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Work order — Smith & Wesson Model 642

Taking the firearm apart for a job such as refinishing, and putting it back together to specification. Generated from the Pew-Takedown entry last updated 2026-10-29. Confidence: medium.

Shop difficulty: Tier 2 of 3

J-frame Airweight: no hammer block (shrouded hammer) and fewer parts than a K-frame, but a stiff rebound slide spring on a steel stud pressed into an aluminum frame that is easy to damage, plus an uncaptured MIM hand spring. Moderate. 57 parts (stand-in: S&W Model 38 Bodyguard Airweight (alloy-frame J-frame .38, shrouded hammer) factory Parts Price Schedule, View # 1-57. Assembly lines (8-10, 20-26, 40-41, 45-47, 51-55) have no number of the). Pew-Takedown's rating, not the manufacturer's.

Bench time: strip ~35 min, rebuild ~55 min (estimate). Actual: strip ______ rebuild ______

Special tools:

• Rebound slide spring tool (Brownells S&W tool) or a Phillips screwdriver just larger than the spring ID — Compressing and re-seating the rebound slide spring over its stud
• Fitted hollow-ground (gunsmith) screwdrivers — Sideplate, strain, thumbpiece and stock screws without burring
• Nylon/brass or rawhide mallet — Tapping the frame to lift a tight sideplate
• Large clear plastic bag — Containing the rebound spring and small springs on removal

Watch for:

• The J-frame rebound slide spring is stiff and tends to take flight whichever tool is used. (both; Smith & Wesson Forum)
• On the aluminum frame the rebound slide stud is a steel pin pressed into aluminum and can crack loose if forced while the spring is worked. (both; Shooting Times)
• On MIM-trigger 442/642s the hand spring fits differently and is frustrating to refit without knowing the layout. (reassembly; Smith & Wesson Forum)
• Smith & Wesson tells owners not to go beyond the field strip; lockwork work is for a qualified gunsmith. (both; Smith & Wesson)

Tools

• Hollow-ground gunsmith screwdriver — The yoke retaining screw. A tapered hardware-store blade will burr the screw head permanently.

1. Clear and make safe

Manufacturer's video: Unloading & Reloading Revolvers (Smith & Wesson)
https://www.youtube.com/watch?v=A88dQCkTllA

1. Point the muzzle in a safe direction and keep your finger off the trigger.
2. Push the thumbpiece forward and swing the cylinder out.
3. Press the ejector rod firmly to eject all cartridges or cases from the chambers.
   Tip: Point the muzzle up and strike the rod briskly so the cases clear fully.
4. Look through every chamber, one at a time, and confirm each is empty.
   Warning: Every chamber, counted. A revolver with one loaded chamber looks identical to an empty one from most angles.
5. Confirm the bore is clear of obstruction.
6. Remove all live ammunition from the work area.

2. Disassemble

Routine cleaning (what Smith & Wesson documents)

1. Complete the Clear and Make Safe procedure and leave the cylinder swung out.
2. Clean the bore and each chamber with a solvent-wetted patch and bronze brush, then dry patches until they come out clean.
3. Clean the front face of the cylinder, the forcing cone, and the recoil shield, where fouling and lead build up fastest.
4. Under NO circumstances clean the chambers or the front face of a titanium-alloy cylinder with an abrasive — no sandpaper, no Scotch-Brite, no crocus cloth.
   Warning: Abrasives disrupt the cylinder's protective surface layer. S&W states this greatly reduces service life through erosion during firing, and voids the warranty.
   Tip: Normal gun cleaning with good oil and solvent is all a titanium cylinder needs.
5. Restrict your choice of solvent to products made for firearms, and avoid prolonged solvent immersion or ultrasonic cleaning — S&W records finish damage from both.
   Warning: Never use ammoniated or other strong alkaline solvents on a Smith & Wesson.
   Tip: S&W's rule of thumb: if you would be happy putting it on your car's paint, it is probably safe on the gun.
6. Come back in 24 to 48 hours. Residue works its way out of the barrel and chambers after the first clean; remove it with a bristle brush and a light re-application of solvent, then re-oil.
7. Apply a light film of good gun oil to all external metal surfaces and wipe clean. In cold climates use an oil that will not thicken.

