I'm new to part design/mechanical engineering and I have the following question.

enter image description here

  • Blue: steel shaft, 5/8" diameter, connected to a motor
  • Green: aluminum disk, 10" diameter, 1/2" thick, 3" hole
  • Goal: the shaft should rotate the disk

The Question: I'm wondering how can the shaft be connected to the disk?

I tried searching for bushings, various forms of couplings, etc, but couldn't find anything that can connect the two.

Does this mean I would have to machine my own coupling, and there are no standard fittings/parts that would do the job?

FYI, the project needs high torque, so I'm guessing (please correct me if I'm wrong) that a coupling needs to have a large diameter as to apply the torque at a greater distance from the center.

  • $\begingroup$ Have you searched on here? There was a similar question a while ago... $\endgroup$
    – Solar Mike
    Aug 1, 2018 at 21:13
  • $\begingroup$ yes I did search here, and many other places online. Maybe I'm using the wrong search terms or something. $\endgroup$
    – Z. Uryum
    Aug 1, 2018 at 21:24
  • $\begingroup$ How high torque? Please note thet the coupling probably does not need to be much larher than shaft. $\endgroup$
    – joojaa
    Aug 1, 2018 at 22:34
  • $\begingroup$ It looks like you will have to make your own coupling, even if you were lucky enough to find an off-the-shelf coupling for these dimensions it would probably be VERY heavy and expensive. Machine your own. $\endgroup$ Aug 1, 2018 at 23:53

1 Answer 1


Masterdrives.com (.PDF - Catalog: QD Bushings) sells bushings of a suitable size but you may or may not want to do some machining to reduce the "E" dimension. Apparently you want bushing type SF, the E length with that taper is bound to fit. 5/8" bore size is available.

Catalog page:

QD Bushings

Another view of one of those T-bearings:

QD Bushing

Alternatively make your own or have one made for you:

Homemade #1

Another design:

Homemade #2

  • 1
    $\begingroup$ Thank you @Rob for the tip this is very useful! and thanks everyone for your comments. $\endgroup$
    – Z. Uryum
    Aug 2, 2018 at 19:06
  • $\begingroup$ One more thing ... QD bushings seem to have two sets of holes (threaded and non-threaded). Do you know why is that? or how is it supposed to be used? Also, is there a way to cap or block the shaft from sliding in/out of the bore? or is the friction grip and keylock enough to keep the shaft secured inside the bushing? Thank you. $\endgroup$
    – Z. Uryum
    Aug 2, 2018 at 19:20
  • 1
    $\begingroup$ Machine Screws have threads from head to the end but bolts have a section under the head with no threading. Press-fit will keep it from sliding off or use the more expensive slit-type with the bolt that squeezes it to the shaft. Unless the motor bearings are rated for pushing and pulling it's assumed that the forces will be rotational. $\endgroup$
    – Rob
    Aug 2, 2018 at 19:24

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