# A bit disappointed with Chicago Latrobe drill bits



## Ultrarunner2017 (Oct 1, 2008)

Hi;
After much frustration using cheap DIY store (but name-brand like Milwaukee) drill bits, I decided to buy a more expensive Chicago Latrobe set from Amazon. The particular set I purchased was:
"Chicago Latrobe 150 Series High-Speed Steel Jobber Length Drill Bit Set With Metal Case, Black Oxide Finish, 118 Degree Conventional Point, Inch, 15-piece, 1/16" - 1/2" in 1/32" increments"

These bits were sold by Amazon LLC, not one of their 3rd party sellers.

I was quite happy with the bits at first, but after using a few of the smaller ones a few times (not more than 5-10 holes) in wood, aluminum sheet, and perhaps some relatively soft plastics, I have become somewhat disappointed. I have used 3 in one oil on all but the wood drilling, and have never felt that I was putting too much force into the drill.
But now I notice that the bits are getting dull a lot faster than I would have thought.

Is this just the kind of tool I can expect today (unless I purchase tungsten carbide or something like that) bits?
Should I invest in a better set of drill bits, a second set of the CL, or maybe a bit sharpener?
The sizes I use most are between 1/8" and 1/4".

Thanks for your advice


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## Yodaman (Mar 9, 2015)

First a drill sharpener. Almost any excuse I can find to buy a new tool or machine works for me. Keeping your drills sharp saves money on replacements. It also provides the best hole quality and safer to use. Dull drill bits are more likely to break becoming a missile in your work space.
That said, I am not sure if sharpening small drills is worth the time spent. I normally buy small drills in packs of 6 or 12 assuming I am going to wear them out quickly or break them.

Regarding Chicago Latrobe. They have been a reputable industrial drill supplier for decades. Although its is difficult say what you are actually getting these days. Since you know these didn't hold up, I would try a different brand. Solid carbide is probably not good investment for any hand drilling. You might consider Tin coated HSS drills or even cobalt, but even cobalt will be a little more brittle.

And last, 3 in 1 oil, is a great all around oil for door hinges and general purpose stuff. But not great as a cutting oil. Dark sulfur based cutting oils work best. But I will concede that almost any oil is better than no oil, and admittedly I often grab a can of WD just for convenience.

Speeds and feeds are whole topic onto themselves, but most people turn too fast and feed to light in metals. Something to consider when drilling, if you are not making a chip, then your just rubbing. And it is the rubbing that generates excess heat and wears your edges. In rigid machine set ups it is common to drill a thousand or more holes in steel before changing them.


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## SeniorSitizen (Sep 10, 2012)

I'm certain there is a machine shop supply not too far away and that's where I buy my black oxide HSS ( high speed steel ) drill bits because that's all I need.

Cutting oil is not needed on any of those materials you listed with the exception of keeping it cool if doing highly precision work where temperature change would be detrimental.

Google* cutting oil* and use a drop of it on steel at a rate of a couple drops / second for small bits and increase a little on larger bits and you'll be fine with a good HSS drill bit. We DIY'ers don't need to flood the cut as a machine shop with recirc pumps would do. 

Save the 3-in 1 lubricating oil for the hair clippers, HVAC blower bearings and the singer sewing machine etc..:biggrin2:


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## mark sr (Jun 13, 2017)

I always use burnt motor oil for cutting oil, sometimes I'll thin slightly with mineral spirits ..... doubt you'd need to do that with the lightweight oils the modern cars use.

I normally sharpen my larger bits but don't bother with the small ones. With a good eye you can sharpen them with a bench grinder - a drill grinder is more goof proof.


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## BayouRunner (Feb 5, 2016)

Most likely your drilling the metals too fast. When you get them sharpened or replaced slow your metal drilling way down and your bits will last a long time. I’m guilty of using any oil that’s nearby, can’t say I’ve ever used a cutting oil. I’m sure that’s the proper way to go but it’s not convenient lol. 


Sent from my iPhone using Tapatalk


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## Glassit (Jan 30, 2016)

Black oxide finished bits aren't a premium material but are quite serviceable. I would be amazed if you managed to dull your bits on the materials you mention. I routinely drill through feet if not yards worth of aluminum with a single bit, and even then they usually only get replaced if I hit concrete on the other side of my workpiece, or snap it. 

Don't take it the wrong way, but I would suggest that you may be experiencing some perception bias. Getting new tools is always exciting but when the new tool glow wears off the reality that it's just another drill bit sets in and it might seem comparably less capable.

If you're drilling a lot of steel you might invest in cobalt bits which will retain sharpness longer but bend easier than other materials. Unless you're doing real precision or production work, most drill bits can be sharpened to a serviceable edge, although not nearly factory edge, with nothing more than an angle grinder and a sharp eye.

Edit to add, carbide is only used in tips of hammer drill bits for masonry applications as far as I'm aware.


