The Art of Skipping Grits: Can You Jump from 120 to 400?
By Frederick M. Hueston
Let’s just get this out of the way, because I know half of you are already shaking your heads.
Yes, you can skip grits. Yes… If You Know What You’re Doing
Jumping from 120 to 400 and eliminating 220 isn’t some reckless shortcut. It’s a calculated move. The problem is most guys try it before they understand why it works, and more importantly, when it doesn’t.
I’ve seen it done beautifully, and I’ve seen it turn a floor into a blotchy mess that needed to be torn back down two steps.
So, let’s talk about how to do it right.
Why Grit Progression Exists in the First Place
Grit progression isn’t arbitrary. Each step is designed to remove the scratch pattern from the previous grit and replace it with a finer one.
- 120 grit leaves a fairly aggressive scratch.
- 220 refines that scratch.
- 400 starts to bring in clarity and light reflection.
When you skip 220, you’re asking 400 to do two jobs at once:
- Remove the 120 scratch pattern
- Establish a consistent 400 finish
That’s a big ask. But under the right conditions, it works.
When Skipping 220 Works
- Your 120 Cut is Clean and Uniform
This is the big one. If your 120 step is sloppy, uneven, or inconsistent, don’t even think about skipping.
You need:
- No visible deep scratches
- No missed areas
- No swirl patterns from poor tooling
- A flat, even cut
If the 120 step is dialed in, the 400 has a fighting chance.
If not, 400 will just highlight every mistake you made.
2. You’re Using Quality Diamonds
Cheap diamonds don’t cut clean, they tear. That leaves a jagged scratch pattern that takes more steps to refine.
High-quality resin diamonds leave a more consistent scratch pattern, which makes skipping a grit possible.
This is one of those areas where saving money costs you time.
3. The Stone Type Matters
Some stones are forgiving. Others will expose you instantly.
More forgiving:
- · Marble (especially softer calcite-based stones)
- · Some limestones
- · Travertine
Less forgiving:
- · Hard, dense granites
- · Quartzite
- · Some engineered stones
On harder materials, that 120 scratch is deeper and tighter. Jumping to 400 can leave ghost scratches that show up under light.
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4. You Adjust Your Technique
You can’t run 400 the same way you normally would and expect it to magically fix everything.
When skipping 220:
- · Slow your machine down
- · Add more passes
- · Overlap tighter
- · Use slightly more pressure, but controlled
- · Work smaller sections
You’re basically asking 400 to act like a hybrid grit. Treat it that way.
The Real Secret: It’s Not About Skipping, It’s About Control
The guys who pull this off consistently aren’t just skipping grits randomly. They’re reading the floor.
They’re checking:
- · Scratch pattern under good lighting
- · Reflection consistency
- · Surface flatness
- · Tool wear
They’re not guessing. They’re verifying.
Where Most Guys Go Wrong
Here’s what usually happens:
They try skipping 220 to save time.
But instead of saving time, they end up:
- · Doing extra passes with 400
- · Chasing scratches that won’t come out
- · Dropping back down to 220 anyway
- · Burning time and pads
Now the job takes longer than if they just ran the proper sequence.
Skipping grits only saves time when everything is working in your favor.
A Practical Approach That Works
If you want to start doing this without risking a callback, here’s how I’d approach it:
- Do your normal metal steps
- Run 120 and inspect carefully
- Test a small area by jumping to 400
- Check it under good light, not just overhead lights
- If it looks clean, continue
- If not, go back and hit 220
Always test first. Never commit the whole floor until you know.
A Word on Production Work
In commercial work, where time is money, skipping grits can make a big difference.
But that’s also where mistakes cost the most.
If you’re running a crew, make sure:
- · Everyone understands what a proper 120 finish looks like
- · Someone is inspecting before moving on
- · You’re not letting less experienced techs make that call
This is a judgment call, not a standard procedure.
When You Should NOT Skip 220
There are times where skipping is just a bad idea:
- · Floors with heavy damage or deep scratches
- · Uneven lippage removal
- · Poor previous steps
- · Highly reflective finishes where clarity matters
- · Hard stone that holds scratches
In those cases, 220 isn’t optional. It’s necessary.
The Bottom Line from the Field
Skipping from 120 to 400 is absolutely doable. I do it. A lot of seasoned pros do it.
But it’s not a shortcut for beginners, and it’s not something you do blindly.
Think of it like this:
You’re not skipping a step. You’re combining two steps into one.
And that only works when everything leading up to it is done right.
If your 120 step is clean, your tooling is good, and you adjust your technique, you can save time and still produce a top-quality finish.
If not, that 220 grit you skipped is going to come back and haunt you.
And usually at the worst possible time, right when the client is standing there watching.
