Lets talk DRILL BITS

balibalistic

balibalistic

Joined
Jul 14, 2004
Messages
2,623
Hey guys,

I braught this same thing up elsewhere,but thaught we should talk about it here to,as it may benifit some guys who do alot of drilling in tough materials.

Several years back when i was modding a knife,a friend who works at a local machine shop gave me an index from 1/16" - 1/2" bits.these are simple black oxide coated hs bits.on the bits it says the size and C-L USA. meaning Chicago Latrobe. in all my experience nothing has even come close to the quality of these drill's. i literally can drill hundreds if not more holes in 3/16" Titanium before having to re sharpen. where as standard hardware store drill's,i cant even get one clean hole.

Until last night the only thing i knew was that they said C-L HS on the shank.but after some input from some knowledgeable machinists i found out what they are and that they are of very high quality.apparently there is another brand which is slightly better called "Guhring".these i have to try as i cant believe there really is something better then the chicago-latrobe :)

So next time you guys place an order through msn or other machine suppliers,give either of these brands a try,i think you'll be impressed!

So,please take some time to let us know what you use,what kind of life you get out of them.this could really benifit everyone who drills like crazy :)
 
I use cheap no-name bits from the hardware store. They suck. Thanks for starting this topic! I'll have to look into those Guhrings.
 
Well, this goes a long way towards explaining why some people here have trouble drilling a few holes when I get hundreds or even thousands of holes in similar situations. I never imagined the hardware store bits were that bad.

You know what, I ended up pressing a bought-it-at-lowes dewalt brand drill bit into production a few weeks ago and it lived in a machining center drilling holes for days. So there are some good bits at the hardware store.

Like you have found, Guhring is good and so is Chicago Latrobe. I think I like OSG the best. Metal-Removal is also good. And it seems like I had good luck with SGS a while back, but I haven't used them in forever. Keep in mind there is more to a good bit than number of holes. There is also hole finish and accuracy and chip control and very importantly: the speeds and feeds you can achieve. I drill some holes at 40 IPM. Dude...

My favorite endmill manufacturer is Data-flute, they know their stuff. They're not too spendy and do customs too. I have some that can literally fill gaylords with chips before needing sharpened. I can feed a 1/2" 4 flt at .035 chip load. Oh yeah. You didn't ask, but there you go...
 
Nathan,i have experimented with speeds at about every range.i drill basically stainless blade steels and lots if titanium.for me i found that using rpm's of about 350 works perfect on both materials,for me anyway. if i'm seeing long spirals of TI all over the place then i'm happy :) with the C-L drills i find they leave and extremly clean exit hole,where i can drill out 25 pilots on one handle without having any real burr's that i need to lapp off.this saves me alot of time and frustration.

I'm sure that proformace also depends on the equiptment being used.for me and my 'ol grizzly mill/drill,the chicago latrobe have proven to be great. for a cnc set up i'm sure other tools are better.i have to order from enco,so i'm going to try a couple metal removal drills in my pilot size (3/32") does metal removal make HSS or Cobalt?

One more thing..,for pilot drilling 3/16" TI,would you reccomend jobber or screw machine drills??
 
Hi,

Yeah CL drills are pretty darn good tools. I also used to like Cleveland Twist too. Mostly I use OSG for drills less than 1/2". I do tend to go for the China made MT drills though. I just can't justify the cost of a 2" Chicago.

Those hardware store drills, if they are HSS, are mostly M2. Or if you are lucky M4. The lightest duty and cheapest of the HSS. Look for cobalt or M42 HSS.

I suspect Nathan, the reason you and I can get a ton of good holes drilled is the machines we use and the sheer amount of practice we get.:) The game changes when you have 6000lbs of iron and a 25hp spindle. We have infinitely variable speeds and feeds, coolants, and a rigidity of tooling and work holding that no Harbor Freight drill press possibly match. I think a lot of the problems guys have in drilling stem from lack of power, poor work holding, improper speeds and feeds, and not using the right coolant or no coolant at all.

dalee
 
I don't know if Metal-Removal makes anything other than carbide. Most of the drills I use are high performance coated solid carbide, (it isn't unusual to spend $50 on a 1/4" bit). But I'm running production. Also, the machines I'm using allow me to use fairly fragile but long wearing cutters like this that have a fairly narrow processing window and little tolerance for chatter. Squealing one of these can damage the cutting edge worse than HSS, which is more durable. Many of the cutting geometries and materials used in production may not be the best choice in home workshops.

I do use Guhring in uncoated cobalt HSS. I wish it was coated carbide, but they're not available in the geometry I want, and preventing hanging chips and loose burrs in deep intersecting holes was more important than cutter life in that instance. I also think they'd be a good choice for home workshops where there is less rigidity and control over feedrates.

Generally speaking, the shortest tool that can do the job is your best bet. I try not to use jobber length unless I have a deep hole.

I also like the generic carbide circuit board drills because they're cheep, they drill nice holes, and the flute geometry minimizes pecking. But I don't know how long they would last in stainless in a drill press.

BTW, I'm not a drill expert. I have to figure this stuff out for every job and try different things to get the best production rates. One of the issues that I deal with is long stringers wrapped around a bit turning 6000 RPM, on a machine without coolant, with 512 holes to drill per cycle. You can't just stop the machine and pull chips off the cutter. These are not concerns to the guy drilling a few holes in his shop, but this is the sort of thing I have to think about, so I sometimes have different priorities.
 
dalee100 said:
Hi,

Yeah CL drills are pretty darn good tools. I also used to like Cleveland Twist too. Mostly I use OSG for drills less than 1/2". I do tend to go for the China made MT drills though. I just can't justify the cost of a 2" Chicago.

