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OT -- Wax versus Graphite shaft packing

Weirsdale George

Stainless
Joined
May 17, 2003
Location
Weirsdale, FL
I am restoring an antique hand-powered double acting water pump. I have on hand two types of compression packing (probably as old as the pump) -- graphite and wax. Which would be the best to use on this reciprocating shaft? (Googling I come up with fancy stuff like graphite impregnated teflon and the such but not the old fashioned packing I have.) Thanks.
 
The modern packing you are hitting on is probably the stuff we used to pack glands on turbine pumps. Meant for high speed rotary action (3600rpm), not a slow moving recip pump rod.
 
George --

Are you asking about wax-impregnated rope and graphite-coated rope packings? The graphited-rope packing I've run into was waxed or greased before being graphited, and was pretty much the old-time standard for reciprocating water pumps. Ideally, the packing rope diameter was half the difference between the packing-box ID and the pump rod OD, and was installed as a stack of single-wrap split rings.

Cutting the rings was best done by wrapping several turns of the uncut rope packing around a wooden rod the same diameter as the pump rod, and then using a knife to cut down the length of the packing. Each packing ring is installed individually, turning each successive ring a half turn from the previous ring so that successive ring joints are 180 degrees apart.

A half-round "yarning" punch that slides freely into the space between the rod and packing box should be used to firmly seat each ring as it is installed. Once all of the packing rings are installed, the packing bonnet should be installed, but only finger tight. Run the pump a while, and then snug the bonnet a bit, repeating the run-and-snug incrementally until only a few drops a minute make it through the packing.

It should go without saying, but the area on the pump rod that the packing rides on really wants to be a smooth cylinder.

John


Edited to add a link that, while obviously written with an eye on a rotary pump, provides good guidance: http://www.batescrew.com/faq/glands/index.html
 
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Interesting, John... that's exactly how the packing in the rotating pumps is installed. Knowing that, I do have a bit to offer on the subject.

Couple of helping pointers on this... cut your first piece to length so it wraps properly, then straighten it out and cut all the rest the same length. That's how we always did them instead of looking for a dowel. Also, lay them out and lightly flatten them with a hammer and they slide in the gland a LOT easier. Get a few seated and use the yarning punch above or simply the packing gland itself to seat them, then pack the rest in. Don't overpack with too many rings it or it'll bind up on you, then you have to pull them out with a pick or pigtail screw and start all over again.
 








 
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