BrassCraft G2CR19X CM5
$34.87 at Amazon
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Compression ferrule sizing: ferrule vs olive
Find the tube size before choosing the ring.
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On this page
- Three parts for a copper stop job
- BrassCraft G2CR19X
- RIDGID 101
- RIDGID 223S
- Ferrule, olive and sleeve compared
- Match the label to the measured tube
- Why 15 mm is different from 5/8 inch
- Measure the tube, not the nut
- Choose the sleeve and insert together
- Can you reuse or mix the parts?
- Follow the instructions for that connection
- Should the compression threads have tape?
- When to choose each repair path
- Questions about compression ferrule sizing
- How we pick and check the sizes
- Related pipe and supply guides
Quick answer
In single-ring plumbing compression fittings, ferrule, olive and sleeve name the same ring. U.S. 1/2-inch nominal copper is 5/8-inch OD, not 15 mm. For an accessible potable-water stop on type L or M copper, get BrassCraft G2CR19X CM5, and cut square before you deburr.
Copper stop replacement: G2CR19X CM5$34.87 at AmazonPrice as of Oct 24, 2026, 5:30 AM EDT · low stock then
Check it on AmazonThree parts for a copper stop job
A complete valve, a tubing cutter and a reamer do different jobs, so the job decides, not a score. None is a universal replacement olive; the sizing chart below identifies the tube before you choose a part.
RIDGID 101, catalogue 40617
$27.98 at Amazon
Check it on AmazonPrice as of Oct 24, 2026, 5:30 AM EDT
RIDGID 223S reamer
$49.98 at Amazon
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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.com at the time of purchase will apply to the purchase of this product.
| Part or tool | Key specs | Pick it if | Skip it if |
|---|---|---|---|
| BrassCraft G2CR19X CM5 | G2CR19X CM5, 1/2-inch nominal inlet, 3/8-inch OD outlet, 125 psi maximum, 40–160°F | You are replacing an accessible potable-water stop on compatible Type L or M copper, the tube measures 5/8-inch OD, and the required outlet is 3/8-inch OD compression. | You need only a loose olive, have 15 mm copper, have an unidentified tube material, or need a valve approved for continuous hot-water recirculation above 115°F. |
| RIDGID 101, catalogue 40617 | Model 101, Catalogue 40617, 1/4–1-1/8-inch capacity, Manual tubing cutter | A new square cut is needed on compatible small copper tubing within the stated capacity, and enough sound tube will remain for the replacement fitting’s full insertion depth. | The only problem is a stuck ring, the stub is already too short, the tube is still pressurized, or you need a tool approved for a different material. |
| RIDGID 223S reamer | Model 223S, catalogue 29983, ¼–1¼ in. OD, 45 cutting edges, copper and stainless | You have a fresh cut on 5/8 or 3/8 in. OD tube and no reamer to clean the inside and outside edges. | You already own a reamer or deburring tool that covers the tube size, or the only problem is a stuck ring. |
The valve offer was new with 8 left from a third-party store on Oct 22, 2026, 7:40 AM EDT. Check current availability on Amazon. For a loose sleeve, tube OD alone cannot establish drinking-water suitability or compatibility with the existing fitting.
BrassCraft G2CR19X CM5 for a copper stop
A valve, a cutter and a reamer don’t compete, so none of them is scored.
My call: choose this stop when the old valve needs replacement and the copper inlet matches. BrassCraft lists G2CR19X CM5 in its G2CR19 configurations. The maker identifies that family as a 1/2-inch nominal compression inlet with a 3/8-inch OD compression outlet. Those two labels refer to different tube dimensions.
Neither BrassCraft’s configuration table nor the Amazon listing says whether a nut and sleeve come in the box. Open the package before you shut off the water. Any included inlet sleeve must suit 5/8-inch OD tube, and the outlet parts must suit 3/8-inch OD.
At the wall, U.S. 1/2-inch nominal copper measures 5/8 inch across its outside. The outlet is sized for 3/8-inch OD tubing. A loose sleeve marked 1/2-inch OD is therefore not the inlet sleeve for this valve, even though both packages may contain the words half inch.
