Caution: Drill bits

[signalmaintainer]

Be careful investing in 60-81 drill bits promoted in the most recent MRH mag. More vetting was needed:

https://forum.mrhmag.com/post/ahhah-moment-economicaldurable-small-drill-bits-13600234?pid=1342231576

[Missaberoad]

Kinda get what you pay for... for 8 bucks it's amazing they are drill bits. 

[signalmaintainer]

Kinda get what you pay for... for 8 bucks it's amazing they are drill bits. 

They do drill through .040" styrene without much effort. That's at least something. This is in contrast to a set I bought quite a while back through Micro-Mark that was sized correctly, but could barely cut through wax.😆

[Chris333]

I bought bits once that were just blanks with no tip or fluting.

[garethashenden]

I bought some cheap #80 drill bits. They weren't drilling so I took one in to the microscope at work. It did have a tip, but it was flat and so far off center that it was completely useless.

I've been buying drill bits from McMaster Carr recently. They're a few dollars each, but they work well and don't break as easily. So I consider it worth the cost.

[Albert in N]

So far, I have had no problem with Harbor Freight drill bits.  I have small hobby sets for my micro drill as well as standard sets for both my 3/4 inch drills. 

[jwaldo]

I ended up with a set of these from somewhere. Don't remember buying them. Not only were the sizes off, but they might as well have been made of lead. I'd never had a drill bit bend like a paperclip or try and un-twist itself until I tried these. Absolute garbage, even at $0 I felt ripped off.

On the other hand, Harbor Freight has a micro drill bit set that is actually decent for a similar price:
https://www.harborfreight.com/carbide-rotary-micro-bit-assorted-set-20-piece-62379.html
The smallest ones in the set (0.2mm, 0.25mm, 0.3mm) are substantially smaller than #80. The only downside is having to buy the whole set again every time I inevitably break the 0.2mm bits.

[garethashenden]

The smallest ones in the set (0.2mm, 0.25mm, 0.3mm) are substantially smaller than #80. The only downside is having to buy the whole set again every time I inevitably break the 0.2mm bits.

If you are after carbide drill bits like that, you can buy just one size. Such as 0.2mm here: https://www.amazon.com/uxcell-Tungsten-Carbide-Jewelry-Engraving/dp/B08146CJK4?crid=3N17JFEED9HQ4&dib=eyJ2IjoiMSJ9.AC8Nl3AfFPW7v0U0h7-eJyxtQcVZVYGGWsKwpU3FwLEkGfPqGnjr6yxVajyuVSgufylcet5dbqe3egY-zXxSMuvtSBB9e8y_d9_PmmVbkMOAcAOksHwPejf5dr7ODoiv_rNbuIFilDDO_la2DGjooM8JoTeTkTvIbIRCCc4ml7BkstPy1N74eTB3ymxWiDKodaqnE-xT1mGCI7zrPgNjLMG9JGJyN-ROQML3ZpbLw3c.uEQlNAx9CzYOzYSf8qzqCm229b1MyJBS_naWSEr_uVk&dib_tag=se&keywords=0.2mm%2Bdrill%2Bbit&qid=1745748083&sprefix=0.2mm%2Bdrill%2Bbit%2Caps%2C126&sr=8-3&th=1

[JeffB]

If you are after carbide drill bits like that, you can buy just one size. Such as 0.2mm here: https://www.amazon.com/uxcell-Tungsten-Carbide-Jewelry-Engraving/dp/B08146CJK4?crid=3N17JFEED9HQ4&dib=eyJ2IjoiMSJ9.AC8Nl3AfFPW7v0U0h7-eJyxtQcVZVYGGWsKwpU3FwLEkGfPqGnjr6yxVajyuVSgufylcet5dbqe3egY-zXxSMuvtSBB9e8y_d9_PmmVbkMOAcAOksHwPejf5dr7ODoiv_rNbuIFilDDO_la2DGjooM8JoTeTkTvIbIRCCc4ml7BkstPy1N74eTB3ymxWiDKodaqnE-xT1mGCI7zrPgNjLMG9JGJyN-ROQML3ZpbLw3c.uEQlNAx9CzYOzYSf8qzqCm229b1MyJBS_naWSEr_uVk&dib_tag=se&keywords=0.2mm%2Bdrill%2Bbit&qid=1745748083&sprefix=0.2mm%2Bdrill%2Bbit%2Caps%2C126&sr=8-3&th=1

Those work well for some things.... I've bought several packages in several different sizes.  The biggest problem I have with them is because the fluting is so aggressive, they tend to catch in the material, threading the drill down through it until you bottom out at the end of the flutes.  Only then can you break the material loose with some aggressive/forceful twisting.

