[RoninB4]

It is true the drill bit is still some what usable.... dependent on the parent material, but the coating supposedly makes the underlying metal harder only on the few thousandths of an inch on the surface "supposedly". You might still get a usable bit after grinding, but.... Not that it is always the case, they used the coating because they don't want to used the expensive HSS alloy/metal in the whole drill bit... so is it still "drillable" after sharpening yes. It will probably not be the same. That was what I was "told" 30 years ago. probably still true today with more marketing wanks.

-Sounds like what I wrote in previous posts " I still believe that many of the cheaper drills that are coated are not made from HSS unless it expressly states it is."

Better to invest in drilling techniques than kept buying more expensive consumables.

-I do agree with that statement. Learn to calculate speed/feed BEFORE buying expensive tooling that gets ruined. Drill chucked up in a hand drill? No problem calculating spindle speed for most ferrous materials, if the flutes "disappear" then it's too fast. Back off the speed until you can see the flutes as the drill rotates. That's not an exact speed calculation but it's a decent rule of thumb if there's no speed setting. If your chips are turning yellow or blue it's too fast. Also be wary of when the drill breaks through the other side of your material, that's when the cutting edge wants to "grab" and the drill tends to shatter/break/chip. This is especially true when drilling brass.

One more thing. Drills, like almost all cutting tools, are considered consumables. That's not the same as disposable. Good quality drills should provide service life in multiples of dozens of holes (if not hundreds) before sharpening is required. If someone is only getting 10-20 holes before it goes dull then it may be operator error causing this. Follow some simple guidelines if you want better results.

 

[Sdot]

FANTASTIC TOPIC!!! So often over-looked (myself admittedly).

Midst of a project currently. Needing to drill 1" hole through steel. Picked up a Milwaukee Black oxide Step bit. This my best option?

Also picked up Milwaukee cobalt bit set the other day. Not terrible - but still took some effort getting through steel using a 1/2" cordless.

Cheers

 

[nadogail]

If you are getting a curl from the drilled material, you are "right on" on the speed and feed, try adjusting your technique until you see that curl. Cutting Fluid helps a lot.

 

[dogdog]

FANTASTIC TOPIC!!! So often over-looked (myself admittedly).

Midst of a project currently. Needing to drill 1" hole through steel. Picked up a Milwaukee Black oxide Step bit. This my best option?

Also picked up Milwaukee cobalt bit set the other day. Not terrible - but still took some effort getting through steel using a 1/2" cordless.

Cheers

1" hole.. ? I love those carbide tipped hole saws... it came out super clean at least for the electrical panels I am drilling out but that was 7/8 for 1/2" knockout... still same same. Milwaukee have a 1" carbide tipped hole saw I think.

There was a thread earlier few months ago regarding these carbide tipped hole saws... that guy "strength and power" or something mention he used it a lot to build his gym stuff.

 

[Sdot]

1" hole.. ? I love those carbide tipped hole saws... it came out super clean at least for the electrical panels I am drilling out but that was 7/8 for 1/2" knockout... still same same. Milwaukee have a 1" carbide tipped hole saw I think.

There was a thread earlier few months ago regarding these carbide tipped hole saws... that guy "strength and power" or something mention he used it a lot to build his gym stuff.

Maybe slightly smaller then 1" - and I did pick up a Milwaukee hole saw that is 1". But thinking the step bit will be a better option?

Thickness of metal is without a doubt smaller then 1/4". Id guess 2-3mm

 

[kenc184]

Read the Norseman explanation why the Magnum works better in 304 SST than cobalt. Then buy one of each bit and try. I doubt you'll will do either, but... how many companies recommend a cheaper product when they sell both types of bits?

I read it and I don't buy it. You are welcome to believe it if you like, a lot of people believe everything they read.
As to them recommending a lower cost item, that's no proof, it may be lower cost to the consumer but way lower cost for them to manufacture and hence higher profit.