Where it does well
- Maker lists the exact CM5 configuration
- Inlet fits U.S. 1/2-inch nominal copper sizing
- 3/8-inch OD compression outlet
- Quarter-turn shutoff for accessible potable-water service
What to watch
- Sold by a third-party store with few left
- Copper inlet instructions specify Type L or M
- Not compatible with 15 mm tube
- Not for continuous-use temperatures above 115°F
BrassCraft’s 400.50 submittal sets the service limits at 125 psi maximum and 40–160°F. It specifies accessible potable-water locations and excludes recirculation or continuous-use temperatures above 115°F. The ordinary hot-water temperature range does not cancel that separate continuous-use restriction.
The copper compression inlet instructions in 425.04 specify Type L or M copper. Do not extend that instruction to Type K just because the outside diameter matches. Likewise, the current submittal reserves its stated PEX application for part numbers containing PXX; this CM5 offer is not identified as that version.
Before loosening the old stop, shut off the upstream water supply as BrassCraft requires. Relieve pressure and let hot water cool. Call a plumber if you cannot isolate the line or the remaining stub is damaged or too short to make the new connection specified by the valve maker.
BrassCraft prohibits connectors with a solid brass cone or bull nose because fractures can develop. Operate the stop fully open or fully closed. If the stop is a termination point, its outlet must be capped; a closed handle does not replace that requirement.
Use the new valve’s own documented connection parts. A nut that happens to screw onto the body does not establish that an old ferrule has the right sealing shape. If preserving the old nut and ring is essential, get the valve maker’s explicit compatibility instruction before ordering this as the replacement.
RIDGID 101 for a square cut
The RIDGID 101 suits a compression repair that genuinely needs a fresh copper end. RIDGID’s ordering table identifies catalogue 40617 as Model 101, with a capacity of 1/4 to 1-1/8 inch. That includes the 5/8-inch OD of U.S. 1/2-inch nominal copper.
That capacity also covers 3/8-inch OD and 1/2-inch OD tubing. It does not tell you which sleeve to buy. A cutter’s range concerns the outside diameter it can accept; the fitting still needs its own matching tube material, sleeve shape and installation instructions.
Its close quarters design is intended for restricted spaces. Check the available working room before deciding to cut an installed stub, particularly when a cabinet panel or wall prevents the tool from moving around the tube. A cutter that accepts the tube diameter still needs room to travel around it.
Where it does well
- Maker identifies Model 101 as catalogue 40617
- 1/4–1-1/8-inch tube capacity
- Capacity includes 5/8-inch OD copper
- Manual tool for restricted working areas
What to watch
- Does not remove a swaged ferrule
- Cutting back can leave insufficient stub length
- A square cut still needs deburring and inspection
Shut off water before starting, as BrassCraft’s compression instructions require, and release pressure before cutting. Allow a hot line to cool. If the upstream shutoff does not hold, stop and have a plumber isolate the supply. A small manual cutter does not make a live water line safe to open.
Cutting off a ferrule consumes tube length. Before making that irreversible cut, check the replacement valve’s required insertion depth and whether the remaining copper is straight and sound. Choose a removal method or a plumber’s repair instead if cutting would leave the valve unable to seat fully.
Wear eye protection while cutting and deburring. After the cut, follow the fitting instructions for a square, round end without burrs, paint or gouges. Cutting and deburring are separate operations; do not assemble the stop on a sharp, unfinished tube end just because the cut looks square.
The Oct 22, 2026 Amazon offer identifies RIDGID 40617 Model 101, new and in stock, sold by Amazon.com. The title’s CC247 prefix does not change the capacity in RIDGID’s ordering table. Match catalogue 40617 and Model 101 when checking the Amazon listing; another cutter’s similar appearance does not establish the same capacity.
RIDGID 223S to deburr the cut
A wheel cutter leaves a ridge of copper inside the cut and a slight lip outside it. BrassCraft’s compression instructions want a square, round tube end without burrs before the nut and sleeve go on. The cutter makes the square end; the reamer finishes it.
RIDGID rates the 223S for ¼ to 1¼ inch outside diameter. That covers both ends of this stop: the 5/8-inch OD copper at the inlet and 3/8-inch OD tube at the outlet, so one reamer does the whole job.
Its interior cone has 45 cutting edges, per RIDGID, so a twist reams the inside, deburrs the outside and bevels the edge. RIDGID lists it for copper and stainless steel tubing and pipe, with knurled edges for grip.
Where it does well
- ¼–1¼ in. OD range covers 5/8 and 3/8 in. OD tube
- Reams the inside and deburrs the outside in one tool, per RIDGID
- Sold by Amazon.com
What to watch
- Doesn’t remove a stuck ferrule
- Too much reaming thins the tube wall
Wipe the chips out of the tube end and off the outside before the sleeve goes on. A shaving under the sleeve can keep it from seating evenly, and loose chips can travel into the new valve.
