March 2017 - Lägler North America

6 Things You Need to Know About Sanding Drums

HUMMEL owners, tell us: How easy is it to remove and replace your HUMMEL sanding drum? Yeah, easy-easy. DIY in the shop, at your trailer, on the jobsite
floor, right? No need to waste time or money for someone else to do it.

If you haven’t swapped out sanding drums yet, we have a one-minute “How to Replace a HUMMEL Sanding Drum” demo
video on our Lägler North America YouTube channel.

Know Why, How + When to Replace a Sanding Drum

Damaged sanding drums lead to damaged floors. Damaged floors lead to customer complaints, callbacks, re-sanding, and a lot of expense on your part. Needless
to say, it’s far cheaper to pay a little attention to the condition of your drum and replace it, when needed.

When you replace a worn or moderately damaged drum, save it. It’s still of use for first cuts when sanding especially rough floors or decks.

Below are photos of damaged drums and the consequences of continuing to use them when sanding wood floors.

Perpendicular Cuts Through the Drum Rubber

These unwanted cuts in the drum’s rubber come from nails, staples or other sharp objects protruding from the subfloor. Careful subfloor prep avoids this
type damage to a sanding drum.

When sanding with a drum that has this damage, you’ll see “streaks” appear on the floor as you sand. Those lines are raised marks that happen because of
the nail-torn grooves left in the drum not making proper contact with the sanding surface.

A drum with this type of damage needs to be replaced.

Sanding Drum Damaged by Nails or Sharp Objects in Subfloor

Wood Floor Streaks Caused by a Damaged Sanding Drum

Material Embedded in Drum Rubber

Loose nails, staples or other debris can stick into the rubber and hold on for the ride. Obviously, that leads to an uneven drum and sanding result. The
debris can damage the drum and belt abrasive. It also leads to gouging the sanding surface.

You might be able to remove the debris from the rubber without leaving or causing damage to the drum. But we recommend you think twice. The slightest damage
can transfer to the floor and, like we’ve said, that becomes way more costly to you.

The safest move is to replace the sanding drum. But save the old drum for special uses, like using it on extra-rough first cuts. That can spare your new
drum some wear, and allow you to put on the new drum for finer cuts.

Gouges Cut in a Wood Floor by a Damaged Sanding Drum

Unbalanced Sanding Drum

A drum that is out of balance makes uneven contact with the sanding surface, causing chatter (photo below). Poor balance is common with aftermarket drums.
Lägler balances its drums using a specially designed machine at the factory in Germany. It’s not unlike how a mechanic shop balances your truck’s wheels.
And the weight tolerance in Lägler’s process is extremely tight [Read “Sanding Drums: Lägler vs Aftermarket”
to learn how tight, and other stuff].

An unbalanced sanding drum needs to be replaced.

Aged or Worn Out Sanding Drum

The rubber layers of sanding drums age, stiffen and wear out much like car tires do. The shape and flexibility of the rubber changes over time, regardless
of the amount of use. If you are using a “new” drum that sat for years waiting to get into the game but in reality is six to eight years old, it absolutely
is due for replacement, no ifs, ands or buts. Just like with car tires, there is a shelf life on the rubber’s usefulness.

Old, worn out drums tend to cut harder on the edges. Lägler drums are designed to have a “football” shape that feathers toward the edges and avoids those
hard edge-cut lines in the floor. As a drum loses its shape over time, it fails to retain that design.

How long does a drum last? The sanding drum you are using daily should be changed every three years. If you sand somewhat regularly, but
not daily, Lägler recommends replacement every five years. To minimize problems with your sanding drum and get the most out of its performance, keep
it clean between uses and check its condition on a regular basis.

Plan for regular replacement, just like you would plan for regular maintenance for your truck or van. It’s part of the investment for consistent, top-notch
performance of a machine your business relies on.

Old, Worn Out Sanding Drums Cause Poor Floor Sanding Results

Marks Left in Wood Floor by Old, Worn Sanding Drum

Dirty Sanding Drum

Dust and debris collect in the aluminum drum cylinder, throwing the balance off. That causes chatter in the floor.

This is easy to avoid with regular cleaning. At least once every month, remove the drum and vacuum out the cylinder. While you’re doing it, look over the
drum’s condition and tend to any maintenance that’s needed.

Uneven Floor Caused by Knotty Wood

This is not a sanding drum issue, but a situation that can be fixed with the right use of a sanding drum. Most common on pine and softwood, the knots are
harder and do not sand as well, similar to end-grain or inlays of different species.

For these situations, use Lägler’s hard drum (recognized by its reddish-colored rubber). It is less flexible and cuts more aggressively, the way you need
for the knots.

Knotty Wood Flooring Is Extra-Tough to Sand

Lagler's Red Drum Is Designed to be More Aggressive on Knotty Wood Floors

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Related Web Pages

HUMMEL Parts Online Catalog

The Showdown: Lägler TRIO vs Multi-Disc Attachments

HUMMEL. The Icon Builders. [Video]

Sanding Drums: Lägler vs. Aftermarket

There are a lot of parts to care about with a “big machine” like Lägler’s HUMMEL. But even if you keep it purring, clean and rolling smoothly, it won’t
do you any good if you use a sanding drum that mars the floor with edge marks, waves and chatter.

