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Wood Auger Marble Lift

I got the idea to build another marble game with the following attributes:


-wood auger to lift 1" diameter marbles

-several, maybe up to 4 bowls where marbles get transferred bowl to bowl

-about same footprint as wood-link marble lifting game already built

-3" diameter auger about 16" high to give same lift as wood-link marble mechanism already built

-will need some method of transferring hand crank power 90 degrees to auger. 
-maybe use wood bevel gears, or old grist mill method, I made on another project

Concept #1

I like the grist mill concept, but I need to get the gears as low as possible, to keep the over-all height down to reasonable limits.

Too much work to make worm gear

After further thinking about it, it would take many man-hours to make this big worm gear by hand.  It has a 3" OD with about 11 teeth.  Boy, that is a lot of material to remove with a Dremel carving tool plus 1/2" drum sander !!!

Is there another option for lifting the marbles?

I searched Youtube and found a Marble Pump on a video by Matthias Wandel. You can see the video using this link.

He sells plans to build the marble pump for $14, so I bought the plans and downloaded them.

How does the marble pump work?

One weakness I have discovered about myself is that I am not really good at visualizing 3D items.  I did not understand how the marble pump works, even though I saw the Youtube videos and downloaded a Sketchup file of the model.

You have 2 sets of motion happening at the same time:  The crank moves the block right to left........and at the same time the marble lifting piston is moving up and down.

  Using Sketchup, I made 4 views of the marble pump, with the crankshaft at 0, 90, 180, and 270 degrees. Once I did this, I now think I  understand how it works.

Crankshaft at 4 positions

Crankshaft at zero degrees


Crankshaft at 180 degrees

Crankshaft at 270 Degrees

Scaling marble pump from 5/8" marbles to 1" diameter marbles

As best as I can tell from the Sketchup plan I purchased for the marble pump, it is designed for 5/8" diameter marbles.   I want my machine to use 1" diameter marbles.  Rather than "reinvent the wheel", I decided to try simply scaling me marble pump by the ratio of the marbles sizes. 

Original model sized for 5/16" radius, I want 1/2 of 1-1/16" for 1" marbles, so ratio of 17/32 to 5/16 = 1.70.

I scaled the model up by 1.7, then made some slight adjustments to get standard 3/4" thick wood pieces.

Next step

I am going to build the marble pump scaled up for 1" diameter marbles, and see if it works ok or not.
I have some 1/8" diameter brass rods, so I might try a piece for the crank.
I will use cheap pine for the wood pieces and see how they work, I may have to go to some hardwoods if the pine does not work.
An interesting question is whether the 1/8" brass crank can pump marbles or lift a stack of 12 to 16 One-Inch marbles, since that is roughly how high I want to go.

Another thing to think about:  Kids can crank up to 100 RPM, which means 100 marbles per 60 seconds, or over 1 marble per second. That seems way too fast for my model.  I may still need to use a worm gear to slow down the machine?

September 28, 2022, Starting to build marble pump

Rather than do pine, decided to go ahead and make pump from hard maple from Menards.

For 1" marbles I want to use, I scaled the pump by 1.7 or ratio of 5/8" marbles to 1" diameter marbles. I then fixed the dimensions to be standard 3/4" thick wood parts.

For the sliding block, for the 1-5/8" side holes, I first drilled through block with small bit, like 1/8", to try to keep the holes concentric with each other.

Drilling the 1-1/16" diameter vertical hole was  challenge, since the depth is much deeper than my special 1-1/16" diameter bit I bought for using on 1" marble machines.  I tried drilling from both sides using 1/8" bit, then use long bit to connect, did not work, bit wondered too far when I tried to connect them.  Drilled from both sides using 1-1/16" bit, had some mismatch, but used dremel to smooth out. Tested bore by putting 1" diameter oak dowel through it, since this will be the piston.

