Polisher type
21 mm long-throw polishers: the 6-inch class
21 mm random orbital polishers pair with 150 mm (6 in) plates, like Milwaukee's 2685-20. What the bigger orbit is said to suit and what to check.
Also listed as 21mm polisher, 6 inch long throw
Short answer
A 21 mm long-throw polisher is a free-spinning random orbital machine built around a 6-inch (150 mm) plate. Milwaukee's M18 2685-20 recommends a 6-inch pad, 5-inch optional, at 2,400-4,500 rpm. ESOTERIC Car Care, a RUPES retailer, describes 21 mm machines as suited to larger flat panels, while RUPES claims its 15 mm machine matches its 21 mm one by running faster.
Key facts
- Motion
- Free-spinning random orbital[1]
- Backing plate / pad size
- Milwaukee 2685-20: 6 in recommended, 5 in optional[3]
- Speed range
- Milwaukee 2685-20 2,400-4,500 rpm (8-position dial)[1]
- Suited to
- ESOTERIC Car Care: larger flat panels[5]A retailer's practical opinion, not a measurement.
- Cautions
- Too much pressure, the wrong angle or improper motion may cause swirl marks or burning[3]Milwaukee's polisher manual warning, written for its random orbital polishers.
Watch out for
- A bigger orbit is not proof of faster correction. RUPES says its 15 mm LHR15ES has equivalent cutting power to the LHR21ES at higher rpm; ESOTERIC's comparison is opinion, not a measurement.
- Milwaukee does not list Amazon. The where-to-buy panel on Milwaukee's US polisher page lists retailers such as Home Depot and ACME Tools, not Amazon or AliExpress.
- SPTA's 21 mm version states no voltage. SPTA's page gives no supply voltage, plug or safety mark for the CP501.
We have no approved 21 mm polisher to list yet. The 15 mm long-throw page lists approved machines.
Questions
What is a 21 mm polisher suited to?
ESOTERIC Car Care, a RUPES retailer, describes 21 mm machines as suited to larger flat panels and 15 mm machines as more versatile on curves. That is a retailer's opinion, not a test.[5]
Can I run a 5-inch pad on a 21 mm polisher?
Milwaukee lists 6-inch as recommended and 5-inch as optional for the 2685-20, and says the backing plate should match the pad diameter. Check your own tool's manual.[3]