Archives for posts tagged ‘shop’

new workbenches & cabinets

This one has been a long time coming. Ever since we moved into our new house I’ve been slowly turning our unfinished, unheated two-car garage into a respectable workshop… insulation, drywall, lighting, heat, climate control, etc. etc. I’ve put a lot of effort into the “bones” of the space but I’ve been hesitating to start building the work surfaces and storage. IMG_0920 In a way it’s good that it took three years to do this, because in that time I’ve gotten to know the space through cold and hot, from woodworking and welding to painting and machining. I know where the floor gets wet when it rains a lot, and I know where the good light comes in at 7am. While I was still hesitant to commit to a design, I felt that I knew enough to take a best guess at what I need now (and what I anticipate needing in the near future) and go for it. Besides, stepping over and around piles of tools, hardware, and raw materials for three years is a miserable way to work.

For me, the first step for this kind of project is CAD, and this is one of the few things for which I actually recommend Sketchup. In my experience Sketchup is a poor tool for modeling anything with curves or circles, or cylindrical or 3-dimensional surfaces. In most cases I would also prefer feature-based modeling (with a modifiable history tree) and parameter-driven modeling even for simple rectilinear objects. But I’ve modeled my house (and garage) in Sketchup for a few reasons. shop_sketchup_1For one thing I’m not designing my house, I’m just modeling it– I enter a dimension once and I never need to go back and change it. The shapes are all rectilinear, almost without exception, so the surfacing shortcomings of Sketchup are irrelevant. Sketchup has a fairly good set of textures to apply to the model and I like the look and feel as you spin a model around. But I think what sold me–particularly for architectural modeling–is the ability to drop your model into Google Earth, in the right spot. At that point you can see the model in its landscape context and even play with the daylight at different times of the day and year and see how the shadows change, etc. Very cool.

So I settled on an overall size and shape that would be reasonably inexpensive and worked well with my shop layout (also mocked up in Sketchup). The construction is a bit of a hybrid between traditional kitchen cabinetry and a typical 2×4 workbench, with a little of my deck-building experience adding some flavor as well. The benchtop is a single 3/4″ sheet of plywood, supported by copious amounts of 2×4 framing, finished with laminate. The front edge is thickened to 1-1/2″ with a second layer of plywood, overhanging by a couple of inches to allow clamping to the bench, and simply painted to match the rest of the cabinets and drawers.

I copied each of the elements in the Sketchup model and pasted them into a single plane so I could arrange them into 4×8 sheets, trying to maximize the yield of each sheet. I did the same with the 2×4 pieces, and color coded everything so I would know which piece went where.shop_sketchup_2

I chose AC plywood (EDIT: I actually used BC plywood) for cost reasons, knowing I would put the “good” side out and paint it, constantly reminding myself that these are garage workbenches and not fine kitchen cabinetry. Still, in hindsight I wish I had sprung for hardwood plywood, as I found that the AC sheets are not flat, resulting in some poor door and drawer face fits.

Good planning leads to quick progress, and the framing came together quickly. These first assemblies were lag-bolted to the wall using a laser level for positioning, then eventually supported along the floor with small 2×4 feet.

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The cabinets were next, using strategically placed 2x4s for strength. Note there are no “backs” to any of the cabinets (simplicity = lower cost). Next I primed the whole thing with Zinsser B-I-N shellac-based primer, tinted gray to more closely match the final color.

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Drawer bodies are not typically 3/4″ plywood but I found the small pieces were a good use of empty space on my sheets, so it turned out cheaper to maximize the 3/4″ plywood sheets than to buy separate 1/2″ plywood. It is typical however to make the drawer face a separate part, as it makes the final fit & alignment much easier.

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Doors and drawers were notched for a nice extruded drawer pull, which I bought in an eight foot extrusion and cut to length myself. There was some extra work (and router fixturing) involved in getting the notches just right but I think it was worth it.

