The Dale Maley Family Web Site

Subtitle

Hand-Cranked Whale

I have made a lot of hand cranked toys for kids and adults to play with.

A friend of mine sent me a link to a hand-cranked whale.


Sketchup

I used Sketchup to design the whale. I allowed a 1/4" between segments, by sawing out 1/4 thick slices as shown on the sketchup drawing. I decided to make the body from common pine.  The 4 fins will be made of red oak. All the fins stick out 2 inches from the body.  I used a 1/4" square mortise tool to make slots in the whale body.  I then used the Dremel with a drum sander to shape the fins.


Making the body

I glued up 2 pieces of 1.5" thick pine to get 3 inches, then planed it down to 2.25 inches thick.  I glued the paper pattern from sketchup onto the body, then band sawed the whale shape (it is too thick for scroll saw).


I used my mortising machine to cut 1/4" wide slots into the bodies, to accept the fins.  I made the fins out of red oak, so they were sturdy.   I shaped the fins using my Dremel with a sanding drum.  I did not glue in the fins yet because I want to be able to saw the 1/4" wide spaces between segments using my chop saw.


Flexible connection between 5 segments

I can't tell from the video how the 5 segments were connected.  My first guess was a screen door type spring.  I bought a 1/4" diameter spring from mcMaster-Carr in chicago, because my local ace only had 3/8" diameter springs.


Spring Idea did not work

Biggest problem was that the 5 segments rotated on the spring.  They need to stay aligned as the segments move up and down.

For Plan B, I tried making a 1/4" wide notch about 3/4" wide and 3/4" deep in the ends of the segments.  Then put in a 1/4" diameter oak dowel, use drill press to drill hole through body and dowel, and insert brass rod.  Basically a hinge joint.  This seemed to work well, and is pretty sturdy from a child breakage perspective.  The brass rods are 0.072" diameter, from mcmaster-carr.


Wire idea fails

On the model in the video, they used wire for the crankshaft, and the connection from the crank to the 3 body segments.  I made up a mock pine frame, and set up my model with the same wire.  It failed because the wire bent on the crankshaft.


I'm guessing the video model whale body is made from light weight plastic, and the wire can support it.  My model is a wood body, which is much heavier, and too much weight for the spring..


I could try a 1/4" oak dowel as a straight vertical support into the bottom of the 3 segments.  I suspect this won't work, because I think the segments need to rotate around the pivot point. 


Maybe I stay with heavier 0.072 diameter brass wire as the vertical upright.........solder a washer on the bottom of the rod.........and make a wood crankshaft?   Boy, there is a lot of trial & error work on doing this model!!

1st Crankshaft design fails

I got the crankshaft designed and made 3 lobes for the 3 vertical drivers.


But when I hooked the 1st vertical wire to the crankshaft lobe, the wire bound up !!   I used a 1.25" throw for all 3 lobes.  The wire would not bend enough as the lobe went through its total travel of 1x 1.25 or 2.50 inches.    I guess I should have known this, because it is similar to an internal combustion engine where the connecting rode rotates on the piston!!

I still want to keep the wire from the body down to the driver, so it allows the 5 segments to rotate as they stroke.  I came up with a new design to try.


Vertical wood slider design

I am not quite sure how I will connect the wire to the top of the new vertical slider, we will have to work that out.


Another Brain Fart

I made the design above and tried the first vertical driver...............and discovered I just needed to pin the top joint............not have 2 swivel points as drawn !!

I found some 3/8" axle caps of wood that should work great !


Eliminate the wires

I decided to eliminate the wires, and connect to the whale using wood.  I designed a 2x2x2 oak block to change the vertical driver orientation so wood can be screwed to the body.


Video

I made a short video of the whole thing working...............


Remaining issues to work out

Model will not crank consistently if handle is moved to RH side instead of left side.  Some of the remaining issues to solve include:


-may have to put bearing in center of crank to keep it from distorting, which causes binding
-vertical slider that goes through top rectangular hole has too much slop in and out, depending on the fit between the slot width and the width of the slider. I could a guide bar on

  each side of the square blocks to keep them aligned.
-alignment of crank journal to top vertical slider not perfect, could align better.

-weight of whale causes the top sliders to tip in.


Jan 1, 2020, work on project

I added a center bearing on the crankshaft.   It may not be absolutely necessary for the design, but It can't hurt any.


I drilled and pinned the crankshaft, which helped a lot with ability to crank it.


Since the weight of the whale is cantilevered on the front of the vertical sliders, I decided to add spacers in an effort to force the vertical sliders to be angled to the back..........so the weight of the whale segments will pull it forward.  This helped, but I think I need another set of 3 spacers on the bottom to keep the verticals slanted. NOTE: adding the 2nd set of spacers on top really helped to keep the 3 vertical sliders tipped towards the back.............so weight of whale does not pull it too far forwards.


I also have a problem with the middle vertical becoming disconnected from the block and whale.  I am going to have to adjust the length of the sliders, or change the 1.25 inch stroke I have on all 3 crankshaft lobes.


Updating the Design

I decided to update the design, and make it fancier for the final model.  I did it in Sketchup 7, but used the rendering in Sketchup 14.


Status end of day Jan 2, 2020

Once I got the angular rotation correct for the 3 cam lobes................the model cranked smoothly and worked great !

On the 3 top blocks, 2x2x2 inches..............I rounded the edges on the router table using a 3/8" round-over bit.  Because the pieces are small, I used the yellow clamp to hold them while routing.   I put some 80 grit sandpaper in the drum sander for the drill press............and it quickly removed the burn marks on the white oak.


The 3 slots in the horizontal upper piece that hold the 3 vertical drivers, the 1/4" wide slot is 15/16" long, more than the 3/4" width of the 3 vertical drivers.  This lets you tip the 3 verticals towards the back of the toy using the 6 slotted guide pieces.



Golden Oak Stain

Assembly Drawing

I am re-using the hand crank design from the Ferris Wheel Project.  The red piece you grip stays put in your hand as you turn, which is much more comfortable that a fixed dowel that must turn in your hand.


Assembly

I decided to use Kreg pocket screws, to allow easy dis-assembly for possible future repairs from kids using the toy. I will also use some brass screws.  You must use steel screws first to cut the thread in the hard red oak, then I will replace them with brass screws.


When I made the 2 vertical end pieces with the 7/16" diameter holes for the crankshaft, I drilled them together so they would align better. I did not drill the bearing piece at the same time.  I may have to slide the bearing piece against both ends, and drill them again, so the bearing lines up better with the end pieces.

After "dry assembly", I will mark what edges I want to round over with the 1/8" round-over bit on the router.  I will also finish sand and stain the parts, use 1 coat of polyurethane........before final assembly.


Crank Design and Manufacturing

I was out of stock of 1.5" diameter dowels, so I turned down a short piece of hard oak that was 2x2x10 inches on my old 1939 Montgomery Wards lathe.  I painted the body in enamel red, like the ferris wheel crank.


More decorative holes

I added some more decorative drilled holes to the vertical pieces.


Finish

I did just 1 coat of polyurethane on the model pieces. 


Parts ready to assemble

Making sure bearing is aligned with 2 end pieces

Finished Model

Design now in Google Sketchup Warehouse for use by anyone

Closing Thoughts

In retrospect, I should have ignored all the wire driving mechanism on the original video of the whale...........and designed my own beefy wood crankshaft and drivers..........which is what I ended up doing.  My whale is relatively heavy wood, while the original video is super lightweight plastic.  I needed the beefier wood drive for my model.   My models also need to have a rugged design so they withstand use by children.