My call: if you don’t own a reamer, buy the 223S with the cutter. Go easy on type M copper’s thinner wall; you want a clean edge, not a smaller tube.
Ferrule, olive and sleeve compared
For the household single-ring connection, terminology does not create a winning side. The fitting design and measured tube determine the correct part.
| Question | Ferrule | Olive / compression sleeve | Ahead |
|---|---|---|---|
| What does it mean here? | A ring compressed by the nut into the fitting seat | The same job in a single-ring plumbing fitting | Even |
| Which diameter matters? | The tube OD specified for the exact fitting | The tube OD specified for the exact fitting | Even |
| Does the word establish material? | No; identify the maker’s specified part | No; brass and plastic sleeves have different applications | Even |
| Can the name prove interchangeability? | No; nut, ring and body must be compatible | No; a shared OD is only one requirement | Even |
| What is outside this comparison? | Front and back ferrules in instrumentation fittings | Special adapters and proprietary ring designs | Neither label replaces the system instructions |
Conex names its sealing ring an olive and shows it with a capnut and fitting body. BrassCraft uses sleeve in its compression instructions. A shop’s choice of noun tells you little about the dimensions of an unidentified ring. Order the part number for the fitting, after confirming the tube OD.
A two-ferrule instrumentation connection needs a separate explanation. Swagelok’s instructions refer to a front ferrule and back-ferrule geometry. Do not translate a household single-ring assembly into that system by adding another ring or copying its tightening sequence. The parts and procedures belong to their own fitting families.
| Choice | Photo | Use and key spec | Strength | Limit | Amazon |
|---|---|---|---|---|---|
| BrassCraft G2CR19X CM5 | | Accessible copper stop; 1/2-inch nominal × 3/8-inch OD | Whole valve with a documented application | Type L or M inlet; not for 15 mm tube | Check it on Amazon |
| RIDGID 101 / 40617 | | Square cuts; 1/4–1-1/8-inch tube capacity | Capacity includes 5/8-inch OD copper | Cuts tube; does not extract the ring | Check it on Amazon |
| RIDGID 223S / 29983 | | Deburr the cut; ¼–1¼-inch OD | Inside and outside edges in one tool | Does not extract the ring | Check it on Amazon |
Match the label to the measured tube
Read across a row. The last column is a different dimension to avoid, not a claim that every ring of the named size fits every brand.
| Tube description | OD, inches | OD, mm | Ring / fitting size to identify | Different size to avoid |
|---|---|---|---|---|
| Actual 1/4-inch OD tubing | 0.250 | 6.350 | 1/4-inch OD | 6 mm |
| Actual 3/8-inch OD tubing | 0.375 | 9.525 | 3/8-inch OD | 10 mm |
| Actual 1/2-inch OD tubing | 0.500 | 12.700 | 1/2-inch OD | U.S. 1/2-inch nominal |
| U.S. 1/4-inch nominal copper | 0.375 | 9.525 | 3/8-inch OD | 1/4-inch OD |
| U.S. 3/8-inch nominal copper | 0.500 | 12.700 | 1/2-inch OD | 3/8-inch OD |
| U.S. 1/2-inch nominal copper | 0.625 | 15.875 | 5/8-inch OD | 15 mm |
| Metric 15 mm tube | 0.590551 (rounded) | 15.000 | 15 mm | 5/8-inch OD |
| U.S. 3/4-inch nominal copper | 0.875 | 22.225 | 7/8-inch OD | 22 mm |
| Metric 22 mm tube | 0.866142 (rounded) | 22.000 | 22 mm | 7/8-inch OD |
Nominal copper relationships: BrassCraft Nominal/O.D. conversion chart. Metric sizes: Conex Compression catalogue. Inch-to-millimetre figures are calculated using 25.4 mm per inch. The chart identifies dimensions; the fitting maker must also approve material and service.
Start with the words printed next to the fraction. A sleeve marked 1/2-inch OD belongs to tube measuring 0.500 inch outside. U.S. copper marked 1/2-inch nominal measures 0.625 inch outside.
Those are separate rows, despite the shared fraction. Keeping OD in your size notes prevents that mix-up.