Making the Piston

Used 1" oak dowel. Drilled 1/4" hole since I am using 3/16" diameter brass crankshaft, then made 2 band-saw cuts to make the connecting groove. Used old wood clamps to hole piece while bandsawing.

When I assembled everything up, the piston was hitting the top board, so I shortened it about 3/16" and then it worked ok.

Making the crankshaft

Since the crank has to lift a column of 15 to 20 marbles with 1 inch diameter, I wanted it as strong as possible.   I keep brass rod in stock in my shop, and I did not think I could bend 1/4" diameter brass to this shape, so I went with 3/16" dia brass rod.

I printed out the pattern from Sketchup, and I used that as my "gage" to tell if I was bending it correctly or not.  I used a combination of the blue bending jig, plus my vise, plus vice-grips, and a hammer to keep working the rod until I got as close as I could to the right shape as shown below.

When I assembled everything up, the curve at the ben of the crank rubbed on the 2 outside box pieces.  I countersunk an area around the crank hole using a 1/2" bit, then it worked smoothly.

Problems making 2 slots in main sliding block

I thought best method to cut the 2 vertical slots in the main maple sliding block was by using my Delta mortising tool with a 1/4" by 1/4" bit.  The mortising tool worked ok, but I had tear-out of the maple leaving a jagged edge. The edges of the grooves need to be smooth for the 3/16" brass crankshaft to rub on.  I used a file to try to file them as smooth as possible.

Other options include making the block from glued up segments with the slots scroll sawed in.  Another option would be to not drill the vertical 1-1/16" hole until after mortising the grooves.

Another option would be to drill a starting hole, then scroll saw the grooves on both sides at once. I think 2.25" thick piece will fit in my scroll saw. [I checked and it won't fit]

EUREKA -- It Works !

It works, but I want the hand crank on the right side of the base board, then a right handed person turns it clockwise looking to the left.  As configured, it runs backwards !!

Need to figure this out and how to switch it.

The Nature of the Beast

I made an animation model of the marble pump to try to understand why I can't simply change the crank direction and get the opposite impact on which side the marbles are lifted.

1. Use Sketchup, set model at 0 crank degrees

2. Export JPG of Sketchup

3. Convert JPG to Gif because my program only accepts Gif files

4. Increment crank 45 degrees and then repeat steps 2 and 3

5. Continue to increment crank 45 degrees until get to 360 degrees.

6. Create animation using free UnFreez program, import Gif's in correct order, pick speed of 50

7. Result is animated Gif file showing motion

I did CW = clockwise crank rotation first. You can use this link to see the animation.

Next I made a 2nd animation showing CCW direction on the crank. You can use this link to see it.

As you can see from the animations, you cannot simply change crankshaft rotation direction to change on which side of the pump the marble is lifted.

Since I want the pump on the RH side of my model, I need to rotate the crank in a CCW direction for the marbles to enter in front and exit in the back.  Since I want the crank to rotate CW for right handed people, I will used  a 3 and 6 inch wood gear to change the crank input from CW to CCW on the marble pump.

Updated Sketchup Design

Standard exit piece under bowls

Since I have 5 bowls with a track exit under the center hole, I will try to standardize and make a common exit piece. Then I will use lapping pieces of track to add onto them.

Added alternate flipper switch to Model

I got concerned that kids would be too impatient waiting for the balls to work their way down 4 or 5 round bowls to feed into the vertical column I added the flipper switch from the Marble Machine project I did a year or so ago. I will use a track to return some marbles to the loading point, which should be much faster than the 4 or 5 bowls.

Starting to build parts

It took quite a bit of trial and error to cut the V-notches in the 2 vertical risers that hold the marbles. I doweled them to the top of the marble pump, then added a 90 degree bracket on the back to hold them with 2 screws.

Near-Miss on the Safety side of things

The top block, on top of the 2 vertical chutes, has 2 intersecting holes. I drilled the vertical through hole first with no problem using my 1-1/16" Forstner bit.

