Fitting extractor to slide - details
Part 2 - shims
A well fit extractor will not move fore and aft. If it does, the critical hook-to-breechface distance will change during firing which can result in feeding malfunctions. A well fit extractor will not rotate in its tunnel. If it does, the angle of the tensioning wall will change relative to the horizontal plane of the pistol as the case moves down the breechface when the barrel unlocks and drops after firing a round. This can result in erratic ejection, empty case stovepipes, hot brass to the face, etc.
The previous post covered fitting the firing pin stop to the slide. Here we will explore how to prevent the extractor from clocking as well as preventing it from moving fore and aft. A few years ago parts manufacturers (
EGW,
Harrison) began offering extractors that had no FPS slot in them. This allowed professional 1911 'smiths to cut the slot to the exact size and location they wanted to lock the extractor in place. However, many of the top professional 1911 'smiths prefer using shims to accomplish the same result.
HOOK - TO - BREECHFACE DISTANCE
Preliminary information
HTBD =
Hook-
To-
Breechface
Distance
FPS =
Firing
Pin
Stop
The following dimensions and details are based on fitting a .45 extractor. Dimensions for other calibers can be found in previous posts.
The HTBD of the extractor must be no less than .075" and no more than .085". Most extractors will be too long for a specific slide (HTBD greater than ..085") but occasionally you will run across one that is too short (HTBD less than .075"). The closer the hook is to .075" the less likely it will be to contact the case bevel and the less material will need to be removed from the nose to clear the case bevel.
If the FPS extractor slot cannot be relieved enough by filing to correct the HTBD, a shim can be used. Before we make a shim, we need to know how thick it needs to be and where to put it. That is detailed in Steve's extractor tuning article above and is directly related to the HTBD.
Where does the shim go and how thick should it be
Example #1 - If your extractor's HTBD is .090" (too long), you would place a .015" thick shim on the back wall and file the front wall to move the extractor rearward to get an HTBD of .075"
Example #2 - if your extractor's HTBD is .065" (too short), you would place a .010" thick shim on the front wall and file the back wall to move the extractor forward to get the minimum HTBD of .075".
Remember, the FPS must fit the extractor slot snugly no matter what thickness of shim you use.
Shim material
You can use steel or brass shim stock of the correct thickness or get a set of feeler gauges. Brass stock works easier than steel, it is easier to cut, file, and sand. Plus you can use scissors to cut it out which is easier than using snips on steel.
Making a shim
Method #1
Cut a piece of shim material out, hold it against the part of the extractor where you need the shim to go, and use a marker to get the rough outline. You may need three hands so get a pal to help, use a small pair of needle nose locking pliers to hold the edge of the material, or you can literally superglue it in place and then mark it. It doesn't have to be perfectly sized, just close so you can file/sand it to fit.
Method #2
I used an
old extractor and super glued the new shim to the back wall so I could shape the shim. I used emery cloth and a small flat file to carefully shape the overhanging edge of the new shim until it matched the contour of the extractor. That way you don't scratch up a new extractor with files and emery paper. You CAN use the
new extractor to do this of course and use some 1000 grit to smooth everything. Either way will work.
I used a small bench grinder to rough shape a steel one. No need for that if you use brass. But if you use steel shims and can gently work it against a grinder you can indeed make it work. Use those same locking pliers to hold onto an edge and then finish it off with snips. The resulting shim before shaping is still pretty small and if you need to flatten it out/straighten it, you can use the flat large end of a brass punch to press it onto a flat surface. Do not beat it with a hammer as that will make it thinner and ruin your measured thickness. The flatness is needed to match up to the extractor wall when you glue it.
Method #2 . . . continued
Rough shaping the shim that was glued to the extractor was done using a a flat file. It is easy to feel the difference between the brass and the steel as you file. Go easy, you don't want to mar the steel extractor, just match the shape of the shim to the profile of the extractor wall. You don't want the shim to overhang the extractor or it will interfere when inserting it into the tunnel.
This is the shim ready to go. Now pry it off carefully with a thin edge, a pocket knife perhaps, and glue it to your extractor that you will be installing in the pistol.
