Is there a proper name for this kind of toothed disk?



I'm building a piece of furniture with an adjustable part and would like to use a toothed disk similar in concept to the examples show below. Before having it custom made, I am searching for a manufacturer, maybe buy something off-the-shelf. Problem is, I'm not even sure what this would be called... Can you tell me a proper/generic name for this?

A web search for "toothed disk" turns up a lot of cogs and wheels, however only one of those hits is for something similar to what I am looking for (and is discontinued): discontinued Sachtler part

The concept is that 2 of these disks are fastened to the opposing pieces. Pulling the 2 pieces together with e.g. a bolt causes the teeth to engage, and so the 2 pieces are fastened to each other at a fixed angle, which can be adjusted to suit needs.

Other real life examples that I have seen this used in:

  • Height adjustable piano stand: Height adjustable piano stand
  • Adjustable press arm: Adjustable press arm


Posted 2017-01-03T16:53:01.697

Reputation: 273

4The first picture is called a "Devil's contact lens":. ;) – Brock Adams – 2017-01-04T02:08:32.643

Looks like something you could make with a router on a sled, a 45° bit, and a rotary indexing table. I mean, assuming you don't have a little CNC machine :) – Samuel – 2017-01-04T21:27:45.047



What we have here is a Hirth Joint.

A Hirth joint or Hirth coupling is a type of mechanical connection named after its developer Albert Hirth. It is used to connect two pieces of a shaft together and is characterized by tapered teeth that mesh together on the end faces of each half shaft.


Posted 2017-01-03T16:53:01.697

Reputation: 33 416

I learn something new here every day. These might help (though I'm not sure about sizes):

– Aloysius Defenestrate – 2017-01-03T17:08:59.583

Didn't realize that the two halves of the washer weren't separable. Mea culpa. – Aloysius Defenestrate – 2017-01-03T20:41:55.893

5Possibly useful for searching, from the WP article: "Hirth-like joints are often found on camera support equipment, where they are called rosettes." – Timbo – 2017-01-04T00:51:11.333

Thanks @Timbo, that's useful info too. You should consider making it a separate answer just for completeness' sake. I missed that in the WP article... – fr13d – 2017-01-04T14:31:50.120

I only ever saw not quite those but similar disks in Ikea furniture and there they were used to "dig" into wood to stay in place better. – Maurycy – 2017-01-05T11:24:28.837

1@Maurycy: I believe those are generally referred to as 'threaded inserts', 'insert nuts' or 'tee nuts' depending on how they dig into the wood. – Timbo – 2017-08-24T23:45:05.187


Expanding from my comment on isherwood's answer. From the Hirth Joint article:

Hirth-like joints are often found on camera support equipment, where they are called rosette [joint]s.


Posted 2017-01-03T16:53:01.697

Reputation: 205