For an existing copper stub, record both the measured dimension and the nominal description if known. For example, write U.S. 1/2-inch nominal copper, 5/8-inch OD. Compare that complete description with the fitting specification rather than searching for half inch alone.
A valve marked 1/2-inch nominal × 3/8-inch OD has two connection sizes. The first describes its inlet in the copper sizing system. The second describes the outlet’s tubing size directly. Matching a sleeve to the smaller outlet says nothing about what fits the larger tube at the wall.
Why 15 mm is different from 5/8 inch
Convert the physical outside diameter before treating a metric olive as an inch-size replacement.
Five eighths of an inch equals 15.875 mm. Compared with 15 mm, the difference in diameter is 0.875 mm. That is a dimension calculation, not a tested leakage threshold. The two labels should lead you to different fitting specifications rather than an attempt to force one olive onto the other tube.
The larger pair is closer: 7/8 inch equals 22.225 mm, which differs from 22 mm by 0.225 mm. Small numerical differences still do not establish a seal. Look for the maker’s written adaptation instruction for that exact tube standard and fitting instead of using extra wrench force to compensate.
| What you read | What it establishes | What it does not establish |
|---|---|---|
| 15 mm vs 5/8 inch | 15.000 vs 15.875 mm tube OD | A common replacement ring |
| 22 mm vs 7/8 inch | 22.000 vs 22.225 mm tube OD | Permission to interchange sleeves |
| Conex 15 mm / legacy 1/2 inch | A named BS 659 compatibility entry | Approval for U.S. 1/2-inch nominal CTS |
| Conex 22 mm / legacy 3/4 inch | A named BS 659 adaptation requiring a different ring | A general 22 mm / U.S. 7/8-inch sleeve interchange |
British legacy copper needs its own check. Conex’s section 1.9 is explicitly about imperial tube to BS 659. Its table allows 15 mm fittings on the named legacy half-inch tube without an adapter. That table does not describe U.S. 1/2-inch nominal copper, whose OD is 15.875 mm.
For its 22 mm fitting on the specified legacy 3/4-inch BS 659 tube, Conex calls for an exchanged compression ring. That is a documented adaptation within the Conex system. It is not permission to mix any 22 mm olive, American tube and unidentified compression body.
If a house contains imported fittings or older British tube, compare the tube standard and fitting markings with the maker’s documentation. A remembered half-inch description cannot identify which national sizing convention was used. Keep the U.S. conversion chart and Conex’s BS 659 table separate until the tube is positively identified.
Measure the tube, not the nut
A caliper reading should describe the tube’s outside surface. Nut width and an already compressed ring answer different questions.
| Object measured | Useful information | Why it cannot replace tube OD |
|---|---|---|
| Bare, sound tube | Outside diameter for the sizing chart | Still needs material and fitting identification |
| Nut across the flats | Wrench size | Wrench opening is not tube size |
| Male compression threads | Connection identification with maker data | Thread diameter is not the tube’s sealing diameter |
| Loose ring bore | A part dimension before assembly | Bore clearance is not the nominal tube label |
| Old compressed ring | Evidence of the previous connection | The ring has already changed shape |
Measure an exposed, round portion of the tube rather than the ring bulge. Keep the caliper square across the outside surfaces and compare more than one orientation. If the tube is visibly dented or out of round, treat the reading as a repair problem before treating it as a shopping dimension.
A loose sleeve must slide over the tube before it is compressed. Its measured bore therefore need not equal the exact tube dimension on the package. Use the tube-size designation in the fitting maker’s drawing rather than treating a loose ring’s bore measurement as its nominal size.
The sleeve’s outside diameter is another separate measurement. It must cooperate with the nut and seat of its fitting. Measuring the old ring’s outside and finding a similar-looking item online leaves the tube clearance and seat geometry unresolved. Use the maker’s replacement identification instead of turning a rough measurement into a compatibility claim.
- 1Make the line safe
Before any disassembly, shut off the upstream water as BrassCraft requires, relieve pressure and allow hot water to cool. Call a plumber if you cannot isolate it. You do not need to loosen a sound connection just to read accessible tube markings.
- 2Record the tube dimension
Measure sound bare tube OD with a caliper, such as the General Tools 147 digital caliper, and write the units. Record 0.625 inch or 15.875 mm explicitly if that is the identified U.S. half-inch nominal copper size.
- 3Record the fitting family
Photograph the valve or fitting markings and note inlet and outlet separately. Identify the maker’s sleeve, nut and any required insert before ordering.
