Craftsman CMCG400B: problems, parts and running costs

Checked: 2026-10-17

Summary

The CMCG400B is a bare-tool 4-1/2 in. cordless angle grinder with a brushed motor and 8,500 RPM, sold at $69 by Lowe’s, Acme Tools and Ace Hardware (2026-10). Owner evidence is thin: one reviewer reports the kit version dying after about three years of intermittent use, and the brushed motor is the standing durability question against Craftsman’s newer brushless V20 grinders. Buyers new to the platform must add a battery and charger, typically $50-100 or more, which pushes the total toward the brushless competition.

Common problems and fixes

Brushed motor versus brushless durability — the brushed design may be a durability concern next to the brushless models, but no failure-rate data was published; Craftsman’s own comparison for the brushless CMCG450B uses the brushed CMCG400M1 kit as its baseline. [1][5][13]
Battery sold separately — the tool ships bare, so the battery and charger are additional purchases that significantly affect total ownership cost, and runtime per charge was not documented in the sources. [1][8]

The 3-year limited warranty is listed as 36 months parts and labor, which is competitive for this class. [1][2]

Parts and consumables

Spanner wrench — included for wheel changes; no replacement data was published. [1]
V20 battery and charger — sold separately; a 2.0Ah battery and charger kit is typically $50-100 or more depending on retailer and promotions, and Craftsman’s 2026 ADVANCED battery kits list at $139 for 3.0Ah and $199 for 6.0Ah MSRP (Craftsman, May 2026). [1][12]

Yearly running cost

A new-to-platform owner pays $69 for the bare tool (Lowe’s, Acme Tools, Ace Hardware, 2026-10) plus a battery and charger, typically $50-100 or more depending on retailer and promotions. Grinding wheels wear out and are replaced as needed, and no wheel prices were published. For reference, Craftsman’s 2026 ADVANCED battery kits list at $139 for 3.0Ah and $199 for 6.0Ah MSRP. [3][5][11][12]

When it is a good buy

At $69 bare (Lowe’s, Acme Tools, Ace Hardware, 2026-10) it is one of the least expensive cordless angle grinders on a major US battery platform, and a low-cost entry if you already own V20 batteries. [2][3][5][11]

Craftsman CMCG452B (brushless, tool only) — $99 at Acme Tools, down from $129.99; the better choice for frequent or heavy use, since the brushless line delivers up to 65% more power. [5][13]
Kit version CMCG400M1 — with a 4.0Ah battery and charger, $189 at Acme Tools; the better choice if you have no V20 battery or charger yet. [5]
A corded grinder — the usual pick for heavy, continuous work, where cordless grinders suit quick tasks. [14]