RIDGID K-400 vs K-45: Drum or Sink Machine?

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Quick answer from a licensed plumber: Buy the RIDGID K-45 if you mostly clear sinks, lavs, tubs and showers. It is a hand-held machine for 3/4 to 2-1/2 inch lines that weighs 12.6 to 13.8 lb with cable, per RIDGID. Buy the RIDGID K-400 if you clear 1-1/2 to 4 inch lines like laundry, floor drains and branch lines. RIDGID says the K-400 is not designed to remove roots. The two overlap only from 1-1/2 to 2-1/2 inch (our arithmetic), so a busy shop may want both.

For most fixture clogs: the RIDGID K-45AF, a hand-held AUTOFEED sink machine for 3/4 to 2-1/2 inch lines. Check the RIDGID K-45AF on Amazon

The RIDGID K-400 and K-45 do not compete for the same drain. The K-45 is a hand-held sink machine for 3/4 to 2-1/2 inch lines: lavs, kitchen sinks, tubs, showers and urinals. The K-400 is a drum machine on a cart for 1-1/2 to 4 inch lines. They overlap only from 1-1/2 to 2-1/2 inch (our arithmetic), so the question is which lines you clear most. If you are pricing the RIDGID K400 as your first machine, this page shows where it stops and where the K-45 takes over. For every machine type together, see the best drain cleaning machines. I run RIDGID and Milwaukee tools on my own jobs; every spec below comes from RIDGID’s manuals and catalog.

K-400 vs K-45 Side by Side

	K-45 / K-45AF (sink machine)	K-400 (drum machine)
Design	Hand-held, variable speed switch and FOR/REV switch	Wheeled drum machine, foot switch and FOR/OFF/REV switch
Line size	3/4 to 2-1/2 in. (manual); 3/4 to 3 in. (catalog)	1-1/2 to 4 in.
Cable diameters	1/4, 5/16, 5/16 inner core, 3/8 in.	3/8 and 1/2 in. integral wound
Cable in the drum	Up to 50 ft, depending on cable	100 ft of 3/8 in. or 75 ft of 1/2 in.
Max line length	30 to 45 ft, depending on cable	Up to 100 ft, depending on cable
Speed	0 to 650 RPM (manual); up to 600 RPM (catalog)	170 RPM (120V)
Motor	250 to 280 W universal (manual); 280 W (catalog)	1/3 HP induction, belt drive
AUTOFEED	K-45AF models	Add-on or AF kits; 12 to 15 ft per min
Weight	12.6 lb manual feed, 13.8 lb AUTOFEED, with C-1IC cable (manual); 16 lb with largest cable (catalog)	40 lb machine only; 66 lb with 3/8 x 75 ft cable (manual); 60 lb with largest cable (catalog)
Electrical	Double insulated, polarized plug; GFCI on 120V units if equipped	Grounded; GFCI built into the cord
Keep cable outlet within	6 in. of the drain (setup steps); 12 in. (safety rules, manual-feed steps)	2 ft of the drain
Limits, per RIDGID	Secondary drain lines up to 2-1/2 in. (manual)	Not designed to remove root blockages
Linked kit	35473 K-45AF, 5/16 x 25 ft C-1IC	52363, 3/8 x 75 ft C-32 IW

From RIDGID’s K-400 and K-45 operator’s manuals and its Diagnostics & Drain Cleaning catalog, read on October 1, 2026. Where RIDGID documents give different numbers, each is shown. Every linked listing was sold by Amazon.com and in stock that day.

Which One Should You Buy?

Start with the line size you clear most

Plumber’s note: most sink, lav and tub clogs sit in 1-1/4 to 2 inch pipe close to the fixture (our judgment, not a RIDGID figure). That is K-45 work. Laundry standpipes, floor drains and 3 inch branch lines are K-400 work, and so is 4 inch with the 1/2 inch cable. RIDGID’s manuals both say to use the drain cleaner only for the recommended drain sizes, because the wrong size can twist, kink or break the cable. Plumber’s note: a 3/8 inch cable driven into a 4 inch line has room to loop and knot; RIDGID’s K-400 manual warns that feeding cable into a larger drain can make it kink or knot. Match the cable to the pipe.

