Connecting motor to wheel

[transatlantic]

I'm looking for ideas on how I could connect the following wheel, to the motor shaft below? Ideally, I would like to connect it directly, without a belt.

Wheel : Bore size 13mm
Motor : 8mm shaft diam, 25mm shaft length, M4 thread.

Any ideas?

 

[tcmtech]

Adapter bushing and set screw.

 

[transatlantic]

wouldn't that be something I would need to get specially made? did a quick search and couldn't see anything off the shelf that was 13mm to 8mm?

 

[ronsimpson]

https://www.servocity.com/set-screw-shaft-couplers
Search through this sight for a while. They do what you want to do. It might take a while to find the answer.
---edited----
https://www.servocity.com/heavy-duty-clamping-shaft-couplers

https://www.servocity.com/clamping-shaft-couplers-6776

https://www.servocity.com/0-770-set-screw-d-hubs

 

[dknguyen]

If you can find the space, drill a hole into the side of the wheel (use a hand drill!) and use a setscrew. Every other solution includes buying or machining a hub. that the shaft slides into that bolts to the wheel.

In your case, it sounds like the shaft is smaller than the bore, so maybe use some material to close that gap...like epoxy fill or wood. If you use epoxy you can use a 8mm rod wrapped in wax paper as a plug to keep the hole clear as the epoxy cures so you can twist it out and insert the motor shaft.

If it's not very high torque then you might be able to get away with all of this and just JB-weld or epoxy the motor shaft right into the wheel but it may not be as durable or as removable as you want.

Honestly, I've always found attaching shafts to random wheels a major PITA. I wish more motors had square shafts and I had a square drill.

 

[hyedenny]

If the bore in the wheel is smaller than the shaft, then get a small round file and a small flat file and carefully file away until it fits! Hopefully, it won't have to be exactly concentric.
Depending on what type of plastic it is, you may be able to heat it up locally until it's pliable enough to force the shaft through, position it, then let it cool in place.

 

[transatlantic]

https://www.servocity.com/set-screw-shaft-couplers
Search through this sight for a while. They do what you want to do. It might take a while to find the answer.
---edited----
https://www.servocity.com/heavy-duty-clamping-shaft-couplers

https://www.servocity.com/clamping-shaft-couplers-6776

https://www.servocity.com/0-770-set-screw-d-hubs

Not sure what you mean with that. Those are for connecting two shafts. I have an 8mm shaft on the motor and a 13mm hole on the wheel.

 

[transatlantic]

If you can find the space, drill a hole into the side of the wheel (use a hand drill!) and use a setscrew. Every other solution includes buying or machining a hub. that the shaft slides into that bolts to the wheel.

In your case, it sounds like the shaft is smaller than the bore, so maybe use some material to close that gap...like epoxy fill or wood. If you use epoxy you can use a 8mm rod wrapped in wax paper as a plug to keep the hole clear as the epoxy cures so you can twist it out and insert the motor shaft.

If it's not very high torque then you might be able to get away with all of this and just JB-weld or epoxy the motor shaft right into the wheel but it may not be as durable or as removable as you want.

Honestly, I've always found attaching shafts to random wheels a major PITA. I wish more motors had square shafts and I had a square drill.

Thanks for the idea, I may try that if nothing simpler crops up.

If the bore in the wheel is smaller than the shaft, then get a small round file and a small flat file and carefully file away until it fits! Hopefully, it won't have to be exactly concentric.
Depending on what type of plastic it is, you may be able to heat it up locally until it's pliable enough to force the shaft through, position it, then let it cool in place.

As mentioned, the wheel bore is 13mm and the motor shaft is 8mm

 

[alec_t]

What is the depth of the 13mm hole (i.e. the wheel thickness)?

 

[transatlantic]

What is the depth of the 13mm hole (i.e. the wheel thickness)?

About 35mm

 

[ronsimpson]

I have connected one of these to the motor shaft and then used 4 screws to connect to a wheel.


This next item; you can get with a 8mm hole for the motor and on the other end with a 13mm hole for a short 13 shaft that fits into the wheel.

 

[transatlantic]

Ive only seen the couplers with up to 10mm bore unfortunatley. Have you actually seen an 8 to 13mm?

 

[ronsimpson]

I have some that are 0.25 inch. They are used to extend the length of a radio volume knob.
I know I have used a drill press to enlarge the whole size.

