Indexable vs Replaceable Tip vs Solid Carbide Drills – Which One is Best for Your Machining?

Drill selection impacts efficiency, cost, and quality. Let’s explore indexable insert, indexable tip, and solid carbide drills. The right drill can really make or break productivity, so let’s break it down. I’m Justin, technical sales engineer with KYOCERA. And I’m Andy Greaves. I’m the East Coast applications engineer for KYOCERA SGS. [Music]

So let’s explore drill selection. Choosing the wrong drill can lead to poor hole quality, rapid wear, and increased cost. Solid carbide drills deliver precision for small-diameter, high-speed application. Indexable insert drills are best for large-diameter holes and high-production environments, while indexable tip drills balance that cost and precision for mid-diameter holes.

Let’s take a minute to talk about those indexable drills. Indexable insert drills are best for high-volume environments where speed and efficiency are key. They are commonly used in heavy equipment manufacturing for large-diameter through holes and materials like cast iron, steel, and stainless steel. When might an indexable insert drill not be the best solution?

Yeah, so you can’t have a one-size-fits-all drill. So indexable insert drills, although they’re great for roughing, they aren’t ideal for high-tolerance applications or where a high level of a smooth wall finish is required. They are better for shallower holes as well. They are versatile in the fact that you can use them for high and low production rates, but if you’re doing a deeper hole, a solid carbide tool is better.

Sure, I’d agree with that. One cool thing, though, about indexable drills is that we can implement different insert geometries for different materials and applications. For instance, positive rake inserts reduce cutting forces and tool failure in materials like stainless steel and heat-resistant superalloys, whereas heavier-duty inserts can allow for cross-hole drilling, interrupted cutting, or higher-feed materials like steel and irons.

Yeah, absolutely. Indexable tip drills, however, do combine the precision and reusability of an indexable drill. The carbide tip gives greater accuracy for the hole, while the reusable body helps maintain the cost. So they’re ideal for mid-diameter holes in a wide range of materials because you’ve got that versatility of different tips to add to that. That same drill body will accept a wide range of tip diameters and geometries, which will save shops time and money. They’re great for shops that drill a wide range of hole sizes, materials, and part features.

Yeah, that versatility is really good for the smaller, medium-sized shops. They don’t want to be buying a new body for every tool, or a new insert, or a new solid carbide drill. One day they might be making something like an aluminum component and the next an Inconel component, and for that they are able to get that benefit of choosing a different tip to get the job done.

The solid carbide drills are really good for smaller diameters with high levels of precision, needing a high RPM and feed rate. An example of this is micro drills in the PCB arena. They require very accurate, small-diameter holes, and that solid carbide stiffness and rigidity really does give a valuable process.

And to add to that, one other area where solid carbide drills really add a lot of value is in tough materials like titanium or Inconels. Due to that solid carbide rigidity and their slick, polished coatings, they give superior surface finishes for critical applications in aerospace and medical industries.

So all these three types of drills have different features. One solid feature that they all have, between tip drills, indexables, and solid round tools, is through-coolant capability. Absolutely, yeah. Again, the main benefit there is through-coolant can improve chip evacuation for deep-hole performance. Now, high-pressure coolant, say 1,000 PSI plus, absolutely helps improve chip evacuation, especially in deep holes, but it’s not always needed. You know, the high pressure isn’t always needed. It’s just extra helpful.

Expanding more on solid carbide drills, the through-coolant is really critical in deep holes. So for deep holes, I’m talking eight, ten, twelve times D for a solid carbide application. We do do higher in our micro range as well, but in this arena, the through-coolant really does help get those chips out of the hole quickly and effectively because otherwise they start to pack, and that can cause tool failure very quickly.

Another improvement in performance is high-performance coatings that our drills are offering. Sure, both in the indexable side and in the solid carbide drill arena. So having a coated drill allows for a better lubricity of the flute and gets the chips out of the cut area very quickly. This really helps protect the base carbide substrate from heat and wear and helps stop chip adhesion and material sticking as it’s evacuated up the hole and out of the tool.

Now, one important consideration, though, that we all have to think about is costs associated with the different styles of drills. Yeah. Now, the number one thing is obviously to pick the right tool for the job, no matter what, but we all have to envision and examine the cost applications. So solid carbide drills are going to be costlier, but they are best for precision and finishing tasks, not as much for roughing. Okay. They are used for applications and are best for those applications requiring high-quality finishes because they help avoid rework, right, in subsequent processes.

We all have to consider also where we might be using the wrong tool for the job. If you’re struggling with a hole size or tolerance, especially in tough materials, that may mean that the drill type is wrong. Or maybe if you’re seeing poor finishes or burrs, that might suggest an improper geometry on the inserts or a tip, or the wrong style of solid carbide.

A key factor in drill design is the number of margins that the drill has. So in a lot of materials, we need a double-margin drill. So I’m talking four points of contact for the drill. This really does help make an accurate, straight hole with an improved surface finish as well. One of the downsides to a double-margin drill, however, is the fact that because there’s more additional points of contact, there’s more heat generated. There’s more friction, and the heat and the friction breaks down the coating quicker, which can lead to premature tool failure. In hard-to-machine materials such as stainless steels and Inconels, we use a single-margin drill where there’s less contact, less heat, less friction, and then you get a better-performing product.

Also, the number of flutes is critical when selecting a drill. Obviously, most drills come in two flute, but we do offer three-flute-count drills for aluminum and cast irons in the solid carbide range of tools.

A few final takeaways here: indexable insert drills are efficient for large holes, roughing, and high-volume environments, where tip drills balance the cost and precision for mid-size holes, and solid carbide drills are best for high precision, small diameters in high-speed applications and difficult-to-machine materials. It’s important to match the tool to the diameter, material, the production volume, and finish requirements.

And always, don’t forget, it’s not always a plug-and-play application. Take the time to experiment and optimize the process because by playing with those speeds and feeds and potential pecking cycles, you’ll be able to get more out of the drill, get a higher level of tool life and a better hole.

Thanks for joining us today on Tips & Chips. If you found this helpful, like, comment, and hit the notification bell. If you’ve got any questions or tips that you’d like to share with us, please leave us a comment, and we’d love to hear from you. Do you need help with your application? Visit the link in the description for more resources. And as always, keep those chips flying. [Music]