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Anyone drill their Carbon Fiber FF tube for mounting accessories?


A62335

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Just curious as to if it can be done without "compromising" the carbon weave. I would eventually like to add a bipod stud and maybe a rail for mounting a JP short range sight. Please add pictures if you have them, I want to get as many ideas as I can before I start hacking up my tube.

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I have drilled the clark tube I have in several places. No problem. If you want to mount anything though, you really need a backer plate. Something like the ones clark furnishes to mount the sling swivel stud to.

Peter Adams

FY-39604

Peter nailed it guys with the backer plate comment. Mounting a sight should be no problem but I would be leary of mounting a bipod since the pressure on the stud could cause the stud to wallow. Pressure on the bipod stud when shooting should not be a problem. Most of the pressure will come when you fold and unfold the bipod. The Clark tube Peter has is quite robust compared to some others so YMMV.

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I drilled my briley tube just the other day, (18) - 1/2" holes total for venting, no problem. The tube is still solid as it was (plus a bit lighter.) I used just a backing washer/locking nut for the sling stud. Carbon fiber is bit trickier to drill just because it is so slick, I had to use a brand new bit just to get it to cut through the fiber without fraying. With the Briley tube, I was able to use fine sand paper to clean up the sharp edges without affecting the tube's cosmetic.

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Be VERY careful when creating Carbon Fiber dust. These strands are very small diameter and are not something you want down in your lungs for the same reasons you don't want to breathe asbestos fibers...well is wouldn't be called asbestosis but I can't spell pneuomoconiosis...maybe fibrosis is easier?

I know in cycling even a deep scratch in the weave is considered dangerous...different stressors and different potential outcomes from damage

Interesting question. I would like to know how long the drilled FF tubes last after some use.

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When drilling/cutting carbon fiber, either do it with a powerful fan blowing the dust AWAY from you, or the preferred/safest method is to do it wet, like it a constant spray or under water. Carbon fiber dust can and will get in your lungs and will never, ever, ever come out and does pose a health risk.

I've cut one Clark tube and drilled another both under water and it worked out very well both times. Sealed the edge back up with clear nail polish.

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+1 to what others have said about not breathing this stuff.

I was wearing a mask when I did it and was spraying water on the cuts while I did them... You don't want to breathe this stuff...

As to durability remember the Clark tube is way overkill from a strength perspective. The diameter and thickness is much greater than actually required. I suspect it was a case of getting the closest tube available in bulk that was about the right size. Would you have a problem if you drilled lots of holes close together? Probably... but that would be true to a greater or lesser extent no matter what material you had chosen. Don't go crazy making it look like swiss cheese and you'll be fine.

BTW I used West Systems epoxy (left over from boat building) to paint the holes to keep them from raveling.

Peter Adams

FY-39604

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So how do you guys make sure stuff is pointing in the right direction (i.e. parallel to the bore)? I did this to a DPMS aluminum tube, but feel I got lucky and used a piece of rail with a curved base.

Rich

Did mine on a drill press. I rigged up a V-base to sit the tube in (to be sure the holes are perpendicular to the center) and used the laser on the drill press to align the holes longitudinally.

BTW, I agree about the caution not to breath in this fine carbon dust. Not good for long term health.

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If it's an unmounted Clark tube then it's easy, as the tube is not attached to the barrel nut yet. Use a pipe wrap from an index point on one end, mark a lateral line to the other end, and lay out your holes as desired. Trick would be to cover the tube in masking or gaffers tape and draw out every hole or drill point as well as bisecting lines to make sure is comes out square.

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If it's an unmounted Clark tube then it's easy, as the tube is not attached to the barrel nut yet. Use a pipe wrap from an index point on one end, mark a lateral line to the other end, and lay out your holes as desired. Trick would be to cover the tube in masking or gaffers tape and draw out every hole or drill point as well as bisecting lines to make sure is comes out square.

I sure learned the hard way a few years back, drilled a sling stud hole in an alum. tube without making absolutely sure that it was perpendicular to the bore=> crooked bipod! :angry2:

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I purchased mine from these guys several years back. I drilled and tapped mine and it's never come loose yet.

When I purchased it, they guy said one of his partners had done the same and had used his hard for years without any loosening.

If it had loosened, I would have just drilled it out and put a backer on it. But I don't even use a bipod anymore ... I monopod off of cinched 40's and that's been good enough for me.

Just thought I'd toss that out, don't think a backer plate is crucial for any install, no matter the maker.

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Remember the vtac tube is not carbon fiber. It is aluminum. The barrel nut that the vtac tube uses is also heavier. So of course the vtac unit is heavier. I do like the barrel nut that jp uses for the vtac. It allows you to torque the barrel nut independently of having to worry about the hand guard alignment. It also allows the easy removal of the handguard for working on the gas system. For instance if you use a rifle length handguard on a gun with a mid-length gas system (which is what I do).

One solution to this is to modify the clark to secure the handguard to the barrel nut in the same way that the jp does it (small screws through the handguard into the barrel nut). The metal in the clark barrel nut is not thick enough to tap.. So a friend and I cooked up conversion that used T-nuts attached to the inside of the barrel nut with high temp epoxy. It works ok but was pain to build.

If I could get the jp barrel nut by itself I would try to find a carbon tube that's inside diameter was compatible with the outside diameter of the barrel nut and go that route.

Sorry to drift your thread slightly...

Peter Adams

FY 39604

Edited by caspian guy
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Remember the vtac tube is not carbon fiber. It is aluminum. The barrel nut that the vtac tube uses is also heavier. So of course the vtac unit is heavier. I do like the barrel nut that jp uses for the vtac. It allows you to torque the barrel nut independently of having to worry about the gas tube alignment. It also allows the easy removal of the handguard for working on the gas system. For instance if you use a rifle length handguard on a gun with a mid-length gas system (which is what I do).

One solution to this is to modify the clark to secure the handguard to the barrel nut in the same way that the jp does it (small screws through the handguard into the barrel nut). The metal in the clark barrel nut is not thick enough to tap.. So a friend and I cooked up conversion that used T-nuts attached to the inside of the barrel nut with high temp epoxy. It works ok but was pain to build.

If I could get the jp barrel nut by itself I would try to find a carbon tube that's inside diameter was compatible with the outside diameter of the barrel nut and go that route.

Sorry to drift your thread slightly...

Peter Adams

FY 39604

You could get a PRI. It's lighter than my JP and already has holes.

imgp4681.jpg

IMGP4703.jpg

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What I should have said above about the Vtac part is that torquing the barrel nut doesn't effect handguard alignment/indexing . (Sorry for any confusion that caused). The indexing of the outer receiver nut is what controls the index of the handguard.

However due to the construction of the inner barrel retainer nut of the JP system it is easy to remove one of the nubs separating 2 of the gas tube notches if one of the gas tube notches doesn't line up at the torque level you want to use.

I'll edit the above response.

Peter Adams

FY-39604

Edited by caspian guy
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I think the "frustrating" part of the VTAC handguard for me is the outer nut not being "tight" to the upper receiver and it not having any bearing on the barrel's fit (i.e. due to the inner nut). But it's like you said Peter, that's why John says use Loctite to align the gas tube hole in the outer nut to the upper receiver.

Rich

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  • 2 years later...

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