June 2017 - Lägler North America

This won’t surprise you, given Lägler is a German manufacturer, but the company focuses a lot on efficiency.

Lägler cares about that in its production processes, and we care about helping sanding professionals be the most efficient they can be on the job. Knowing how
to get the most out of their machines – whatever brand they are – in the smartest way (least effort) will pay you back every day.

Efficiency when sanding floors saves wear on your body, your abrasives and machines. It saves you time. And all that saves you money and lets you move
on to the next job sooner.

What is Sanding Path Displacement?

One technique for being more efficient when sanding with the big machine is to find the right line for your sanding path displacement, and be consistent
with it.

A sanding path is the forward and reverse sanding motion on the same path without displacement of the sanding drum, meaning that forward and reverse path
is exactly over the top of itself in both directions.

Sanding drum displacement refers to how far over you move from one forward-reverse path to the next. (That should almost always mean moving
left to right across the room.)

The ideal amount of sanding path displacement is 50 percent, meaning each time you start the forward sanding motion you will be sanding over half the previous
sanding path’s width. Another way to look at it is you move to the right half the sanding drum’s width.

We follow that 50 percent rule because it helps us to avoid visible differences from path to path. If you’re using a Lägler sanding drum, its slightly
spherical shape also prevents edge lines from the drum being cut into the floor.

A lower amount of sanding path displacement causes a higher stripping rate. If your sanding path is only 25 percent, then you are only moving to the right
one-quarter of the drum’s width. In that case, you are sanding 75 percent of what you sanded during the previous path.

Increasing the sanding path displacement reduces the number of paths across a room, but there is a consequence (see the drawing below that highlights the
double-overlap at the outer edges of the drum).

Because at the outer edges, the outer 25 percent of the drum on each side, the floor gets sanded twice as much as the rest of the floor. Higher displacement
reduces the evenness of the wood floor.

Again, the ideal sanding path displacement is 50 percent.

Along with efficiency being a key to success in sanding floors and business, consistency is important. If you are not consistent with your sanding path
displacement, then you will not produce consistent sanding results. That will lead to inconsistent results with final outcomes of jobs.

That will affect your business overall. And that will affect our business. We’re in this together.

Learn More, Earn More

Learn more. Download Lägler’s free manual, “Sanding of Wooden Floors,” online at laegler.com.

Get hands-on training on a practice floor, with sanding path displacement (and so much more). Call Lägler North America to schedule one-day training and
Lägler Premium Sanding Technology (PST^®) certification in Denver. You can get a one-on-one session or bring your crew (up to five in a class).

Learn more about PST^®.
Schedule your one-day training by calling us at 800-848-6635 (800-8-HUMMEL).

Wood Subfloor Guidelines for Installing Wood Flooring

You know the subfloor needs to be three things if you want to have a great installation: The subfloor must be dry, flat and clean.

Here is the gist of the guidelines for wood subfloor prep from Lägler’s “Sanding of Wooden Floors” manual and from the industry horse’s mouth, the National Wood Flooring Association.
(Looking for concrete subfloor knowhow? Read “How to Prepare a Concrete Subfloor.”)

What Should Wood Subfloor Moisture Content Be?

You’ve measured moisture content in the subfloor and in the wood flooring to be installed. What’s the acceptable difference between those two readings?

When installing solid strip flooring (less than 3” wide) moisture content readings need to be within four percent. For solid plank flooring (3” or wider),
the difference needs to be within two percent.

How to Know a Wood Subfloor Is Flat

For installations using mechanical fasteners of 1 ½” and longer, the subfloor needs to be flat to ¼” within a radius of 10 feet or 3/16” within six feet.

For glue-down installations and those using mechanical fasteners shorter than 1 ½”, the subfloor should be flat to 3/16” within 10 feet or 1/8” within
fix feet.

Here is the basic but effective test. Using a long, straight edge set on the subfloor, lightly drag it across. Because the guidelines describe the tolerance
in terms of a radius, hold one end of the straight edge as the pivot point and rotate around that point as you drag the edge.

You’ll recognize if the floor is good. Flat is flat. If the tool you are using teeter-totters on a high spot or hits a dip that makes it look like a bridge
spanning a depression in the subfloor, you’ve found a spot that needs a closer look.

For more details on wood subfloor prep, read “How to Prep a Wood Subfloor” or dig
into section two of Lägler’s Sanding of Wooden Floors Manual, free to download online.

Now let’s get back to the two options you have for flattening a subfloor using a multi-disc sander or buffer.

Using a Sanding Machine for Subfloor Prep

The graphic above shows to use milling discs on your multi-disc sander or buffer on a concrete subfloor, if the subfloor is rough with screed or adhesive
that needs to be removed.

For wood subfloors, do not use milling discs. Either use a milling drum on your big machine, or use the multi-disc or buffer to sand a wood subfloor. Milling
discs will dig into a wood subfloor if you stop the machine.

If you are using the milling discs to remove that kind of material with a Lägler TRIO, do not use the Velcro seal around the machine housing. The seal
can be damaged while milling.

You also can increase or decrease aggression when using milling discs on the TRIO by adding or subtracting the indexable, hard-metal inserts.

For sanding a wood subfloor flat, choose your sanding grit by whether you’re having to grind screed or priming material down or if you’re flattening uneven
plywood. If using a TRIO, you can choose to use the Velcro rings (“donuts”) or not. Leaving them off will increase aggression.

For sanding high spots in the wood, you can start with 40 or 60 grit. You likely need to choose a coarser grit for smoothing the spots with added materials:
16, 24 or 40.

Always use as fine a grit as possible but as coarse a grit as needed, for any sanding job. (Learn more about sanding abrasive quality, materials and selection:
“How to Minimize Sanding Efforts and Maximize Profits.”)

If using a buffer for prepping a subfloor for wood floor installation, Lägler’s recommendations are like its guidelines for using a multi-disc sander.
Shown in the graphic below.

Use a milling disc to cut screed, adhesives and priming material for most aggressive cutting. If the buffer you are using for subfloor prep is the Lägler
SINGLE, you can increase or decrease aggression with the milling disc by adding or subtracting the indexable ceramic inserts.

If sanding, you can increase aggression by leaving off the Velcro ring, or donut, between the sanding plate and the abrasive. If you use the Velcro ring,
it needs to be combined with hook-and-loop abrasives. We recommend using external dust collection.

If using the SINGLE, fasten the Velcro seal around the machine housing. For more aggressive cutting, use the water reservoir designed to add up to 44 pounds
(22 kilograms) on top of the housing.

Summary

Like with any wood flooring job, flexibility is key. Multi-disc sanders and buffers can flex for the situation, making subfloor prep easier and producing
the top-notch results you need to carry the whole project to a successful finish.

Learn more and get hands-on on a practice floor. Call Lägler North America to schedule one-day training and Lägler Premium Sanding Technology (PST^®)
certification in Denver. You can get a one-on-one session or bring your crew (up to five in a class).

Learn more about PST^®.
Schedule your one-day training now by calling us at 800-848-6635 (800-8-HUMMEL).

Karleugen Lägler is director of Lägler GmbH. With 50 years in the floor sander manufacturing company, he is the world’s leading floor sanding expert.
Lägler GmbH offers free downloads of its “Sanding of Wooden Floors” manual in six languages at laegler.com.