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## Ultrarunner2017 (Oct 1, 2008)

Thanks guys;
I am probably drilling too fast, but my 1/8" drill bit was not sharp enough when I started the hole (just one hole). I don't think I used that one for more than a dozen holes. Now I remember what I used that 1/8" drill for before yesterday; Plaster. Now I'm talking real Plaster of Paris, not sheetrock. Perhaps I should be using oil when I drill in plaster?

I checked the whole set today and find that the 1/8", and the 5/32" bits are not sharp. The 1/2" is not too bad, but has some rounding at the point. I am testing the bits by placing the tip against the pad of one of my fingers and giving it a light twist. I can easily feel the sharp edges on the good ones.

About sharpening bits; I have to agree that I should not try to sharpen the smaller ones. I will purchase additional bits for the most common smaller sizes. When I was ordering the Chicago Latrobe bits on Amazon, I didn't see any loose ones available. I will have to check online to find a jobber supply near me.

So far as oil goes; I use the 3 in one only because it was convenient. When I went to Home Depot and asked one of the sales guys about "cutting oil" he looked at me as though I were speaking a foreign language that he did not understand. So I know that I can't get cutting oil at a big-box store.
I do have a nice oil can full of 5W-30 motor oil. I had completely forgotten about that oil when I needed it yesterday.
Then there is the problem of keeping the bit oiled. I was drilling a pilot hole through aluminum siding (don't know why this piece is aluminum when the wall is vinyl) which was above my head and facing down, so the oil would tend to run out of the hole. I drilled for maybe 15-30 seconds at a time and re-oiled the bit each time. I suppose I should shorten the drilling intervals.

If I do decide to purchase the Drill Doctor, I will get the 750X and not one of the less expensive models. I have lots of old worn out bits I can practice on.
The description of the 750X says it will sharpen bits from 3/32 to 3/4". I think they claim it can do masonry bits too. That would be real nice. I have several old masonry bits that are pretty much useless but may be worth saving if I can sharpen them.
But like you are telling me, I am skeptical about its ability to properly sharpen the smaller bits. But if it will do a good job on 1/4" and up,
Now, what is the difference (besides the price) between the 750X and the DD750X? They look like the same machine on Amazon, but the DD750X is about $20 higher.


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## SeniorSitizen (Sep 10, 2012)

Maybe you ain't listening. Forget the G D oil for aluminum, plastic, cast iron and brass.

Speed of your drill bit in steel with cutting oil. If it will run 2,000 rpm that's where it needs to be drilling steel with cutting oil using a 3/16" bit. Larger bits will be reduced in speed.

For aluminum and plastic drilling with the 3/16 size bit. That cutting speed in feet/minute is so much higher than steel your cordless or any other hand drill motor won't run fast enough to damage a good bit.

In aluminum gutter down spouts, if a 1/8 or 3/-16" drill bit running at top speed of my Makita wouldn't drill through it in less than 5 prefer 3 seconds I'd throw it at a jack rabbit and get me a bit that would. I have made spade bits from a nail that works better than the bits you were sold.

Just chalk it up to experience with the amazon, H Depot and Lows trash.

Pictured is what a twist drill bit should look like. When held vertical directly in front of your eyes the cutting lip should be the only thing seen and absolutely no part of the heel visible behind that cutting lip. Then rotate it and look at the other lip.

I sharpen my bits free hand on a bench grinder but at least the pic will give you an indication what to look for from your drill doctor.

Edit: for those that like to keep a little cutting oil on the bit when drilling steel, a small cheeeeeeeep artists brush dipped in the oil and allowed to rub on the bit works rather well, even when drilling horizontal.


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## Glassit (Jan 30, 2016)

Plaster of Paris and sheetrock are both gypsum, which is a rock. Look how quickly cutting sheetrock makes a utility blade go dull. Can't expect a drill bit to stay sharp if you drill even a soft rock with it, and half a second on concrete will destroy them.

Fastenal sells single Norseman bits at a good price. Very good quality and USA made, and packs of black oxide bits.

Cutting oil in Home Depot is in the plumbing section- threading oil same thing. Don't use motor oil, it needs high sulfur content to lube, and you don't need oil at all unless drilling steel or something harder.


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## Ultrarunner2017 (Oct 1, 2008)

Thanks for identifying my mistakes. Perhaps when drilling plaster/sheetrock I should use a masonry bit?
I will look for the Norseman bits for building my supply of the smaller sizes.
Thanks for the idea of using a cheap artist's brush. I'll get some thread oil for next time I drill steel.


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## Yodaman (Mar 9, 2015)

Ultrarunner2017 said:


> Thanks for identifying my mistakes. Perhaps when drilling plaster/sheetrock I should use a masonry bit?
> I will look for the Norseman bits for building my supply of the smaller sizes.
> Thanks for the idea of using a cheap artist's brush. I'll get some thread oil for next time I drill steel.



