The object here is to make a high speed output from a relatively slow speed induction motor which is a lot quieter than these high speed brushed motors. The possible uses for this could be: Mount it under a table to use as a small spindle moulder type machine, mount it on a cnc (it would be a bit heavy but it could work for this), small high speed polisher and maybe some things i have not thought about too.
If you use a 2 pole motor then that will give you a final speed of around 10000rpm but you will lose a lot of the motors power, I am guessing that you will be left with .1kw from a .37kw motor. So dont be expecting to run circular saws with this setup maybe 4 inch sawblades but nothing much bigger. For a start I doubt if the gears you are using here will stand up to to much force being pushed through them without stripping if any physics people out there know the relevent maths I would be interested to hear it and what size motor would be usable.
Keep your eyes peeled however because I am looking out for a bicycle hub gear (like they used in the raleigh choppers etc.) and once I find one I am sure that will be able to handle much more torque and may even be capable of getting useable force out of a much bigger motor, maybe even enough to run a full sized spindle moulder or circular saw.
This instructible requires ripping apart a cordless hammer drill and maybe a router. So unless you have broken ones lying around then forget it, put up with the noisy router and use the cordless hammer drill for its intended purpose.
The parts you see in the picture where harvested from a Bosch cordless hammer drill ( sorry dont have the model number ) I think it has to be a hammer drill as the standard drills use plastic ring gears and planet gears I very much doubt if they would stand up to this abuse.
All these parts (amongst others) are used to reduce the speed and increase the torque of the dc motor used in the drill, we however are going to use them to increase the speed of our motor which as I said above will decrease the available torque.
You are going to need a clean work area to finally put this all together if it has even a small amount of dirt in there at best it will stop dead and at worst it could shred the gears.
I am sure there will be people who will say "just use v belts" and yes you could easily use v belts to get the same speed from the same motor, in fact I have a old Davla table saw that does just that with a more powerful motor 1.5kw I think but that is little less noisy than my mac allister circular saw with its brushed motor. I am looking for quiet operation and hopefully this will provide just that.
Step 1: Make a Boss
start by making a boss to fit your motor shaft. It doesnt need to be anything fancy, just a slug of 40mm round bar bored out to fit the shaft and one or two grub screws to hold in onto the shaft.
If you want to get all serious and you are able you could put a keyway in it too but you will still need a grub screw to hold it in place.
Take the chuck driver and remove the tangs on the back (not the planet gear pins you can remove these by knocking them out with a punch but keep them safe you will need them) which are used to drive the chuck in the drill simply grind them down with a angle grinder but dont go mad you want to keep it flat at the back. With the benefit of hindsight I now realise you could make use of these tangs by opening out your boss to accept them, they may even help with keeping it all square.
Once you have removed the tangs you need to attach this part to your boss, if you can find a shaft the same size as your motors shaft with a tapped hole in the centre then this is ideal you can secure the Chuck driver in place with a countersunk bolt this will help you attach it dead centre on your boss. otherwise your just going to have to be really careful and do it on the motors shaft.
Brazing would be a good solution here but I dont have access to any brazing gear so welded mine in place.
As you can see by the picture my pins are discoloured this is due to heat and will have destroyed the hardness of these pins so I suggest you remove them before working on this part then replace them once you are ready. All is not lost though I can still remove them and replace them with the pins from the secondary sun gear as they will not be needed, just a little harder to get them out this way.
Step 2: Fitting to the Motor
You now need to measurement from the top of the boss assembly to the motor seating ring because you need to make the first bit of the housing to fit this measurement quite precisely. You will notice that mine is in two bits this was more due to making it up as i went along rather than any design. I suggest it would be better made in one part.
Step 3: Ring Gear Section
This needs to be a fraction smaller than the thickness of the ring gear so the top plate once tightened will clamp it in its proper place.
Step 4: Nearly There.
As far as the drive gears are concerned anyway, slot the sun gear inside the the setup and you are at a stage where you have a high speed drive. It will run with just gravity holding the sun gear in place I will get a video posted as soon as I can but please take care when testing like this, if it does work its way out of the gears it is likely to go shooting off in any direction.
You now only need to decide what your going to do with it.
I am going to use it to drive 6mm shank router bits will post pics as I progress.
Step 5: The End Product
Once again my rush to complete has let down my instructable as I forgot to take camera for final stages but however it was not hard but did add to the noise output quite a lot which I assume is due to me not getting everything lined up well enough, will work on that in the future. Basically I dismantled the knackered router I had and sawed through the shaft to remove the coil. then turned the shaft to fit inside the final sun gear. to keep it in place I drilled a 3mm hole part way into the shaft and used a 3mm ball bearing as a key. I will take and post some pictures when I take it apart for regreasing. The only hiccup I have had is when it stopped turning because I somehow forgot to tighten the grub screw on the boss and it worked its way loose.
It is still quieter than your average router though (NOTE: you wont believe me from the video if you have the volume too loud I found setting it to around 1/3 was approximatly right on my pc). The video shows me using a rounding off bit with my machine, it is pretty good and produces a reasonably smooth cut. I have finally calculated that the bit is spinning at around 9560rpm a little on the low side for routers and it shows if you use a bit that removes more wood than the rounding bit. Regardless of how you have the volume set you will notice that the noise increases quite a bit while cutting wood, when it is just running on its own however it is not bad.