Howdy all,

Week before last, we discovered a hub crack on the #4 right side wheel center on Polson 70 at the Mt. Rainier Scenic Railroad. This is a cast iron wheel center, and as you can see in the photo, the crack had just begun at the edge of the keyway. Though banding the hub is a legal repair, I did not feel it would be effective in this instance. Luckily, a hub crack repair was undertaken by George Sapp at Railtown 1897 on the Sierra 3 using a "metal lock" product. After speaking with George and hearing of his success, we elected to use this method which was provided to us by a company called "locknstitch." I have no affiliation with the company but can say I was pleased with the product, and figured others might be interested in its uses for hub or saddle repairs.

The product is basically a series of holes drilled in sequence to form a multiple dog bone opening. This opening is filled with 1/4" strips of corrosponding pattern which also help to draw the crack closed. Photo two shows the hole pattern which was completed in a bit less than a day to a depth of 3.250" using a mag drill and the drilling jigs provided. Photo three shows the cavity filled with the lock strips and peened so as to expand the strips into place. The final step was to drill, tap and insert drawing stitch pins at the four corners of the lock, and the rest of the crack. You can see an open hole with counterbore ready to tap and insert the last of these pins. These stitch pins have a thread form which draw the metal together rather than spread.

After a weekend of service on our steep grades, with plenty of rain, and downed leaves with a "couple" wheel slips, the repair is holding very well. I hope this might be of some use to others presented with a similar problem!

Stathi

For further informational purposes, here is the link to the website for Lock-N-Stitch, Inc.

http://www.locknstitch.com

Thanks for posting that message. Topics like this are what make RYPN an interesting place to visit for us that work on similar equipment.

If the repair holds, and keeps the press-fit forces (squeezing that axle and trying to tear the hub apart) at a pressure that is close to original, then that in one incredible product!

Agreed, that is one interesting repair. We welded up a pretty deep "V" on a cast iron hub, and it turned out pretty good, but it wasn't fun at all. I hope never again to weld on cast spokes or hubs. They were inspected by a top notch contractor and the wheel work was completed, but never again do I want to do that kind of work. Found it very nerve wracking and stressful. But this repair above facinates me, not sure that I fully understand it or not? Never in a million years would I have thought of that approach.

Also agree that posting repairs like this which I think are kind of esoteric to most of o us is one of the things that keep me coming back for sure. Thanks and Cheers, John.

We used the Locknstitch products to repair cracks in a cast iron Buda Gasoline Engine block several years ago. Still working fine. Cracks were in the top of the block between the cylinder bore and the valve seats. Not sure if they would work inside the cylinder bore itself.

This product is used extensively to repair all kinds of difficult items, pumps, cylinder heads, even flywheels.

They also have a very good tutorial about the difficulties of repairing cracks in cast iron via welding.

Highly recommended product, worth the cost for difficult repairs.

Cheers, Kevin

Say... I wonder if this technique would work on fixing those GE 44 Ton engines that were discussed recently...

When the M&H RR near Harrisburg (PA) used to run steam, they used this product to repair a cylinder saddle crack on their CN 2-6-0. The 91 Ran for a few seasons after that and I believe the repair held up well.

Dave

joe6167: I saw that topic too! I would suggest sending a PM to the guy who started the topic so it doesn't get lost amongst all the other suggestions! This could be exactly what he needs!

IIRC, this repair method for castings has been around a LONG time. This or similar "stitching" techniques were used for cylinder head and engine block repairs on auto engines at least as far back as the 1950's. It's pretty cool that there are still people out there who know how to do it.

What does the FRA have to say about this technique?

This method was used many years ago to repair cylinder cracks running the entire length of large Corliss steam engine cylinders in sugar mills. Seems like the first thing to try on cylinder saddles. If it doesn't work, you're not out much time and expense compared to the alternative.

Dear hamster:
The FRA (49CFR, Part 230) generally does not specify repair methods.
Banding cracked wheel hubs is one of the few instances where a repair is shown (230.114(c) Drawing 31).
Welding and brazing cracks in wheels, cylinders, frames, etc. has always been standard railroad practice to return locomotives to "safe and suitable" condition.
J.David

Thanks for the reply, J.D. I knew that it is forbidden to weld on axles, but was not sure about wheels, hence the quesiton. My journey into all things steam is made easier when folks are willing to share experience and knowlege.