The Gumball Machine

This project is used often here in Langley BC for grade 8 Woodwork classes. I've been using it for the last few years. At first I thought the kids wouldn't be interested but they are REALLY excited about this project and since than the kids have built 100's. This Instructable is meant for the shop class but anyone with a drill press can do it.

Here are the Learning Objectives:
-The student will learn to  Measure and Layout a design than apply that knowledge in a practical and fun project.
-The student shall demonstrate the safe use and setup of a drill press.
-The student learn the effective use of sandpaper with wood.
-The student will use creative design and problem solving to build a unique design with wood.

Materials:
-Wood Blank approx 3" by 3" by 5"
-Assorted pieces of 1/8", 3/8", 1/2" plywood or solid wood.
-1 piece of 1" dowel... about 4" long.
-Assorted dowel pieces... 1/2" diameter works well.
-1 Canning Jar. 500ml is best.

Tools:
-1" Forstner drill bit.  (i have 3 set up on 3 different drill presses.)
-1/2" Forstner drill bit (for attaching leg dowels)
-3/4" Forstner drill bit (for drilling hole in gumball dispenser)
-Drill press
-Assorted clamps (Jorgensen's work really well)
-Sandpaper 120G, 180G
-Band saw or scroll saw

Submitted by HD Stafford Middle School  for the Instructables Sponsorship Program

The wood Blank I use is from cedar poles used in fencing. Don't use pressure treated stuff... it can be toxic. I put them through the jointer and planer so that they are 3" square. If you have higher level grades they can do this step but my students are a bit young to be doing this.

Set up the Bandsaw with a sliding fence and a clamp. Show the kids how to mark off 5" and cut. Encourage the students to take their time and cut slowly so the cut will be straight. You can use any saw you want to but i find the band saw works well. I use the "5 rule" which is:

-Keep guard 5mm above workpiece
-Keep fingers 5cm away from blade
-Keep all 5 of the digits on each hand.

Pull out a ruler, pencil and square.
Layout a centerline along the front face and top. The kids can choose at this point if they want the turning dowel that dispenses the gumballs coming from the side or the front. I call it the "nose" (front) and "arm" (side). If you want you can limit the design variables to keep it simple or go all out. I  once had a group of fine arts girls who made the most amazing gumball machines with all sorts of creative designs. One girl did a gumball machine which was a tree... the turning mechanism was on the side disguised as a branch with a swing hanging from it. As she turned the dispenser the string wound up and raised the swing. Awesome design.

Once the kids decide, layout the hole centers. The Nose (or arm) are centered 11/2" down from the top edge and the mouth is 1 1/2" up from the bottom edge. Mark the top hole where the gumballs go in centered in the middle of the top. I explain it all with drawings on the board than move the kids to a table and actually demonstrate. If you have any kids in your class who are special needs and might find measuring tricky; set up before hand to use theirs as a demo. Just don't point it out... most kids don't want to be treated differently from others. Its all about inclusion!

I set up 3 drill presses with all the clamps setup and ready to go with 1" forstner bits. Eases up on line-ups for tools. Don't want the kids to be idle!
Jorgensen clamps are great for this... check out the pictures. The best sequence for drilling is to do the mouth starter hole... drill it in only 1/4" and than the nose (arm) hole next. The top hole can be done next and the angled mouth hole last.

Some details....
Drill the nose (arm) hole in about 2 1/2". its okay if it goes almost all the way through the block.
Drill the top hole in about 2"
I've built a jig that holds the block at a 45deg angle for drilling the long mouth hole. What also works well is to rotate the drill press base 90 deg and clamp the block on at the correct 45deg angle. I've also seen simple shims done but remember you're dealing with a 1" drill bit attached to a big motor being controlled by a kid. Might as well make it student-proof!
***update*** i have attached some pics of the jig to help everyone out...
When you drill the deep angled mouth hole be sure the kids put the top hole DOWN... every class i get a kid drilling in the wrong direction.. :-) The depth is kind of hit and miss... just keep going until the drill goes through the nose(arm) hole completely.

The 1" dowel is for the dispenser. To figure out the length push the dowel all the way into the nose (arm) hole  until it bottoms. If it is really tight you can set the kids up on the lathe and a piece of emery cloth and get them to turn it down until it spins smoothly in the hole. Keep an eye on them that they don't try to use the disk sander or belt sander. Disastrous results with dowels spinning at outrageous speeds.

Once the dowel is in place and spins easily you can mark a cutting spot depending on how much they want sticking out. Take this moment to also mark the center of the dowel through the top hole. This is where they will drill the 3/4" hole for the gumball to drop into.

Cut the dowel with a handsaw. Don't use the bandsaw or it will invariably spin a piece of dowel. not good.

Mount the dowel in a drill press mounted with the 3/4" forstner. Drill  in about 5/8" of an inch. You want to go deeply enough that the gumball doesn't stick out and stop the dowel from spinning and spitting out the gumball.
The kids love it if you explain what happens if you drill all the way through... you gently turn the dowel and OHNO the gumballs rain out all over the floor. Feel free to exaggerate at this point.

