Thursday, March 18, 2010

Roto-Caster (Part 2)

I knew when I took on this project that it was going to be a challenge as this is my first year every really working with wood and certainly my first time working with gears and moving parts that are not hinges. I have encountered a few problems (and general tips that seem to be missing) with the instruction I posted from the Internet in Part 1.

The first is the top arrow which refers to the larger of the two black gears. This gear has a set screw in it and has to be tuned to the point of contacting the bolt that goes through it. This gear is meant to move with the bolt as the caster rotates causing the white gears to move the inner, smaller frame (Hint: the white gears need to be tapped to a larger size so that they do not split (or tear up your hand) when putting the bolt in.)

This same large gear brings me to my second problem which is the arrow at the bottom of the first image. Because of the thickness of the gear, the small amount of clearance between it at the outer frame and the possible chance of warped wood, any time the caster rotated, the gear would hit the outer frame and stop moving. To solve this problem I had to re-cut the piece of wood for the outer frame on the left and attach it to the end of the base as oppose to on top of it (you can see in the image below where the two pieces used to be joined and where they are located now.) This move allowed me an extra 3/4 inch clearance and I would recommend just planning on this change from the beginning and buying slightly longer carriage bolts.

Finally, the third problem comes with the smaller of the two black gears, as seen in the image below and the middle arrow in the top image. Although this gear has a set screw in it just like the large black gear, you do not want to set this screw to lock with the through bolt. Instead, this gear needs to remain still with the wood on the outer frame. This requires having a grove for this gear to fit and making sure it stays in place and does not rotate with the bolt. My solution to this was a good amount of strong epoxy.

The last and final problem I hope to encounter in this piece is that, although I ordered the motor over 2 weeks ago, it took me contacting the seller on Ebay to find out that the motor I ordered was out of stock and that they were refunding my money. So, please stay tuned for Part 3...

Friday, March 5, 2010

Roto-Caster (Part 1)

I have been working on making a set of salt and pepper shakers using a mold. Originally I turned and carved some wood forms, made a mold with an inner part and tried to cast them out of resin. Although the second casting turned out much better than the first, I still found myself to be unhappy with the visible seam on the interior of the shakers. After discussing this with a friend, he suggest that I try slip casting (a very common way of working in ceramics.)

Now, if you do not know much about resin, it is a lot more fluid then slip and dries at a much slower rate (on average 24 hours). I did a test to see if this would work and realized very quickly that not only did it waste a ton of resin, it would take forever to build up enough layers to make the shakers. So, back to the drawing boards.

After another discussion with the same friend, he suggested that I look into roto-casting, which is a industrial process to make hollow forms where a machine continues to rotate on two axises as the liquid dries, leaving a smooth even application of the material throughout the mold. After doing some research online, I found out that not only could you make your own roto-casting machine, there were several detailed instructions available online to make them.

A few links below include a video of a home made roto-caster and a link to the site I am using to build mine:

Thus far, I have ordered all the parts and am waiting for them to come in. Please note that if you try to build one, the company no longer carries the A 6G 3-110037 Urethane Belt, but does have a similar product that is A 6B 3-110037 that is the same thing, just made out of a slightly different material.

With the use of the internet, access to a woodshop and the helpful people at ACE Hardware, I have found all of the materials I need to make this happen. Below are the pictures of all of the wooden parts that I have built while waiting for my internet orders to come in.

This first image are the built wooden parts (unassembled).

Assembled with bolts.

Rotated to show the two moments that take place.

And finally with the braces that will hold the mold once finished.

So, that is what I have to update so far. Stay turned for Part 2 and hopefully many future castings. Although I am taking a brief vacation to attend the 2010 SNAG Conference in Houston, I hope to have this up and running in the next 2 weeks.

Hello and welcome to my blog, Mastering Metals.

My name is Erika Uzmann and I am currently a first year graduate student at Miami University. This first year has been a lot of planning and deciding what direction I want to head in for the next two years of my life. One of my biggest goals has been to really start to network myself and get some professional feed back. With that in mind, I have wanted to get a professional website for a long time now and I finally have! Please visit my site at:

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