Step drill bit

tvrgeek

tvrgeek
User
They are all about the same. If course, like most drill bits, false labeling as they are titanium COATED. Drill is just HSS. About mid priced. Been using various brands for years. Quite handy and does a better job of a round hole rather than triangular in thin sheet. Always start with the biggest twist bit hole you can. One can get cobalt alloy ones for a lot more money if you need to hog out in stainless.
 

Oka

Oka
Corporate Member
I have a bunch of these. I found most on job sites, they are pretty handy when doing Electrical or sheet metal drilling. I only really use them on wood when I need to enlarge a hole and I do not have the size bit handy.

If you can get the ones with 2 or 3 cutters not one. They are easier to manage and they cut better.

FYI -Titanium nitride coating that gold coating uses titanium nitride (a form of Nitrogen) usually in a ceramic base. It is usually applied in a vapor to the metal. The advantage of the coating is it has a high surface hardness, it lowers friction, so less heat, and fills in the micro voids that are natural in tooling. This in turn prevents failure and adds to the life of tool. And, with the lower friction the tool bit stays sharper, longer. So, it is an easy cheap way to improve a HSS tool. Even with this I have seen varying qualities of this coating so be familiar with the tool brand.
 

tvrgeek

tvrgeek
User
I have found the coatings actually do little. OK, if drilling cast iron so no oil, the lower friction may help the cutting edge stay cooler, so positive for that. Mild steel, well if you are not using oil, your fault. Wood? All totally irrelevant unless may being production quantity in Pulpelheart and in that case, shame on you for not using carbide. Stainless, well better be using a Cobalt alloy bit anyway. I have used one of these steps in SS, but it will dull really quickly. I might see if they make one in Cobalt. ( Just drilled the hole for an O2 sensor bung last week.)

Look at a used one under a magnifying glass and you can see the cutting edge is not coated after the first hole. I have used a diamond hone to tune a couple of mine. so obviously, it is not the edge that remains coated. My favorite one is a smaller one with smaller steps. It is not coated. All of mine ( just counted 7) are single edge. Two edge may lead to a triangular hole like a twist drill. Faster, true. A few cheap ones have a round shank where most have a triangular shank to help prevent spinning in your chuck, especially a hand tight one. I have found they tend not to jam in thin stock as easily as a twist drill.

IMHO, In most cases, I think it is the bling factor of gold color vs black oxide or raw HSS that is most significant, not actual performance. Performance comes more from the base alloy of the bit.

Titanium nitride - Wikipedia
To say it is a form on Nitrogen is like saying water is a form or Hydrogen. Very misleading.

I would agree to look at the brands and history of who makes the longest lasting bits. There are a lot of at least attempting to do objective testing of twist drills on the WEB. All HSS is not the same and the finish quality is not the same. I now buy packs of bits in plain HSS from machine tool suppliers rather than big box stores. Mostly for smaller than 1/4 inch as I am not good at sharpening small bits.

A lot to take in. Far more if you GOOGLE carefully.
 

blackhawk

Brad
Corporate Member
Tvrgeek - I have to respectfully disagree on the effect of coatings. I work full time in a manufacturing plant where we do a lot of metal machining. We had a product that we machined on a Bridgeport CNC knee mill. Same parts day in and day out with the same height and width, just different lengths. We used a plain endmill for at least a year. We had to change that endmill out every week. I decided to try a titanium nitride coated endmill, same brand, style, helix, everything. Only difference was the coating. The coated endmill lasted a minimum of 3 weeks, most of the time 4 weeks. We have been using the coated endmill ever since, going on 5 years. The titanium nitride coating improved the longevity of the endmill by 3-4 times.
 

tvrgeek

tvrgeek
User
Can't argue with direct experience. I have had different experience with twist drills in hand or drill press from a hobbyist/homeowner/woodworker/British car maintainer. My small uncoated step I use most frequently and it is just as sharp as my bigger coated ones. Controlled production is an entire different animal.
Curious, who is your drill bit supplier? I could use a bunch of split point stub drills. No need to use jobbers to drill holes in sheet metal.
 

Oka

Oka
Corporate Member
The description is only for those who would not understand what a Nitride is. Didn't think we needed to go down chemistry and molecular mix designs path. - I'll try to be clearer in the future for all the sticklers out there -;)
The important thing with the Titanium Nitride coatings is it lowers friction, therefore heat, increases surface hardness albeit it is a thin coating and improves the surface consistency of the tool. On wood you probably would not really notice that improvement much, but on Metal it is very noticeable.
 

tvrgeek

tvrgeek
User
Just my battle against the almost correct, and sometimes totally wrong information the WEB. It is natural for people to pick up things that are not correct and remember them.

FWIW, Harbor Freight ad today has their 2-piece Warrior set for $14.

I see they have picked up the old Sears "good, beter, best" game.
 

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