Original question: How do I name/ describe this bolt so that I can search for and purchase it?

I have a troublesome towel rack that I’ve been fighting with, off and on, for several years. After much analysis it turns out to simply be a very poor design, allowing one of the hollow towel rods to fall to the floor.

Closely examining the design there are a pair of existing 1/2” 40-TPI #5 machine screws that I could replace with shoulder bolts, and securely attach to the troublesome rod with set screws, but I have no idea how to search for a shoulder bolt with a head that will accept (hopefully pre-drilled and pre-tapped) set screws perpendicular to the bolt threads. While a single set screw on each bolt head would be ideal, I could need up to three, to ensure the rod is properly held in place. The “shoulder part” of the new bolt will need to be at least an additional 1/2”-3/4” long, on top on the 1/2” threaded part.

How do I describe and search for the bolt I need? How likely am I to find exactly what I’m looking for? If what I’m looking for isn’t readily available, what modifications do you recommend I make to this proposed design?

Thank you in advance!

The fully assembled towel rack The fully assembled towel rack. (The sides rotate apart letting the bottom rod fall.)

One of the screws to be replaced, the parts it fits together with, and inside the hollow rod. One of the screws to be replaced, the parts it fits together with, and inside the hollow rod.

close up of the troublesome joint assembled close up of the troublesome joint assembled. (I will need a “shoulder bolt” to extend through the funnel, and into the rod, where I can drill holes for the set screw.)

  • Show a couple of pictures then it may be easy to come up with suggestions. But taking a bolt and drilling and tapping a thread is one possibility - depending mainly on skill and tools.
    – Solar Mike
    Jun 28, 2020 at 7:22
  • please post a picture of the towel rack and the problem area
    – jsotola
    Jun 28, 2020 at 7:42
  • 1
    Are you sure you aren’t throwing good labor after bad, trying to save a flimsy piece of imported junk? It doesn’t sound like it was very well built in the first place. Jun 28, 2020 at 14:08
  • 1
    Are you sure that a ton of epoxy wouldn't keep everything from rotating and falling off? Jun 28, 2020 at 15:43
  • @Harper - Reinstate Monica - Yes, it’s probably a piece of junk, but, as I didn’t choose it, it’s probably better that I get it working than replace it. Jun 28, 2020 at 19:17

1 Answer 1


I would get a long threaded bar cut to length to use the existing threads in the end brackets.

Seems to be the simplest option and only needs cutting to length.

  • I like the simplicity of the solution (or at least part of me does). The rod actually has some plastic obstructions in it, but they seem to be easily pushed down. I need to make sure I can actually push these out the other end. I own a hack saw, but would prefer someone machine cut it, then ship it to me. I need to see if I can find a vendor that would do this. Thanks again. Jun 28, 2020 at 13:12
  • 1
    Yeah, don’t even get that bespoke. Just use threaded rod and 2 couplers. Couplers are hex shaped rods with an internal passage threaded the same. So inside the pipe you go machine screw -> coupler -> threaded rod -> coupler -> machine screw. Done and dusted. You only need to do it on the lower one. The threaded rod only needs to be coarsely to length; you can do that with a hacksaw or Dremel. Jun 28, 2020 at 14:23
  • @Harper - Reinstate Monica - yes... I was going back and forth between a solid cut rod, and what you suggested. Either way I need to either push the plastic barriers out the other end of the rod, or drill through them. (I suspect I can simply force them out the other end: They already recede when pushed.) Jun 28, 2020 at 19:11
  • FYI, I anticipate marking this the accepted answer when I successfully use it to repair the towel rack. Jun 28, 2020 at 19:44
  • You know that saying about bringing a knife to a gun fight? Well, I learned the hard way you don’t measure screw diameter or thread pitch with a ruler. After purchasing a steel dial caliper, I believe I have either a 1/2” #7-27 TPI or a 13mm M3.8-.95 machine screw but neither appear to be standard sizes. Also, the length of the threaded bar you suggested that I use, I’ve measured to be 25.5”, and, as you suggested, I expect to need to cut that to length, if that matters. Jul 26, 2020 at 0:49

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