TiN drill bits

I have some TiN bits and I have been happy with them. They cut quickly and cleanly. There was a recent post on the forum stating that with this type of bit, you need to avoid excessive pressure and let the bit cut on its own with just enough pressure to keep the bit moving. According to the poster, the coating is somewhat brittle and can flake off the cutting surface if too much pressure is applied. I don't have enough experience to endorse or refute this claim, but it is consistent with what I know about physics and materials science. 

 

Bosch certainly has an excellent reputation. I don't have any of their TiN bits but I have a few Bosch power tools and router bits and they are first rate. You might want to look on Amazon.com for buyer reviews on bit sets, and for a good price on Bosch. 

Hiawatha is right. Great bits, but as with all drill bits, take your time and let the bit itself do the work, don't force it through, especially if you're using these with steel. Some cutting oil goes a long long way.

It depends on the materials you will be drilling, and the frequency that the drills will be used. Unless you are planning to drill stainless and alloy metals, the TiN (and other coated) bits are an expensive luxury, costing double to triple. For around the house and general hobby use, polished finish, split point drill bits will suffice. For better wear resistance, you may wish to consider cobalt drill bits; more costly than plain high speed steel, but cheaper than coated bits. The only coated tools I use are milling cutters because they take a beating and are expensive to replace, so the coatings pay for themselves. Check out MSC Industrial and McMaster Carr for what is available and pricing. They both carry top brands. Of course if Santa Claus has extremely deep pockets, than coated carbide would be the ultimate.

 

Larry

The high tech bits I save for high tech metals. I have the better "Drill Doctor" to sharpen my non coated, old fashioned bits. Broke or dull I fix-um. Does an anti-walk split back cut tip too. It has paid for itself many times over, and I will buy one again immediately if it dies.

Number and letter sets together as one, are my preference. Though really large, actually often a bang for the buck. I normally check with a local contractor/industrial supply houses(heat&AC, plumbing, electric, etc), Grainger, or even Harbor Freight for deals on machining stuff, rather than the local big box hardware.  

I have one of those full sets of bits including fractional, wire gauge (number) and letter bits.
I don't think I have ever used the letter bits.

I use the wire gauge bits (number) very frequently, probably as often as the fractional.

 

This time of year many stores will have fractional drill bit sets on sale with deep discounts. Common sources are Ace Hardware, Lowes, and Home Depot. Over the years I've stocked up.

 

 

 

I don't know about the angle of the bit cut, but I use the two sets below (both bought through Amazon).  The Steelex Plus D1138 HSS Tin Dill set (left) is a great set, which I got on Amazon for around $55 meets all your criteria except the reduced 3/8 inch shank. With 115 bits it always has a size for everything from 1/16 to 1/2.  I've used it to cut mild steel, wood , plastic, composites, etc.  About $55.  The wood case, about $37 normally, has five bits in each of 20 sizes from .3 mm to 1.6 mm, all suitable for a pin vise which I use for fine work.  I've never used these on anything but wood or plastic.  

 

I am a big believer in not buying expensive drill bits (or saw blades) or trying to resharpen old bits (my experience is they walk a lot more thereafter).  I view them as disposeable units. I don't buy the cheapest, but these are examples of great value.  I've never had one go dull but some of the small ones do break from time to time and I tend, despite taking some care, to lose the odd bit from time to time.  So I just buy a new set when they are on sale about ever two years and chuck (pun intended) the old one (I recently got a new set of 115 pieces for $23!!) and just renew the entire set. 

 

I have many types and kinds of bits in sizes up to 35mm. they all get dull after a few uses, no exceptions, even carbide masonary bits. a decent bench grinder with a fine grit wheel and a diamond wheel and about 2 hours of practice and you can master sharpening. the key is sharpening, take the time to learn and you will be very happy with the results.

Cutting oil goes a long ways in extending the life of any drill bit, heat is the enemy.  I agree with the previous John, you can eventually dull them.  I bought a large box of multiples of every size, and when one gets dull, I just replace it.  I figure the box will last my lifetime.

 

Sharping the Titanium bits is possible, but they're no longer Titanium as it's only a coating.

 

Been a custom fabricator for 30plus years.
Every new guy starts off with a complete set of number, letter and fraction bits in a long metal box.
Guaranteed in a few years that same guy is missing the E (.250) the 7, 21, and a few other of the common tap and clearance hole bits.
Usually they will have litle bulk pack engel elopes of these sizes in the drawer. Use them till they are dull and toss them.
Then the never go back to the set unless they run out and can substitute the next size till they reorder.

Specialty bits are best used in controlled production environments with the proper coolants, spindle speeds and feed rates.

Using good old HSS bits, either you get the feel for them quickly, or you get frustrated and stop doing your own work.
Just MHO

Exactly how I handle them, when they get dull, I pull out a new replacement and the dull one goes into the bin.  I'm sure I could learn to sharpen them, but life's too short to spend time doing that.

 

 

quote:

Guaranteed in a few years that same guy is missing the E (.250) the 7, 21, and a few other of the common tap and clearance hole bits.
Usually they will have litle bulk pack engel elopes of these sizes in the drawer. Use them till they are dull and toss them.
Then the never go back to the set unless they run out and can substitute the next size till they reorder.

