I have noticed there are many very interesting projects on this forum that use the 28BYU with the ULN driver, and I plan to make several projects wit this cheap and simple motor, and maybe some other similar Stepper motors.
One common problem I am facing is that I have not been able to locate anyone who makes couplers or gears that fit this device. Most projects seem to be made by people who have access to machining hardware which I don't
Can anyone share a good source for this?
I have searched all over eBay, and model shops and even sent question to motor suppliers, but all ask me to let them know if I find anything.
It will be much easier to drive stepper motors with a proper stepper motor driver board. The Pololu A4988 is an example.
I presume you are talking about hardware that will fit the 28BYJ motor. What diameter shaft does it have and what exactly do you want to connect to it? Also, I think you need to explain how you want to arrange the motor and other stuff that it drives. For example could you use a toothed belt drive - these are commonly used in RepRap projects (see the RepRap forum).
Stepper motors don't run very fast so an unbalanced connector would probably not cause a problem. The brass connectors in large electrical "chocolate block" connectors will fit the 5mm shaft on the steppers I have. Crude but functional.
Hi
The motor has a 5mm shaft diameter with a flat section , and i was hoping to connect it to a small toothed drive that would drive a larger wheel which drives a M5 brass rod.
I am looking for a end shaft of 1RPM.
I am trying to make a 'Barn Door tracker' controlled by an Arduino board.
See picture below, examples from Meccano.
Any ideas??
Thanks
Perhaps you could bore the Meccano pinion to 5mm to fit on the motor shaft? Then you could use Meccano parts for the rest of the project.
@MarkT - I did mention the A4988 just as an example, but just out of curiosity should I infer from your comment that what I call "proper" stepper drivers (a) aren't available or (b) aren't necessary for very low current stepper motors?
Yes I think I will bore out the Meccano to the required dimension. This requires precision drilling and alignement otherwise it will not work.
I also knocked out the center of the larger gear and now have to find a way to fix / solder a M5 nut in its place. That was when the motor turns, the M5 brass rod will go up and down.
I am just amazed how little mechanical hardware is available for these types of applications. It is very strange. It looks like a good opportunity for someone to set up a show to handle this type of products....
As there is already a centred hole in the pinion drilling it out to a larger size should be fairly simple. Use good quality drill bits and ideally have the drill in a stand to keep it steady and vertical. Another possibility is to hold the pinion in the drill and fix the drill bit in a vice - guarantees concentricity.
I suggest you clamp the nut on the gear with a piece of threaded rod and a second nut. Then you can spin it and check that it's concentric. I would be tempted to fix the nut with epoxy rather than solder unless the loads are very high or the temperatures are high. JB Weld epoxy can withstand higher temperatures and claims to be used to fix engines. A friend glued an injector in a diesel engine with it.
Hi
I decided to take your advice.
I opened the centre hole of the smaller gear, and it now fits on the motor.
I am now planning to tap the larger gear with an M5 thread. Bought the thread cutter on ebay, (only few pounds) any will try this.
As a backup I have ordered the epoxy and will use that with M5 nut, and cleared hole.
A couple of things to watch when trying to tap the hole in the large gear ...
You need some arrangement to hold the tap perpendicular. For example if you have a drill stand mount the tap in the drill chuck and put the gear on the base plate of the stand. Turn the chuck by hand only. Another possibility might be to drill a hole in a piece of timber so the tap is a snug fit, but not actually screwing in the wood. Then hold the wood in a vice so that the hole is perpendicular over the gear. YouTube is probably a good place for lessons about tapping (lessons about most things!).
You need to drill the hole to the correct size for the tap. An M5 tap needs a 4.2mm hole. You might get away with 4.5mm but 4mm is likely to be too small. It may be worth trying in a scrap of metal first.
Hold the boss of the gear while you are tapping. If you hold the gear by the toothed part the boss will come away from the gear.
Turn the tap slowly. It is very easy to strip the threads or to re-start the tap in the wrong place. Regularly unscrew the tap a little bit to make the cut pieces beak off.
If you have the boss that came off the gear in the picture perhaps you could practice tapping that. (And if successful, glue it back in place with epoxy).
One common problem I am facing is that I have not been able to locate anyone who makes couplers or gears that fit this device. Most projects seem to be made by people who have access to machining hardware which I don't
Can anyone share a good source for this?
Gears are almost always specialized, but in general you should be looking for "shaft couplers" -- I imagine you have just not looked in the right places, or used the right search terms. McMaster-Carr sells a huge variety of shaft couplers in both American and metric measurements. McMaster-Carr
Hi,
I managed to succeed in Tapping the Meccano gear that I bought.
http://
I had to buy a small Tap to thread it, but now it works well. I think this is preferable to the glue or insert alternatives that I had as backup plans.
I am planning to use this with a Rotalink stepper i bought on Ebay, with a Easydriver stepper driver.
Robin2:
Turn the tap slowly. It is very easy to strip the threads or to re-start the tap in the wrong place. Regularly unscrew the tap a little bit to make the cut pieces beak off.
My little extra would be turn the tap back-and-forth the whole time, not just occasionally
and unscrew it the whole way at least once, cleaning the tap before re-inserting. WD40
or other good penetrating lubricant will help. Trying to tap anything smaller than M3 by
hand (without a jig) is likely to break the tap. Don't buy cheap taps for small sizes, they
cut too big and clumsy (esp in soft Al)
I have it on good authority that machine taps (with helical flutes) are far superior to
the commonplace ones (machine tapping doesn't involve reversing at all I believe).
