Question Using strap wrench and torque wrench simultaneously?

[SaltyWombat]

I'm the kind of guy who wants to use a torque wrench to properly attach a valve at a specific torque value. How awkward would it be to use a strap wrench to secure the cylinder with one hand and then use the torque wrench with the other hand? Would I be much better off getting a chain vise?

I have limited space, so I can't attach a chain vice to a wall or workbench leg. I'd have to mount it horizontally on a piece of plywood or attach it to a telephone pole with ratchet straps.

 

[Boarderguy]

Valves aren't that tight... hold out with your knees and maybe other arm then tighten it.

 

[johndiver999]

Tap the wrench with a mallet and hold the tank in between your knees. That is tight enough, half the shop monkeys probably just bash the handle with a mallet.

 

[-JD-]

"lazy tip" Lay it down and let the ground/floor hold the strap-handle for you. You can always sit/kneel on the cylinder for control.

 

[-JD-]

Tap the wrench with a mallet and hold the tank in between your knees. That is tight enough, half the shop monkeys probably just bash the handle with a mallet.

I don't know about shop monkeys and bashing, but I was shown the tap-to seat method by a pretty well-known and respected shop owner, and my instructor. When traveling with my pony, a good swat with the heel of my palm while holding the bottle between my legs seems to do the trick.

 

[johndiver999]

LOL, there is a specified torque for the valve. I seem to recall somewhere like 75 or 100 foot lbs? "Tap to seat" and "bash the handle" are really just semantics.

I honestly think it is better to use a wrench and maybe a mallet rather than barehanding the process. but if that is what a scuba instructor told you....

 

[SaltyWombat]

It's 40 - 50 ft lbs for my cylinder and valve combo. Depends on the cylinder and valve.

 

[-JD-]

LOL, there is a specified torque for the valve. I seem to recall somewhere like 75 or 100 foot lbs? "Tap to seat" and "bash the handle" are really just semantics.

I honestly think it is better to use a wrench and maybe a mallet rather than barehanding the process. but if that is what a scuba instructor told you....

A friend's brother would narrate torque when we were wrenching with him using high-precision descriptive phrases like "motor-mount tight"

DGX: 50 foot-lbs.: Installing the Valve in the Cylinder | Dive Gear Express®
Catalina 40 pound-foot, 50 pound-foot MAX: High Pressure Aluminum Gas Cylinders | Composite Cylinders - Valving of SCUBA (Air) Cylinders Aluminum Cylinders | Composite Cylinders | Impact Extrusions

More germane to "tap-to seat", also from Catalina: High Pressure Aluminum Gas Cylinders | Composite Cylinders - Valving of SCUBA (Air) Cylinders Aluminum Cylinders | Composite Cylinders | Impact Extrusions

Hand tightening of the valve should seat the valve completely on the cylinder (i.e. no gap between the valve and the cylinder). If there is still a gap between the valve and the bottom of the cylinder lightly tap the valve handle with a rawhide or rubber mallet to seat the valve completely. The valve should only rotate 45o (1/8 of a turn) from the point of hand tightening to fully seated. If you decide to seat the valve using a torque wrench, following are recommended torque values by Catalina Cylinders and the CGA:

 

[Jimchris]

I use a crows-foot and torque wrench, using my thighs/knees to hold the cylinder steady. for smaller cylinders I have a chain vise that fits into a bench vise to steady things.

 

[Bob DBF]

Valves aren't that tight... hold out with your knees and maybe other arm then tighten it.

I take it you haven't put in a 1/2" NPT lately.