Craftsman V20 CMCS500B: problems, parts and running costs

Checked: 2026-10-18

Summary

The CMCS500B is a brushed, 6-1/2-in bare-tool circular saw whose weak points are short battery endurance, labored cutting in dense wood and thin spare-part support, not the core cutting itself. A moderate owner spends roughly $49.74 a year on electricity, blades and battery depreciation, excluding the saw and charger. It is a good buy at the $99.00 bare price Lowe’s and Ace listed in October 2026 only if you already own V20 batteries; starting from zero makes the $149.00 kit the better deal.

Common problems and fixes

Weak battery endurance — TechGearLab’s 2020 test measured 184 linear feet of 3/4-in plywood ripped per 4 Ah charge, second-to-last in a 13-saw field, and rated the battery category 4.0 out of 10 [2]. Fix: carry a second charged V20 pack for long ripping sessions, or drop to the corded CMES510 for all-day work [6][9]. The 3-year limited warranty covers the tool for defects in materials and workmanship; battery coverage varies by pack model and wear is excluded [1][14].
Motor bogs down in dense stock — the saw labors through laminated veneer lumber and full-depth crosscuts, and a May 2026 Lowe’s buyer reported frequent stoppages and short perceived battery life [2][4]. Fix: use a sharp blade rated for at least 6,000 RPM, let the motor reach speed, and don’t force the feed [2][14]. Damage from wear or abuse is excluded from warranty coverage [1].
Blade changes are awkward — owners complain about inconvenient blade-guard placement during swaps [4]; the manual requires removing the battery and using the spindle lock and correct clamping hardware [14]. Fix: follow the manual procedure and never wedge the spring-loaded lower guard open [2][14].
Lower blade guard and dust port are hard to get — part #90591151 (lower guard) is listed as no longer available at PartSelect and ToolPartsPro, and the dust port #N742612 is also listed as unavailable there, which limits self-service on a safety-critical part [11][12]. Fix: use authorized CRAFTSMAN service rather than improvising a guard [11].
Retailer spec drift on speed — the manufacturer page says up to 4,000 RPM while the Lowe’s and Ace listings advertise 4,200 RPM, with no independent measurement [1][3][5]. Treat 4,000 RPM as the figure; the discrepancy is unresolved [1][14].

Parts and consumables

6-1/2-in 18T blade, CRAFTSMAN CMAS265018 — $14.99 at Ace (October 2026); replace by condition (dull, missing teeth, wobble or damage), not on a published schedule [13]. Any alternative 6-1/2-in, 5/8-in-bore blade must meet the manual’s 6,000-RPM minimum rating [13][14].
Blade clamp washer, #5147826-00 — $6.40 at PartSelect (October 2026), in stock; replace if damaged, lost or no longer securing the blade [11].
Blade retaining bolt, #90591453 — $6.40 at PartSelect (October 2026); replace when damaged, lost or stripped, and confirm Type 1 compatibility before ordering [11].
Hex wrench, #90502723 — $6.40 at PartSelect (October 2026), in stock; the saw includes one, so replace only if lost or damaged [11][1].
Shoe, #90592910 — $38.95 at PartSelect (October 2026), special order; no calendar interval, replace when damaged [11].
V20 4.0 Ah battery, CMCB204 — $129.00 at Lowe’s (October 2026) as a standalone pack; the saw ships without one [6][1].
V20 battery and charger kit, CMCB204-CK — $159.00 at Lowe’s (October 2026); a one-time starter purchase, not an annual consumable [7][8].

Yearly running cost

No verified all-in annual cost exists. A hypothetical moderate user doing 100 full charges a year, replacing one $14.99 blade and amortizing a $129 battery over four years would spend about $49.74 a year, excluding the saw, charger, sales tax and any service [6][13]. Electricity is a few cents per charge: a 4 Ah pack stores about 72 Wh, and at an assumed 0.10 kWh per recharge and $0.25 per kWh that is about $0.025 per charge, or $2.50 for 100 charges — illustrative inputs, not measured wall consumption [1][2][6]. The four-year battery life is an assumption, not a tested average; runtime varies with material and duty cycle [6].

When it is a good buy

Lowe’s listed the bare tool at $99.00 (October 2026); Ace’s main page also showed $99.00, with a $79.20 promotional price on another page [3][5]. Buying thresholds: $60 or less delivered is an attractive deal for an existing V20 owner, $61-80 is reasonable, $81-99 is marginal, and at $99 or more compare the alternatives below [3][6][7][8][9][10].
Starting from zero, the $149.00 CMCS500M1 kit (saw plus 4.0 Ah battery and charger) at Lowe’s (October 2026) usually beats $99.00 bare plus a $159.00 battery-and-charger kit [8][7][3].
The corded CRAFTSMAN CMES510, about $89.00 at Lowe’s (October 2026), is the better choice when outlet power is available and cordless is not required [9].
For a shop already on Ryobi 18V ONE+, the brushless RYOBI PSBCS01B at $119.00 tool-only at Home Depot (October 2026) is the platform-specific alternative [10].