Those hardware store drills, if they are HSS, are mostly M2. Or if you are lucky M4. The lightest duty and cheapest of the HSS. Look for cobalt or M42 HSS.

I suspect Nathan, the reason you and I can get a ton of good holes drilled is the machines we use and the sheer amount of practice we get.:) The game changes when you have 6000lbs of iron and a 25hp spindle. We have infinitely variable speeds and feeds, coolants, and a rigidity of tooling and work holding that no Harbor Freight drill press possibly match. I think a lot of the problems guys have in drilling stem from lack of power, poor work holding, improper speeds and feeds, and not using the right coolant or no coolant at all.

dalee
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Yeah...

Nathan the Machinist said:
I installed this new machine in the office where I work this morning. 30 HP (or Haas power anyway), 12,000 RPM, 24 tool side mount ATC, High Speed Machining.

IMG_1399.JPG



It isn't my mill, but it will be my baby.
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The split point jobber bits from Tracy have been great for me. Far nicer than what I was using and very inexpensive.
 
Cleveland Twist , that reminds me , I visited them years ago. The only thing I can remember is that the black oxide is put on with 1100 F steam !!
 
I'm using a B&D $100 drill press and Triumph HSS bits, with plenty of Gunk brand dark cutting oil. This is certainly the best set-up I've used so far, but I'm very much open to suggestions. Is this a proper oil? It was all they had at the local store and I figure it's better than nothing.

The press only slows down to 620RPM spindle speed, so I have to be careful. But as I practice more, I'm getting better at making nice clean curlies without squealing the bit.

Dumb question of the day: what number size or fraction size bits should I use? I like 1/8" pins and 1/4" thong tubes, but I feel stupid sanding them down a bit so they will fit nicely in a 1/8" or 1/4" hole :o
 
Hi,

One thing you can try is to repoint your drill to 135 degrees rather than the standard 118. I find that it sometimes works better for me. Not always though. A flood coolant really goes a long way to getting the most out of a drill too.

I tend to find carbide drills don't work well in manual drill presses or mill/drills. Due to their brittleness they tend to really need a really ridged setup and a very smooth feed rate. But everyone's mileage can be different.

Nathan, that Haas looks like it will move some steel! Wish I had one in my garage. Just to play with you know:D

dalee
 
Yeah, dalle, these are 135 degree split points and seem to get right into the center-punch with no problems. Definitely better than other hardware store brands I've tried that would drill one or two holes in 1084, then just sit and spin in the center-punch :mad:
 
James_Terrio said:
Dumb question of the day: what number size or fraction size bits should I use? I like 1/8" pins and 1/4" thong tubes, but I feel stupid sanding them down a bit so they will fit nicely in a 1/8" or 1/4" hole :o
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Hi,

Depends on a few things. How tight do you want them to fit? Slip, light drive, or maybe press fit?

First thing you need to do is actually measure the pins and tubes to see what size they really are. And measure to see just how round they are too. You might be surprised. For your setup I would drill a 1/64th undersize and then ream to finish size. So if I wanted a 1/8" slip fit of a pin, I'd drill 7/64" then ream it to .126". for a light drive fit, drill the same and ream it to .1245".

Even then, don't be too surprised if you need to adjust the fit to suit your liking.

dalee
 
I want a slip fit to ensure I get epoxy all around the pin (which I also cut small slots in the side of, again for the epoxy to get into. I don't peen them usually.

Where do I get reamers like that?
 
Hi,

Those kinds of reamers can be bought from Enco, MSC, J&L Supply, and other industrial supply stores. Just look for decimal reamers.

You may want to get .125" and a .126" reamers. You never know what size hole you will get with a drill press until you actually make one. And they will be oversized if wrong.:D

dalee
 
Thanks for the info, dalee. This is a great thread, one I really need.

Any more thoughts on the best types of cutting oil? I'm working with Aldo's 1084, 440C, "regular" D2, and have some CPMD2 and CPM154 I haven't even started on yet, if that makes a difference. I don't have any kind of coolant system on my press, I just put some oil in a little bottle and keep the steel and bit wet with it.
 
Hi,

I like Cool Tool. But most any heavy cutting fluid would be fine. One thing to keep in mind is some cutting fluids can cause staining of the steel during heat treat if not cleaned off first. Maybe not much of a concern if you are going to grind and polish the surface after heat treat.

dalee
 
Cool, I think I will go ahead and use up this pint of Gunk cutting oil I have, and maybe follow your recommendation when it's gone. It does seem to work OK. I haven't noticed any staining, perhaps because I like to drill my holes very early in the process.
 
You need good fluids for tapping, broaching and forming. About every other operation, the fluid is more to keep things cool than anything. Water would work fine if it didn't make everything rust.

There can be some tendency for the sides of the bit to gall or seize onto the side of the hole, and for there to be heat inducing friction as the chips are ejected up the flutes, so the cutting oil is beneficial, but just about anything you might use will be adequate for drilling holes. If I'm using a Bridgeport, I very seldom bother with anything.

As stated earlier, drilled holes are just bulk material removal. If you want it round, straight and a specific size, you need to drill undersized and ream.
 
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