The Apartment Workshop Series: Workbench

Due to a job change I no longer have access to the plethora of tools at my old job.  While there are some local hackerspaces, I really like having access to equipment whenever inspiration strikes, rather than having to wait unil the hackerspace is open (also working in your boxers on a Saturday morning). So I am setting up a small workshop in my apartment living room, were I plan to do everything from soldering to machining. This will be the first in a series of articles showing how I setup  and fill this space with various toys.

Every good work shop starts with a good workbench. My money-is-no-object bench would be a Lista cabinet with a maple butcher block top.

18733s3.tifUnfortunately these are disgustingly expensive when bought new and, unless you get lucky on craigslist or an auction, they are still expensive used. My goal is to replicate the Lista bench, but for an order of magnitude cheaper.

One of the first things you should do when designing a workbench is to think hard about what you will actually be using it for. A bench designed for SMT electrical work is a lot different than one for taking engines apart. I plan to use my bench for tool storage, some soldering/electronics, parts storage, machining (once I get a small mill and lathe), light assembly, and taking things apart. I took each of those tasks and figured out what requirements they would impose on my design.t

For tool storage (specifically, hand tools) the Lista cabinets are great as the many thin drawers allow for an enormous amount of storage in a small footprint. Lista cabinets are very similar to rolling tool carts found in garage shops (minus the caster wheels), so that’s where I started looking. I spent several hours researching rolling tool carts on garage journal and reached several conclusions. If you’ve got the money, tool truck boxes (snap on, matco, etc) are hard to beat. They offer the best construction, but at a hefty price tag. Surprisingly, Craftsman tool boxes were generally regarded as the worst quality, people described them as having thin gauge sheet metal, and really bad drawer slides. Also surprisingly, Harbor Freight tool boxes were said to be the best tool box for your money, decent quality, but still affordable.

I ended up getting Harbor Freight item#67831 and selling off the top box to recover some funds. Make sure you get the 26″ model, the brownish 30″ one is much lower quality.

With the tool storage figured out I started looking for a work surface. I like working on wood, as I can sand down and refinish it when it becomes too loaded up with crud (it also looks nice). I went looking for a low cost alternative for the maple top on the Lista bench, and found the Numerar series countertops from Ikea.

It isn’t as deep as I’d like (25″), but the construction (almost 1.5″ thick beech!) and price were spot on. I ended up getting the longer 96″ version, figuring I could always trim it down and use the extra as a lower shelf.

Next up were finding sturdy legs. I considered using wood 4×4 posts, but since this is in my living room and very visible, I wanted it to look a little nicer. I chose speed rail fittings and 1 1/4″ sch 40 aluminum pipe, as they are very strong, but gave it a slightly industrial look. I later found out that McMaster has a nice selection of pre made work bench legs, some with cut outs for electrical outlets.

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For medium sized parts storage I wanted to utilize the area under the work surface by hanging pull out drawers. Since I don’t have access to a cabinet shop to make custom drawers, I came up with my own solution. In my experience work bench drawers usually end up as a disorganized pile of random parts you don’t know what else to do with. Since the drawers are just one large space everything ends up mixing together.

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My solutions to this was bins with a divider grid system. These bins are dividable down to spaces 1″x1″, allowing for the creation of all sort of odd sides compartments. They also come in a variety of depths and colors, and are stackable.

The drawers slides ended up being one of the harder problems to solve. How do I hang these bins on the under side of the work surface? They have a large lip, and sloped sides so I couldn’t just attach off the self drawer slides. I considered building a self underneath that they could rest on, but interfacing with the speed rail was problematic. I really needed a bracket that the bins could slide on, supported by the lip that runs along the outside. If you know machine tools think of it like box ways. I initially thought about making my own from aluminum square tubing, but that would have been a lot of machining time to cut all the slots and holes (I needed to make about 8-10 slides).

I was browsing McMaster one day and found this aluminum extrusion that is normally used as trim around panels. It has the perfect shape to function as a slide, but still allow me to have a spot to screw it to the underside of the bench.

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With all the parts acquired I could start putting it all together. I first layer out the hole pattern for the leg fittings, insetting them slightly for appearance.

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3/16″ clearance hole for a 1/4″ lag bolt.

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The drawer slides came next, I drilled and counter sunk holes for  #8 wood screws. I had to counter sink them as the drawer would hit any fastener proud of the surface when pulled out.

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Aligning and spacing all the slides.

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Here’s the almost finished bench. I put on several coats of tung oil to act as a sealer, turning it a golden color. After this was taken I also added an additional leg in the center towards the front, as it needed a little more support mid-span.

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I ended up using the full length of the counter top material since it fit in the space and you can never have enough work surface.

If you’re curious here’s a few shots of the drawers filled with parts.

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Modern Dining Table Part 3: The Conclusion

Part 1 and Part 2 here.