The 1/8" or 3mm shanks aren't super convenient either, but they work well enough and being so cheap makes it worth the hassle most of the time.

One place I won't buy drill bits from any longer is Micro Mark.  Their drill bits are garbage...  Dull as hell right out of the package, and I'm not sure that the material they used in them is even hardened/tempered.  Just crap drills.

Other than paying a pile of money for high quality HSS drills from McMaster or MSC, you're best bet is finding some NOS Maxon drills at small out of the way hobby shops.  Always had good luck with them.

Jeff

[peteski]

I use PC board (Tungsten Carbide drill bits) as much as I can and to me the 1/8" shank for all the drill sizes is an excellent feature.  I only need to use the 1/8" collet in my Dremel and the runout is minimized (it can be pretty bad with smaller collets).  The split point tip they use is quite aggressive but that is not a problem when using a drill press or even with careful hand-drilling.  Split point also prevents wandering.



Another great source for those bits is https://drillcity.stores.turbify.net/  but I have scored some excellent deals  for boxes of 50 (same size bits) on eBay.  I always buy plenty  of spares because those bits are very fragile.

I would love to find a source of standard miniature HSS drill bits with split point tip, but I can only find those  in larger sizes.

[signalmaintainer]

Those work well for some things.... I've bought several packages in several different sizes.  The biggest problem I have with them is because the fluting is so aggressive, they tend to catch in the material, threading the drill down through it until you bottom out at the end of the flutes.  Only then can you break the material loose with some aggressive/forceful twisting.

My experience as well.

One place I won't by drill bits from any longer is Micro Mark.  Their drill bits are garbage...  Dull as hell right out of the package, and I'm not sure that the material they used in them is even hardened/tempered.  Just crap drills.

My experience as well.

[Maletrain]

Peteski, What speed (rpm) do you find these carbide micro-bits work best on materials like brass and nickel silver sheet and rail?

[garethashenden]

Peteski, What speed (rpm) do you find these carbide micro-bits work best on materials like brass and nickel silver sheet and rail?

As fast as possible. At least that’s the answer from a normal machining point of view. The smaller the tool, the faster it wants to go. The limiting factor here is how rigidly the workpiece is being held. If it’s in a vice and a drill press, you can probably run it as full speed. But wear some safety glasses just in case.

[Maletrain]

That is kind of what I expected from the basic physics.  And the packets of bits say "30,000 rpm".

My Dremel says it goes 5,000 to 35,000 rpm, but that is not in a rigid press, so wobble stress is an factor for bit integrity. 

My Unimat SL with the extra reduction/increase pulley will calculate out to a lot more, but that calc is not reliable due to the effect of the drag from the pulleys, so I probably should use a tac to measure it.  (I would expect these tiny bits to provide almost no additional load to slow it more.)

So, given the alternatives, and the desire to use bits, designed for thin copper clad over fiberglass, on thicker metal, I am looking for actual experience-based recommendations.

(And I do wear a face shield for such high rpm things.)

[peteski]

Yes, for their as-designed operation they spin very fast (I believe it is 100,000 rpms for the really small bits like #80).  Basically the smaller diameter the bit is, the faster is should rotate.
My drill press can't achieve those high speeds (or even Dremel's 30,000 rpms), so I use them at lower speeds but feed them into the material much slower.  I pretty much drill all the holes in metal using my drill press.

I also use those bits for hand-drilling in plastics by mounting them in a pin vise or even holding their bare 1/8" shaft between my fingers.  I do break them sometimes, but I have often hand-drilled fairly deep holes in plastics with bits down to #85.