I then started to drill the horizontal hole on the drill press, and then the bit caught and threw the block against the wall.......and also a chip broke out.

In retrospect, I should have clamped the piece in a vise, then clamped the vise to the drill press table before drilling. You always have a chance of the bit catching as it intersects another hole at 90 degrees.  I was able to glue the chip back in and save the block.

I used my Dremel with both some burr tools to make a smooth transition, I also sanded in the drill press with a 1" diameter sanding drum.

Top Piece assembled to 2 vertical V-groove columns

I used some tapered shims to set the gap between the 2 pieces correctly........and a 1 inch marble.

Direction switching Flipper assembly

Since I had built this assembly before for the big Marble Machine project, I really did not have any issues making the pieces or gluing up the assembly.  I mounted using 2 screws to the 2 vertical V-block columns.........I also made a clearance hole in the outer guide piece for the screwdriver to fit into :)

Loading Chute Assembly

The only challenge here was clamping up the assembly!

I used a piece of 1x4 to simulate the top of the marble pump machine, then clamped it to this piece.....worked well.

Torque Check - Input Torque

I have been concerned it would take excessive torque to drive the marble pump when it had the weight of 15 or so marbles of 1 inch diameter.  Once I had the input chute attached, I put vise-grips on the input shaft and turned it counterclockwise like it will be on the finished model.........and it did not take too much torque to drive it.   I think my two gears and hand crank should drive it fine.

There is a delay between discharging marbles because the sliding block does have to come back to load a new marble, then go the other way to take it up.

Red Oak Coupling

I need to somehow connect the 3/16" dia brass crankshaft to a 3/4" diameter dowel.  I'm going to try to use this coupling to do it. I don't have the bolt hole drilled in it. The 3/4" dowel will have a cut in the end so the coupling can squeeze it against the brass rod.

Scroll sawing 2 gears from Red Oak

I printed out full scale patterns for both gears from Sketchup, then glued them on using white Elmer's I can wet and rub off paper with scrubbing pad when I am done.

Trying to get rid of excessive run-out in gears

Because I drill the shaft hole before I scroll saw the teeth, I always have some run-out of outside of teeth to shaft hole.

I made a set-up to try sanding the OD of the gears on my horizontal belt sander.  I made a tool with 2 quarter-inch dowels in it, so the tool keeps the gear from rotating if it catches, versus my fingers !  Tool worked ok.

Success !!

I got the marble pump, 2 gears, and crank assembled to the base.

I was nervous about everything working ok................but it worked great in test mode !!!!!!!

You can use this link to watch a video of the model in action.

Unexpected gear run-out

When I got the gears together and running, I noticed the big gear axle hole is not perfectly perpendicular to the side face of the gear............which means my drill press table must not have been perpendicular to the spindle?  I know the drill press is off a little bit, but not that much.  The big gear still works, but looks funny.  I need to come up with a better way of making the gear with no run-out in either direction.

State of Model on Oct 19, 2022 when I videotaped the model above.

Starting to build the bowls and tracks

I had a general ideal of how I wanted to lay out the bowls and I just started building with no specific drawing.

I decided to use 3/8" versus 1/4" diameter dowels to support the feeder bowls...........this was good idea because 3/8" dowels are much sturdier.

The standardized piece that fits under the bowls also worked well, just took some time to make the assemblies.

State of Model on October 28, 2022

Success !!   Nov 1, 2022

I got the model built and started operating it.  Some changes I had to make:

1. sometimes marble skipped over the top of the dumper instead of falling into it.  I shortened the feeder chute by making a semi-circle in the end of the bottom, seems

   to have fixed.

2. Had some binding when I cranked it.  Loosened up connector to marble pump, cranked, and still had some binding of gears. Took round hand file and cleaned bottom of teeth

   on both gears.  Ran smoothly after that.  Still seems like a little binding in the marble pump.  I will inspect when I take it apart before polyurethane.