This weekend I wrapped up my modern dining room table project by installing the legs. Rather than 4 individual legs, I chose two trapezoid shaped metal frames on each end.

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This table won’t have an apron, which gives rigidity to a table. Think of the point where the table attaches to the legs as a hinge. The further away from the hinge that the leg is supported the more rigid the connection, so apron = good, stretcher = better.

With a leg configuration like I have you’d normally need a stretcher between the legs to prevent the table from wobbling side to side.

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How to make a stable table. able.

To eliminate the need for a stretcher, the flanges where the top connects to the legs were made extra wide by adding a piece of 3/16″ angle to the steel tubing.  1/4″ lag bolts secure the legs to the top (pre-drill so you don’t split the wood!)

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I wanted some contrast between the legs and the warm natural look of the reclaimed wood table top. Rather than paint the legs I had them clear coated, allowing the welds and tube seams to show through.

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I need to put some felt pads under the legs to protect the floor, but other than that I’m going to call this one done.

Suppliers:

Wood table top: http://www.americanmaad.com/tables

Legs: http://www.etsy.com/shop/TRRTRY

Cardboard Mockup: The Original Rapid Prototyping

I often find it hard to get a sense of scale when designing things using CAD software. Staring at a model on a 24″ screen can sometimes make small objects look massive, and large objects tiny. Placing  references (such as a person) next to your model helps some, and there are many free human models for pretty much all CAD platforms. However nothing beats a physical prototype. If your part is small enough 3D printers are perfect. For larger parts you have to get creative. The final frame will be made of 80/20 aluminum framing, but I did not want to commit to cutting it up just yet, as I was still playing with the frame dimensions. I needed a cheap material that was easily formable, yet sturdy enough to hold its own weight, next to my door was the answer: double wall cardboard.

Just as architects use cardboard to construct scaled down buildings, I built a 1:1 model of my mold-a-rama replica. Using only packing tape and cardboard, I was able to quickly (and cheaply) build a model that’s accurate to about 0.25″.

I started by measuring the outside dimensions of my model in solidworks, and transferring those to cardboard. Here’s some tips I learned from doing it:

  • The boxes I had on hand were medium to small-sized, with fold lines all over. If you can’t cut around the lines, take another piece of cardboard and tape it over the fold line to reinforce it.
  • Reinforce the corners by making a long  L-bracket and tape it to the inside.
  • Cardboard tabs can be used to prop up unsupported spans of cardboard.
  • Get some good blades for your utility knife, I like Irwin bimetal blades. They make cutting through thick double wall cardboard a breeze.

And here’s the end result:

Cardboard mockup

Those 3rd grade arts and craft skills are finally paying off.

As I suspected it was bigger in full-scale than what I thought it would have been.

Another benefit is that the interior volume is very close to the usable space inside the actual machine. I was able to place most of the bulkier components inside, allowing me to play with layout:

Interior layout

From left to right: air compressor, injection cylinder, plastic melt tank, water pump (blue thing peeking out), water chiller.

Moving components around inside the cardboard model was so much faster than doing it in CAD. It also gave me a better idea of how much space I need between components.

The layout above is mostly complete. I have since gotten an air tank that sits in the back left corner. The stainless box you see is the starting point for the plastic melt tank (I’ll go into more detail in the next post where I’ll show off some of the components  that have already been bought)

This method really only works if what you are building is mostly flat panels that meet at right angles. If you’ve got a contoured model and you are set on using cardboard, make an STL file of your part with layers that match your cardboard thickness and print out patterns. This can be done using the free software AutoCad 123D (http://www.123dapp.com/make)

Modern Dining Table: Part 1

I’ve started designing a dining table for our new apartment. I really like the aesthetic of reclaimed wood and steel tables, unfortunately a pre-made table like this costs in the $1500 to $3000 range. Way more than I can spend on a table. The designs are very simple and I figured I could make one myself. After some digging I found a local shop that will build the table top out of reclaimed douglas fir. The legs are designed by me and will be either made by myself (pending purchase of a TIG welder) or will be sub-contracted to a fabrication shop.

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Canon Rebel 300D Sub-Mirror Pin Repair aka My Pictures Are All Half Black

Are the pictures from your Canon Rebel DSLR coming out with the lower half of the frame black? When you take off the lens and push the main mirror up, does the small mirror below the main mirror not lift up completely? If so, your sub-mirror pin is broken and causing the darkness. There is a pin that functions as a hinge for the sub-mirror. When it breaks the mirror does not fully fold up into the main mirror and thus blocks some light to the CCD sensor. You can manually fold the sub-mirror into the main mirror, which will fix the problem at the cost of your autofocus functionality.

In a move of remarkable engineering Canon decided to make a critical high-stress pin out of plastic. Who would have guessed that a tiny plastic pin would break after being flexed 20,000 times? The only way to really fix the issue is to install a new metal pin, which Canon eventually did.

Cross section of Rebel mirror box

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