Fix My Glock: Difference between revisions

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* the frames are relatively easy to print
* the frames are relatively easy to print


Despite the brilliant simplicity of the design, it's still a precision machine that relies on well made parts, correct assembly, and maintenance of precise tolerances. Beginners expecting a "cookbook" build often find themselves with a malfunctioning gun and no idea how to fix it. This guide  
Despite the brilliant simplicity of the design, it's still a precision machine that relies on well made parts, correct assembly, and maintenance of precise tolerances. Beginners expecting a "cookbook" build often find themselves with a malfunctioning gun and no idea how to fix it. While this guide can help you find problems in a completed build, it's main focus is helping you not encounter those problems in the first place.
 
This guide is not meant to provide "quick fix" answers. If you have the attention span of a coked-out squirrel, consider purchasing a mass-produced Glock. Law Enforcement "trade-in" Glocks are widely available at prices significantly cheaper than buying all the parts for a build. However, if you're willing to take a methodical and detail-oriented approach, read on ...


== Troubleshooting Your Print ==
== Troubleshooting Your Print ==
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** Con: Support scars are on "visible" areas of the completed frame. Not a big disadvantage with tuned support interfaces.
** Con: Support scars are on "visible" areas of the completed frame. Not a big disadvantage with tuned support interfaces.
* Angle: Horizontal (rails parallel to build plate). This is the correct orientation for both rails-up and rails-down prints. Do ''NOT'' angle the frame up or down. Layer adhesion strength is directly proportional to layer surface area. Angled printing reduces layer surface area in critical places like the front rail and locking block pin holes. "Intuitive" arguments in favor of angled layers opposing the direction of frame stress are provably incorrect.
* Angle: Horizontal (rails parallel to build plate). This is the correct orientation for both rails-up and rails-down prints. Do ''NOT'' angle the frame up or down. Layer adhesion strength is directly proportional to layer surface area. Angled printing reduces layer surface area in critical places like the front rail and locking block pin holes. "Intuitive" arguments in favor of angled layers opposing the direction of frame stress are provably incorrect.
=== Calibration ===
You're going to be installing commercially manufactured parts in your frame so it's critical that your frame dimensions be correct. Many filaments have some amount of shrinkage as they cool. If you do not account for that, you may have difficulty fitting parts and/or getting the build to function. The solution is using a calibration print to measure dimensional changes and adjust scaling factors in the slicer. There are many tools available -- from [https://www.thingiverse.com/thing:1278865 simple calibration cubes] to complex designs like [https://vector3d.shop/products/califlower-calibration-tool-mk2 Califlower] and [https://vector3d.shop/products/calilantern-calibration Calilantern]. The infamous [https://www.3dbenchy.com/ 3D Benchy] is actually a calibration tool with detailed measuring instructions on the website.
In all cases, you need to print the calibration tool with the same settings you plan to use for your Glock frame. Changing things like infill or number of walls to speed up the print may give you incorrect results. Take measurements on your calibration print using a set of calipers that are accurate to at least 0.1mm. Inexpensive Chinese digital calipers like you can find at Harbor Freight are usually good enough.
If you have a Prusa-derived slicer (Prusa, Bambu, Orca, etc.) you will compute ((actual / expected) x 100) and use that for "Shrinkage" in the filament settings in your slicer. Some slicers have separate Shrinkage settings for XY and Z dimensions, so use appropriate measurements for each.
It is also recommended that you tune flow ratio since that can have a significant effect on strength. [https://ellis3dp.com/Print-Tuning-Guide Ellis' Print Tuning Guide] has a section on "Extrusion Multiplier" tuning that covers this. Ideally, you should run all the calibration tests in Ellis' guide, but shrinkage and flow ratio are usually enough to get a usable frame print.
=== Pin Holes ===
The four pin holes (front rail, trigger, locking block, rear rail/trigger housing) give many people grief. Even with good printer calibration, these holes will often print just slightly undersize. Designs keep the tolerances on these tight because you can always make the holes larger, but it's pretty hard to make them smaller. Always test fit pins before assembly. The pins should fit snug, but not tight. Installing the pins with any significant amount of force will lead to frame failure. If it doesn't immediately crack the frame, it will create stress that significantly weakens the frame around the pin holes.
If a light tap is not enough to get a pin through the hole, the hole must be enlarged. There are two recommended ways to do this:
# Use high-quality metric (3mm and 4mm) drill bits to cut the holes to the correct size. Do NOT use fractional inch sizes that are "approximately" the same. Do NOT use a power drill for this. Use a hand chuck or simply clamp the bit with Vise-Grip pliers so you can turn it by hand. Don't force it -- let the bit do the work. Work slowly and carefully to keep the hole straight and remove as little material as possible.
# Chuck the actual pin in a variable speed power drill. Align the pin with the hole in the frame and run the drill at low speed to "spin" the pin into the hole as though you were driving a screw. Friction will heat the polymer in the frame allowing it to deform to the exact size of the pin. Keep in mind that you do not want to actually liquefy the polymer, just get it hot enough to deform around the pin.
The second technique will produce the strongest holes, but takes a little more practice to get right.


