Modular Marble Machine #5: The Crank

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Blog entry by William posted 04-12-2013 11:25 PM 2283 reads 0 times favorited 18 comments Add to Favorites Watch
« Part 4: Base Plates Part 5 of Modular Marble Machine series Part 6: Riser Blocks »

If you’ve been keeping up, we are just about ready to start building the actual pieces to make a marble run. The only thing we have left is a crank handle to operate the pump assembly.

To attach a shaft to the pump, running to the outside of the base box, we are using a half inch dowel. That dowel has a hole drilled the same size as the metal shaft. Then the dowel is split with a band saw down the middle of that hole. This slips over the shaft.
Next we have to pinch the dowel down onto the shaft. To do that we take a block of wood and drill a half inch hole through it. Then we drill and countersink four holes for screws. Then we split the block right down the middle of the half inch hole. Next, drill the hole larger on the countersunk side, just large enough for the four screws to pass through cleanly without catching threads. We want the screws to pull this top piece to the other one. So the threads do not need to catch that piece at all or it won’t tighten.
After all that is done, and the screws are in the block to hold it together, slip the block onto the metal shaft. Put the wooden dowel through the side of the box and slip it over the metal shaft. Now pull the block back over the wooden dowel and tighten it down, pinching the dowel down onto the metal shaft.
This all creates a good enough fit to turn the pump rod. Now, if something jams up enough to completely stop the pump, this clamping system will slip. That is on purpose. You’d rather the rod connection slip than for a jam to destroy some part of the pump, or anything else. A jam is unlikely as long as we do everything else correctly, but you never know. It’s better to be safe than sorry.

Now this part is not actually necessary, but I thought the outside of the box looked too plain. So I decided to add a dress up piece with an arrow cut out with the scroll saw. I made this out of a piece of walnut for a nice contrast to the color of the box.

Next, in my opinion, there was just too much play in the wooden dowel shaft as it came through the side of the box, so I added a block to the inside to give it more stability.

Then I made the crank from a piece of sapelle. The crank handle is made out of mystery wood. It is a piece of wood that a friend sent me for pen blanks that I have yet to properly identify, so I’m calling it mystery wood for now.
The reason I used a pen blank for that part is that I just needed a small piece of wood to turn for a crank handle, and this piece looked good to me next to the walnut and sapelle. All the dowels I have are softwood, mostly pine. I did not want to use pine for the crank handle, so I turned a piece for it on the lathe.

Now everything for a functioning feed system and base is finally complete. We can now start on actually building pieces.


18 comments so far

View DIYaholic's profile


19623 posts in 2704 days

#1 posted 04-12-2013 11:44 PM

The foundation is set! May the build commence.

I like the addition of the “stabalizing block” for the crank/shaft, along with the crank handle direction indicator!!!

-- Randy-- I may not be good...but I am slow! If good things come to those who wait.... Why is procrastination a bad thing?

View William's profile


9949 posts in 2871 days

#2 posted 04-13-2013 12:03 AM

Thanks Randy.
When are you going to build a marble machine?


View StumpyNubs's profile


7604 posts in 2830 days

#3 posted 04-13-2013 12:05 AM

You sure know your way around a marble machine! When it’s done can I have it? I promise to never lose my marbles! :)

You’d better keep it, I probably WILL lose my marbles.

-- Subscribe to "Stumpy Nubs Woodworking Journal"- One of the crafts' most unique publications:

View DIYaholic's profile


19623 posts in 2704 days

#4 posted 04-13-2013 12:17 AM

I can’tz be buildinating a marble machine….
I ain’t gotz no marbles!!! No, I didn’t lose my marbles….
I never had any!!!

-- Randy-- I may not be good...but I am slow! If good things come to those who wait.... Why is procrastination a bad thing?

View Dave's profile


11429 posts in 2869 days

#5 posted 04-13-2013 12:51 AM

Its getting bigger.
Mouse trap the game comes to mind.
looking good William

-- Superdav "No matter where you go - there you are."

View gfadvm's profile


14940 posts in 2719 days

#6 posted 04-13-2013 12:57 AM

William, Your creations just amaze me! I was lost when you posted the pump! But I’ll be following along as your stuff always turns out to be fascinating. I had Hell getting my candy machine to work! Think I’d best stick to boxes.

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

View William's profile


9949 posts in 2871 days

#7 posted 04-13-2013 01:22 AM

Thanks guys.

Stumps, you should check out the base installment. I used a machine designed by some guy named Stumps.


Dave, it isn’t mouse trap quality yet, but wait until I’m done and it may just be comparable.

Andy, these marble machines are definately only for someone who likes testing, testing, retesting, and then doing over and testing some more. Hey, maybe I have lost my marbles.


View grizzman's profile


7836 posts in 3333 days

#8 posted 04-13-2013 02:00 AM

its looking really good william, im always intrigued with these marble if we could only identify that darn piece of wood…lol…grizz

-- GRIZZMAN ...[''''']

View William's profile


9949 posts in 2871 days

#9 posted 04-13-2013 02:41 AM

No worries Grizz, it isn’t one of the blanks you sent. These came from another friend from up north.
I was looking earlier, I now have about fifty to sixty marble run track pieces to make and about as many spacer blocks. So I still have my work cut out for me. Just saying that I think makes me want to go to bed.


View JL7's profile


8667 posts in 2994 days

#10 posted 04-13-2013 02:47 AM

You keep cranking it up! Looking good as always… many more marbles do you have left to lose?? I’d think you’d be out by now…..

-- Jeff .... Minnesota, USA

View William's profile


9949 posts in 2871 days

#11 posted 04-13-2013 03:04 AM

I’ve got a few trick, eh marbles, up my sleeve.
This is the fourth one I’m working on now.
All have been closely tied to someone else’s plans.
I plan on my fifth being a creation of my own design.
Thanks Jeff.


View Jamie Speirs's profile

Jamie Speirs

4168 posts in 2886 days

#12 posted 04-13-2013 08:37 AM

William is is coming along really nicely
The pen blank is sensible as you need a good strong piece
Your arrow idea must be shown to the designer, I can imagine
that the wrong direction could mess up some bits.
This is definitely the machine to let you try out new designs on.

-- Who is the happiest of men? He who values the merits of others, and in their pleasure takes joy, even as though 'twere his own. --Johann Wolfgang von Goethe

View stefang's profile


15881 posts in 3363 days

#13 posted 04-13-2013 08:54 AM

Looking good!

-- Mike, an American living in Norway.

View William's profile


9949 posts in 2871 days

#14 posted 04-13-2013 11:13 AM

Thank you Stefang.

Jamie, actually, turning the crank the wrong way won’t hurt anything. It would just back the marbles up into the feed chute. I think the arrow was a nice touch though.
Thank you. I’m glad everyone likes it.

I feel I’m boring sometimes giving all the details of a project such as this. I decided to do a detailed blog about it because, with the last three marble machines, I’ve gotten contant questions from people regarding if they’re hard to do, how much time it takes, and such. They aren’y hard at all. They do require a lot of patience though, and they are extremely time consuming.

Thank you all for taking the time to read all my rambling ons about the build of things such as this though. I appreciate the fact that someone takes the time out of their day to do that.


View Roger's profile


20929 posts in 2833 days

#15 posted 04-13-2013 11:34 AM

Yes, the arrow is a nice touch.

-- Roger from KY. Work/Play/Travel Safe. Keep your dust collector fed.

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