Hand-held or on the floor

The K-45 goes where the drain is. You hold it, aim the cable outlet within 6 inches of the drain and work the variable speed switch. The K-400 sits on the floor within 2 feet of the opening. You feed the cable with gloved hands and run the motor with a foot switch. Both manuals say one person must control both the cable and the switch. On the K-400 that frees both hands for the cable, which matters on a long run.

Weight and getting to the job

RIDGID lists the K-45 at 12.6 to 13.8 lb with cable in its manual and 16 lb with the largest cable in its catalog. The K-400 is 40 lb for the machine alone and 66 lb with 3/8 by 75 foot cable in the manual, and 60 lb in the catalog. That is roughly three to five times the weight (our arithmetic). The K-400 rolls on its cart, and RIDGID says the wheels handle stairs; the K-45 carries in one hand.

AUTOFEED

Both machines come in manual feed and AUTOFEED versions. On the K-45AF, a lever advances or retrieves the rotating cable. On the K-400, AUTOFEED is a bolt-on assembly (catalog number 26773) with a handle that advances or retrieves at 12 to 15 feet per minute, per the manual. Either machine with AUTOFEED can still be fed by hand. The linked K-45AF has AUTOFEED; the linked K-400 kit is manual feed.

Best for Sinks, Lavs, Tubs and Showers

RIDGID K-45AF Sink Machine (35473)

Hand-held sink machine · 3/4 to 2-1/2 in. lines (manual) · 1/4, 5/16 and 3/8 in. cables, up to 50 ft in the drum · variable speed 0 to 650 RPM (manual) · AUTOFEED · 12.6 lb manual feed, 13.8 lb AUTOFEED with C-1IC cable · double insulated, GFCI on 120V units if equipped

RIDGID’s manual calls the K-45 a hand-held machine for secondary drain lines, the kind found in kitchens, bathrooms and utility rooms, from 3/4 to 2-1/2 inch with the correct cable. The drum holds up to 50 feet of cable, depending on the cable. You hold it by a hand grip, run it with a variable speed ON/OFF switch and a FOR/REV switch, and lock the cable with a slide-action chuck. RIDGID’s catalog lists the K-45 at 3/4 to 3 inch and up to 600 RPM with a 280 W motor; the manual lists 0 to 650 RPM and 250 to 280 W. Both numbers are shown here.

The linked machine is catalog number 35473, the K-45AF, which RIDGID’s catalog lists with AUTOFEED and a C-1IC cable: 5/16 inch by 25 feet, inner core, with an inner drum. The manual rates 5/16 inch inner core cable for 1-1/4 to 2 inch lines up to 45 feet long. The Amazon listing says this cable suits 3/4 to 1-1/2 inch lines, which matches the manual’s rating for plain 5/16 inch cable, not the inner core version. RIDGID’s catalog lists its 5/16 inch K-45 cables for 3/4 to 2 inch lines and its 3/8 inch cables for 1-1/4 to 3 inch lines. If you would rather feed by hand, the manual-feed K-45 (36018) comes with the same C-1IC cable.

Weighs 12.6 to 13.8 lb with cable, per the manual, so you carry it to the fixture
AUTOFEED advances and retrieves cable with a lever; the manual says it helps keep hands and the work area clean
Variable speed switch plus FOR/REV in one hand-held unit
Inner drum for quick cable changes; RIDGID says it helps prevent cable flip-over and drum leaks

Tops out at 2-1/2 in. per the manual (3 in. per the catalog); not for 3 and 4 in. lines or mains
Line length limits of 30 to 45 ft, depending on the cable, per the manual
The cable is not attached to the inner drum, so the last 5 to 7 ft need care
Hand-held, so your arm and grip carry the load on a tough clog

Verdict: The machine for sinks, lavs, tubs, showers and urinals: small lines where a 60 lb drum machine is too much.

