Our readers keep the lights on and my morning glass full of iced black tea. As an Amazon Associate, I earn from qualifying purchases.
You need to lock a pulley, gear, or bearing tight on a shaft without the collar chewing up the surface or slipping under load. A one-piece collar forces you to slide everything off one end to install it. Set-screw-only designs leave a dent. That is why a two-piece clamping collar (a split ring that wraps around the shaft anywhere) exists — it tightens evenly and holds fast without marring your expensive shaft. The trick is picking the right bore (the hole size), material, and clamping force for your job. This guide walks you straight to the collar that fits your exact setup.
I’m Min — the founder and writer behind Gadgets Feed. This guide is built by comparing the manufacturers’ published specifications and the patterns across verified customer reviews, so you get each pick’s real strengths and trade-offs instead of marketing spin.
Every collar here is a genuine two-piece split design, and we matched every bore (the hole diameter), outside diameter (the overall width), and thickness (how much shaft length it covers) to real-world use cases so you can confidently buy the right 2 piece clamping collar the first time.
Quick Picks
- Coastal Machine Works 1.00″ Bore — 303 Stainless Steel (2 Pack) — Premium Pick
- Bore 1” AZSSMUK Double Split Stainless Steel (4 Pack) — Best Overall
- Bore 2” AZSSMUK Double Split Stainless Steel (2 Pack) — Heavy-Duty
- DAOE 1-1/2″ Bore — Black Oxide Carbon Steel (2 Pack) — Top Performer
- uxcell 1-1/4″ Bore — Aluminum Alloy (2 Pack) — Budget Champion
How To Choose The Best 2 Piece Clamping Collar
Picking the right collar is mostly about matching three measurements to your shaft and the space around it, then choosing a material that handles your environment. Here is what to look for.
Bore Diameter Must Match Your Shaft Exactly
The bore is the hole that wraps around your shaft. If it is even a few thousandths of an inch too big, the collar wobbles or fails to clamp; too small and it will not fit at all. Measure your shaft diameter with a caliper (a tool that measures precise thickness) and pick the collar with an identical bore spec — a 1.00 inch bore is for a 1 inch shaft.
Outside Diameter and Thickness Affect Clearance
The outside diameter (OD — the overall width of the collar) and the thickness (sometimes called width — how much shaft length it covers) determine if the collar fits in your space. A larger OD gives more clamping surface but needs more clearance around the shaft. A thicker collar distributes axial load (force along the shaft’s length) better but eats up space along the shaft — so check both numbers against your available room.
Material Decides Durability and Corrosion Resistance
Stainless steel (303 or 304) resists rust and is ideal for wet environments, outdoor gear, or marine applications. Carbon steel with black oxide coating is stronger for heavy industrial loads but can rust if the coating chips. Aluminum is lightweight and rust-proof but less durable under high torque (twisting force) or shock loads (sudden impacts).
Quick Comparison
On smaller screens, swipe sideways to see the full table.
| Model | Best For | Bore Diameter | Material | Thickness | Amazon |
|---|---|---|---|---|---|
| Coastal Machine Works 1.00″ Stainless | Precision machinist & outdoor use | 1.00 in | 303 Stainless Steel | 0.50 in | $18.96Amazon |
| Bore 1” AZSSMUK Stainless (4-Pack) | Multiple positions on one shaft | 1.00 in | 304 Stainless Steel | 0.50 in | $22.99Amazon |
| Bore 2” AZSSMUK Stainless (2-Pack) | Large-diameter shafts & heavy loads | 2.00 in | 304 Stainless Steel | 0.69 in | $29.99Amazon |
| DAOE 1-1/2″ Black Oxide | High-strength press & industrial use | 1.50 in | Carbon Steel, Black Oxide | 0.56 in | $14.99Amazon |
| uxcell 1-1/4″ Aluminum (2-Pack) | Light duty & cost-conscious builds | 1.25 in | Aluminum Alloy | 0.50 in | $13.19Amazon |
In‑Depth Reviews
1. Coastal Machine Works 1.00″ Bore — 303 Stainless Steel (2 Pack)
Precision-machined in the USA with a brushed finish that resists corrosion — so you can install it outdoors and forget it.
