Combination countersink/pilot hole bits are great to have around. They save time and keep the conical chamfer centered on the clearance hole. But there are two potential downsides: 1) when you need a size you don't have on hand; or 2) if you lose or break one of the pilot hole bits. Though not unheard of, if your project calls for larger clearance holes closer to 1/4", suitable combination bits are uncommon in most tool kits. Even if you have the right size, you can still misplace or break the bit. Without a backup or replacement bit compatible with the countersink portion, you must stop work. Of course, you could use a traditional dedicated (non-combination) countersink you lose the advantage of foolproof centered cones, and frequent bit changes cost you time. This is where these adjustable countersinks really shine.
Because of the fit of the countersink against each bit and the angle of the countersink cutter, the countersunk hole matches the dimension of the bit itself. This provides a universal fit to any diameter bit, including metric-sized drill bits.
Unlike some adjustable countersinks on the market, the Infinity countersink is made in two pieces and uses two Allen screws to evenly tighten against the bit. Others use a single Allen screw and compress the countersink, limiting the accuracy of the fit and ultimately the success of the cutting action.
As the cutting edges of the countersink are carbide, they can be used for cutting numerous materials beyond wood. Using a metal cutting lubricant will significantly prolong the life of your bit when drilling in aluminum and other non-ferrous metals
In the "getting more for your money" category, you can flip the countersink over on the bit and use it as a depth stop in an emergency. Handy!
Another way to get more value from a tool, you can use the countersink to widen existing holes by using a bit or drill rod of the same diameter as the existing hole, and use the countersink to create a perfectly centered starting recess for the next size up — no wandering or off-center boring to worry about.
If you're looking for a tool that is more or a "multi-tool" by performing multiple tasks in a single piece, look no further. The Infinity Adjustable Countersink will get used often in your shop!