MAGNETICALLY ACTUATED GARBAGE DISPOSAL

[solo]

@solo

Sounds like the device was a form of levitation to remove most of the friction from the bearings. It would still be fun to see.

The other thing that is really fascinating as a kid it to see magnetic braking (eddy current effects). If you have never seen this take a rare earth magnet and drop it through a 3 or 4 foot long copper pipe of inside dimension similar/close to the magnet size. Mentally time the fall. Then drop the magnet outside of the pipe and compare the two times. You use Copper because it is a good conductor and is non-magnetic.

Sounds like a science fair project for the grandkids.

 

[Provincial]

Hi @Provincial

Good idea! Yes, it is amazing what we will put up with for so long. Sometimes we get so used to an inconvenience that we don't even recognize it. I have my own list and my wife has an even longer one ... for me!

You could probably provide the time delay with a 555 time IC or maybe something even simpler. Either way you seem to need constant power to the electronics. If I understand correctly you only need for the Reed switch to contact as the door is moving. Then the contact is broken as the magnet move on past the sensor. You might be able to get around needing a power supply and only need a battery by using an FFT transistor to control the SSR input and resistors and capacitor at the FFT gate to provide the delay timing. There would be no power drain for the control when the operation is complete.

If you would like I can see if I can figure out a very simple circuit to fit in my disposal controller. Then with the cheap SSR that I used you could power the lights to most of or all of the house! But if you already have a plan and have spent the money then ....

Put some sort of thick coating on the magnet to protect it. Dip it in epoxy or anything (RTV, construction glue, etc.) to keep the salts and water a way. Maybe connect the sensor like I did and the drill a deep hole in the end of a longer board to hold and protect the sensor and then use the board for attaching.

By the way, connect a switch to near the house door to activate the circuit might be nice so that you can turn out the light, get in the car with the garage door light on and then open the garage door.

Another thought. If you have an old garage door opener system it is probably chain or belt driven. Attach the magnet to the belt or chain and put the sensor a few feet from the motor box. Just depends on your configuration, but I would prefer to have it up and out of the way. Mount the electronics box on the garage door motor box. Once every 10 years or so you would have to climb a ladder and change the batteries. Or their might be a DC power source at the door opening motor. I am assuming you have a wireless door opener and their would be DC for the receiver.

Dave L.

I had prewired a circuit for this light in EMT conduit. I just have to mount the magnet, sensor, and control. I bought an $8.00 time control from Ebay, so I'll try that for now. I'm mounting everything but the light socket at ground level so I won't have to get on a ladder. I'm even mounting the light where I can replace the lamp with an extension pole. I'm too old to be climbing ladders!

I'll experiment with the stuff I have, but will contact you if it isn't working as well as it should. Thanks very much for the offer of help!

By the way, as a result of our conversations about feed rates over on the PM section, I've decided to purchase a 32-tooth gear from Grizzly to adapt to my Metal Max so I can cut 1.75 MM pitch threads. I'll let you know how that works out.

 

[B2]

Hi @Provincial

By the way, as a result of our conversations about feed rates over on the PM section, I've decided to purchase a 32-tooth gear from Grizzly to adapt to my Metal Max so I can cut 1.75 MM pitch threads. I'll let you know how that works out.

Please do let me know. It has been a year since those conversations so they are a little blurred! I do not recall what set of change gears you actually have, but my poor memory is that there were only a couple. Is this incorrect? I think the sheet name that we were using for the Metal Max is uwMMLB-Norton. I ran the spread sheet TPI generator on a few external gears and found that with 4-B and 40-127 at the gear box side and 32-120 at the spindle side I found that you should get 14.55208 TPI = 1.74545 mm/thread.

On the other hand I just threw in a bunch of change gears to see what would happen if you had others to choose from. There were closer fits plus there was an exact match, but do you have these gears? (40, 48 or 35T) .

Exact 1.75mm pitch at rows (column A) 4976 and 5013:


Dave L.

 

[Provincial]

Dave, looking at my notes, it appears that the 32T gear is for 1.25 MM threads. I didn't have notes for the 1.75 MM thread, probably because I couldn't find a 35T spindle gear. I guess I'll have to find a blank to modify or have one printed if I need to cut 1.75 MM threads.

It is kind of frustrating that a "metric" capable lathe would not have gears for some common metric threads. An easy corner to cut, I guess.

 

[B2]

@Provincial

I don't have a clear idea of what external gears you actually have to work with for your Metal Max. What are they? Let me know and I will run the program again.

I bought a Prusa 3D printer a year ago and have only made a few things on it. I was thinking of making a gear for my older SB lathe, but have not tried yet. I suppose if you provided the CAD program and the Gcode I could try for you.

When I got my 1440GT I started using the SB-10 Heavy less and less. Then I started thinking I might do a restore job on the SB. I actually prefer to use it due to the past experience, but it is not very precise any more... to the point that I actually have trouble cutting a thread via multiple passes.

Dave L.

 

[Provincial]

@Provincial

I don't have a clear idea of what external gears you actually have to work with for your Metal Max. What are they? Let me know and I will run the program again.

I bought a Prusa 3D printer a year ago and have only made a few things on it. I was thinking of making a gear for my older SB lathe, but have not tried yet. I suppose if you provided the CAD program and the Gcode I could try for you.

When I got my 1440GT I started using the SB-10 Heavy less and less. Then I started thinking I might do a restore job on the SB. I actually prefer to use it due to the past experience, but it is not very precise any more... to the point that I actually have trouble cutting a thread via multiple passes.

Dave L.

Dave L.

Sorry for the time lag.

I determined that that gear position C-6 is 1.0 mm lead when using a 40-tooth gear in both the upper and lower positions of the banjo drive. To get 1.25 mm, I need to speed it up by a factor of 1.25, and by changing the lower gear to a 32-tooth one, it speeds up the quick-change input by that amount. I can get a 32-tooth gear from Grizzly for their G9249 12 x 37 lathe which I hope will fit, or at least can be modified.

Your analysis for the 1.75 mm pitch agrees with my conclusion that I can use the B-6 position. The thread chart says that a 40-tooth upper gear and 40-tooth lower gear gives 2 mm pitch in that position. With a 30-tooth upper gear, it gives 1.5 mm pitch. To split the difference and get 1.75 mm pitch, a 35-tooth gear in the upper position should work perfectly. This agrees exactly with your calculations.

I'll have to verify the modulus for these gears and then look for a source. The upper gear has no hub, is 10.3 mm thick, has a 16 mm bore and a 5 mm keyway.

We can continue this discussion on the old x-feed rates on PM lathes thread, which is where we originally started this discussion.

 

[B2]

Hi @Provincial
I replied at the following thread, which I had used to originally post my threading Excel workbook. So we have moved it out of this thread.

TPI Feeds X-Feeds: Generalized Excel file for your Lathe

Dave L.

 

[wachuko]

Brilliant. I have the same situation and did not wanted to drill a hole for the vacuum switch...

This is a great idea! Thank you for sharing.