Drilling gypsum drywall is not a problem for HSS. Drilling plaster can be a different animal. Some plasters have sand in them which will wear a HSS edge rapidly. And in that case a carbide tipped masonry drill is a better choice.


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## 123pugsy (Oct 6, 2012)

One thing not mentioned.
HSS* split point *bits are the best. They don't have a flat spot on the end which just heats up the steel. We use them on stainless steel with no cooling and can drill a lot of holes. 1/8 size of course. Larger sizes slow down and cool a bit, even just dunk the bit in water every now and then.


I've tried all the gimmick cobalt, titanium, Kryptonite, coated stuff, you name it. HSS works the best.


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## Ultrarunner2017 (Oct 1, 2008)

OK. So HSS drill bits work best for all-round use. That's not to say I don't need a few masonry bits for those projects that involve drilling into concrete, brick or other masonry.
I have a very old SCM brand 5/16" masonry bit that is too dull to be of any use, yet I never tossed it.
Can this type of bit be sharpened?

Next question:
I have read here and elsewhere that smaller bits (I am going to assume anything smaller than 1/4") should be replaced rather than sharpened. I guess that makes sense considering how difficult it would be to get a proper edge on such a small bit. Of course the Drill Doctor claims to be able to sharpen bits 3/32 to 3/4.

Final question:
Which route would you take if you don't own either a Drill Doctor or any sort of bench grinder?
Would you purchase a bench grinder and learn to sharpen your bits, or would you purchase the Drill Doctor (model 750X)?

I watched a few YouTube vids on sharpening bits on a bench grinder. Looks pretty simple - BUT... the guys doing the vids have obviously done the job a hundred times before. Getting it just right seems like it will take a LOT of practice.

Thanks for your advice.

FW


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## 123pugsy (Oct 6, 2012)

The bench grinder can be used for more than just drill bits.
This is how I would go.

1/8" split point HSS jobber bits are short so they won't break easy and come in packs of ten.

Use these for pilot holes, then change over to the bigger bit to finish.


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## Ultrarunner2017 (Oct 1, 2008)

OK. Bench grinder it will be. But my budget is pretty tight. I'm looking at HD. DeWalt makes an 8" and a 6". The 8" is near the high end of my budget ($128). Or I can get their 6" for about $100.
I would imagine that for drill bit sharpening I can use the 6", but if spending a bit more for the 8" will give me significantly more usability, then I can go that way.

HD also has some really cheap grinders. Ryobi and Wen for two. What do you think about those guys?
Also, would the stock wheel be right for the purpose, or would I need to purchase an additional wheel?

Edit: After reading some of the reviews for DeWalt's 8" (DW758) grinder on Amazon, I have serious doubts on buying anything DeWalt. Sounds like they're having serious QA problems.


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## mark sr (Jun 13, 2017)

The size of the wheel doesn't make a lot of difference, the motor/amp does.
I have a homemade bench grinder I put together over 35 yrs ago that uses an old washing machine motor.


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## Ultrarunner2017 (Oct 1, 2008)

mark sr said:


> The size of the wheel doesn't make a lot of difference, the motor/amp does.
> I have a homemade bench grinder I put together over 35 yrs ago that uses an old washing machine motor.


There was a review on Amazon of the DeWalt 6", and he said the top of the wheel was level with the top of the motor housing, preventing him from sharpening a lawnmower blade. I suppose that one needs to consider what he will be sharpening before selecting a grinder. For drill bit sharpening I don't suppose it makes any difference at all. Either 6" or 8" will do the job. What should matter is the stability of the wheel. I don't think it would be possible to get a good result with a wheel that wobbles too much.

Before I make any choice on a grinder, I need to study some of the how-to's on drill bit sharpening. I have never done this before.


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## 123pugsy (Oct 6, 2012)

They're all pretty much junk from overseas these days.
You might as well grab a HF unit.

An old garage sale unit would be nice but they never come up.
Perhaps CL?


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## Yodaman (Mar 9, 2015)

Regarding a 6 or 8" grinder, as long as the cost difference is negligible, I would go with the 8. A 8" wheel will have 35% more surface area than 6", which will equate to more grinding and less dressing


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## Glassit (Jan 30, 2016)

Cobalt bits are HSS with a lowish percent cobalt alloyed in so they lose their edge more slowly at higher temps. It's a small difference but in field work when we drill heavy steel myself and all the guys I buy bits for get noticeably more holes per bit with cobalt. When drilling thick steel we stop and add oil several times but it smokes out quickly and the bit temp rises quickly between doses. Cobalt gives just enough leeway that we don't smoke bits quite as quickly. This is in commercial aluminum framing when drilling 3/8" holes in 1/4"+ thick steel so for most applications they are unnecessary and probably not noticeably better as was said above, just putting the info out there. Agree that most titanium coated bits are junk.


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