3. Added a deflector on the chute the dumper unloads to, had to do the same thing on the big Marble Machine.

4. Deepened taper on last big bowl, but marbles did not drop faster.  I drilled an 1/8" hole in side of bowl and stuck in a dowel, now marbles drop faster.

5. Had to add a fence on the last bowl, just like on the wood version of the marble lifter.

I was worried the marbles would come out too fast and if they just went on 1 track of feeder bowls, the model would quickly run out of marbles and you would crank and nothing would happen until the marbles returned to the pump.  Adding the divider was a good idea, because 1/2 of the marbles can return fairly quickly to the pump. With about 6 marbles in the loader, I did not run out cranking at a reasonable speed.

You can use this link to see the model in action.

State of Model on Nov 1, 2022, when I got it running ok

Painting and Staining

I used cherry stain on some of the red oak parts...........the rest were 4 paint colors that I keep in stock.  I used shellac on the oak parts to seal them.

Boy, there is a lot of pieces in this model!

Solved Coupler Slipping problem

Before I painted everything and after, every so often the coupling would slip and marbles would stop rising.

I first blamed it on the rough spots on the vertical slot in the marble pump..........but I studied it some more and it occurred just when the pump was trying to lift a marble.

I happened to check the top of the vertical stack, and a marble was  stuck near the top!!!!!!!!

I took out the marbles, looked down into the 2 v-notch channels, and I had some mis-alignment between one of them and the 1-1/16" hole in the top maple block!!!   I removed the maple block, used the Dremel to remove some material on the vertical v-block, put it back together, and no more slipping of the coupling !!!

Will have to add angled dowel at top of 2 vertical v-notches

The marble pump plan said to put in this dowel, but I had no problems before I painted everything.

But, after painting I started to get marbles rising to the top of the maple block and falling off the wrong way !!   Guess I will have to add the little dowel in.

Divider not always working

I used same design as the big Marble Machine, but sometimes it stays stuck such that several marbles go down the same side before it flips.  I can try making the top of the divider a little taller and see if that works. I made it a little taller and it works ok now.

Updating Sketchup Model

Since I did a lot of "build as you go" on this model, it took a little while to make an "as-built" drawing of the model.

You can use this link to download my model.

Youtube Video

I made a Youtube video of the model in Action. You can use this link to see the video.

Photos of the Finished Model

Closing Thoughts on This Model

I was nervous the Marble Pump would not scale up from handling 5/8" to 1 inch diameter marbles, but it handles the marbles fine.

If I build another marble pump, I would change how I made the marble pump, so I could get smooth edges on the vertical slots for the crankshaft to turn in.  I used a mortising tool, but it made jagged edges when it broke into the center hole.

The only other option I can think of is to make 5 different plates and glue them up, then drill the center hole. Would be time consuming, but would give perfect edges.

I was also nervous the game would run out of marbles as you keep cranking it, but with about 6 marbles in the inlet chute, you don't run out.

The 2:1 speed reduction on the gear set is about right.  Plus, to make a right handed person model, the marble pump has to turn the opposite direction as a CW crank, so the 2 gears reverses the input crank direction as required.

Model now ready for the grandchildren to test it out!

Dec 27, 2022 Follow-up

Model has withstood testing on several occasions by grandchildren, they love cranking it as fast as they can go !!

I noticed the crank was slipping in Late December and I traced it to a stuck marble about 3 inches up the split towers.  I dis-assembled and measured the marble with my plastic micrometer. I measured in 2 measurements 90 degrees from each other because 1 measurement does not catch it:

Oversize Marble          1.010 inches    Blue

regular size 1               0.990

regular 2                       1.000

regular 3                       0.980

Another oversize          1.020        Red

WOW!    ten-thousands of an inch oversize was enough to get that marble stuck in the tower!!

I steel wire brushed all 4 surfaces in the 2 towers, then used my round flat bottom sander to smooth out.

Hopefully I took out enough to handle any oversize marbles.