Filing the front or back wall of the extractor's firing pin stop slot
Time to fit your newly shimmed extractor to the FPS. If you added a .010" shim, you'll need to remove about the same from the opposite wall of the FPS extractor slot. In this case I shimmed the rear wall and will reduce the front wall because I am pulling the extractor back to reduce the HTBD. My original HTBD was in excess of .085" so a .010" shim will result in a tad more than a .075" HTBD but well within the min/max parameters.
You'll need to use a flat file with a safe edge. Position the flat edge down against the bottom wall of the extractor. Keep the file square as you remove material. Check your progress frequently using the FPS! You can use a black marker to mark every cycle so you can see that you are evenly removing material. I also used my calipers to check how much I was removing. In my case the width of the extractor FPS slot measured .083" and the FPS thickness measured .096" so I needed to remove ~.013". Do not go purely by this number though . . . check the fit of the FPS as you go.
One tip is to watch the bottom wall as you file. As covered in the previous post, make sure the edges of the FPS are rounded so that it will not be prevented from sitting flush against the all three slot walls.
Don't over file the vertical part of the wall. By the time you get the FPS to fit into the extractor while it is in the tunnel, you may create a bit of slop front to back if you get too aggressive. You don't want any slop as this will allow the extractor to move slightly fore and aft which defeats the whole purpose of fitting the new FPS.
You check this by installing the extractor in the tunnel and making sure that the front and back wall of the extractor FPS slot lines up with the walls of the slide with the extractor in the tunnel. They should match basically perfect. Test this also by making sure the FPS, once it will fit into the extractor slot, sits flat to the bottom wall.
There is no way I can justify the expense of a TIG just to diddle with extractors. So a way to deal with extractor [hook-to-breechface distance] and clocking without welding is a god-send.
Once the extractor with its newly glued shim is installed, it will be captive and cannot fall out. The extractor tunnel, FPS, and FPS slot will hold the shim in place if the glue loosens. You will need to be careful taking the extractor out and re-glue it if needed.
@Oldpistol has spoken to me about silver brazing the shim permanently in place and provided me with some parts and education, but that may take me a bit and I will address it in a future article or add on.
Checking the final fit
Once you have the FPS where it is snug and able to be installed by hand, measure the HTBD. It should now be reduced by the amount of the shim you created way back at the beginning. I measured using my home made gauges and I got the .075" gauge to slide just under the hook without forcing it. Perfect! My .466" gauge also slides between the extractor tensioning wall and the opposite guide block with a tiny bit of touching. Perfect! Now it is time to go shoot and test!
CLOCKING
A less likely to be needed shim, particularly if you're fitting an oversized FPS such as one from
EGW that has been snugly fit to the slide, is a shim to eliminate clocking. Since I have not yet figured out how to measure the gap between the installed FPS and the back wall of the extractor FPS slot, it is a trial and error process in which shims of various thicknesses are cut then test fit with the shim, extractor, and FPS assembled together in the slide.
TOOL LIST & SUMMARY
In the remaining pictures you can see my homemade gauges made from a stack of feeler gauges. I used the cutout four to use for measuring HTBD. The first three measure .075" and if I use the last three that is .085". Just take the four sizes you need to add up to whatever specific dimension you want to measure and put them in order. I cut them out thinner so they would slide under the hook without hitting the left guide block.
The single big one is shaved down to measure .466" wide and is used to measure deflection by sliding it between the tensioning wall of the extractor and the left guide block.
Here are the tools I used:
- 6pc gunsmith file set
- small locking needle nose pliers
- small snips/cutters
- emery cloth
- 800gr and 1000gr paper
- krazy glue
- digital calipers
- my homemade gauges
I’d like to thank
everyone involved in the forum that offered advice and personal experience. Steve helped co-author this post on shimming and fitting as I conversed with him and many others including
@cavelamb @log man @Oldpistol . From expert gunsmiths to lowly first timers that take the chance to try! Here are the resources I found that inspired me and got me to start working on 1911’s. I have only traveled inches and I have miles and miles to go.
Steve in Allentown Extractor fitting
Log Man's post on fitting an oversized FPS