Yoke and cylinder removal (not documented by S&W)

1. Read this first: Smith & Wesson does not publish this procedure. It is common gunsmith and armorer practice, recorded here because people do it, not because S&W sanctions it.
   Warning: S&W's manual directs additional maintenance to a qualified gunsmith. The wrong screwdriver on a sideplate screw marks the frame permanently.
2. Complete the Clear and Make Safe procedure and leave the cylinder open.
3. Identify the yoke retaining screw — the forward-most sideplate screw on the right side of the frame, ahead of the trigger.
   Tip: Screw positions differ across frame sizes and eras. Confirm against a parts diagram for your exact model before turning anything. The model and internal serial numbers are stamped inside the yoke, visible with the cylinder open.
4. Using a properly fitting hollow-ground screwdriver, remove the yoke retaining screw.
5. Draw the yoke and cylinder assembly forward and out of the frame as a unit.
6. Clean the yoke bearing surfaces and the inside of the cylinder's bore, then reverse the order to reassemble.
7. Never attempt to remove a hybrid aluminium/stainless barrel assembly with a standard barrel wrench.
   Warning: S&W states this will destroy the barrel shroud and possibly the frame. The shroud is keyed into the frame by a metal tab. Only a gunsmith with S&W's special tool should remove it, and it is reinstalled torqued to 20 ft-lb.
8. Go no further. Removing the sideplate to reach the lockwork is genuinely gunsmith territory, and prying it off rather than tapping the grip frame will bend it.

3. Refinish

The components the procedures above separate. Coating, masking and cure are outside this database; follow your coating system's instructions. A part the manufacturer marks "factory fit" should not be swapped or reworked.

Labelled parts in the manufacturer's documents:

• Model and features identification (labelled photo of the revolver) — Smith & Wesson Revolvers (Modern Style) Safety & Instruction Manual, p. 14
  https://www.mcarbo.com/.Owners%20Manuals/S-W_Revolver_Owners-Manual.pdf#page=14

4. Reassemble

Yoke and cylinder removal (not documented by S&W)

1. Reverse the steps of "Yoke and cylinder removal (not documented by S&W)".

Reassembly

1. Slide the yoke and cylinder assembly back into the frame, seating the yoke fully in its frame cut.
2. Start the yoke retaining screw by hand, then tighten it snugly with the correct screwdriver.
   Warning: Do not overtighten.
3. Close the cylinder gently by hand.
   Warning: Never flick the cylinder closed — it springs the yoke and puts the revolver out of time.
4. Perform the function check.

5. Torque

No manufacturer torque values are recorded for this firearm.

Notes: The manufacturer's documents give no torque value. They say: "The barrel assembly is re-installed using the same tool and an accurate torque wrench." (Safety & Instruction Manual, Revolvers - Modern Style - J, K, L and N Frame (p/n 416560000, REV S&W_REVOLVER_112119), linked from smith-wesson.com revolver product pages, p. 26 (Gunsmith Advisory))

Fit or check on rebuild

• Timing / carry-up: each chamber must lock before the hammer falls, single and double action — The hand torsion spring must engage the hand; a hand pulled back too far loses spring tension and the cylinder will not index.
• Cylinder gap (barrel-cylinder) and end shake; crane alignment — The Army issues gauges for exactly these checks when the cylinder/yoke group is replaced.
• Firing-pin (hammer-nose) protrusion and hammer-block function — Same TM lists a firing-pin protrusion gauge; the hammer block must ride up on the rebound slide pin before the sideplate goes on.
• Sideplate seats flush with no forcing; strain screw fully tightened — A sideplate that is not flush binds the grips and parts behind it; a backed-out strain screw gives light strikes (well-known S&W check).
• Trigger reset with the rebound spring fitted — The rebound slide spring is also the trigger return spring.
• Rebound slide stud tight in the aluminum frame — The stud is pressed into aluminum and can loosen or crack during spring work.