This collar delivers an exact fit without guesswork. Its 1.00 inch bore (the hole diameter) grips a 1 inch shaft, while the 1.75 inch outside diameter (OD — overall width) and 0.5 inch thickness keep it compact. Two 1/4-28 socket head screws (a standard screw size) pull the halves together with even 360-degree pressure — unlike set-screw collars, it will not leave a dent or burr on your shaft. The 303 stainless steel (a grade that resists rust and corrosion) stands up to moisture and harsh chemicals easily, so it is a natural pick for marine rigs, food equipment, or outdoor gear. Weighing 6.6 ounces for the pair, it is 82% lighter than the DAOE black oxide collar, making it far friendlier for weight-sensitive setups.
Buyers report it as a “precision-machined USA-made shaft collar,” highlighting that the bore diameter is engraved on the face for quick identification — a small but welcome detail when you have multiple collars in a toolbox. Each edge and hole is deburred, so you are not fighting rough metal during installation. The two hex screws stay tight even under abusive vibration. The only practical trade-off is that the pack does not include an Allen wrench, so you will need a 4.5mm or 5/32 inch hex key ready.
Why it’s great
- Made in the USA with 303 stainless — excellent corrosion resistance for wet or outdoor environments
- Two-piece split design grips without marring the shaft, unlike set-screw collars
- Engraved bore size on face for easy identification in a mixed bin
Good to know
- No Allen wrench included; you need to supply your own 4.5mm or 5/32″ hex key
- At a 1.00 inch bore, it is only for shafts that measure exactly 1 inch
Best for: Machinists and DIYers who need a corrosion-proof, precision collar that will not scar a shaft.
Skip if: You need a budget multi-pack for a one-time temporary fixture — the premium price is overkill for that.
2. Bore 1” AZSSMUK Double Split Stainless Steel (4 Pack)
Four collars for the price of two — so you can lock multiple components on a 1-inch shaft without buying another set.
If you need to lock two bearing faces and a sprocket along a single shaft, this 4-pack saves you a second purchase. Each collar has a 1 inch bore diameter (hole size), a 1-3/4 inch outside diameter (OD — overall width), and a 1/2 inch width, all machined from 304 stainless steel (a grade that resists rust and handles welding heat). The two-piece split design installs or removes any collar without sliding components off the shaft end — a huge time saver on packed assemblies. Weighing 0.37 kilograms for the set, it is heavier than the Coastal collars because you get double the quantity, but the 304 stainless offers the same excellent corrosion resistance for industrial and outdoor use.
Buyers consistently praise the “good quality at a good price” and note that beveled edges make handling smoother. One owner used them to “grip right below the bearing” on a Jeep TJ swaybar, confirming the split design holds tight under real suspension loads. Compared to the Coastal Machine Works collar, this set is a better value when you need four collars for the same bore size, and the 304 stainless is every bit as rust-resistant. The minor catch is that the set screws are standard hex, so keep a 3mm or 1/8 inch Allen wrench handy.
Why it’s great
- Four collars in one box — ideal for multi-point shaft clamping and bearing retention
- 304 stainless steel resists corrosion and welding heat better than regular steel
- Two-piece split design installs anywhere on the shaft without disassembling the entire line
Good to know
- Screws are standard hex — you need to supply your own Allen key
- At 0.37 kg the set is heavier than some 2-packs, but you get double the collars
Best for: Anyone clamping multiple positions on a 1-inch shaft — bearings, pulleys, or stops.
Skip if: You only need one or two collars — the 2-pack from Coastal Machine Works is more economical for light use.
3. Bore 2” AZSSMUK Double Split Stainless Steel (2 Pack)
Oversized 2-inch bore for big shafts — built with 304 stainless to shrug off moisture and weld splatter.
