Makita 9903 3 in. x 21 in. Belt Sander

Makita Model: mktn9903
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CA Residents
Prop 65 Warning
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WARNING: Some dust created by power sanding, sawing, grinding, drilling, and other construction activities contains chemicals known to the State of California to cause cancer, birth defects or other reproductive harm. Some examples of those chemicals are: lead from lead-based paints, crystalline silica from bricks and cement and other masonry products, and arsenic and chromium from chemically-treated lumber. Refer to product manual/instructionsCancer
Makita 9903 3 in. x 21 in. Belt Sander Makita Model: mktn9903

Product Features & specs :

Makita 9903 3 in. x 21 in. Belt Sander

Powerful 8.8 Amp motor - quietest in its class.
Variable speed (690-1440 ft./-min.) with electronic speed control.
  • Quietest sander in its class (85dB)
  • Auto-tracking belt system tracks belt without adjustment
  • Unique design allows flush sanding to the corner of the wall with nose and side of sander
  • Front grip design for comfortable operation
  • Dust bag for a cleaner work environment
  • Optional sanding shoe available for precise sanding depth control
  • Sands wood or metal and removes paint and rust
  • Long 16.4 ft. power cord for easy maneuverability
  • Double insulated
What’s Included:
  • 3 in. x 21 in. Belt Sander - 9903
  • Abrasive Belt #80 - 742308-3
  • Operating Manual
  • Dust Bag - 122591-2
Power Source
Belt Length
3 in
UL Safety
No-Load Speed (RPM)
CSA Safety
Belt Width
21 in
Wifi compatibility
Case Included
Speed Type
Bluetooth Compatibility
Motor Type
Switch Type
Dust Collection Type
Dust Bag
ETL Safety
11.63 in.
5.5 in.
6.7 in.
9.5 lbs.
Warranty Term
1 Year

Reviews :

4.4 / 5.0
7 Reviews
5 Stars
4 Stars
3 Stars
2 Stars
1 Star
Yes, I would recommend this to a friend (4)
Powerful (5)
Easy To Use (1)
Best Uses
Frequent Use (2)
Large Projects (1)
Works great
I am very pleased with this belt sander, by far the best I’ve ever bought.
March 28, 2019
Makita 9903 belt sander
After reading hundreds of positive reviews on this sander I've come to the conclusion that people really don't know what I truly balanced belt sander is. It runs heavy on the one side therefore leaving gouges. OK for heavy construction work like decks but not furniture or kitchen cabinets. The best sander I've used to date is the Bosch 1274dvs which has been discontinued. The only one left on the market that might have a shot at being balanced is the triton 3 x 21. The reason I gave it a three star rating is because it is heavy-duty construction. The engineers that designed these tools should have to try to make a living with them.
December 29, 2018
Easy To Use
Best Uses
Large Projects
Thumbs Up!!
Excellent tool. Good quality and performance.
September 23, 2018
over 2 years ago
Describe Yourself:
Avid Do-it-Yourselfer
Would you recommend this product?
Excellent piece of machinery
This tool handled my small sanding projects with ease. The stock belt is not very good, but when outfitted with a Diablo belt it really performed well. Belt tracks and stays adjusted, it is easy to handle and has plenty of power even when loaded down with a bit of pressure. Dust collection seems exceptional. Makita sanders are tops in my opinion, a bit more pricy but worth the cost.
October 5, 2013
Would you recommend this product?
Good Sander
Good sander with quality controls. Variable is nice, belts tracks easily, easy to replace. The only ding is it being a 3x21. Returning for a 4x24, that little extra bit makes a big difference on the job. Other than that a quality Makita product I would recommend to anyone doing any type of DIY project.
December 11, 2011
Would you recommend this product?
Best Uses
Frequent Use
Great product
Easy to use, works very well on Glass fab
May 20, 2011
Would you recommend this product?
Best Uses
Frequent Use
Walks the talk
In carpentry & painting a belt sander is indispensable. In professional duty this sander is the best I've ever used. Efficiency & sustainability are key when being paid for your time. Customers expect the best in the fastest time possible. I am very satisfied with this sander. The balance is exceptional and sanding in close is simple. Belt changing takes seconds and it practically tracks itself. I am amazed! Wish I had gotten so much sooner, but I use my tools till they can't hold up to the task at hand. Should have started with a Makita but I didn't if you're looking to replace yours don't wait! You'll be glad you own this Makita.
September 14, 2010

Q & A :

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I am looking for the shoe or what ever it is called that fits on the 9903 sander to prevent gouging. I saw it once in the corner of the page when I ordered the sander and now I can't find it. It is a big plate that goes on the bottom of the sander. Can anyone help me?
Terry D on Dec 19, 2016


Warranty Information

Makita Standard Warranty

The Makita Standard Warranty applies to both new and factory-reconditioned Makita tools. Every Makita tool is thoroughly inspected and tested before leaving the factory. If you are not satisfied with any Makita tool within 30 days of purchase, return it and Makita will provide a replacement or refund. Each Makita tool is warranted to be free of defects from workmanship and materials for the period of ONE YEAR from the date of original purchase. Should any trouble develop during this one-year period, return the COMPLETE tool, freight prepaid, to one of Makita's Factory or Authorized Service Centers.

Each NEW Makita Lithium‐Ion Power Tool, Battery and Charger is warranted to be free of defects from workmanship and materials for the period of THREE YEARS from the date of original purchase

If inspection shows the trouble is caused by defective workmanship or material, Makita will repair (or at its option, replace without charge).

This Warranty does not apply where:
  • Repairs have been made or attempted by others
  • Repairs are required because of normal wear and tear
  • The tool has been abused, misused or improperly maintained
  • Alterations have been made to the tool
In no event shall Makita be liable for any indirect, incidental or consequential damages from the sale or use of the product. This disclaimer applies to both during and after the term of this warranty. Makita disclaims liability for any implied warranties, including implied warranties of "merchantability" and "fitness" for a specific purpose, after the one-year term of this warranty. This warranty gives you specific legal rights, and you may also have other rights which vary from state to state. Some states do not allow the exclusion or limitation of incidental or consequential damages, so the above limitation or exclusion may not apply to you.