StarTech RK4236BKB 4-Post Server Cabinet Review
When you buy through the Amazon links on this page, we may earn a commission at no extra cost to you. Learn more
Last updated October 31, 2026
The StarTech RK4236BKB is a good buy for a small business server room, an office comms corner or a serious home lab that needs a lockable, deep, mobile 42U cabinet and does not want to assemble anything. It is a poor fit if you need quiet operation, generous clearance under a standard interior door, or a bundle that arrives with fans and power already in it.
It ships fully assembled, its rails adjust from 6 to 36 inches, and it is a passive enclosure with no fans. The steel, the lockable mesh doors, the independent rail adjustment and the factory assembly are what justify its price; the current price is on the product card.
What the RK4236BKB does well
The cabinet's strongest asset is how much depth it can swallow and how precisely you can set it. Four vertical rails, with the front and rear sets adjustable independently from 6.0 to 36.0 in (15.2 to 91.4 cm), let shallow network gear and deep servers share one enclosure. Independent adjustment also lets you leave room behind the deepest server for cabling and exhaust instead of pushing it against the rear door.
It arrives built
The RK4236BKB ships fully assembled, so there is no flat-pack, no bag of bolts and no afternoon with an Allen key. The work moves from assembly to positioning, which matters when the cabinet weighs 275.3 lb empty and comes on a freight pallet.
Security and access
The front and rear doors are steel mesh and lockable. The front door is both removable and reversible, so you can hang it to open the way your room allows. The side panels are solid steel, lockable and removable, each with its own quick-release lock, which helps when you need to reach the side of a switch or a cable run without opening the front.
Airflow path
Mesh front, mesh rear and a vented top give a front-to-back path through the cabinet. The design is passive: it lets air through, it does not move air.
Mobility and grounding out of the box
Casters and leveling feet are both already installed, so you can roll the cabinet into place and then level it, or leave it on casters. A grounding wire is included and can be used at the front or the rear.
Standards, capacity and hardware
The RK4236BKB is 42U and 19-inch, EIA/ECA-310-E compliant, with square mounting holes and U markings on the rails. It holds a full rack of EIA-310-compliant servers and network gear, and the warranty is 5 years. The box includes 50 M6 screws, 50 M6 cage nuts, 50 washers, a hex key, two side-panel keys, two door keys, a manual, casters, leveling feet and a grounding wire.
Where the RK4236BKB falls short
The biggest expectation gap is what the box does not contain. There are no fans, no power distribution, no shelf and no cable management. You get steel, doors, rails, casters, feet, a grounding wire and mounting hardware. Everything that makes the cabinet work, from airflow to power to cable support, is bought separately.
No acoustic treatment
Mesh doors pass sound as readily as air. This is not a quiet cabinet; it is an open one with a lock on it. Reviews at other retailers mention that sound insulation could be better, which is the nature of a ventilated enclosure.
The rear door is more limited than the front
The rear door is lockable but neither removable nor reversible. Only the front door gets that treatment. In a tight room where you service equipment from behind, plan the space accordingly.
Height with casters is the fit risk
Total height with casters fitted is 75.7 in (1922 mm). A standard interior door opening is around 80 in, which leaves only a few inches of clearance. Anyone planning to roll this into a basement, through a hallway or under a low ceiling must measure the route, not just the room.
The rolling load limit is far below the static one
The stationary rating is 2000 lb (907 kg); on casters it is 397 lb (180 kg). A cabinet you intend to move must be loaded to the lower figure. This is the number most often missed and the one that decides whether mobility is real for your build.
It is heavy and awkward to move
Because the RK4236BKB weighs 275.3 lb empty and arrives on a pallet by freight, getting it off the pallet and into position is a job for two or three people. It also ships as a freight item rather than a parcel, and freight items commonly carry restricted return terms, so check the seller's return policy before ordering.
Rail adjustment is a real procedure
Rails ship pre-installed. Changing depth means loosening hardware at the top and bottom of each rail, repositioning cage nuts, sliding the rail and re-tightening, and it must be done with no equipment installed. Plan the depth before you load it.
Hardware count varies slightly
The included screw, cage-nut and washer counts are quoted as roughly 50, with slight variations, across the product information. Treat about 50 of each as the working figure and buy spares if you are filling all 42U.