 It was pointed out to me that if the dowel is pulled on it would rain gumballs! Great point! The fix as suggested is to drill a small clearance hole in the back of the block so that a screw can be pushed through and screwed into the dowel... make sure it isn't too tight or the dowel won't turn. Thanks for the suggestion jonny!

I've done this project usually by allowing the kids to paint. This works well but sometimes it really backfires. Kids that want to do the bare minimum will just paint the bare block with a dispenser sticking out he side. I've found that kids will often do this as a way of self-sabotage... "if I don't try than I won't be disappointed if it sucks" seems to be the idea. Well... I wont let kids do that. I've noticed so often that if I push kids to do well they will work to meet high goals. Set low standards, get poor results.
So here's my plan.
Don't let them use paints. Teach them how to make legs, feet, arms, eyes, mouths... whatever they can throw at you... out of wood. With a scroll saw the kids can cut really amazing stuff.

Insist they come up with 10 simple sketches all using the same block proportions. Don't let them be the same theme... Talk about the designs, discuss what they like most, make practical suggestions than send them back to the drawing table to draw a full-size sketch. When they come back to you, break down each piece into what it would look like and how it will attach to the block.
See what works for you... to paint or not to paint... I've seen great results both ways but I think the trend is to make more thoughtful designs if they can't use paint.

My basic method for attaching parts is to use a forstner bit of the same size as the dowel I'm using. In the drawings I've drilled 2 holes in the bottom of the block for legs... the same hole size is in the feet. This works well because the dowels can be glued in without being bottomed in their holes... allows the kids to not have perfect matching dowel lengths.

A note about feet... Make them big. If they are small the gumball machine will be tippy...

I like to Give the kids lots of ideas for stuff to add so heres some more details for you to share...

-Lay the block down with the wood next to it and trace out the details...
-bandsaw or scroll saw the parts, sand them well.
-Attach them to the body with dowels like in the last step or use an air nailer and glue. Obviously I don't let my students use the air nailer... "But why NOT Mr. Mitchell!!!!?" is what i get... I just look at them as though they had sprouted a new arm...
-Detail with a sharpie.
-Kids like to add on parts to the turning mechanism... The one in the middle has the moustache that turns...
-Go weird with bodyparts... eyes of different sizes, arms with giant hands and wrong numbers of fingers... stuff like that...

I use the 500 ml canning jars that have the center piece that pops out. That disk is great for squirting small amounts of glue onto for other projects... Buy as many of the jars as you can. I've noticed that they are really hard to get during the winter and spring... people are not canning as much than...

Unscrew the jar, pop out the center piece than use an airnailer to attach the lid to the block. Use low pressure or it will go right through the metal lid. Be sure to not do this over the dowel... some nails will go in enough to stop it from moving..   :-)
I've used small screws and nails before but this method is really easy.

I dole out the gumballs or they will be gone in a very short time... Just flip the block over onto the jar and screw it on... to test it turn the nose (arm) and one gumball should roll out. If it jams the student will have to go and drill the 3/4" hole a bit deeper. If they rain out the kid has clearly drilled the hole all the way through... kinda funny, actually.

On the last page I have a marking page that the teachers out there are welcome to use... And a few thoughts on marking...

Thanks for reading through this instructable! I hope you try this with your students... It really is great to see what kids can come up with! 

I thought this would come in handy for the teachers in the audience... This is called criterion referenced assessment. ya i know... "WHAT?" All it is is a bunch of guidelines for grading. It works well with kids because they can look at the sheet and understand the grade and how to improve. I always give kids time to re-submit after making changes. Woodworking is pretty subjective so I think its fair to let kids change things in their favor.

This grade method is also very objective (i hope). In our district we are NOT allowed to grade in a subjective way which is tough in our area so this is as objective as possible.

Gumball Machine Marking Sheet

NAME:_____________________________________DIV:____________TOTAL    /60

 

AREA	0-10	11-15	16-20
Block Construction	Missing holes, holes not drilled on center, wrong sizes, unsanded, Block not to specified size	All holes drilled, fairly smooth from top to bottom. Centered close but not perfect..Okay transition for gumball, sanding okay…needs more…block sized but not square	Holes all 1”, All holes centered perfectly, smooth flow in holes for gumball, sanded perfectly smooth, block exactly as specified, square, well sanded edges
Gumball Distribution	Does not work. Jams or allows flow of gumballs. Hard to turn	Works but needs to have block held while turning, gumball falls through but roughly	Spins perfectly, no effort needed, smooth but not wiggly. Gumball falls through perfectly
Decoration and Details	None or very little managed, parts on weakly or uneven.	Parts all there as in drawing but not exactly. Needs sanding or straightening, base is tippy	Stable, smooth, exactly like drawing. Sanded well, all pieces attached well… no glue-out, solid