 

Largely true. I've purchased bulk packs of the ones I've dulled or broken.

I also use my drill bits for two other purposes:

 

I will hold a bit in my hand, or in a pin vise, and use the bit to clean out holes were necessary. One example would be the rollers on a 364 log loader. Those rollers need to turn freely. I find a bit that just fits. Don't want to enlarge the hole, just clean it.

 

I have also used the shanks of my drill bits to try to get a good approximation of the diameter of a hole. I find the smallest bit that is too large and the largest bit that fits to estimate the hole size.

To me the bottom line is that drill bits - at least good enough quality drill bits, are cheap.  The115 piece set I posted a photo of above, bought on sale, is around 35 cents per bit.  For that cost, its not worth fussing with trying to sharpen, etc.: I view them as commodity, disposable units: wear them out of lose them and just replace when needed.  

 

I also used them for other applications.  Yesterday I needed to add some weight to a seven-inch long box trailer I had scratch build for a 1:50 'Sctreets big-rig.  I just picked out three big (roughly 3/8 inch) drill bits in sizes I probably will not need soon, each about 6 inches long and dropped them in the trailer.  They worked so well I went ahead and epoxied them into it as permanent weights.  Not what they were intended for, but they worked so well . . . 

Here's a photo of very small bits, brand new out of the box.  It's good practice to check the bit before applying it to your handiwork.  (Model Expo = junk)

 

 

Using good old HSS bits, either you get the feel for them quickly, or you get frustrated and stop doing your own work. 

 

 

I agree, its good quality high speed bits for me.  

 

Bill

Well, I do shop at Model Expo for model shipbuilding wood, etc., but not tools.  I've had similar experiences.  Ugh.

A buddy of mine who is an amateur gunsmith taught me a neat use for dull or broken drill bits. Cut to length, they make great super-hard pivot or fixing pins for various applications (mainly in guns, but elsewhere as well). 

Wow, great discussion here.  My concern was that they would work for metal but wood or plastic would dull them.  Appears that a good set should be just fine for my around the house and layout light metal and wood purposes.

If you drill in brass, you need zero rake drills.  I have no idea where one buys them, but I have become proficient with a Dremel cut- off disc and a magnifying light.

 

I have found that drilling in zamak can present the sams sorts of problems, so I use zero rake drills there, too.  The HSS drills are designed for mild steel, a material found only in rare places on model trains.

 

I find a good center punch and pilot hole, all done with magnification, aid in good concentric accurately located holes.  I also find that a good drill press is simply required.

 

This is all opinion, but you should know I build my own locomotives out of brass.  If you are drilling anything larger than a #43 hole, the zero rake is a safety consideration - you can get hurt when a regular drill bit bites into brass and starts flinging it around the work area.

bob2:

 

Thanks for the tip. That's a new one on me - I have occasionally had problems with drill bits grabbing in brass, but this is the first time I ever heard of a zero rake bit. I did some Googling and the only commercially made zero rake bits I could find were for Plexiglas and acrylic - they have 90 degree points and are not suited for metal. I did, however, find a nice how-to for modifying your own. Next time I have to drill brass I guess I'll have to get out a honing stone. 

I've always liked drill rod for making pins, so the idea of old broken drill bits for that is a great one - good idea!

My 115pc set is from Harbor Freight....lettered, fractional and decimal bits...same looking as the one Lee showed. Usual price is around $55 but it's even better when they have a big sale. I think I got my last set for roughly $32-$35 on sale{it was low to mid 30's}, but that was 4 or so years ago.

Do you know why?  I've been doing it for years with the 115-piece set I posted a photo of earlier and had no problems.  I nearly always use a drill press, though.

 

Excellent information everyone.

 

As always.

 

 

Shipping will be a killer.

 

Lee - the bit grabs the brass, and either flings it around in a circle, or breaks in the hole.    It is not much of a problem with smaller drills - I routinely use standard helix drills up to about 2-56, or #43.  There is no need, because a steady hand and a Dremel cut-off wheel will put the flat rake on there freehand.  Drawings are in an early 1990s issue of OGR.

 

If you look at the angle of lathe cutting tools you will find the same thing, and generally an explanation of why different rake angles for different materials.  This is standard stuff, and has been known for a very long time.

 

Purchasing low helix drills for brass is almost impossible.  Americans no longer have need of such tools.  I am an example- I spend way too much time on the iPad, and not enough time drilling stuff.  I did make a water separator for my new SP Deck this evening, using a lathe and a drill press.

Another way to help reducing the drill walking is to use the shorter screw machine length  drills instead of the longer jobbers length.  As for drilling wood, there are some really fine designs for drills for drilling wood.  Most cut the outer fibers of the hole before drilling out the inside leaving a clean splinter free hole.  In my old shop we always bough HSS drills with the black finish in bulk envelopes. There were several indexes around the shop, and these were refilled regularly from the envelopes.  We did not resharpen our own drills.  Without a proper drill sharpening machine, it impossible to get both sides to cut together, which will result in drilling oversized holes.  It cost about $4.00 to get a drill sharpened, so the small ones went right into the trash when they were dull.  Many of our larger drills were very old.  When the sharpening shop ran into a drill that was not HSS they go right into the scrap.  They will not sharpen them.  Special coated drills were only used for special projects.  We did use cutting fluids and kept several different fluids, like lard and kerosene, around for copper and aluminum.  The shop did a lot of small parts in brass and 360 high lead free machining brass was always used.