When your shaft is 2 inches in diameter, most collars simply do not come in that size. This 2-pack fills that gap with a 2 inch bore (hole size), a 3 inch outside diameter (OD — overall width), and an 11/16 inch thickness — a full 2.0x wider bore and 2.0x larger OD than the 1-inch collars, giving it significantly more surface area for high clamping force. The two-piece split design lets you wrap it around an installed shaft without pulling anything apart, and the 304 stainless steel construction shrugs off moisture, chemicals, and weld splatter that would corrode carbon steel.
Owners mention using these on Jeep TJ swaybars and other heavy chassis components, often commenting on the “good quality at a good price” and the convenience of beveled edges. The 11/16 inch thickness compared to the 1/2 inch on smaller collars means it eats up more shaft length, so measure your available space before ordering. One reviewer noted they “used to grip right below the bearing,” confirming the split design works for bearing retention on large shafts.
Why it’s great
- 2-inch bore fits large-diameter shafts that most collars skip entirely
- 304 stainless steel resists rust and corrosion in outdoor or industrial settings
- 11/16 inch thickness provides more axial load (force along the shaft) capacity than standard 1/2 inch collars
Good to know
- At 3-inch OD, requires ample clearance around the shaft — check your space
- You will need a larger hex key for the set screws; not included
Best for: Large machinery, agricultural equipment, or any 2-inch shaft needing a corrosion-proof split collar.
Skip if: Your shaft is smaller than 2 inches — the 1-inch or 1.5-inch options fit your setup better and save money.
4. DAOE 1-1/2″ Bore — Black Oxide Carbon Steel (2 Pack)
Carbon steel strength with a black oxide finish — for raw clamping power on heavy press work.
For jobs that demand raw axial and radial support (force along and around the shaft) — like pressing in a wheel bearing or holding a heavy fixture — this collar is the workhorse. With a 1.5 inch bore (hole size), a 2-3/8 inch outside diameter (OD — overall width), and a 9/16 inch thickness, it offers a noticeably larger footprint than the 1-inch collars while staying compact enough for tight engine bays or press frames. The carbon steel construction delivers superior strength over stainless or aluminum, and the black oxide coating adds weldability and corrosion resistance that handles shop-floor abuse. At 12 ounces for the pair, it is 3.7x heavier than the uxcell aluminum collar, but that weight is a direct trade-off for significantly higher clamping force.
Buyers highlight its versatility: one owner used it as a “press adapter for Jeep rear wheel bearing install,” noting that the split design let them loosen and slide it on and off easily while the press plates supported the collar gap. Another clamped one above and below a monitor arm junction to stop sagging, calling the two-piece design “inexpensive for DIY stabilization.” The 1/4-28 set screws (standard screw size) bite firmly into the shaft, and the black oxide finish holds up well in automotive and general industrial use. The catch is that carbon steel can rust if the coating scratches, so avoid prolonged outdoor exposure without a protective layer.
Why it’s great
- Carbon steel with black oxide — stronger than stainless and corrosion-resistant for shop use
- 1.5 inch bore with 2-3/8 inch OD offers a beefy clamping footprint for heavy loads
- Split design proven for press applications and DIY stabilization fixes
Good to know
- At 12 oz (0.34 kg), it is noticeably heavier than stainless and aluminum alternatives
- Black oxide coating can chip or rust if exposed to constant moisture — not ideal for marine use
Best for: Automotive press work, heavy industrial fixtures, and anyone who needs maximum clamping force on a 1.5-inch shaft.
Skip if: You need corrosion protection for outdoor or wet environments — 303/304 stainless is safer there.
5. uxcell 1-1/4″ Bore — Aluminum Alloy (2 Pack)
Aluminum alloy that weighs only 0.1 kg per pair — perfect for light-duty fixes where you want to keep weight down.
When your budget is tight and the load is light, this aluminum collar gets the job done for pennies. It offers a 1-1/4 inch bore diameter (hole size), a 2-1/16 inch outside diameter (OD — overall width), and a 1/2 inch thickness, all carved from aluminum alloy that resists rust and corrosion without the weight of steel. The two-piece split design installs in seconds — open it, wrap it around the shaft, and tighten the screws.
