slamfire51
03-27-2011, 12:11 PM
Here is a pictorial of how I modify a gas tube. Your methods may vary.
STRIPPING A GAS TUBE
NOTE: THIS WHAT I CALL A REAR PIECE DUE TO NOT RECALLING THE PROPER NAME.
http://i25.photobucket.com/albums/c80/Canis-latrans/rearpiece.jpg
ITEMS REQUIRED
Dremel with cut-off discs and 1/2" drum sander.
Drill press (makes all this easier, although, a hand drill will suffice)
MAPP torch
Sandpaper
White out pen (to mark weld locations)
3/8" short socket extension
Hammer
Small vise grips w/front jaw "teeth" removed
Vice
Propane torch
Acid core solder
Center punch
Proper size drill bits (weld size will determine dill bit size. Sizes vary from AK to AK)
Locate welds on tube.
http://i25.photobucket.com/albums/c80/Canis-latrans/Gastubeflangeremoval003.jpg
http://i25.photobucket.com/albums/c80/Canis-latrans/Gastubeflangeremoval001.jpg
Mark weld spots on flanges.
http://i25.photobucket.com/albums/c80/Canis-latrans/flangerelocation001.jpg
Center punch marked welds, and drill with a bit large enough to completely remove the weld.
http://i25.photobucket.com/albums/c80/Canis-latrans/flangerelocation004.jpg
Welds drilled.
http://i25.photobucket.com/albums/c80/Canis-latrans/flangerelocation005.jpg
Carefully slide rear flange towards the center of tube. Cut tube in half just in front of the front flange.
Remove front flange and clean as per instruction below.
http://i25.photobucket.com/albums/c80/Canis-latrans/flangerelocation010.jpg
There are welds on the rear portion of the tube that need to be located and the welds have to be drilled as well. After drilling welds, remove piece.
http://i25.photobucket.com/albums/c80/Canis-latrans/flangerelocation015.jpg
http://i25.photobucket.com/albums/c80/Canis-latrans/gastubeswelds-.jpg
Clean the areas where the flanges will be relocated on the tube with fine sandpaper and degrease. At this point, the location of the front HG flang is not known. So, it's a good idea to remove all finish from the tube. This can be done with less effort if you wait and cut the proper length as described below.
Clean and degrease the ID of the flanges and rear piece.
http://i25.photobucket.com/albums/c80/Canis-latrans/seansgastube009.jpg
CUT TUBE TO PROPER LENGTH
This procedure will be done only after you have repositioned the lower handguard retainer in it's proper place, and gas block in place.
With the lower HG retainer in place and locked down, you can now measure the gastube length.
Measure the length between the points shown in pic. Add 1/8" to measured length.
http://i25.photobucket.com/albums/c80/Canis-latrans/tubemeasurement002-34.jpg
If you are modifing a gas tube for a pistol, you will need to make sure there are the maximum amount of flutes in the finished length. In the pic below, you will see the the bottom gas tube has the rear HG flanges closer to the flanges than a std. gas tube. This is required so gasses will be confined in the tube until the bolt unlocks and begins it's way rearward.
http://i25.photobucket.com/albums/c80/Canis-latrans/flutelengths001-1.jpg
After you have cut the tube to the proper length, it is time to flare the front of the gastube so it will fit onto the gas block. Pic by pic of the procedure is shown below.
--Put the tube in a vice with the front facing you. Use a MAPP torch to heat the tube cherry red.
http://i25.photobucket.com/albums/c80/Canis-latrans/gastubemod005-2.jpg
--Take the vice grips and round out the flanges one at a time. Reheat as neccesary.
http://i25.photobucket.com/albums/c80/Canis-latrans/gastubemod006-2.jpg
--After the flanges have been semi-rounded, reheat again and quickly take a "SHORT" 3/8" socket extension and drive it into the tube until the tube is round. You may have to to repeat this step a couple times to get the desired results.
http://i25.photobucket.com/albums/c80/Canis-latrans/gastubemod011-2.jpg
--This is how the tube should look after using the extension.
http://i25.photobucket.com/albums/c80/Canis-latrans/gastubemod016-2.jpg
--Next, use a Dremel (every builder should have one. It's the handiest tool made, IMO) with a drum sanding attachment and 60grit sanding drum. Remove just enough material inside the drum to get a good fit on the gas block.
http://i25.photobucket.com/albums/c80/Canis-latrans/gastubemod018-2.jpg
PLACING HG FLANGES IN THEIR PROPER PLACE.
--Slip the front HG flange onto tube.
--Slip rear HG flange and rear piece onto tube.
--Align the rear piece flush with the rear of the tube. Make sure the bottom lip is on the bottom and centered.
--Slip the rear HG flange onto the rear piece, and align the rear flange with the front flange.
--CAREFULLY and without moving the rear piece, slip the rear flange forward out of the way.
--Solder the rear piece in place, making sure there is no excess solder will prohibit the rear flange from slipping over the rear piece. (If there is excess solder, let the tube cool, then remove excess solder)
--Now slip the rear flange onto the rear piece and solder it in place, making sure it lines up with the front flange.
http://i25.photobucket.com/albums/c80/Canis-latrans/flangerelocation.jpg
--Leave the front flange unsoldered for the time being.
