The main decision when picking a shaft coupling is how much misalignment your setup can tolerate. A flexible coupling can absorb minor angular and parallel offset; a rigid coupling holds shafts in precise alignment. This guide compares four couplings across that spectrum, with listed prices from $12.05 to $38.65. You'll also see the key differences in shaft size, mounting style, and installation approach.
Quick Take
The four couplings divide cleanly by purpose: a CNC flexible coupling for a small flexible shaft, a rigid sleeve set with multiple bore options, a rigid coupling with four set screws, and a flange-mount hub collar. Match the coupling type to your shaft size and alignment needs.
Listed Price Comparison
| Product | Listed Price | Price Bar |
|---|---|---|
| Face Flange Mounted Shaft Collars Hub Mount Shaft Collar Couplings Alum or Steel | $38.65 | |
| Rigid Shaft Coupling Coupler Motor Transmission Connector Sleeve DIY Motor Motor | $34.59 | |
| Shaft Coupling 7/8" Bore 1-3/4" OD 2" Length Rigid Coupling, 4 Set Screws | $34.32 | |
| 40Cr Steel CNC Flexible Shaft Coupling Fits For 4.76mm (3/16") Flexible Shaft | $12.05 |
Decision Matrix
| If you need... | Consider... |
|---|---|
| A flexible coupling for a 4.76mm (3/16") shaft | 40Cr Steel CNC Flexible Shaft Coupling |
| A rigid coupling for a 7/8" bore | Shaft Coupling 7/8" Bore Rigid Coupling |
| A flange-mount hub collar for a 1" shaft | Face Flange Mounted Shaft Collars Hub Mount |
| A multi-size sleeve set for small motor/DIY builds | Rigid Shaft Coupling Coupler Motor Transmission Connector Sleeve |
Product Notes
Face Flange Mounted Shaft Collars Hub Mount Shaft Collar Couplings Alum or Steel
The listing combines clamping with flange-face mounting: three tapped counterbored holes and three unthreaded holes give you a choice of mounting arrangements, and the collar clamps evenly around the shaft to reduce the chance of marring. It is shown in aluminum black anodize with a 1" inside diameter, and the description says keyway versions use a standard ANSI keyway. That makes it a candidate for setups where alignment and mounting flexibility come before price. The tradeoff is the $38.65 listed price, the highest on this page, and the 1" inside diameter is the only size shown.
40Cr Steel CNC Flexible Shaft Coupling Fits For 4.76mm (3/16") Flexible Shaft
This is the only flexible coupling in the group and the only one that specifically lists a 4.76mm (3/16") shaft fit. It is CNC-machined from 40Cr steel, with a 42mm length and a bore designed 0.02mm smaller than the marked diameter for a tighter installation. If installation is difficult, the description recommends heating the part to 200-300°C before fitting. At $12.05, it has the lowest listed price of the four. The limitation is that the listed bore is sized for that single 4.76mm flexible shaft, so it won't cover larger or multiple shaft diameters.
Rigid Shaft Coupling Coupler Motor Transmission Connector Sleeve DIY Motor Motor
This rigid coupler is oriented to DIY motor builds, 3D printers, and model cars, boats, and planes. The description lists bore sizes from 3mm to 12mm, M4 screws, and total lengths of 22mm with 14mm, 16mm, or 18mm diameters, so it can adapt to a range of small shafts. Because it's a rigid coupling, it does not allow eccentricity, and the listing notes that the shafts must be fully adjusted during use. At $34.59, it sits in the upper price range. The limitation is that you have to select the right bore pairing from the listed options, and there's no flexibility for misalignment.
Shaft Coupling 7/8" Bore 1-3/4" OD 2" Length Rigid Coupling, 4 Set Screws
This uxcell coupling is specified for a 7/8" bore, 1-3/4" outside diameter, and 2" length, with four set screws to lock the shaft. The description says it is made from 45# (ASTM1045) steel with a black oxide coating for corrosion resistance. As a rigid coupling, it keeps the connected shafts in line, so you'll need to align things before tightening. The listed price is $34.32. The limitation is that it's built for that specific 7/8" bore, so it's less adaptable to other shaft sizes. A California Prop 65 warning appears in the listing.
Final Recommendation
- Flexible shaft application: Choose the 40Cr Steel CNC Flexible Shaft Coupling for the only flexible option in this group.
- Rigid coupling with set screws: Choose the uxcell Shaft Coupling for a fixed-bore rigid joint.
- Flange or hub mount: Choose the Summit Collars Face Flange Mounted Shaft Collar for its multiple mounting holes.
- Small motor or DIY with varied shafts: Choose the Rigid Shaft Coupling sleeve set for its broad bore range.
