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Posted: 1/27/2016 2:31:50 PM EDT
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Gentleman ,
looking for some insight on how to mill the safety detent hole & what size{s} drill bit to use . Is there a specific jig for this task ? Also what size drill bit will be needed for the roll pin hole in regards to the trigger guard ? Is there a specific jig for this task as well ? Any insight would be greatly appreciated . |
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I have not seen any 80% lowers that require you to drill the features you ask about, or any jigs that have those holes.
The CNC Guns jig has the most extra features in it to complete his 20% lowers. The safety detent hole is stepped (Two diameters) so dont just drill it straight through if you do need to drill this feature. |
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Quoted: Gentleman ,
looking for some insight on how to mill the safety detent hole & what size{s} drill bit to use . Is there a specific jig for this task ? Also what size drill bit will be needed for the roll pin hole in regards to the trigger guard ? Is there a specific jig for this task as well ? Any insight would be greatly appreciated . Any "80%" should have those holes already drilled. Or are you starting from a "0%" raw forging? |
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Lots of info here Check Here First which is tacked at the top of the BIY forum
and here 0% Forging which covers everything for machining every part of the lower receiver. |
| There are only three holes for the trigger guard, two in the back for the roll pin and one for the detent in the trigger guard, it goes in the right front side. Dont drill the hole all of the way through the left front side, it wont hurt anything but will just be an extra hole in your gun that is not supposed to be there. |
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Quoted:
Here is an excerp from Ray-Vin's PDF on completing a 0% lowers.. http://photos.imageevent.com/scl_electronics/cfguns/ar15/websize/image.jpeg hth, Ca_Longshot If you actually read the drawing, the distance is .199" from the bottom of the shelf to the bottom of the .156" hole. Not that is going to make that much difference... |
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Quoted:
If you actually read the drawing, the distance is .199" from the bottom of the shelf to the bottom of the .156" hole. Not that is going to make that much difference... Using the previous post blueprint piece... Here is another piece.. 
So 1.316" - 1.128" = .188" from the grip shelf to the bottom of the .156' hole... Ca_Longshot |
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Quoted:
Using the previous post blueprint piece... Here is another piece.. http://photos.imageevent.com/scl_electronics/cfguns/ar15/websize/Safety%20detent.jpg So 1.316" - 1.128" = .188" from the grip shelf to the bottom of the .156' hole... Ca_Longshot Quoted:
Quoted:
If you actually read the drawing, the distance is .199" from the bottom of the shelf to the bottom of the .156" hole. Not that is going to make that much difference... Using the previous post blueprint piece... Here is another piece.. http://photos.imageevent.com/scl_electronics/cfguns/ar15/websize/Safety%20detent.jpg So 1.316" - 1.128" = .188" from the grip shelf to the bottom of the .156' hole... Ca_Longshot Your section D-D is wrong. From Rock Island Drawing 8448608 (19204). From the top deck to the top of the grip shelf is 1.328" (View #4). From the top deck to the centerline of the pivot pin is .250" (View #3). From the centerline of the pivot to the center of the hammer pin hole is .375" (View #2), and from the center of the hammer pin to the center of the safety hole is .089" (.314 - .225 = .089) so the distance from the top deck to the center of the safety hole is .714". (.250 + .375 + .089 = .714) From the center of the safety hole to the top of the .156" detent hole is .405" (View #1, Section D-D), so from the top deck to the top of the .156 detent hole is 1.119" (.405 + .714 = 1.119) Subtract that from the top deck to the top of the grip shelf = .199 (1.318 - 1.119 = .199) 
But, you can see that the tolerance in the .405" dimension is +/- 0.010", so using .188" is only .001" out of spec. It won't affect anything. Actually, if you throw in all the other tolerances, the depth of the .156" diameter detent hole can be as deep as .219" or as shallow as .174".... but, the important dimension is the length of the .125" hole, it should start at .405 +/- .010" from the center of the safety hole. |
