I’ve been building up to this for a while and have had some preliminary sketches kicking around since pre-Covid-19, yes, as long ago as that!! The fact that I have now got 6 or 7 sets of sides that will need profiling at some stage has moved this project up the priority list (ahead of the fret slot saw) so today I started the CNC machining of the top plate and the drive gear ring for the main turntable. This has 100 teeth and the other small gear, which will will be mounted on the motor spindle, has 10 so the sanding disk will be spinning at about 140rpm. I do have a speed controller as well so if this seems a little fast I can slow it down a bit. The gears are created with a little app in VCarve called Gear Maker and, once created, I can export them as Illustrator files and incorporate them in my main drawings.
I laser cut a trial in 2mm MDF to allow me to check the spacing of the gear centres but I think it all looks ok so far. The main turntable bearing is a 450mm diameter heavy duty lazy Susan rotary thing which I am hoping is up to the job.
The sanding dishes will simply locate on the turntable on registration pins so they can be easily swapped over for different radii or for flat.
I‘ve had a busy day! All the parts are machined and mostly assembled, with the exception of the spacers that will form the sides of main turntable assembly. Tomorrow I will machine a new MDF dish with the 8mm drive pin holes in. Not sure if I will need a central screw to hold the dish to the turntable but this can be added is required later. I will also draw up the plywood base unit, which will have storage shelves for a couple of radiused dishes and for a flat one for the rim front.
I have run it and it spins really nicely although it is a bit noisier that I expected. Maybe the ‘lazy Susan’ bearing ring is being pushed a little hard but it will have to do for now. Hopefully it will settle down a bit once it has been run for a bit.
Further updates over the weekend if I manage to find time between watching all the Live Streaming!
It lives!! I didn’t have time to machine the sanding dish itself today but the rest of the machine is fully assembled, wired up and ready to go! I have mounted the speed controller knob on the underside as this won’t need to be played with on a regular basis. The main NVR switch is mounted on the front panel and the start seems to be fairly soft so I’m not worried about the laminate drive gear coping with the strain. I’m now in two minds about mounting it on a permanent base as it will take up so much more space whereas now, apart from the motor, the whole assembly only measures just over 75mm thick and could easily be stored on edge when not in use and now be clamped to a bench when needed. I hope to have pics and vids of it being used ‘in anger’ in the next week or so, just depends on other work demands.
It lives!! I didn’t have time to machine the sanding dish itself today but the rest of the machine is fully assembled, wired up and ready to go! I have mounted the speed controller knob on the underside as this won’t need to be played with on a regular basis. The main NVR switch is mounted on the front panel and the start seems to be fairly soft so I’m not worried about the laminate drive gear coping with the strain. I’m now in two minds about mounting it on a permanent base as it will take up so much more space whereas now, apart from the motor, the whole assembly only measures just over 75mm thick and could easily be stored on edge when not in use and now be clamped to a bench when needed. I hope to have pics and vids of it being used ‘in anger’ in the next week or so, just depends on other work demands.
