Polisher type
15 mm long-throw polishers: the 5-inch class
15 mm random orbital polishers usually run a 125 mm (5 in) plate: RUPES LHR15ES, Milwaukee 2684-20, FLEX XFE 15. Speeds, plates and limits.
Also listed as 15mm polisher, 5 inch long throw
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Short answer
A 15 mm long-throw polisher is a free-spinning random orbital machine, usually with a 125 mm (5-inch) plate: RUPES's LHR15ES (corded), Milwaukee's M18 2684-20 and FLEX's XFE 15 (cordless). RUPES says its 15 mm machine runs at a higher rpm than its 21 mm one for equivalent cutting power, a maker claim. ESOTERIC Car Care, a RUPES retailer, calls 15 mm machines more versatile on curves and in tight spaces.
Key facts
- Backing plate / pad size
- 125 mm / 5 in (RUPES LHR15ES); Milwaukee 2684-20: 5 in recommended, 6 in optional[1][4]
- Power source
- Corded (RUPES LHR15ES, 500 W) or cordless (Milwaukee M18; FLEX 18 V)[1][2][3]RUPES's page states no supply voltage.
- Example models
- RUPES BigFoot LHR15ES; Milwaukee M18 FUEL 2684-20; FLEX XFE 15 150 18-EC (US kit 459542)[1][2][3]
- Suited to
- ESOTERIC Car Care: more versatile for curved areas and tight spaces[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[4]Milwaukee's polisher manual warning, written for its random orbital polishers.
Watch out for
- 21 mm is not automatically stronger. RUPES claims its 15 mm LHR15ES matches the LHR21ES's cutting power by running at a higher rpm. That is a maker claim, not an independent test.
- Bare tools have no battery. Milwaukee's -20 suffix is the bare tool; it runs on genuine M18 REDLITHIUM packs only.
- Pad overhang is a maker choice. RUPES pairs a 125 mm plate with 130-150 mm foam pads; Milwaukee says plate and pad diameters should match on its polishers.
- Voltage is not on RUPES's page. RUPES's global page states no supply voltage, so check a US 120 V version before buying.
What fits
Product details below are the seller's own description unless a source is shown. Pick the variant named for each item.
15 mm corded random orbital polisher
FLEX FC3321-Z 120 V brushless random orbital polisher (15 mm)Choose the FC3321-Z listing that includes the 5 in (FT333) and 6 in (FT334) backing plates.
Sold on Amazon: check 'Ships from' and 'Sold by' on the Amazon offer before you buy, and look for a North American certification mark on the tool's nameplate.
Check price on Amazon Opens amazon.com15 mm cordless random orbital polisher (FLEX 24V)
FLEX FX3321-Z 24V brushless cordless random orbital polisher, 15 mm (tool only)Choose the FX3321-Z tool-only listing; battery and charger are sold separately.
It runs on FLEX 24V packs, so pair it with genuine FLEX batteries and a FLEX charger. As with any Amazon pick, check 'Ships from' and 'Sold by' on the Amazon offer before you buy.
Check price on Amazon Opens amazon.com
Next size up: 21 mm long-throw. For the motion itself, see free-spinning dual-action.
Questions
Is a 15 mm or a 21 mm polisher better?
Neither is better for every job. ESOTERIC Car Care, a RUPES retailer, calls 15 mm machines more versatile on curves and in tight spaces and 21 mm machines suited to larger flat panels; RUPES claims equal cutting power at different speeds.[5][1]
Can I fit a 6-inch pad on a 15 mm polisher?
On Milwaukee's 2684-20 the manual lists 5-inch as recommended and 6-inch as optional, with a matching backing plate. Other makers set their own rules, so check your tool's manual.[4]