The dreaded chatter marks. It seems that just about everyone who’s ever had a career in hardwood floors has run into this problem. While there are many schools of thought on how to fix chatter marks, City Floor Supply has two solutions that we favor above all else.
What causes chatter marks?
Before we get into solutions, let’s take a second to discuss why chatter marks happen in the first place. Chatter marks are repeated imperfections on the floor that are between ½” and ¾” apart.
They are traditionally caused by some sort of failure in the big machine. Bad sandpaper alignment, uneven wheels, incorrect drum pressure, imbalanced drums, loose V-Belts, failed bearings, or even poor subfloor construction are all common issues that could produce chatter marks on the floor.
It should also be noted that chatter marks can come about from using too fine a grit of sandpaper with a big machine. While big machines are great at initial cutting passes, aggressively sanding with the highest grits can lead to complications.
Once the chatter marks appear, there are two solutions we recommend to fix the problem.
How to fix chatter marks in a wood floor
Solution #1: The first solution is to hardplate. This involves taking an aluminum felt backed block (hardplate) and attaching it to a floor buffer. You can then attach attach a Velcro Abrasive disc or bolt on a paper disc.
The hardplate spreads the sanding out in a larger surface area and will not allow the abrasive to follow the chatter pattern. This is a very effective method for cutting through the peaks and valleys of chatter to get the floor flat again.
Solution #2: Our second solution is to use a multi-disc sander like the Lagler Trio. This sander is manufactured by the same company that produces the Hummel. The Trio lives up to the impressive German engineering behind the Lagler name. Click here to learn more about the Lagler Trio.
One of the biggest benefits to the Trio is that it is a sander that is specifically designed for use in the finish sanding stage. The Trio has three sanding discs which move in a planetary motion, which is powerful enough to eliminate cross-grain scratches and other complexion flaws.
However, the Trio will not dig into the floor and interfere with the topography. In other words, this sander will not dish the grain out when sanding floors. The Trio is an especially good tool for parquet floors where there can be multiple species of wood side by side in various directions.
Prevention is the best medicine, but when that fails, chatter marks can still be fixed
While the best way to prevent chatter marks is to keep up with maintenance of your big machine, chatter marks will sometimes show up on your hardwood floor. Once they do, it’s advisable to fix them via a buffer with a hardplate or using a multi-disc sander like the Trio.
For a more in-depth look, check out our video about this superb machine.
It’s great to see discussion like this, as for years we’ve seen confusion on the industry over the term “Chatter”. The article is correct in its description. It is nearly always a flaw in the floor’s complexion, and with the exception of some of the heavy split drum machine chatter that is still common in some circles, the type of chatter discussed here has nothing to do with a floor’s sand job topography. Replacing or scraping your wheels – a common suggestion on the topic – is very unlikely to resolve your chatter problem. To discover if your sanding machine is the culprit for chatter (not a subfloor issue), you should ask a few questions: Has prominent chatter that is difficult to buff out been present at least somewhat consistently over the last several jobs? Has this problem come on fairly suddenly? (Can you remember cleaner-looking sand jobs in the not-so-distant past?) Have there been any noticeable changes in how the sanding machine sounds or feels? One or more ‘Yes’ Answers to these questions would point you in the direction that something is going on with your machine, and attention should be towards your machine’s motor driven moving parts. That is, with a sanding belt installed for sanding on your machine, turn it on, stand back and everything that is moving would fall under this category. If I had to give up a list of ‘usual suspects’ for this, I’d say in order: Sanding Drum, Guide Rollers, Upper Roller (including bearings), V-Belts, V-Belt tuning and V-Belt Pulleys…On machines over 7 years old, I would add Motor Bearings, Drum Shaft bearings and Dust Fan Unit. ALWAYS beware of non-OEM replacement parts, as these are very often troublesome.
Hard-plate buffing and multi-disc finish sanding machines are quite handy for tackling those chatter problems that do occur from time to time (outside the obvious fault of the belt sander) as the article states, though I must confess I get a little uneasy when a TRIO-user starts asking me if I think he can start slacking on his belt sander’s maintenance because his TRIO will eat up all such manifestations on the floor. It’s all about being on the most efficient path to the finished product and all steps should compliment each other. If your belt sander is indeed not performing at its best, you are probably going to come out ahead to shell out for some service to it.