Hi, can anyone help please? I have a customer who'd like a few of the 160 Control Cock washers for the old style control cock. They believe them to be a different size to the later one but don't have the means to measure them. Could anyone tell me what the OD, ID & thickness should be or if they are the same as the regular ones? Many thanks!
As far as I can tell, they are the same. At 3/4" and 1/2" respectively, the OD and ID are the same on both styles of control cock. I can't see Tilley altering the thickness of the washer.
Standard size. Although for my example I stamped them out of sheet. I could not release the knob so I split two and put them at 180-degrees so I didn't have to risk damaging the knob Alec.
You could also use a length of graphited string and wrap it around the spindle. Alternatively, twist a short length of PTFE tape into a string and use that instead.
Actually PTFE works very well. It stands the heat, it compresses well, it seals with minimum friction and provided you use the type most suitable for gas fittings, is fuel proof. A short cut perhaps but a bodge ? Less of a bodge than cutting O rings in half.
Why would anyone cut an o-ring in half? Especially one that small? I have made o-rings for vessels but they tend to be 6-10mm cross section and a few meters long. I don't like joining o-ring cord less than 3mm diameter, its not very forgiving even with an alignment jig. Alec.
As a gland packing Teflon/PTFE performs better than Viton. It compresses to seal very well and certainly stands the heat but it has a much lower friction coefficient so makes the control spindles easier to turn. Ace hardware in the US sell a Teflon string which is just about right for the job but as Henry says gas quality PTFE twisted into a string works just as well. ::Neil::
I switched to PTFE string for all my plumbing works. I buy Loctite 55 which is rated to 150 deg C and suitable for gas.