TO BE CONTINUED WHEN TIME ALLOWS.
STRIPPING A GAS TUBE
NOTE: THIS WHAT I CALL A REAR PIECE DUE TO NOT RECALLING THE PROPER NAME.
http://i25.photobucket.com/albums/c80/Canis-latrans/rearpiece.jpg
ITEMS REQUIRED
Dremel with cut-off discs and 1/2" drum sander.
Drill press (makes all this easier, although, a hand drill will suffice)
MAPP torch
Sandpaper
White out pen (to mark weld locations)
3/8" short socket extension
Hammer
Small vise grips w/front jaw "teeth" removed
Vice
Propane torch
Acid core solder
Center punch
Proper size drill bits (weld size will determine dill bit size. Sizes vary from AK to AK)
Locate welds on tube.
http://i25.photobucket.com/albums/c80/Canis-latrans/Gastubeflangeremoval003.jpg
http://i25.photobucket.com/albums/c80/Canis-latrans/Gastubeflangeremoval001.jpg
Mark weld spots on flanges.
http://i25.photobucket.com/albums/c80/Canis-latrans/flangerelocation001.jpg
Center punch marked welds, and drill with a bit large enough to completely remove the weld.
http://i25.photobucket.com/albums/c80/Canis-latrans/flangerelocation004.jpg
Welds drilled.
http://i25.photobucket.com/albums/c80/Canis-latrans/flangerelocation005.jpg
Carefully slide rear flange towards the center of tube. Cut tube in half just in front of the front flange.
Remove front flange and clean as per instruction below.
http://i25.photobucket.com/albums/c80/Canis-latrans/flangerelocation010.jpg
There are welds on the rear portion of the tube that need to be located and the welds have to be drilled as well. After drilling welds, remove piece.
http://i25.photobucket.com/albums/c80/Canis-latrans/flangerelocation015.jpg
http://i25.photobucket.com/albums/c80/Canis-latrans/gastubeswelds-.jpg
Clean the areas where the flanges will be relocated on the tube with fine sandpaper and degrease. At this point, the location of the front HG flang is not known. So, it's a good idea to remove all finish from the tube. This can be done with less effort if you wait and cut the proper length as described below.
Clean and degrease the ID of the flanges and rear piece.
http://i25.photobucket.com/albums/c80/Canis-latrans/seansgastube009.jpg
CUT TUBE TO PROPER LENGTH
This procedure will be done only after you have repositioned the lower handguard retainer in it's proper place, and gas block in place.
With the lower HG retainer in place and locked down, you can now measure the gastube length.
Measure the length between the points shown in pic. Add 1/8" to measured length.
http://i25.photobucket.com/albums/c80/Canis-latrans/tubemeasurement002-34.jpg
If you are modifing a gas tube for a pistol, you will need to make sure there are the maximum amount of flutes in the finished length. In the pic below, you will see the the bottom gas tube has the rear HG flanges closer to the flanges than a std. gas tube. This is required so gasses will be confined in the tube until the bolt unlocks and begins it's way rearward.
http://i25.photobucket.com/albums/c80/Canis-latrans/flutelengths001-1.jpg
After you have cut the tube to the proper length, it is time to flare the front of the gastube so it will fit onto the gas block. Pic by pic of the procedure is shown below.
--Put the tube in a vice with the front facing you. Use a MAPP torch to heat the tube cherry red.
http://i25.photobucket.com/albums/c80/Canis-latrans/gastubemod005-2.jpg
--Take the vice grips and round out the flanges one at a time. Reheat as neccesary.
http://i25.photobucket.com/albums/c80/Canis-latrans/gastubemod006-2.jpg
--After the flanges have been semi-rounded, reheat again and quickly take a "SHORT" 3/8" socket extension and drive it into the tube until the tube is round. You may have to to repeat this step a couple times to get the desired results.
http://i25.photobucket.com/albums/c80/Canis-latrans/gastubemod011-2.jpg
--This is how the tube should look after using the extension.
http://i25.photobucket.com/albums/c80/Canis-latrans/gastubemod016-2.jpg
--Next, use a Dremel (every builder should have one. It's the handiest tool made, IMO) with a drum sanding attachment and 60grit sanding drum. Remove just enough material inside the drum to get a good fit on the gas block.
http://i25.photobucket.com/albums/c80/Canis-latrans/gastubemod018-2.jpg
PLACING HG FLANGES IN THEIR PROPER PLACE.
--Slip the front HG flange onto tube.
--Slip rear HG flange and rear piece onto tube.
--Align the rear piece flush with the rear of the tube. Make sure the bottom lip is on the bottom and centered.
--Slip the rear HG flange onto the rear piece, and align the rear flange with the front flange.
--CAREFULLY and without moving the rear piece, slip the rear flange forward out of the way.
--Solder the rear piece in place, making sure there is no excess solder will prohibit the rear flange from slipping over the rear piece. (If there is excess solder, let the tube cool, then remove excess solder)
--Now slip the rear flange onto the rear piece and solder it in place, making sure it lines up with the front flange.
http://i25.photobucket.com/albums/c80/Canis-latrans/flangerelocation.jpg
--Leave the front flange unsoldered for the time being.
TO BE CONTINUED WHEN TIME ALLOWS.