6. Function check

• Verify every chamber is empty before each check.
• Cock the hammer slowly and confirm the cylinder locks up at each chamber before the hammer reaches full cock — this is carry-up.
• With the hammer at full cock, try to rotate the cylinder by hand. It should be locked, with only minimal play.
• Press the trigger in single action and confirm a clean hammer fall.
• Cycle the action in double action through every chamber and confirm the cylinder indexes and locks each time.
• Confirm the cylinder latches closed securely and the release frees it cleanly.
• Check that cylinder endshake is minimal and the cylinder gap looks even. If either seems off, see a gunsmith.

If any check fails, the firearm is not safe to fire. Stop and see a licensed gunsmith.

Sources

1. Smith & Wesson Revolvers (Modern Style) Safety & Instruction Manual — Smith & Wesson primary
   https://www.mcarbo.com/.Owners%20Manuals/S-W_Revolver_Owners-Manual.pdf
2. Safety & Instruction Manual, Revolvers - Modern Style - J, K, L and N Frame (p/n 416560000, REV S&W_REVOLVER_112119), linked from smith-wesson.com revolver product pages — Smith & Wesson primary
   https://smith-wesson.canto.com/direct/document/tquc8lb05d2hl96gi51fuh2m46/2Ppiam-m3ty8iZtHw_DoQfTzAsI/original?content-type=application%2Fpdf
3. Smith & Wesson Model 642 — product specifications, SKU 163810 — Smith & Wesson Brands, Inc. primary
   https://www.smith-wesson.com/product/model-642
4. Virtual Patent Marking | Smith & Wesson — Smith & Wesson primary
   https://www.smith-wesson.com/company/virtual-patent-marking
5. J frame sideplate removal — Smith & Wesson Forum anecdotal
   https://smith-wessonforum.com/threads/j-frame-sideplate-removal.205737/
6. Do-It-Yourself Smith & Wesson J-Frame Trigger Job: How-To — Shooting Times secondary
   https://www.shootingtimes.com/editorial/diy-smith-wesson-j-frame-trigger-job/473688
7. How does the hand spring fit on 442/642 — Smith & Wesson Forum anecdotal
   https://smith-wessonforum.com/threads/how-does-the-hand-spring-fit-on-442-642.89800/
8. Change of a 686 rebound spring — Smith & Wesson Forum anecdotal
   https://smith-wessonforum.com/threads/change-of-a-686-rebound-spring.330582
9. Installing Smith & Wesson Spring Kit — Shooting Times secondary
   https://www.shootingtimes.com/editorial/gunsmithing_st_installswspringkit_200812/100181
10. Smith & Wesson Model 38 (Bodyguard Airweight) - factory Parts Price Schedule, View # 1-57 (scanned image; exploded view at SW38.jpg) — Smith & Wesson (factory sheet), scan hosted by CFN Parts primary
    https://cfnparts.com/image/catalog/products/data/Instruction%20Manuals/SmithWesson/SW38PL.jpg

Educational guide only. Some information comes from non-authoritative sources. Always consult your manufacturer's manual and a licensed gunsmith. Verify your firearm is unloaded before every procedure. Full disclaimer: https://github.com/Fundamental-build-LLC/Pew-Takedown

Legal notice: this material is third-party information compiled from sources of varying reliability and is provided for general informational and educational purposes only. It is not gunsmithing, technical, safety or legal advice, it is not verified or endorsed by any manufacturer, and it must not be taken as fact. Any work on a firearm beyond the routine field stripping described in its own owner's manual should be performed only by a licensed and insured gunsmith. You use this material entirely at your own risk. Fundamental Build LLC and the project's contributors make no warranty of any kind and accept no liability for death, injury, damage or loss arising from its use. Full terms: LEGAL.md.