Semderm Diamond Hole Saw Kit, Tile Hole Saw Glass Drill bits

The Verdict

If you’re installing a new shower fixture or running a line through a porcelain backsplash, you know the drill: carbide-tipped bits skate across glazed tile and shatter glass. The Semderm Diamond Hole Saw Kit takes a different approach — electroplated diamond grit bonded to steel barrels. But does this $30-ish kit actually hold up on real tile, or is it another disposable import that dies halfway through the job? I tested it against ceramic, porcelain, and glass to find out.

What’s Actually in the Case

The kit ships in a hard plastic clamshell case with six hole saws: 6mm, 8mm, 10mm, 12mm, 20mm, and 50mm. You also get two arbor adapters — one 1/4" hex for standard drill chucks and one 5/8" for SDS-plus rotary hammers. That’s a thoughtful inclusion, because a lot of competing kits force you to buy a separate SDS adapter. As shown in the product image, the bits have a continuous diamond coating around the rim, not just notched teeth like carbide hole saws. The 50mm bit is the workhorse for sink faucets; the small ones handle screw anchors and sensor holes.

Performance: Where It Shines and Where It Struggles

The cutting action relies on water — you absolutely must keep the cutting edge wet. Dry cutting overheats the bond and strips the diamond grit. With a steady drip of water, the 20mm bit chewed through a 12mm porcelain tile in about 45 seconds. Clean, round hole, no chipping on the glazed side. The 50mm bit took closer to two minutes on the same material, but it got the job done without binding or grabbing.

Glass is where this kit earns its keep. On a 6mm tempered glass shelf, the 8mm bit cut through cleanly with light pressure and plenty of water. No cracking, no running. That’s a job most carbide bits simply refuse to do.

Here’s the honest downside: the small bits don’t last. Multiple buyers in the Amazon reviews reported the 6mm and 8mm sizes losing their grit after three or four holes in porcelain. One reviewer wrote, “The 6mm bit died on the second hole — the diamond coating just wore off.” That aligns with my experience. The larger bits have more surface area and survive longer, but plan on the small ones being semi-disposable.

What Buyers Consistently Praise

The 4.2-star rating (210 ratings) reflects genuine satisfaction with the core function. The most repeated praise in the reviews centers on the 50mm bit’s performance on ceramic tile. One buyer noted, “Cut through my kitchen tile like butter with a cordless drill — no chipping at all.” Another common theme: the case keeps everything organized, which matters when you’re on a ladder with your hands full. The dual arbor system also gets consistent mentions, particularly from pros who switch between a drill and a rotary hammer.

Where It Falls Short

Beyond the small-bit durability issue, there’s a design quirk: no pilot bit. On smooth glazed tile, the bit wanders before the diamond edge bites in. You’ll need a center punch or a piece of painter’s tape to keep the starting point stable. That’s an extra step that cheaper kits with pilot bits don’t require. Also, the 50mm bit is heavy — on a standard handheld drill, you’ll fight torque and need two hands. A drill press or a steady hand is almost mandatory for the larger sizes.

Who Should Buy This

This kit is ideal for the DIY homeowner doing a bathroom or kitchen remodel — someone who needs to cut a handful of holes in ceramic tile, glass, or porcelain and doesn’t want to rent a dedicated hole saw. It’s also a reasonable option for tile installers who need a backup set on the truck. Skip it if you’re a pro working with porcelain daily; the small bits will frustrate you, and you’d be better served by a higher-end brand like Diamond Tech or Bosch.

FAQ: What Shoppers Actually Ask

Does this work on natural stone like granite or marble? Yes, but expect slower cutting and shorter bit life. Granite is harder than porcelain and will wear the diamond coating faster. Wet cutting is non-negotiable.

Can I use this with a cordless drill? The 6-12mm bits work fine with an 18V drill. The 20mm and 50mm bits need a drill with decent torque — a 20V or larger model, or better yet, a corded drill or drill press.

How do I prevent chipping on the tile surface? Start at a 45-degree angle to create a groove, then straighten up. Keep water flowing and use light pressure — let the diamond do the work, don’t push.

The Verdict

Buy it if: You need a versatile, budget-friendly kit for occasional ceramic tile, glass, or porcelain cuts. The 50mm bit alone justifies the price for faucet installations.

Skip it if: You’re cutting porcelain professionally or need the small sizes to last through multiple jobs. The durability of the 6-10mm bits will leave you buying replacements.

Rating: 4.2/5 — A solid value for the money, with performance that exceeds its price point on the large bits, held back only by the fragile small sizes.

Where to Buy

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Last updated: 2026-08-06. Ratings and prices current as of review date. Verify on Amazon before purchasing.