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There is another error in this drawing that I see... It has the 1.968", .375" and .225" dimensions listed as "reference dimensions" [notated in a box], these are not reference dimensions, these are "actual dimensions". A "reference dimension" is a dimension on a drawing that is given for convenience, but the actual location is located by calculation. An "actual dimension" is located by measuring from a datum line or datum surface, and should have a tolerance associated with them... |
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Quoted:
Your section D-D is wrong. From Rock Island Drawing 8448608 (19204). From the top deck to the top of the grip shelf is 1.328" (View #4). From the top deck to the centerline of the pivot pin is .250" (View #3). From the centerline of the pivot to the center of the hammer pin hole is .375" (View #2), and from the center of the hammer pin to the center of the safety hole is .089" (.314 - .225 = .089) so the distance from the top deck to the center of the safety hole is .714". (.250 + .375 + .089 = .714) From the center of the safety hole to the top of the .156" detent hole is .405" (View #1, Section D-D), so from the top deck to the top of the .156 detent hole is 1.119" (.405 + .714 = 1.119) Subtract that from the top deck to the top of the grip shelf = .199 (1.318 - 1.119 = .199) http://i2.photobucket.com/albums/y9/lysanderxiii/Untitled_zpsyml8xxly.png http://i2.photobucket.com/albums/y9/lysanderxiii/Untitled2_zpsirggxki1.png http://i2.photobucket.com/albums/y9/lysanderxiii/Untitled2_zpse6bezvxo.png http://i2.photobucket.com/albums/y9/lysanderxiii/Untitled2_zpsyllbpcs4.png But, you can see that the tolerance in the .405" dimension is +/- 0.010", so using .188" is only .001" out of spec. It won't affect anything. Actually, if you throw in all the other tolerances, the depth of the .156" diameter detent hole can be as deep as .219" or as shallow as .174".... but, the important dimension is the length of the .125" hole, it should start at .405 +/- .010" from the center of the safety hole. Quoted:
Quoted:
Quoted:
If you actually read the drawing, the distance is .199" from the bottom of the shelf to the bottom of the .156" hole. Not that is going to make that much difference... Using the previous post blueprint piece... Here is another piece.. http://photos.imageevent.com/scl_electronics/cfguns/ar15/websize/Safety%20detent.jpg So 1.316" - 1.128" = .188" from the grip shelf to the bottom of the .156' hole... Ca_Longshot Your section D-D is wrong. From Rock Island Drawing 8448608 (19204). From the top deck to the top of the grip shelf is 1.328" (View #4). From the top deck to the centerline of the pivot pin is .250" (View #3). From the centerline of the pivot to the center of the hammer pin hole is .375" (View #2), and from the center of the hammer pin to the center of the safety hole is .089" (.314 - .225 = .089) so the distance from the top deck to the center of the safety hole is .714". (.250 + .375 + .089 = .714) From the center of the safety hole to the top of the .156" detent hole is .405" (View #1, Section D-D), so from the top deck to the top of the .156 detent hole is 1.119" (.405 + .714 = 1.119) Subtract that from the top deck to the top of the grip shelf = .199 (1.318 - 1.119 = .199) http://i2.photobucket.com/albums/y9/lysanderxiii/Untitled_zpsyml8xxly.png http://i2.photobucket.com/albums/y9/lysanderxiii/Untitled2_zpsirggxki1.png http://i2.photobucket.com/albums/y9/lysanderxiii/Untitled2_zpse6bezvxo.png http://i2.photobucket.com/albums/y9/lysanderxiii/Untitled2_zpsyllbpcs4.png But, you can see that the tolerance in the .405" dimension is +/- 0.010", so using .188" is only .001" out of spec. It won't affect anything. Actually, if you throw in all the other tolerances, the depth of the .156" diameter detent hole can be as deep as .219" or as shallow as .174".... but, the important dimension is the length of the .125" hole, it should start at .405 +/- .010" from the center of the safety hole. Any idea on where I could find that entire print set? I'd like to make some wall sized posters to frame and display in the office. Thanks Wes |
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Quoted:
Any idea on where I could find that entire print set? I'd like to make some wall sized posters to frame and display in the office. Thanks Wes Nice and big, original Rock Island prints |
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