30 grit and 60 grit metal bond diamonds are both common choices for concrete floor grinding, but they are not used for the same job. The right choice depends on the floor condition, concrete hardness, machine pressure, scratch pattern, and what step comes next.
For metal bond tooling options, review our Metal Bond Grinding Tools.
What 30 grit metal bond diamonds are used for
30 grit metal bond diamonds are normally used when the contractor needs stronger cutting action. They are commonly selected for opening the concrete surface, removing light surface contamination, leveling minor uneven areas, and preparing a floor before a finer metal step or hybrid transition step.
A 30 grit tool leaves a more visible scratch pattern than a 60 grit tool. That is not always a problem. If the next step is planned correctly, the scratch can be refined by a finer metal bond tool, a hybrid pad, or a resin polishing sequence.
30 grit is often a practical starting point when the floor is closed, hard, uneven, or slow to cut. It can also help when the contractor needs production speed before refining the floor.
What 60 grit metal bond diamonds are used for
60 grit metal bond diamonds are usually used when the floor has already been opened and the contractor needs better scratch control. They are less aggressive than 30 grit and can help prepare the surface for a smoother transition.
A 60 grit tool is often useful after an aggressive first cut, before moving into Hybrid Pads, or before preparing the floor for polishing.
If the floor already has a reasonable profile and does not need heavy opening, 60 grit may be a better starting point than 30 grit. This can reduce unnecessary deep scratches and save time in later steps.
When 30 grit is the better choice
Choose 30 grit when the floor needs more cutting power.
This can include:
Hard concrete that is slow to open
Surface paste that needs to be removed
Minor leveling work
A floor that needs stronger scratch creation before refinement
A project where production speed matters more than early scratch control
A coating prep job where the floor needs a stronger profile
If the job involves epoxy, glue, mastic, or thick coating removal, do not assume 30 grit metal bond is the first step. In that case, check PCD and Coating Removal first.
When 60 grit is the better choice
Choose 60 grit when the floor needs refinement instead of aggressive opening.
This can include:
A floor that has already been cut with 16 grit, 20 grit, or 30 grit
Medium concrete that does not need heavy opening
Scratch refinement before hybrid pads
Surface preparation where deep scratches are not wanted
A polishing workflow where the next step must remove the metal scratches efficiently
A floor where the contractor wants better control before resin polishing
If the floor is already open and cutting well, jumping back to 30 grit can create extra work. In that case, 60 grit may be the cleaner step.
Concrete hardness still matters
Grit is only one part of the decision. Bond matters too.
A 30 grit soft bond tool and a 30 grit hard bond tool will not behave the same. The same is true for 60 grit tools.
Hard concrete usually needs a bond that keeps exposing fresh diamond. Soft concrete usually needs a bond that controls wear and prevents the tool from disappearing too quickly.
Before choosing 30 grit or 60 grit, confirm the concrete hardness, the grinder weight, and the job goal.
Do not choose by grit alone
One common mistake is ordering only by grit number.
A contractor may say, “I need 30 grit,” but the better question is:
What floor are you grinding?
What machine are you using?
What bond do you need?
What scratch pattern are you trying to create?
What comes after this step?
If the next step is resin polishing, the scratch pattern matters more than the grit label. If the next step is coating, the profile and surface cleanliness matter more than gloss.
For full workflow planning, review our Solutions page.
Machine fitment affects performance
The same grit can perform differently on different machines. A heavy grinder, light grinder, high-speed machine, or planetary grinder can change the pressure on each segment.
Before ordering, confirm the machine system. Common systems include Lavina, Husqvarna Redi Lock, HTC, Scanmaskin, Diamatic / Blastrac, Terrco, SASE, WerkMaster, STI PrepMaster, ASL, Xingyi, CPS, and Klindex.
For machine-specific tooling, start with Shop by Machine.
Simple selection guide
Use 30 grit when you need stronger opening, faster cutting, or more aggressive surface preparation.
Use 60 grit when you need scratch refinement, smoother control, or a better transition toward hybrid or resin steps.
Use a small test area if the floor condition is uncertain.
Check the scratch pattern before moving forward.
Do not move into resin pads until the metal scratches are controlled.
Related Tools and Next Step
For concrete grinding shoes and metal bond tooling, review our Metal Bond Grinding Tools.
If the floor has coating, glue, mastic, or heavy residue, check PCD and Coating Removal before choosing metal bond diamonds.
If 30 grit or 60 grit leaves visible scratches before polishing, review Hybrid Pads before moving into resin.
If you need help choosing between 30 grit, 60 grit, bond type, and machine fitment, send us your grinder model, floor condition, current step, and target result.