== Troubleshooting Your Build ==
== Troubleshooting Your Build ==
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=== Troubleshooting Failures ===
=== Troubleshooting Failures ===
* Watch this video to better understand how the parts in the gun are supposed to function: https://youtu.be/y2fMRqFEEZI
* Watch this video to better understand how the parts in the gun are supposed to function: https://youtu.be/y2fMRqFEEZI
* Print an Armorer's Backplate (https://www.thingiverse.com/thing:3591065) so you can actually see what's going on with the trigger mechanism. This is particularly useful for troubleshooting firing pin engagement and trigger reset issues. '''''WARNING: NEVER FIRE LIVE-AMMUNITION WITH AN ARMORERS BACKPLATE INSTALLED!'''''
* Print an Armorer's Backplate (https://www.thingiverse.com/thing:3591065) so you can actually see what's going on with the trigger mechanism. This is particularly useful for troubleshooting firing pin engagement and trigger reset issues. '''''WARNING: NEVER FIRE LIVE AMMUNITION WITH AN ARMORERS BACKPLATE INSTALLED!'''''


=== Live-Fire Testing ===
=== Live-Fire Testing ===
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# Remove the magazine. Release and remove the slide. Inspect the frame carefully (magnification is recommended) and verify there are no cracks or other damage. Pay particular attention to the areas around the locking block and the magazine release.
# Remove the magazine. Release and remove the slide. Inspect the frame carefully (magnification is recommended) and verify there are no cracks or other damage. Pay particular attention to the areas around the locking block and the magazine release.
# Repeat the single round test 10 - 20 times, inspecting after each shot. If any frame damage is observed, stop immediately. If there are any failures (failure to fire, failure to feed, failure to eject, etc.) stop immediately and troubleshoot using dummy rounds. If testing is successful to this point, it should be safe to fire aimed shots from a normal stance in subsequent tests.
# Repeat the single round test 10 - 20 times, inspecting after each shot. If any frame damage is observed, stop immediately. If there are any failures (failure to fire, failure to feed, failure to eject, etc.) stop immediately and troubleshoot using dummy rounds. If testing is successful to this point, it should be safe to fire aimed shots from a normal stance in subsequent tests.
# Manually lock the slide in the rearward position using the slide release. Remove the magazine (if inserted).
# Load two rounds into the magazine. Insert the magazine and release the slide to chamber the first round. Press-check to verify the round was chambered.
# Fire one round. Take care to manage the recoil in case there is an uncommanded discharge of the second round. Verify the slide fully returns to battery and that the trigger resets. Press-check to verify the second round was chambered.
# Fire the second round. Verify the slide locks back on the empty magazine.
# Repeat the two-round test a few times to develop confidence in the gun's correct operation.
# Repeat the two-round test sequence but gradually increasing the number of rounds in the magazine. Watch for miss-feeds -- especially as the magazine starts to get near its full capacity.
# Upon completion of the sequence with a full magazine, remove the magazine and release and remove the slide. Inspect the frame carefully and verify there are no cracks or other damage.
# Mount the slide, load a full magazine and chamber the first round. Fire all rounds in succession at about a 1 - 2 second/round cadence. Do not exceed the pace that allows you to reacquire your sight picture after each shot. Verify no malfunctions and the slide locks back on the empty magazine.
# Repeat the full magazine test a few times. Verify no malfunctions.
# It should now be safe to use the gun for normal recreational shooting. Perform a fame inspection every 50 rounds for at least the first 200 rounds. After that, inspect every 200 rounds or after each range session (whichever comes sooner).


== Common Problems ==
== Common Problems ==
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* Video of the failure if it shows something happening
* Video of the failure if it shows something happening
* Not usually useful: photos of the fully assembled gun, photos without explanation/context, video of you racking the slide and/or pulling the trigger a dozen times in rapid succession (save the rapid hand movements for other things)
* Not usually useful: photos of the fully assembled gun, photos without explanation/context, video of you racking the slide and/or pulling the trigger a dozen times in rapid succession (save the rapid hand movements for other things)
[[Category:Guides]]