- 4Check the permitted application
Confirm tube material, temperature, pressure and water-service approval in the maker’s document. Stop if the product page and installation sheet give conflicting instructions.
Choose the sleeve and insert together
A matching outside diameter does not make copper, plastic and PEX interchangeable in a compression connection.
| Tube or fitting situation | Documented requirement | Limit to keep |
|---|---|---|
| BrassCraft water-stop copper inlet | 425.04 specifies Type L or M copper | Equal OD does not approve Type K |
| PEX, 3/8-inch OD or smaller in 225.01 | Plastic sleeve; that instruction says no insert | Do not apply to every plastic fitting or ignore conflicting model instructions |
| PEX, 1/2-inch OD or larger in 225.01 | Brass sleeve plus stainless steel insert | The exact valve must also be approved for PEX |
| BrassCraft G2 PEX application in 400.50 | Parts containing PXX | A plain G2CR19X listing does not establish PEX suitability |
| Conex PE-X / PB applications | Follow the named tube standards and liner requirements | Do not transfer BrassCraft insert rules to Conex |
The insert supports the tube from inside; the compression sleeve acts outside it. Buying one does not establish whether the other is required. BrassCraft’s 225.01 gives a size-specific PEX procedure, while the G2 submittal adds a part-number restriction. Both the assembly procedure and the valve’s own application must match.
BrassCraft’s 225.01 separates PEX at 3/8-inch OD and smaller from PEX at 1/2-inch OD and larger. That size boundary concerns its specified assembly, not every product labeled compression. If the exact valve’s instructions conflict with a general fitting sheet, stop and ask BrassCraft which procedure applies.
Pressure and temperature also belong to the complete application. The G2 stop’s 125 psi maximum and 40–160°F range do not establish a rating for an unidentified sleeve. Its separate exclusion for continuous-use temperatures above 115°F still applies even though the general temperature range extends higher.
| Application check | What to read | Decision |
|---|---|---|
| Copper stop inlet | 425.04: Type L or M copper only | Do not extend the approval to Type K based on OD |
| PEX connection | 225.01: size-dependent sleeve and insert instructions | Confirm that the exact valve also permits PEX |
| G2 PEX identification | 400.50: part numbers containing PXX | G2CR19X CM5 is not identified as that version |
| Continuous hot-water service | 400.50: excludes continuous use above 115°F | Do not substitute the general 160°F limit |
Can you reuse or mix the parts?
Separate a new stop installation from the reassembly procedure of a system designed for that purpose.
| Situation | What the instructions support | Safe purchasing decision |
|---|---|---|
| Replacing an unidentified household stop | No universal compatibility follows from shared threads | Use documented matching new parts; ask the maker if retaining an old ring is unavoidable |
| Swagelok reassembly | MS-12-01 permits repeated reassembly by its stated procedure | Keep the preswaged ferrules with the specified fitting system |
| Mixing Swagelok and another maker | MS-12-01 prohibits mixing or interchanging parts | Do not make a mixed-brand assembly |
| Checking a reassembled Swagelok fitting | Gap gauge is for initial installation, not reassembly | Use the maker’s reassembly procedure, not the initial gauge test |
An installed ring has already been compressed to its previous seat. A new valve may accept the nut’s threads yet have a different seat relationship. That is why thread engagement alone is poor buying evidence. Ask for written compatibility with the exact replacement body if the old ring must remain.
Avoid the opposite blanket claim that all ferrules are always single use. Swagelok explicitly permits repeated disassembly and reassembly of its tube fittings using the prescribed method. Its instructions require depressurizing before disassembly and returning the nut to a marked position. That permission is specific to its system.
Household-stop instructions and instrumentation reassembly instructions should never be blended into a hybrid procedure. BrassCraft’s water-stop sheet includes a do-not-reuse caution, while Swagelok has a dedicated reassembly section. Read each in its own product context; neither establishes an approval to put an unknown old olive into a new household stop.
A stuck ferrule needs a removal plan before a cutting plan. See removing a stuck compression ferrule if the ring will not release. Preserve enough undamaged tube for the replacement fitting’s required insertion depth.
Follow the instructions for that connection
Shut off the water before assembly or adjustment. Release pressure, let hot lines cool and call a plumber if isolation or a sound sealing surface cannot be confirmed.
