The CNC Wheelwright

[Burkhardt]

Here is another one of my wacky projects....(series of 3 picture posts)
I want to build a functional wooden garden cart, something like a 2-wheeled wheelbarrow and I want it completely made from wood, without screws, nails and bolts. To be sure it can be done I started making a wheel over the weekend, kind of like the old wagon wheels, 24" diameter and 16 spokes. Lacking the iron hoop (and having a CNC router at hand), I made the rim segments interlock with dovetails and crooked the spokes to achieve a double dish spoke layout for better rigidity. I used simple 3/4" pine board from HD for cost reasons.

I think it came out quite nice. Now I need to make another one and build the cart box.

Cutting 2 of 16 rim segments (1-sided):


Custom vacuum pod to hold the segments:


Cutting 2 of 4 hub discs (2-sided):


Cutting 4 of 16 spokes (2-sided):


to be continued...

[Burkhardt]

All parts completed:


Starting the rim assembly:


First side dish of spokes:

[Burkhardt]

Trueing up and chamfering on the lathe (sometimes it is good to have a lathe with 24" diameter capability).


Wheel complete and finished with unpigmented stain:


The rim is deeply grooved to install a bicycle tire:

[mtylerfl]

Very cool project!

[Keith Larrett]

That's awesome!

[steve_g]

Impressive!

Just out of curiosity… how far out of round was it?
SG

[Burkhardt]

Thanks guys
I wish I had the skill to build such a wheel with hand tools but for now I can live with the CNC method. Looking at old pictures, the wheelwrights back then had their special machinery as well.

....Just out of curiosity… how far out of round was it?....

The eccentricity was excellent, maybe only 0.02" which is not really surprising since the spokes fit into the pockets snugly and there is not much reason to be out of round, given the accuracy of a CNC machine.

I had bigger trouble getting the wheel not to wobble sideways on the lathe but that was more a work holding issue than an accuracy problem of the wheel. I had the rim assembled on a 1" thick sheet of plastic so it was really flat. For the next wheel I will skip the lathe and rather flip the rim segments over on the CNC to do the chamfer with a V-bit.

[steve]

I think you've just re-invented the weel, very cool!

[Burkhardt]

Also posted on the Vectric Vcarve Gallery forum...

I had several people ask for the design files of the cart and specifically the wheels and I have no problem sharing that.
Just be aware this is not a trivial project, can not be done on a sloppy machine and may need some iterations to get it right (I had to re-do a few parts myself).

But otherwise, enjoy! It was a fun project for me.

You will find the zipped download with a few hints on my web site under the tab "Garden Cart" http://www.tailmaker.net/

You can use any of that for hobby or business purpose as you like. Actually I think the wheels could be made cost effectively when making a whole batch and if the clamping/vacuum holding is customized/automated.

I did not include the file for the v-carved flourish because I have no idea of the copyrights.

[scottp55]

Thanks for the files Gert!
(also downloaded the Guilloche and box clamp again)
scott