This is NOT a coffee cup!

[Billc]

A marketing thought for your invention, Mark, as the title of this thread pointed out, "this is NOT a coffee cup". To call it the Chalkley "Cup" may be miss leading...or even dangerous to those who order it sight unseen.

One of the tests given to school kids is a series of pictures, the student must pick out the one item that doesn't fit with the rest. O.k., in our example we'll use 4 pictures: Your invention, a keg of beer, oh maybe the Atlantic ocean, and a "normal" cup. For the question: Which one of these items doesn't fit?

My point? Maybe calling your invention the "Chalkley Keg" or "Ceg" to be clever.

 

[MChalkley]

Billc - I have referred to it as a "tank" on numerous occasions, since it actually does perform the functions of both cup and a tank and more closely resembles the latter.

MarkC

 

[Harv]

Gordon -

Thanks for turning me on to that ForceField web site for buying my magnets. I'm a huge supporter of small business, and this little home-based operation is first rate.

I ordered my magnets over the internet late Thursday night (Friday morning for all practical purposes), and here I sit with the package in my hand the following Monday. Now that's service.

I now have enough magnet power that I'm thinking about storing my 'Bota in a steel shed and just sticking it to the ceiling so it's out of the way. /w3tcompact/icons/laugh.gif

I can now assemble my second Chalkley Cup and have it ready for field trials this coming weekend.

Can't wait.

 

[MattB]

Thanks Harv, for turning me on to this site! Never have I seen a discussion board that would spend so much time on self holding cups (as opposed to cupholders)

I'm not much of a tractorer myself, but I can offer some insights about the magnets and the design.

Firstly, I'd skip the sign magnet material entirely, and use only a couple or 3 of the hard drive magnets glued to the outer edge of the bottom of the cup (3 would probably be best for stability). Then I'd go to the local supply shop and get some neoprene. My local bearing and belts shop sells the stuff in various thicknesses by the running foot, a couple feet wide. Cut a piece of that out the size of the bottom of the cup, and glue it over the magnets. That will keep it from sliding, and protect you beloved tractor. Double it up if its still too strong.

Not having a magnet in the center will allow the cup to conform to the contours of the tractor's fender. You'd probably have to alter your design to specifically fit the tractor in question.

As for the magnets themselves, we've recently done some lifting tests. Using two flat pieces of steel, hanging the upper plate securely and attaching a magnet to it, then attaching the other plate to the magnet. from the lower steel plate (suspended only by the magnet), we hang a 5 gallon bucket and fill it up with sand. When it falls, take a little sand out, and weigh the bucket.

Using this technique, we were able to determine that even the smaller hard drive magnets can lift a LOT! Item #21 (much smaller than the item #42 which Harv ordered) on our forcefield website was able to lift
more than 60 lbs.

The surplus hard drive magnets are definitely your best bang for the buck (free if you do your own salvage work). In addition to computer shops, you might also check scrap metal dealers (lots of aluminum in hard drives), and surplus electronics stores if there's such a place around.

On a related note, I thought y'all might find this picture, which my mom put together, appropriate for this discussion board.

Happy tractoring!

-Matt B

 

[WVBill]

Matt:

In your test setup, isn't the force of the magnet multiplied or "amplified" by the steel plates? Since each plate becomes magnetized, doesn't that effectively increase the attractive surface area? Would you get the same results if the bucket were attached directly to the magnet?

Just curious.

Also a thought - if you stuck one of these super magnets to the fender of your tractor, wouldn't nuts and bolts then stick to the fender too? This would eliminate the need for the "magnetized parts tray".

Bill

 

[MChalkley]

Bill - Now that's an interesting possibility! Maybe we could stick a couple of those magnets on the underside of the fender, then anything (ferrous, of course) you put on top would stay there. Definitely has possibilities...

MarkC

 

[MattB]

Yes, you are correct in that a steel plate behind a magnet will make it stronger on the other side. In the pictures in this thread of the mega-gulp, that steel bracket being left on the hard drive magnet will make it stick harder to the tractor.

In our tests, if we glued the magnet to a non-ferrous plate on one half, and stuck it to a steel plate on the other, we would probably get slightly less impressive results, but I don't have any glue strong enough to test this with the larger magnets.

Perhaps I will give it a shot when we get around to testing some of the smaller magnets.

As for magnetizing the tractor by placing a magnet directly on it...yes, but only in a very small area around the magnet itself. All your nuts and bolts will jump to the magnet itself...which is not a bad thing. I use them for this purpose all the time when working on cars. Great for holding tools, nuts, bolts....

Those little stainless bolt trays are very useful indeed, and a good value from harbor freight, but if you don't have a harbor freight store nearby, a pie pan and a couple strong magnets will work just as well.

Or just use the plain magnets...

-Matt

 

[Harv]

Matt -

<font color=blue>a steel plate behind a magnet will make it stronger on the other side</font color=blue>

This may explain why my seemingly large magnets don't appear to have the holding power that Mark's do.

I understand your suggestion about placing three magnets around the perimeter of the base, but I'm going to try putting a couple of the incredibly powerful magnets you just sent me into that made-to-order recess in the center. To build up the thickness, reducing slippage and protect my shiny orange paint, I'm going to glue some floor-matting material to the rest of the base and see what happens.

I'll post the results, along with my usual photo spread, as soon as I can.

Thanks for the info and suggestions, Matt. Keep 'em coming.

 

[gordon]

Harv, glad I could help and I'm also glad you got the same great service that I got as well. Hope the magnets work out for you I know that I'm more than happy with the ones that I bought from them. I'm with you on supporting a small business but what even makes me feel better is the great service that you recieve from the quality small businesses. For anyone else interested in getting some strong magnets here is the web address--http://www.wondermagnet.com/dev/main.shtml
Gordon

 

[Harv]

Chalkley Cup - revision #2

I compared the grip strength of my previous magnet with the ones I got from ForceField, and it was no contest. Even the smallest of the new ones proved to be nearly twice as powerful as the one I had been using. Wouldn't you know -- the one disk drive I had to cannibalize had the wimpiest magnets of all. /w3tcompact/icons/tongue.gif

For this revision I decided to go with the "medium" strength magnets (of the 3 different types I bought), which is #41 on the ForceField web site. Although much more powerful than the one I had been using, I opted to use two of them just 'cuz I don't want to mess around this time.

I used 2-part epoxy glue to secure them into the recessed area on the bottom of the cup, and then applied "Goop" to attach rubber floor matting material to the perimeter of the base. It's hard to tell in the attached picture, but the magnets are ever-so slightly recessed relative to the matting. In other words, it's the rubber that makes first contact with the tractor, and the magnets then draw down and compress the matting all around. Makes for a very stable cup.

The lower portion of the attached picture shows a full cup stuck to the side of my pickup truck. No problemo.

The part that was hard to foresee, but in fact worked out quite well, is that by lifting up on its handle, the cup is easily tipped up, breaking the magnetic connection. It is pretty much the only way to separate the cup from a metal surface.

Actual field test this weekend, but so far so good. /w3tcompact/icons/smile.gif