Buyers found creative uses: one reviewer “used these to clamp my office chair height adjustment instead of replacing the piston,” and another used one as a shower head extension collar. The aluminum construction means it will not rust, but it also means lower tensile strength (resistance to being pulled apart) — do not expect it to handle high-torque automotive or industrial loads. One buyer mentioned it was “perfectly machined,” so fit is consistent, but the aluminum threads can strip if you overtighten, so use moderate torque with the included set screws.
Why it’s great
- Aluminum alloy is naturally rust-proof and weighs only 0.1 kg per pair — great for lightweight assemblies
- Cost-effective entry point for DIY projects and non-critical shaft positioning
- Split design allows creative uses like chair piston clamps and shower head extensions
Good to know
- Aluminum has lower strength than steel — not suitable for high-torque or shock-load applications
- Threads can strip if you overtighten; use a light hand with the set screws
Best for: Light-duty positioning, hobby robotics, or quick DIY fixes where weight and budget are the main concerns.
Skip if: You need to withstand heavy industrial or automotive loads — step up to carbon steel or stainless steel for those.
Understanding the Specs
Bore Diameter
This is the size of the hole that wraps around your shaft. Measure your shaft with a caliper (a tool that measures precise thickness) and pick a collar whose bore matches that number exactly — for example, a 1.00 inch bore collar fits a 1.00 inch shaft. If the bore is too big, the collar will spin or slip; too small and it will not fit at all. This is the single most important spec to get right.
Clamping Force – Split vs Set Screw
A two-piece split collar uses screws to pull both halves together, creating even 360-degree pressure around the shaft. This is very different from a set-screw collar (a single screw that pushes a point into the shaft), which can leave a dent or burr. The split design gives you higher clamping force and protects the shaft surface, which matters if you ever need to slide the collar off cleanly later.
FAQ
Can I install a two-piece clamping collar without removing the shaft?
Will a 2 piece clamping collar damage my shaft?
What is the difference between 303 and 304 stainless steel for shaft collars?
How tight should I tighten the screws on a split collar?
Can I use a 2 piece clamping collar as a thrust bearing surface?
Will a split collar work on a threaded shaft?
Which material is best for outdoor or marine use?
How do I know if a 1.5 inch bore collar fits my shaft?
Can I use a two-piece collar as a press adapter for bearing installation?
What outside diameter should I choose for tight spaces?
Final Thoughts: The Verdict
Across the board, the 2 piece clamping collar winner is the Bore 1” AZSSMUK Stainless (4-Pack) because it combines affordable 304 stainless steel, a versatile 1-inch bore size, and the value of four collars in one box. If you need precision American machining for a permanent outdoor fixture, grab the Coastal Machine Works 1.00″ Bore (2 Pack). And for heavy industrial or automotive press work, the standout is the DAOE 1-1/2″ Black Oxide (2 Pack).
How We Picked
We do not accept paid placement, and we did not hands-on test every unit. Instead, we match each pick to a real buyer and use-case by comparing the manufacturers’ published specifications against the patterns in verified customer reviews — so you get each pick’s real strengths and trade-offs instead of marketing copy.
Sources & Methodology
Specifications: manufacturer listings and product documentation. Review insights: verified customer reviews, as of June 2026. Pricing: not shown on this page (it changes often); check the current price via the retailer link.
As an Amazon Associate, Gadgets Feed earns from qualifying purchases. This does not affect which products we feature.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply to the purchase of this product. As an Amazon Associate I earn from qualifying purchases.
CERTAIN CONTENT THAT APPEARS ON THIS SITE COMES FROM AMAZON. THIS CONTENT IS PROVIDED "AS IS" AND IS SUBJECT TO CHANGE OR REMOVAL AT ANY TIME.
Amazon and the Amazon logo are trademarks of Amazon.com, Inc. or its affiliates.