If you have the conical ring and flat ring in combination, you probably have the King style. PM packings are double stacked flat rings, two segments per stack, and depend on flat springs inside a circular retainer to press them against the rod.

Rick, just don't do what I did and forget to use some mold release agent like acetylene soot before you pour the babbit.

I can vouch for the packing from CPI as being a good substitute for the original Paxton Mitchell product. We use it on the Cumbres & Toltec in all our engines. The stuff we use comes in two rings that are each 1/2" thick, which is comparable to the PM packing, so there is no adjustments needed in any of the components. You can eliminate the retaining ring as the CPI packing has springs built in.

Both the King and PM packing were supplied in different alloys. A softer babbitt, like you have, for saturated steam and a bronze material for superheated steam. The bronze alloy will work fine in a saturated application.

It appears from the pictures that you also have rod lubricator swabs on the outside of the packing gland. I have found that cotton rope or felt rod, available from Mc Master-Carr works well in those. The added lubrication will extend the life of both your rods and the packing.

I wouldn't water jet packing or any bearing material as the garnet impregnated in the material is harder than any of the components. If you want to ruin an endmill or reamer as well, feed it into garnet.

Good luck.

Yeh, I forgot about the abrasives in Water-jetting, so I guess that would only leave laser-cutting or stamping (from babbitt plate). Luckily Babbitt is soft enough a quality bench vise would have enough force for stamping (if you had no access to a press or iron-worker).
Rich C.

The plan thus far is to water jet a piece of 5/8" plate with an opening corresponding to the shape of the outside of two segments, with allowances given for 3% shrinkage and for the width of a saw kerf to cut the segments after boring. I will cast it solid then bore it out to the finished size then cut into two pieces. I will also have the plate cut into two halves to facilitate removal of the casting from the mold.

That is my approach to solving the problem. Advice and suggestions are appreciated.

.

The segmented packing is not bronze nor babbit originally. The babbit may be some shops answer to packing however these segmented parts were/are leaded copper. That is why when you clean and look at the piece it looks like copper. When making these pieces the end cuts are very specific so that they work correctly, that is as the I.D. wears the ends keep an alignment and always seal. When these pieces are made the ends are cut with EDM. I think that Historic Machinery Services Corporation, Robert Yuill has correctly made these pieces in the past. The price is not for the faint of heart though. Robert frandsen of steam services of America has success in adapting modern packing to locomotive cylinders.

Kelly -

Do you have a thoroughly modern finished packing/supplier like Parker FlexiSeal, or do you machine your own (+ source)?

.

When getting Southern 401 ready for service at Monticello, we had new old stock King packing we purchased from J. David Conrad for the piston rods and valve rods, as well as the old material. We took small bits of both to the University of Illinois's Materials Research Lab to determine what, specifically, it was. We did this to confirm the material so we could make our own down the road.

This was the Lab's response:

We performed the analysis of the Babbitt material from 401. It is (in atomic percent) ~ 12% antimony (Sb) in a matrix of ~ 88 % lead (Pb). No other elements show up in significant quantity, but must of course be present as trace impurities. From the metallurgical phase diagram, the above composition is right at the eutectic point, so upon cooling below 251 deg. C the liquid will neatly separate into small grains of almost pure Sb in a matrix of almost pure Pb. We found just that in area scans of the composition. Thus, it has the usual design approach for babbit metals: hard grains in a ductile matrix.


This was for both the new old stock King packing, and the old stuff we removed from the loco. Of course, this is a slide valve soak, so I would expect superheat locos to have, as Russ noted, a material with more copper/bronze in it.

Here is the Lab's informal report:



Kent McClure

I'd like to take a moment to thank everyone who has contributed to this thread. This info will be a great help to the C&NW 1385....MLD

I went out to my garage to see what my Ames Unaflow engine used for packing. Its packing was made by American Metallic Packing Co. in Pittsburgh and looks identical to the CPI product. Alternating layers of packing and radial rings. Piston rod for the Ames is approx. the same diameter as the 58's rods so I can make an apples to apples comparison.

To those who use the CPI packing, how do you go about purchasing them? Do you have a contact at a distributor that you work with? Exploring all options.

Rick,

We purchase the CPI packing directly from the manufacturer. Cost is something like $150-200 per set I am told.

Dave, France Compressor bought Compressor Products International (CPI) around 2007, so they are indeed the same products.

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