Check the RIDGID K-45AF sink machine (35473) on Amazon

Best for 1-1/2 to 4 Inch Lines

RIDGID K-400 Drum Machine (Kit 52363)

Drum machine on a wheeled cart · 1-1/2 to 4 in. lines · 3/8 in. cable for 1-1/2 to 3 in., 1/2 in. cable for 3 to 4 in. (manual) · drum holds 100 ft of 3/8 in. or 75 ft of 1/2 in. · 1/3 HP · 170 RPM · foot switch · built-in GFCI · 40 lb machine only, 66 lb with 3/8 x 75 ft cable (manual)

The K-400 is a drum machine. The cable lives in a corrosion-resistant drum spun by a belt-driven 1/3 HP motor at 170 RPM, per the manual. RIDGID rates it for 1-1/2 to 4 inch lines up to 100 feet, depending on the cable. The manual pairs 3/8 inch cable with 1-1/2 to 3 inch lines and 1/2 inch cable with 3 to 4 inch lines. RIDGID’s catalog lists the 1/2 inch cable for “2 to 4 inch (76 to 102 mm)” lines; 76 mm is 3 inch, so we follow the manual. You run it with a FOR/OFF/REV switch and a pneumatic foot switch, and a GFCI is built into the cord.

RIDGID’s Cable Control System is a torque limiter that stops the drum when the cable end stops turning and torque passes a set value, to help prevent cable flip-over in the drum. The manual says it is designed for RIDGID 3/8 and 1/2 inch integral wound (IW) cable and may not protect other cables. The linked kit (52363) comes with a C-32 IW cable, 3/8 inch by 75 feet, the T-260 tool set (bulb auger, “C” cutter, spade cutter and pin key) and gloves, per RIDGID’s catalog. For 3 to 4 inch lines, the K-400 kit 26998 has a 1/2 inch by 75 foot C-45 IW cable. AUTOFEED is an add-on (catalog number 26773), and the manual gives its feed rate as 12 to 15 feet per minute.

Covers 1-1/2 to 4 in. lines with two cable sizes
Foot switch leaves both gloved hands on the cable
Built-in GFCI in the cord, plus a torque limiter for RIDGID IW cable
Cart with a fold-over handle and wheels; RIDGID says it handles uneven ground and stairs

RIDGID’s manual says it is not designed to remove root blockages
40 lb for the machine alone and 66 lb with 3/8 x 75 ft cable, per the manual (catalog: 60 lb with the largest cable)
Must sit within 2 ft of the drain, or the access must be extended, per the manual
Overkill for a lav or a kitchen sink trap arm

Verdict: The machine for tub, laundry, floor drain and 3 to 4 inch branch lines, short of roots and main sewers.

Check the RIDGID K-400 kit (52363) on Amazon

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Before You Buy

List the lines you clear. 3/4 to 2 inch fixture lines point to the K-45. 3 and 4 inch lines need the K-400.
Pick the cable with the machine. On the K-45, 1/4 and 5/16 inch cable is for 3/4 to 1-1/2 inch lines, 5/16 inch inner core for 1-1/4 to 2 inch and 3/8 inch for 1-1/4 to 2-1/2 inch, per the manual. On the K-400, 3/8 inch is for 1-1/2 to 3 inch and 1/2 inch for 3 to 4 inch.
Check the outlet. The K-400 has a GFCI in its cord. The K-45 manual lists a GFCI on 120V units “if equipped.” Both manuals say the cord GFCI does not protect an extension cord, so use a GFCI-protected outlet or a plug-in GFCI.
Know what roots need. Neither machine is a root or main-line machine. RIDGID says the K-400 is not designed for roots.
Plan to look. Both manuals say the best way to judge a drain’s condition before cleaning is a camera inspection. See the best sewer inspection cameras.