This is a hobby, not a precision machine shop.  I routinely sharpen HSS drills and put the proper rake on them down into the sixties.  If your #50 drill cuts a thousandth oversize because you got the drill lopsided it just means the tap goes in easier.  That is very helpful for crankpin screws, because they are 0-80 usually, and the number 56 drill, when sharpened, might cut enough steel out of there to save your eight dollar tap.  Most shops use #55 for those threads - works fine.  My locomotives have hundreds of tapped holes in them and they do not fall apart.

 

But buy new drills - it helps keep the costs down for those uf us with limited tool budgets.

It is surely too late to count all of them, but there are 32 screws holding the driver bearings in place, 12 small crankpin screws, eight screws holding the tender truck side frames together, I could go on.  The valve gear is pinned with 0-80 and 00-90 steel screws, each cylinder block is three pieces, all held together and fastened to the frames with 2-56 steel screws.  Major assmblies ar held together with aircraft grade socket screws.  All holes were drilled with my drills, all hand- sharpened with zero rake.

 

If your bits are grabbing in brass, then your speed and or modeled are wrong.

Brass/ copper usually grabs because you are heating the hole. It may be counterintuitive but if you heat a pipe, the outside gets bigger but the inside gets smaller.
Nothing wrong with using a zero or negative rake but you are now scraping and not drilling.
They are great for acrylic and polycarbonate. Acrylic grabs and shatters. Polycarbonate usually just grabs and melts.

Use a good quality cutting fluid. Too bad the Original AlumaTap is no longer available. 111trico was a great cutting fluid for alum, brass and copper.
And yes, I know it is a carcinogen. But only in the State of California. LOL.

Feed not modeled. Silly autocorrect.

Sharpening a bit by hand on a grinder the right way does take time to learn, and takes a certain "touch" of skill. The Drill Doctor makes it easy, almost fool proof, and takes about a minute to do if you're slow. Chuck the bit, insert chuck in Doctor, slowly spin while gently pushing, done. You cant walk from your car to the drill bit isle, or fill out an online order form that fast. The #750 does 3/32" to 3/4" in multiple angles and adding a spilt to each is optional each time. For ten years, Ive only had to buy the little bits.

I do keep assorted dull bits for the brittle plastics too. Gives softening thru melting a little before it cuts. Ive also melted holes in plastic, running bits high speed in reverse. 

This is from "doityourself.com":

 

The angle of the tool bit you will require depends on the material you are using. For example, in cutting brass you will want a side and back rake angle of 0 degrees, whereas if you are cutting aluminum you will need a side rake angle of 15 degrees and a back rake angle of 35 degrees. It is recommended that you always use the minimum angle required for the task you are trying to accomplish because sharper angles make for weaker tool bits.

 

Read more: http://www.doityourself.com/st...gles#b#ixzz2k6po5FQl

 

Or you could do a Google search.  But don't take my word for it, I am not a professional machinist, and have only built 36 steamers.

 

At about 40 - 80 cents per bit it's just not worth sharpening them as far as I am concerned.  I view drill bits like razor blades - once upon a time we kept one forever and stropped it  to a fine edge whenever it got dull.  Now, we chuck them in the trash and load another when they get dull.  

Sam, unless you plan on drilling a lot of cast iron or stainless steels, uncoated high speed steel is fine and actually preferred for aluminum and plastics. Get your drills at an industrial supply house like Travers Tool, MSC, or McMaster Carr. You can choose import or domestic as well as manufacturer. Avoid places like Harbor Freight or Grizzly which are pretty much cheap imported stuff of dubious quality.

 

Pete

I buy mine through Amazon and I'm sure they are all made overseas and they are inexpensive.  But they do the job.  Of course I do nothing harden than mild steel.

 

I have never had any problem with brass, alum, etc.  The only thing that gives problems is some clear sheets - acrylic or whatever, will crack if I am not super careful.

Lee, there are special drills for plastic with either a 80 or 90 degree point. These will not shatter acrylic. You can google plastic drills to find them. 

 

Pete

Lee, although the small ones are cheap, a larger one will set you back. I can't tell you how many times in the middle of a job I had to re-sharpen bits. I have only one complete index and a broken or dull bit can stop a job in it's tracks. if you learn how to do it, it is a worth while skill. I also have to say not all bits are sharpened properly when new. I fine tune mine til they yield 2 equal waste spirals.

I can understand your price point Lee. Its very valid. Although a penny saved..etc., I do buy extras too. But not having to wait if the bin runs dry is a godsend sometimes. 

Dump them in the trash? You must mean recycle bin, that's good steel!

(If you start throwing out tired old locos, let me know.)