DEWALT DCG405B: problems, parts and running costs

Checked: 2026-10-26

Summary

Owners most often report short battery runtime (about 10-15 minutes of active grinding on a 5Ah pack), an awkward sliding lock-on switch, and the need to buy a separate closed Type 1/41 guard for cutting wheels. Keeping it running costs abrasives only — about $11.94 a year for ten cutoff wheels — with no subscription or brushes. At $150 or less from an authorized seller it is a good buy for people already on DEWALT 20V MAX batteries; above $210 bare tool it is weak value.

Common problems and fixes

Short battery runtime — owners report about 10-15 minutes of active grinding on a 5Ah pack and about 10 minutes on a 4Ah pack; the fix is more or larger packs and breaks to avoid heat; this is a runtime limit, not a defect, and warranty does not cover normal battery drain. [12][13][14]
Will not start after a depleted or reconnected battery — Power Loss Reset intentionally blocks automatic restart when the switch was left on; turn the slide OFF, check the pack, then deliberately turn ON only after confirming guard, wheel and workpiece safety; this is normal protection, not a motor failure. [1][2]
Stops or brakes mid-cut when stalled — E-CLUTCH and Kickback Brake may intervene on pinch, stall or bind; recheck feed force and cut alignment, and seek service if trips recur on light loads; electronics do not eliminate kickback. [1][2][12]
Individual fault and fulfillment reports — one verified buyer reported the grinder stopped working and received support ticket 15201449, and another reported a missing protective component in the box; these are single cases, not a measured defect rate. [13][14][15]
Guard selection hazard — the supplied Type 27 guard covers approved grinding setups, but a closed two-sided Type 1/41 guard is required for abrasive and diamond cutting wheels and must be bought separately; never use the open Type 27 guard for cutting. [2][5]

Parts and consumables

DW8062B5 cutoff wheels (4.5 x 0.045 in, 7/8 in bore) — $5.97 for a five-pack at Home Depot (2026-10); about $1.19 per wheel; owners replace as worn. [11]
Type 27 grinding guard, OEM #N501322 — $14.42 at RepairToolParts or $20.68 at PartSelect (2026-10); replace only if damaged or warped. [16][17]
Side handle, OEM #N401305 — $6.40 at PartSelect (2026-10); replace if lost or broken. [17][18]
Clamp washer, OEM #N115381 — $6.40 at PartSelect (2026-10); replace if bent, damaged or lost. [17]
Flanged hex nut, OEM #N484249 — $22.67 at PartSelect (2026-10); replace if worn or deformed. [17]
Gearcase, OEM #N522578 — $40.44 (2026-10); service-level repair. [16]
Motor and switch assembly, OEM #N509544 — $91.62 (2026-10); a major repair that can exceed tool value. [16]
Rotor, OEM #N537673 — $39.45 (2026-10); service-level repair component. [16]
Baffle #N478435 and spring #N105579 — $2.52 each (2026-10); repair items, not recurring consumables. [16]
DCB205 5Ah battery — $119.00 promotional or $169.00 list at Home Depot (2026-10); not included in the box. [10]

Yearly running cost

No subscription, software account, brushes or compulsory annual plan. A typical light user spending ten cutoff wheels a year pays $11.94 in discs (two five-packs of DW8062B5 at $5.97 each); twenty-five wheels is $29.85. Electricity for 100 full charges of a 5Ah pack is about 9 kWh, or about $1.80 at an illustrative $0.20 per kWh before charger and cell losses. Batteries are one-time capital costs ($119.00 promotional for a DCB205), not annual consumables. No representative annual average for parts, battery cycle life or service was found.

When it is a good buy

Store snapshots (2026-10, before tax and shipping): Home Depot category crawl $169.27 and individual model page $209.92; Toolup $219.00 but unavailable; Crown Tools $149.99 but sold out; Grainger $313.37; Lowe’s requires a location for price; Rexel requires sign-in. DCG407B was $179.00 and DCG413B appeared at $87.15 promotional against $227.99.

At or below $150 for a genuine in-stock DCG405B from an authorized seller: attractive for buyers who already own chargers and packs.
$151 to $175: fair; $169.27 is a reasonable comparison point if the live cart matches.
Above $210 bare tool: weak value unless procurement support matters; compare DCG413B, DCG407B and corded grinders.
New-owner system cost: $169.27 bare grinder plus $119.00 DCB205 5Ah battery is $288.27 before charger, discs, guard and tax.

Alternatives:

DEWALT DCG407B (newer slide switch, $179.00) — better when availability and features fit while staying on DEWALT batteries. [20]
DEWALT DCG410VSB family (variable speed, 4.5-5 in, up to 1,640 MWO) — better when you need speed control and more output. [21]