2
$\begingroup$

I have a motor with a 4mm shaft. I've purchased a propeller that's designed to fit a 1/2 inch shaft. How can I securely couple the two?

$\endgroup$
1
  • 1
    $\begingroup$ Have you asked yourself if attaching something designed for a 1/2 inch shaft with all the weight and strength requirements that implies is a sensible thing to attach to a motor with a 4mm shaft, with all the (lack of) strength which that implies? $\endgroup$
    – TimWescott
    May 9, 2019 at 16:13

3 Answers 3

4
$\begingroup$

If the motor speed matches the speed range needed for the prop, then make an adapter with relevant locking screws or equivalent, balanced as necessary.

something like :

enter image description here

Source https://shaft-collars-couplings.staffordmfg.com/viewitems/shaft-adapter-couplings/shaft-adapter-couplings---step-up-type-with-keyway

$\endgroup$
3
  • $\begingroup$ Can you be a little more specific? I'm kind of a neophyte here. $\endgroup$ May 9, 2019 at 12:12
  • $\begingroup$ @Megalonychidae see update $\endgroup$
    – Solar Mike
    May 9, 2019 at 12:24
  • $\begingroup$ Perfect! Thank you very, very much. $\endgroup$ May 9, 2019 at 18:06
4
$\begingroup$

Following on from Solar Mike's answer, I'm not sure you'll be able to find something off-the-shelf with the diameters you have (mix of imperial and metric units), so you may need to get something custom made instead. I have sketched the following (not knowing what shaft lengths you had, I made a few assumptions - adjust to suit your needs):

enter image description here

The outer diameter is 1/2 inch, while the ID is 4mm. I have toleranced it as H7 hole so that it's a snug fit on the 4mm shaft. The adapter is secured onto the 4mm shaft with 2 M3 grub screws at 90 degrees, you can also use Loctite 638 if you want to be sure. I have added a 1mm chamfer on the end of the shaft adapter.

$\endgroup$
3
  • $\begingroup$ Good job, plus 1. $\endgroup$
    – Solar Mike
    May 9, 2019 at 18:07
  • $\begingroup$ Beautiful sketches, do you mind if I ask what software you used? $\endgroup$ May 9, 2019 at 18:08
  • $\begingroup$ Thanks. I used Autodesk Inventor. $\endgroup$
    – am304
    May 9, 2019 at 18:28
0
$\begingroup$

Use gears, mechanical losses will only be 1 % and that's negligible.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.