BrassCraft 425.04 prohibits connectors with a solid brass cone or bull nose because fractures can develop. Use the stop fully open or fully closed. Cap the outlet if the stop is used as a termination point. Wear eye protection while cutting or deburring the tube.
| Connection in BrassCraft 425.04 | Tightening instruction | Scope |
|---|---|---|
| Copper compression inlet | 3/4 turn beyond hand-tight | The applicable Type L or M copper stop inlet |
| Copper compression outlet | 1 to 1-1/4 turns beyond hand-tight | The copper riser outlet section, continued on printed page 3 |
| Unidentified nut or fitting | No universal turn count | Identify the maker and exact connection first |
The difference between those inlet and outlet instructions is the reason to avoid a universal compression turn count. Even one maker gives separate procedures for different ends of the water stop. Keep the tube seated and square while tightening, and heed the maker’s warning that overtightening can cause future failure.
For BrassCraft’s general compression fitting, 225.01 starts with a square cut free from damage or debris. The nut goes on before the sleeve, with its threaded end facing the fitting. Seat the tube fully in the body before hand-tightening. Those steps establish alignment before wrench force is applied.
That same instruction calls for one wrench to stabilize the fitting and another to tighten the nut. Supporting the body matters when the tube exits a wall and should not twist with the nut. Stop if the tube moves in the wall, the fitting will not seat squarely, or wrench access prevents controlled tightening.
- 1Identify both connection ends
Use the copper compression inlet instructions for the inlet and the appropriate outlet instructions for the riser or connector. BrassCraft tells the installer to choose the instructions that match the purchased configuration.
- 2Prepare sound tube
With water shut off and pressure relieved, wear eye protection while cutting square and removing burrs and debris. Do not assemble over a gouge, dent or paint-covered sealing area. Call a plumber if a usable stub cannot be preserved.
- 3Seat before tightening
Place the nut and correct sleeve on the tube, then bottom the tube in the fitting. Keep it seated and square while following the maker’s connection-specific tightening instruction.
- 4Check the completed connection
Restore water according to the product instructions and inspect for leakage. BrassCraft 225.01 allows tightening the appropriate nut if a leak appears, but warns against overtightening. Shut the supply off again before loosening or taking a joint apart.
Should the compression threads have tape?
BrassCraft’s water-stop compression sections prohibit thread-seal tape. A compression ring seals at the tube and fitting seat.
| Location or material | What BrassCraft 425.04 says | What to avoid |
|---|---|---|
| Compression threads | No thread-seal tape, putty or gasket material | Tape as a cure for a wrong ring |
| Optional permitted thread sealant | A thin coat on male compression threads only | Sealant on the ring or sealing surface |
| Ring / seating surface | Keep free of the thread sealant | Coating the olive to hide damaged tube |
| Different connection type | Read its separate installation section | Transferring tapered-pipe-thread instructions to compression ends |
Thread sealant and PTFE tape are not interchangeable instructions in this document. Where BrassCraft permits thread sealant, it limits placement to the male compression threads and warns that excess can cause failure. That permission does not reverse the explicit ban on thread-seal tape in its compression sections.
If the ring is the wrong diameter or the tube is scratched where the ring must seal, more material on the threads does not resolve the mismatch. Recheck the size and damaged area with the water off. For an existing leak, use the separate under-sink compression leak guide to diagnose the location before selecting a repair.
When to choose each repair path
Choose a part after identifying the failure and the tube. An olive’s familiar name is not a diagnosis.
Correct size, documented matching family
Use the maker’s specified sleeve and nut when the tube OD, tube material and service are all approved. Keep that identification with the part number for future maintenance.
Copper stop needs replacement
Consider G2CR19X CM5 for an accessible potable-water stop with a 5/8-inch OD Type L or M copper inlet and a 3/8-inch OD outlet. Follow the valve’s connection-specific installation instructions.
Metric or legacy tube is uncertain
Pause ordering until the tube standard is known. Conex’s BS 659 adaptation table cannot establish compatibility for U.S. nominal copper.
Pressure will not shut off
Do not loosen the nut or cut the tube. BrassCraft requires shutoff before work. Have a plumber isolate the supply and release pressure before repair.
Gas or an unapproved hot-water service
Do not use BrassCraft’s general compression instructions for gas; they prohibit it. G2 stops also exclude continuous-use temperatures above 115°F. Have a qualified pro choose an approved connection.
Damaged or insufficient copper stub
Stop if the remaining tube cannot provide a square, sound, fully seated connection. A plumber may need to repair the tube before any replacement valve can be installed.