I found a number of brass tubes that are 8mm inside and 13mm outside. They are meant to be a bearing, not a coupler.
I think you need a splined shaft for the wheel. Some way so the wheel and the shaft connect.

 

[Mickster]

The initial post leaves out quite a bit of information, which could be particularly relevant to what is actually required.
If the task at hand is to simply attach the wheel to the motor shaft, then something like the circular flange Ron shows in post #11 should easily do the job.
Place the flange on the wheel, mark some holes and drill the wheel, attach the flange to the motor shaft and then secure the wheel to the flange.

If more precision than that simple process is required, we need to know.

Are you looking purely for an off-the-shelf solution?
Do you require concentric alignment and a minimal amount of run-out?
What tools are at your disposal, to perform any small mods which may be necessary?

If you have a drill press and a 16mm bit, something like this would do the job, as long as you don't require absolute precision:
https://www.banggood.com/8mm-Flange-Coupling-Steel-Rigid-Flange-Coupling-Motor-Guide-Shaft-Axis-Bearing-Fitting-p-1206973.html?cur_warehouse=CN
Drill the wheel center hole out to 16mm, at a depth > 10mm, mark and drill holes for the mounting fasteners, mount the flange to the motor, then the wheel to the flange.

If you have a lathe, you may be able to take successive cuts up to 1.5mm DOC off the flange 16mm boss and turn it down to 13mm, to fit the wheel bore. Mark and drill the mounting holes as required, blah blah.

You may wonder why you are being asked to field a load of questions, but we don't know what you know.

Please state your requirements, otherwise we are just left to guess and offer opinions/ideas/search results which may be way off the mark for what fits your problem.

Regards.

 

[ronsimpson]

Expanding on post #14;
It looks like the motor shaft has a place for a screw on the end. Show in light blue.
I found bushing with 8/13mm size.
Using the item form Post #14.
The wheel, not shown, sits on the bushing and is pinched between the washer and the flange coupling part.

 

[transatlantic]

Thankyou for the further suggestions!

If you have a drill press and a 16mm bit, something like this would do the job, as long as you don't require absolute precision:
https://www.banggood.com/8mm-Flange-Coupling-Steel-Rigid-Flange-Coupling-Motor-Guide-Shaft-Axis-Bearing-Fitting-p-1206973.html?cur_warehouse=CN
Drill the wheel center hole out to 16mm, at a depth > 10mm, mark and drill holes for the mounting fasteners, mount the flange to the motor, then the wheel to the flange.

Unfortunately, there isn't enough meat to drill a 16mm hole, or to mount the flange. If you have a look a the image I posted, there is only about 2mm around the 13mm bore. Although I guess I could attach some kind of hubt


As to your questions. It doesn't need to be super accurate, as long it is running visibly true then that should be fine. It's running at a very low RPM (~60), so any vibration caused by run-out probably won't be noticeable. As for tools, I do have access to a drill press, but not a lathe.

 

[Mickster]

Going a little bit further with TCM's suggestion from post #2..

Unless there is going to be a lot of load on the wheel, this could be made with a drill press, but you would also need a washer welding on the end and a tap to make holes for set screws. I left the length at 36mm to allow for a washer with an ID of 13mm to be slid over and tack-welded in position.
The wheel would be sandwiched between the welded washer and another washer, secured with an M4 bolt going through to the motor shaft.
You could use set screws which protrude slightly and file a key-way into the wheel, to prevent the load on the wheel from unscrewing the M4 bolt, depending upon direction of course. If the motor turns clockwise when looking at the shaft end, this is something you will need to consider.

Drill 4mm and 8mm holes as shown, in a length of 13mm rod, drill & tap holes for the set-screws.
Measure the depth of the 13mm hole in the wheel and position the washer so that the shaft will be a couple of mm short of being flush with the outside of the wheel.
Weld the washer from the back and clean up as required.
Secure the bushing to the motor shaft, mount and secure the wheel with another washer and M4 bolt.



Just an idea, I hope you can use it for your application.
Regards.

 

[transatlantic]

Hmm. very good! .. but I would need to drill exacty on center for all that to line up! ... gonna do a little research to see how I can accuratly drill holes in rod section

 

[Mickster]

Check this out:

 

[transatlantic]

I like this technique