The product in this review
StarTech RK4236BKB
See on AmazonChecking the RK4236BKB's dimensions against the gear you plan to install
The height with casters, the maximum rail depth, the rolling load and the external width settle most of the fit questions before you order.
Rack size and width
The RK4236BKB is 42U with 19-inch mounting, EIA/ECA-310-E compliant, with four vertical rails and square holes with U markings. Usable mounting height is 42 units of 1.75 in, or 73.5 in.
External dimensions
The cabinet measures 23.6 in wide, 39.4 in deep and 75.7 in high with casters. The width is the cabinet body, not the 19-inch mounting face, so add clearance on both sides for the doors to swing and the panels to come off.
Adjustable mounting depth
Rails adjust from 6.0 to 36.0 in, front and rear independently.
Load ratings
The stationary rating is 2000 lb and the rolling rating is 397 lb. Size to the rolling figure if the cabinet will ever move, because the casters carry the load in that case.
Doors and panels
The front door is lockable mesh, removable and reversible. The rear door is lockable mesh only. Side panels are solid steel, lockable and removable. The top is vented, and the top and bottom panels are removable with cable-access covers.
Cooling, mobility and weight
Cooling is passive. Casters and leveling feet are pre-installed, and the feet adjust up to about 3.94 in to level on an uneven floor. The unit weighs 275.3 lb.
Assembly, included parts and warranty
The cabinet ships fully assembled. The box holds 50 M6 screws, 50 M6 cage nuts, 50 washers, a hex key, two side-panel keys, two door keys, a manual, casters, leveling feet and a grounding wire. The warranty is 5 years.
Compatibility
The RK4236BKB takes EIA-310-compliant 19-inch rack-mount devices, including servers, network switches, routers, telecom and A/V equipment.
Setting it up
Setup goes smoothly when the route and the floor are checked before the pallet arrives. The manual asks for three people to unpack and move the cabinet, and two can position and level it once it is inside.
Unpacking and positioning
Roll the cabinet on its casters, then lower it onto the leveling feet for a permanent install; the feet take the load off the casters and let you level on an uneven floor.
Set the depth first
Adjust the rails before anything goes in. The manual warns against adjusting rails with equipment installed, so decide the rail-to-rail depth while the cabinet is empty.
Load from the bottom up
The manual warns against extending more than one sliding component at a time because of tipping risk.
Ground it
The grounding wire is included and grounding is required, not optional. Use the front or rear lug as your layout allows.
Indoor use and floor check
The cabinet is for indoor use only, and cabinets should not be stacked.
The StarTech RK4236BKB is a well-built, deep, lockable, factory-assembled 42U cabinet for a fixed server room or office install. Buy it if your space, doorway and floor are already measured and you accept that fans, power and cable management are yours to add.
Check 75.7 in with casters, 36 in maximum rail depth, 397 lb rolling. Confirm the seller's freight and return terms, and check the current price on the product card.
Frequently asked questions
What do buyers on Amazon say about the StarTech RK4236BKB?
One buyer on Amazon praises the solid steel construction and points out that the cabinet turns up in a single piece. One review at another retailer mentions sound insulation could be improved, which is expected of a mesh enclosure that passes air.
How much can the StarTech RK4236BKB hold once it is rolled on its casters?
Rolling on casters, the cabinet is rated for up to 397 lb (180 kg). The 2000 lb (907 kg) figure applies only when the full weight rests on the leveling feet.
Will the StarTech RK4236BKB clear a standard interior doorway on its casters?
Yes, but with little margin: with casters on, the cabinet stands 75.7 in (1922 mm) tall, while a typical interior opening is around 80 in. Measure every doorway and ceiling on the route before it arrives.
Is grounding the StarTech RK4236BKB optional?
Grounding is a requirement rather than an optional step, and a grounding wire is packed with the cabinet. You can attach that wire at the front or at the rear, whichever suits how the rack is arranged.
Can the front and rear rails of the StarTech RK4236BKB be set to different depths?
Yes. Each rail set moves on its own, so the front pair and the rear pair can sit at different depths in the same cabinet. That means a shallow switch can be mounted at one depth while a deep server sits further back, and the space left behind the deepest unit stays free for cabling and exhaust.