Shaft packing

unplugged88 · Oct 14, 2019

I have a question regarding packing sizing.

I have correctly measured the bore diameter and shaft to determine the correct sizing of packing. However, after ordering/receiving the packing the width measure under 0.010" - 0.0150" the required dimension. The graphite packing material is not accurately square.

Do manufacturers do this intentionally to allow easier installation? Will it expand enough on compression??
Or is the packing purchased just of poor and inconsistent quality?

Thanks for any clarity.

4GSR · Oct 14, 2019

Yep, it's loose going in.
Once in and the gland nut is tighten a bit. Fire up the pump and pressure will pack it off more and may require tightening the gland nut a little more.
Oops! Hydraulic cylinder here, same principal, still works the same on cylinders as on pumps. You want it loose, if it was tight, it would expand before it got into the gland bore and really be a mess!

Ken

MattRiddle · Oct 14, 2019

Is the packing pre-cut or bulk packing by the roll?

Either way, it should come out square if placed around the shaft the correct way. Most quality packing is made this way to prevent keystoning when placed around the shaft.

Tyrone Shoelaces · Oct 15, 2019

I used to work for a company that made gland packing. When I was using it the packing came in a roll so I made a simple jig that enabled me to cut all the packing sections to 1) the correct length 2) at an angle so you had a scarf type joint when it was installed.
Obviously you install the sections so the joints are all in a different position IE 12 o'clock, 6 o'clock, 3 o'clock, 9 o'clock etc.

Regards Tyrone.

Bill D · Oct 15, 2019

What kind of packing is smooth within 0.01 inch? All I know is the rope type packing or solid teflon? which is not that smooth and consistent before compression during installation.
Bill D

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Shaft packing

unplugged88

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4GSR

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MattRiddle

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Tyrone Shoelaces

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Bill D

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