Makita GA5020 5 in. 10.5 Amp SJS Corded Angle Grinder: problems, parts and running costs

Checked: 2026-10-18

Summary

No widespread defect pattern has been reported for the GA5020; the real buying risk is paperwork — the lock-on switch, the no-load RPM and the cord length all differ between the manufacturer page, the manual and retailer listings. Running costs are consumable grinding and cutting wheels plus cheap, user-replaceable carbon brushes. It is strong value at $189 and fairly priced at $209.

Common problems and fixes

Lock-on switch listings disagree — Makita’s USA page specifies a rear-handle trigger with no lock-on, the shared manual describes a lock lever for continuous operation, Burns Tools lists Lock-On: Yes and PartsSource lists No; verify the exact switch at purchase. [1][2][3]
No variable speed or constant speed control — those electronics sit in the GA5020C variant; the base GA5020 does not have them. [2]
RPM listing error — one Home Depot listing claims the 10.5 Amp motor delivers 10,000 RPM; the official spec is 11,000 RPM, and 10,000 RPM is the GA5020C/GA6020 figure. [1][6]
Cord length conflict — 8 ft (2.5 m) per the manual and PartsSource against 17.75 ft in a Northern Tool listing that is now no longer available. [2][3][4]
Spindle thread varies by region — the US model is 5/8-11 UNC; a Philippine retailer lists M14 x 2.0 for its regional variant, so US buyers should confirm 5/8-11 at purchase. [1][2][5]
Thinning retail availability — Northern Tool’s GA5020 listing is marked no longer available, though Home Depot, Burns Tools, Toolup and Pacific Power Tools still carry new units. [4]

Parts and consumables

Carbon brushes — sit behind external caps for field replacement without a strip-down; they are inexpensive and commonly stocked by parts retailers. [1]
5 in grinding and cutting wheels — the main running cost; the kit includes a 36-grit INOX wheel. [1][2]
Tool-less wheel guard — replacements are commonly stocked; included with the tool. [1]
Lock nut, lock-nut wrench, inner flange, side handle — replacement hardware commonly available; Makita publishes a parts breakdown for the GA5020. [1]

Yearly running cost

No yearly total is published. Consumable grinding and cutting wheels dominate, and carbon brushes are cheap to replace behind the external caps. There are no subscriptions, proprietary cartridges or other consumables.

When it is a good buy

US retail in 2026-10: Home Depot lists the GA5020 at $189.00, with another Home Depot listing at $209.00; Burns Tools, Toolup and Pacific Power Tools list it at $209.00; PartsSource, an industrial supply channel rather than a typical retailer, asks $302.32. [3][6][9][10] At $189.00 it is strong value for a professional-grade grinder with the SJS clutch and electric brake; at $209.00 it is fairly priced but sits against newer brushless cordless models and Makita’s own variable-speed corded grinders. [1] Alternatives: the GA5020C is the better choice when constant speed under load matters; Makita Canada’s factory-reconditioned GA5020-R at CA$53.00 is the budget route; on generator or DC-only job sites the AC/DC switch makes this the more flexible tool. [2][11]