Flat Depressed Center Grinding Wheel vs Type 27: When to Use
By Supergrit Abrasives | Published: 2026-10-22
Category: Comparisons
Learn the key differences between flat depressed center and standard Type 27 grinding wheels, and when to choose each for metal grinding tasks.
Quick answer
Choose a flat depressed center grinding wheel when you need a flush grinding surface on flat workpieces and can work with a shallower cut. A standard Type 27 wheel is better for aggressive stock removal and accessing tight corners.
Why shape matters for grinding reach
A flat depressed center wheel (often called a Type 27 flat) has a completely flat grinding face with a slight recess around the arbor. This design lets you grind flush against a surface without the raised hub of a standard Type 27 wheel getting in the way. The trade-off is that the flat profile reduces the wheel's depth of cut, making it less effective for heavy material removal or for reaching into deep grooves.
RPM and wheel construction
The flat depressed center wheel we carry (7" diameter, 3/32" thick, 7/8" arbor) is rated for 8,500 RPM. Its thin profile—3/32 inch—makes it ideal for light grinding, blending, and finishing passes where you want to avoid gouging the workpiece. Thicker Type 27 wheels (typically 1/4 inch) can handle higher side loads and last longer under heavy pressure, but they also remove more material and leave a rougher finish.
Flat vs Type 27: Trade-offs at a glance
- Flush grinding capability: Flat depressed center wheels let you grind right up to a vertical edge or weld bead without the arbor nut or raised hub interfering.
- Depth of cut and aggression: Standard Type 27 wheels have a deeper recess that allows more aggressive stock removal and better access to corners and fillets.
- Wheel thickness and control: Thinner flat wheels (3/32") provide finer control for blending and finishing; thicker wheels (1/4") are more durable for heavy grinding. Match wheel thickness to your task: thin for precision, thick for production.
Product facts
- 7" DIAM X 3/32 THICK X 7/8" ARBOR FLAT DEPRESSED CENTER GRINDING WHEEL PFX GERMANY (80182) 8,500: This flat depressed center wheel measures 7 inches in diameter, 3/32 inch thick, with a 7/8 inch arbor, and is rated at 8,500 RPM. The thin 3/32" profile gives you precise control for light grinding and blending, but it will wear faster than a thicker wheel under heavy use.
7" DIAM X 3/32 THICK X 7/8" ARBOR FLAT DEPRESSED CENTER GRINDING WHEEL PFX GERMANY (80182) 8,500
Which wheel fits your work?
Best for
- Light grinding and blending on flat surfaces where flush contact is needed
- Finishing passes and weld blending where minimal material removal is desired
Not ideal for
- Heavy stock removal or deep corner access
- Grinding in tight fillets or inside corners