You can see where we’re headed here, right? We recommend the Lägler sanding drum, of course. But, like everything with Lägler, there is a reason behind
the design. There are reasons we recommend the Lägler drum, and only the Lägler drum.

It simply isn’t the apples-to-apples trade with aftermarket versions like you might think.

In this post, we explain why Lägler recommends not using aftermarket or recycled drums, and how you can know whether a drum you are buying is an authentic
Lägler drum.

The Importance of the Sanding Drum

The quality and condition of your sanding drum is crucial for sanding success. It transfers the machine’s performance to the sand paper, which then impacts
the floor.

If a drum – the aluminum core, weight and outer layers of rubber – is older than four years, visibly worn out or damaged, or the rubber has hardened, it
needs to be replaced. We can promise a drum past its quality of life will give you sanding results your clients will not appreciate.

The “Football” Shape of Lägler Sanding Drums

When looking at a new Lägler sanding drum, it is easy to miss seeing that the drum’s diameter is larger in the middle than it is at the edges. But this
shape is crucial to the quality of a sanded surface. It also is why you do not need to dress a Lägler drum.

Non-Lägler sanding drums have a flat shape, touching the floor from edge to edge of the drum. While overlapping sanding paths, a small change in elevation
occurs. That leads to a flat sanding drum leaving marks where its edges cut the floor.

Lägler removes this risk of edge-cuts with its drums by decreasing the drum’s diameter from the middle to the outside. That slightly oblong shape, kind
of like a football, is exactly what’s needed for feathering at the edges while sanding.

Lägler drums focus sanding pressure evenly in the center portion of the drum, assuming you have leveled your HUMMEL wheels (extremely easy to do; watch
our one-minute video). You will be able to see that by the wear pattern on the abrasive belt.

Known Problems with Aftermarket + Recycled Sanding Drums

The market offers aftermarket and recycled sanding drums that fit on the Lägler HUMMEL, but they are not equal replacements for a Lägler original drum.
They cause damage to floors.

That damage leads to call-backs and more expense on your part as the sanding professional to fix the issues with the floor and to replace the faulty drum
so it doesn’t continue to cause problems.

On occasion, Lägler receives warranty claims for drums, and they are rejected. Virtually all these claims are based on problems that come from using non-Lägler
drum.

Problems that occur with aftermarket and recycled drums are:

Improper balancing, which leads to waves and/or chatter in the floor.
Vibrations caused by waves and chatter transfer throughout the HUMMEL, leading to damage to the machine.
The flat design of aftermarket drums does not provide the same predictable pressure per square inch, causing less-aggressive sanding results.
Flat-shaped drums cut the floor at their edges, leaving marks and causing uneven sanding throughout the project.
Non-Lägler drums often have a damaged or imprecise core; this also leads to damaging the floor during sanding.

4 Visible Signs of Aftermarket Drums

Sanding drums that are not Lägler originals manufactured at Lägler headquarters in Germany have a few tell-tale signs. Here are four clear ways to see
that a sanding drum is an aftermarket drum.

Overlapping rubber layers. There are two layers of rubber on a drum. Aftermarket drums overlap, creating a hardened spot that will cause
vibrations that lead to waves. Lägler drums have rubber layers of even thickness, with the outer layer applied evenly on top of the inner layer, no
overlap.

No “football” shape. Adding to what’s been described in the section about football shape above, the larger contact area of non-Lägler
drums reduces aggression by up to 20 percent.

Worn out bore. Lägler does not reuse old sanding drums. The bore where the drum slides on and off the drum shaft gets worn out. To reuse
a drum, each bore would have to be replaced to be able to guarantee the refurbished drum is properly balanced. The cost of that effort makes recycled
drums too expensive.

Out of balance. Lägler uses special screws as balancing weights on the sanding drum core’s lid. Those weights are new for each drum. Lägler
has perfected its balancing act, keeping each end of the drum within less than 4/100 of an ounce. Sanding drums being recycled for resale need to be
re-balanced because of new rubber being applied, but drums that try to reuse old cores and old weights can’t be properly balanced.

The Bottom Line of Using Aftermarket Sanding Drum on You HUMMEL

The issues laid out above not only lead to poor sanding results, they cause more frequent sanding drum replacements. That costs you more money.

We’re sure you’ve heard, “You get what you pay for.” You probably have said that to a hesitant client or two over the years, too, when they are considering
hiring your competitor with a lower estimate, right?

Think about all we’ve said in this blog post, and it’s easy to understand the importance of a just-right drum to the livelihood of Lägler as a company.
Bad drums lead to bad experiences and bad sanding results with Lägler’s HUMMEL; that would lead to a loss of sanding pros’ confidence in Lägler in
142 countries worldwide. A big deal.

If you have questions about Lägler sanding drums, or anything else Lägler, comment below or call us at 800-8-HUMMEL (800-848-6635) during
weekday business hours.