At some point later this winter or early spring we will have to replace quite a few of the studs on the J&L 58's boiler. These are the studs that hold the various appliances, brackets etc. on to the shell. The end that threads into the shell is tapered and the corresponding hole in the shell is also tapered.

What is the procedure for making and installing the studs? How do you get the stud threaded into the shell tight? What is used as a thread sealant? I'm assuming the studs have to be made of certified material.

Another issue is that I don't have stud taps. I can't afford Bob Franzen's set of 15 taps and what do I need a set of 15 for when I only have about three different sizes that I need and are all on the small end. I did have our machinist make a new washout plug tap so I guess we will do the same for the stud taps if I can't find another option.

Thanks!

Rick:

The recommended materials for locomotive boilers, including studs, can be found in part 3 of the NBIC code. I don't remember it off the top of my head but I'll look tomorrow if you can wait that long.

Most threaded locomotive boiler stuff is 12 tpi.

I should know because I ordered a plate burnout for the new dome lid last year to the correct spec. At any rate I can get the bar stock from Alro, whenever I figure it out.

SOME American boiler threads are 12TPI. Others are 11.5. Unless you are careful, there's a lot of room for error. Your machinist can make a tap for chasing the threads once you have a good spec.

Tapered turning and threading in the lathe. I have had a lot of success using EXPANDO as sealant for studs.

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Thanks Kelly. That is exactly the information that I was looking for! Merry Christmas!

I only have part 2 of the NBIC here unfortunately.