If the existing valve works and the only question is ring terminology, the chart may be all you need. There is no reason to buy a new stop just to translate olive into ferrule. For a genuine choice between connection systems, see compression vs push-to-connect shutoff valves.
If you are replacing the supply connector rather than the wall valve, identify that outlet separately. Our toilet supply-line size guide covers the fixture-side sizing question. A correct inlet ferrule on the wall stub does not establish which connector belongs on the valve’s outlet.
Questions about compression ferrule sizing
Is a compression ferrule the same as an olive?
In an ordinary single-ring plumbing compression fitting, yes: ferrule, olive and compression sleeve describe the ring squeezed by the nut into the seat. Conex uses olive; BrassCraft uses sleeve. The name does not establish whether another maker’s ring has the right dimensions or shape.
Check the fitting family as well as tube OD. Instrumentation fittings can have front and back ferrules with their own assembly rules, so the household single-ring explanation does not cover every product called a ferrule.
What size ferrule fits U.S. 1/2-inch copper?
U.S. 1/2-inch nominal copper is 5/8-inch OD, or 0.625 inch. Identify a ring and fitting specified for that OD and approved for the tube and service. A sleeve marked 1/2-inch OD corresponds to a different physical tube dimension.
For the BrassCraft stop discussed here, the copper inlet instructions specify Type L or M. Do not extend the application to Type K or another material solely because the outside diameter matches.
Why will a 1/2-inch compression sleeve not fit my half-inch pipe?
The sleeve label may refer to actual tube OD while your copper pipe label refers to nominal size. Actual 1/2-inch OD is 12.700 mm; U.S. 1/2-inch nominal copper is 15.875 mm outside. Confirm which label you have before ordering another sleeve.
Measure sound bare tube rather than the nut or the old compressed ring. An unusually large or small reading on damaged tube is a reason to inspect the tube, not to force a ring into place.
Is 15 mm the same as 5/8 inch?
No. Five eighths of an inch is 15.875 mm, so the diameter differs by 0.875 mm. This calculation is not an interchangeability approval. Use a fitting specified for the measured tube, or a maker-documented adapter for the exact standards involved.
Conex’s 15 mm / legacy half-inch entry concerns BS 659 tube. It must not be read as an exception for U.S. 1/2-inch nominal copper.
Is a 22 mm olive interchangeable with 7/8 inch?
Seven eighths of an inch is 22.225 mm. That is 0.225 mm larger than 22 mm, and closeness alone does not approve a shared olive. Match the tube standard and fitting maker’s parts.
Conex specifies a special replacement ring when adapting its 22 mm fitting to the named legacy 3/4-inch BS 659 tube. That is a specific adaptation, not a universal metric-to-inch replacement rule.
Should I measure the tube, nut or old ring?
Measure the outside diameter of sound, bare tube. Nut width identifies wrench size; nut threads need maker data to identify the connection. Neither is the tube diameter. An old compressed ring has also changed shape and can conceal the tube beneath it.
A loose sleeve’s bore is also different from its stated tube size because the sleeve must slide onto the tube before compression. Use the maker’s tube-size designation and matching fitting family; a rough measurement of a used ring cannot establish both.
Can I reuse the ferrule when replacing a shutoff valve?
Do not assume an old ring and nut match a replacement valve because the threads engage. Use the valve maker’s documented matching components; obtain explicit compatibility guidance if retaining the ring is necessary. Shut off water and release pressure before taking the connection apart.
Some other systems allow reassembly. Swagelok describes a procedure for its preswaged ferrules, but that procedure does not authorize reuse in an unidentified household stop.
Can a different brand’s nut and ferrule fit my valve?
Matching tube OD and engaging threads are insufficient proof. The nut must load the correct ring against the intended seat. Get the fitting maker’s written compatibility information or use the specified matching parts.
Swagelok explicitly prohibits mixing or interchanging its parts with other manufacturers’ parts. Keep that rule attached to its system rather than assuming similar-looking ferrules are interchangeable.
Does plastic or PEX tubing need an insert?
Follow the exact fitting’s instructions and tube approval. BrassCraft 225.01 specifies a brass sleeve and stainless insert for PEX at 1/2-inch OD and larger; for 3/8-inch OD and smaller it specifies a plastic sleeve without an insert.