Running Either Machine Safely

The two manuals share most of their rules. Wear safety glasses and RIDGID drain cleaning gloves, with latex or rubber gloves underneath when chemicals or bacteria may be in the line. Test the GFCI before each use, and do not run either machine while you or it stand in water. Feed at least a foot of cable into the drain before you start, so the end cannot whip. Do not let the cutter stop turning while the cable is turning; pull the cable back from the obstruction, then feed it back slowly and let the spinning end dwell in the blockage. Run REV only for a few seconds to free a stuck tool or start through a trap, and never retrieve in REV. Both manuals also say to pull a fixture such as a toilet or urinal rather than feed the cable through it.

For tool size, both manuals give the same rule of thumb: start with the smallest tool to get water moving, and keep the largest tool no bigger than the inside diameter of the pipe minus one inch. The K-400 kit ships with a bulb auger for exploring and pulling hair, a “C” cutter for grease and a spade cutter for floor drains, per the manual. Most K-45 cables end in a bulb auger; its C-4, C-6 and C-6IC cables have a male coupling for other heads. Plumber’s note: when the line is flowing, run water while you retrieve the cable. Both manuals call for it, and it rinses the cable on the way back in. For hand tools and other machine types, see types of drain snakes, and for cordless options, Milwaukee M12 vs M18 drain snakes.

FAQ

Can the K-45 clean a 3 or 4 inch line?

No. RIDGID’s K-45 manual lists 3/4 to 2-1/2 inch lines, and its 3/8 inch cable is rated for 1-1/4 to 2-1/2 inch lines up to 30 feet. RIDGID’s catalog lists the K-45 up to 3 inch. For 3 to 4 inch lines, RIDGID pairs the K-400 with 1/2 inch cable.

Can the K-400 clear roots in a sewer line?

No. RIDGID’s K-400 manual says the K-400 is not designed to remove root blockages. RIDGID’s catalog lists larger drum machines, such as the K-750 and K-7500, for 3 to 8 and 3 to 10 inch lines. Our cable machine vs jetter guide covers the step up.

Can I run either machine in reverse?

Only as the manuals describe. Both manuals say not to run the cable in REV except to back a tool out of a blockage or get it started through a trap, and only for a few seconds. Both say running in reverse can damage the cable. Never retrieve the cable in REV.

What gloves should I wear?

RIDGID drain cleaning gloves. Both manuals say never to grasp the rotating cable with anything else, including a glove or a rag, because it can wrap around the cable. Latex or rubber gloves can go under the RIDGID gloves for chemicals and bacteria. Every K-400 and K-45 comes with one pair of RIDGID drain cleaning gloves, per the manuals.

Is there a bundle with both machines?

Yes. Amazon lists a RIDGID bundle with the K-400 and the K-45AF. Per the listing, it includes a K-400 with AUTOFEED and 75 feet of solid core cable, a K-45AF with 25 feet of inner core cable, gloves and manuals for both.

Why Trust Plumbing Picks

Plumbing Picks is written by a licensed Georgia journeyman plumber who uses RIDGID and Milwaukee tools on jobs. Every spec here comes only from the RIDGID documents listed below or from the Amazon listings we link. On October 1, 2026, every linked listing was sold by Amazon.com and in stock. If you buy through a link we may earn a commission at no extra cost to you. Nobody pays to be included here. More on who writes this and how we pick.

Sources

RIDGID: K-400 Drain Cleaning Machine operator’s manual (999-998-156.10)
RIDGID: K-45 Drain Cleaning Machine operator’s manual (999-998-285.10)
RIDGID: Diagnostics & Drain Cleaning Product Catalog (K-400 and K-45 pages, application charts)
Amazon listings for the RIDGID 52363 and 26998 K-400 kits, the 35473 K-45AF and 36018 K-45 machines and the K-400 + K-45AF bundle (linked above)

Bottom Line

The K-45 and K-400 split by pipe size. The K-45 is the hand-held machine for 3/4 to 2-1/2 inch fixture lines, with AUTOFEED on the AF models. The K-400 is the floor machine for 1-1/2 to 4 inch lines, with a foot switch, a built-in GFCI and a torque limiter for RIDGID IW cable. Neither is a root or main-line machine. Pick by the lines you clear most, and match the cable to the pipe.