Clark Custom barrel nut - torque?

[walrus]

I'm putting together an AR and plan on using a Clark Custom carbon fiber freefloat tube. Due to the way the nut is designed (see pic) a regular barrel wrench isn't going to work. The instructions sent with it and their website recommend using a pipe or strap wrench to tighten the nut, but I'm worried about that method not putting the correct amount of torque on the nut. As far as I can tell there aren't any strap wrenches that have a way to attach a torque wrench. What do you guys recommend doing to attach this thing properly?

[dmanflynn]

Contact a local machine shop, give em the specs on the gas tube holes center to center or just bring them the nut and have them machine you a wrench. I know it sounds complicated but I've found sometimes that if you cant find a tool, using something inadequate can ruin a part. And most machine shops can do it for very little.

[Neo Mara]

You need this wrench
http://www.midwayusa.com/viewproduct...tnumber=497211
but to use it on a torque wrench I think you'd have to cut out a square in the barrel wrench for the drive on the torque wrench.

You'll also need vice block that goes inside the upper, a DPMS claw wont work because you have to tighten it from the back.