The G2 submittal also limits its PEX application to parts containing PXX. A size-dependent instruction in the general fitting sheet does not approve G2CR19X CM5 for PEX. If the exact model instructions are unclear, ask BrassCraft before assembly.
Should compression threads have PTFE tape?
BrassCraft’s water-stop compression instructions prohibit thread-seal tape, putty and gasket material. They allow an optional thin coat of permitted thread sealant on male compression threads only, away from the ring and sealing surface.
That is not permission to cover an olive with sealant or compensate for a wrong size. Identify the actual leak location with the water off before adjusting or replacing the connection.
How we pick and check the sizes
Why trust this guide
Isaac Daniels, a licensed journeyman plumber in Georgia, is responsible for PlumbingPicks. The size relationships come from BrassCraft and Conex documents. We keep their product-specific restrictions with each connection instead of applying one rule to every ferrule.
How we pick
We read the maker’s conversion chart, submittals and assembly instructions, then matched the offered model to those documents. Our choices serve three jobs: replacing a compatible copper stop, making a square tube cut and deburring it. They don’t compete, so none is scored.
We re-read the Amazon offers on Oct 22, 2026, 7:40 AM EDT. All three were new: the valve from Jam E-Solutions LLC with 8 left, the cutter and the reamer from Amazon.com, in stock. Availability can change.
| Check | Rule | Result for these choices |
|---|---|---|
| Size identification | Match tube OD and fitting family | Copper stop inlet identified separately from outlet |
| Maker match | Exact maker model must exist | G2CR19X CM5 configuration, RIDGID 40617 / 101 and RIDGID 29983 / 223S verified |
| Application | Keep tube and service restrictions | Type L/M copper stop; cutter capacity stated separately |
| Offer | New genuine branded model, in stock at the dated check | Valve stock limited; cutter and reamer in stock on Oct 22, 2026 |
| Scoring | Only score genuinely comparable items by one published formula | No score: a valve, a cutter and a reamer do different jobs |
A loose sleeve matching 5/8-inch OD still needs approval for the tube material, fitting seat and water service. BrassCraft’s copper-stop instruction is narrower than a generic size label: Type L or M copper only. Ask the fitting maker for compatibility information when its documentation does not resolve the application.
The selected G2 stop is specified for accessible locations. That restriction still applies if the tube measures the correct 5/8-inch OD. If the proposed repair goes behind a finished wall or serves an unfamiliar system, have a plumber confirm the permitted connection before buying.
Sources
- BrassCraft, Nominal/O.D. conversion chart, p.1; U.S. copper nominal-to-OD relationships. Read October 20, 2026.
- BrassCraft, G2CR09/19/39X quarter-turn angle stop product submittal 400.50, Rev.9.25, pp.1–2; limits, PXX restriction and connection sizes.
- BrassCraft, G2CR19 product configurations and specifications, 12-in-nom-comp-x-38-in-o-d-comp-2; CM5 configuration. Read October 20, 2026.
- BrassCraft, Water Supply Stops Installation Instructions 425.04, Rev.11/19; copper compression inlet p.1, copper outlet pp.2–3, safety and sealant instructions.
- BrassCraft, Compression Fittings Installation Instructions 225.01, Rev.3/20, p.1; tube condition, assembly order, PEX sleeves/inserts, two wrenches and gas prohibition.
- Conex Bänninger, Compression Technical Brochure TB/UK/V2/17.02.2025, sections 1.2, 1.5 and 1.9, printed pp.1–3, and ring catalogue p.35; olive terminology, liners, metric sizes and BS 659 adaptation.
- Swagelok, Tube Fitting Instructions MS-12-01, March 2021 Rev.F, English page; reassembly, depressurization, inspection gauge and no-mixing cautions.
- RIDGID, Close Quarters Tubing Cutters, ordering table for catalogue 40617 Model 101; 1/4–1-1/8-inch capacity. Read October 20, 2026.
- RIDGID, Model 223S inner/outer reamer, catalogue 29983: ¼–1¼-inch OD capacity, 45 cutting edges, copper and stainless. ridgid.com.
- Amazon Creators API, offer reads October 20, 2026 and Oct 22, 2026, 7:40 AM EDT (B07Z2XX2M2, B001P307PO, B001P81OKG), search read 12:44 EDT and image read 13:03:50 EDT; model titles, sellers, New condition and availability.
- Calculated size conversions use 25.4 millimetres per inch; rounded metric-to-inch figures are identified in the chart. These calculations do not establish fitting tolerances.