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The final paint job was porch & floor paint in an olive-drab green. I left the insides of the cabinets in primer, as I suspect the shellac-based coating will be more durable for horizontal surfaces where things will be resting on it. The bench top is white laminate, which I’ve found is a great functional work surface– you can easily see small screws and stuff and it resists attack from glue and other chemicals. I’ve had similar melamine surfaces on my outfeed tables, which were dismantled to provide their melamine particle board for the shelves inside each cabinet. Generally I don’t trust particle board for shelves, so I cut some 1″ angle-iron, painted it white, and screwed it to the front edge of each shelf to prevent sagging.

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The final product…almost. The trim bit I used to rout the edges of the laminate took a bunch of paint off the front edges of the countertops, so I need to go back and touch them up. Next task: fill up the cabinets with all my shop stuff.

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This lowered area is for my miter saw, which matches the height of the step in the bench. This way I can let long material run across the 8′ bench to the left.

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CNC mill parts

Tonight I finally finished the metal parts for the CNC conversion. These were made from a subset of the “phase 1” plans I purchased, and are all the custom parts I need to attach my stepper motors to the G0704 mill.

aluminum and steel parts for my G0704 CNC milling machine conversion

Most of these were pretty straightforward. The standoff-looking parts are steel rod, parted off to length and then drilled and tapped. The fatter bushing-looking things are aluminum, also round rod that was drilled out then trimmed to length. The big flat aluminum parts were a little more challenging, requiring some milling, but the holes were all center-punched and drilled on the drill press (I still don’t trust positioning on the mill due to the backlash in the screws).

steel part for my G0704 CNC milling machine conversion

This cylindrical steel part took several hours. Starting from a 1.5″ steel rod, I first turned the skinny stem part, then flipped it around to bore out the inside. The tricky part was getting the piece clamped into the lathe so it was perfectly concentric to the shaft I already turned. Apparently my three-jaw chuck is not perfectly centered, so I used the four-jaw chuck and aligned the part manually using a dial indicator attached to the cross slide. According to the indicator I got within half a thou for concentricity… good enough!

steel part for my G0704 CNC milling machine conversion

Once it was centered I bored out the inside and put the little shoulder on the end. Next it was drilled and tapped (for set screws), then off to the mill to make the flats on the shaft.

The most challenging part was probably this aluminum bearing block, shown here in the four jaw chuck. Again, concentricity here is key, so a lot of time was spent getting this guy aligned when I flipped it around.

aluminum part turned on a 9x20 lathe for my G0704 CNC milling machine conversion

Technically I’m ready to mount the motors to the mill, but I’m hesitant to start the process. I’ve gotten used to having a milling machine available, and once I take the handwheels off it’ll be out of commission until the CNC conversion is complete and working! Here we go…

milling machine modifications, part __?

In this minor modification I added a 50 lb. gas spring between the column and the head, meant to assist the Z-axis motor in lifting the weight of the head.

gas spring modification G0704 milling machine CNC

The stock part is a 50 lb. gas spring with ball-joint fittings, McMaster part #4138T621. I simply drilled a hole in the column (and tapped it for 5/16-18) for the lower pivot, but the upper pivot point wanted to be above the top of the head to allow for a full 12″ of travel. I designed and machined a simple aluminum part to extend the upper pivot point and mounted it to the head. While I was at it I also machined a nice little cap to cover the hole where the Z-axis crank was.
gas spring modification G0704 milling machine CNC

The backlash in the lead screws has been giving me relatively poor surface finishes, so I bead blasted these parts to even them out. I like the look, but the “toothy” surface really grabs onto dirt.

I was hoping to double the rapid speed I could get out of the Z-axis, but I didn’t quite make it… It went from 15 in/min to about 25 in/min, although I just bought some better way oil so we’ll see if that makes up the difference.

CNC surface machining

I’ll be posting more about exactly what this part is in the near future, but for now I’m super excited about making my first surfaced part on the mill…

This is ABS, which I’m using to test the program before moving on to brass. Good thing too, because one of the last commands jammed the end mill down into the part… I pressed the reset button just as the bottom of the collet was carving out a pocket in the ABS and nothing was damaged, but if I was using brass things would have been ugly.

The end mill is a 1/4″ three flute uncoated carbide ball end mill. The spindle speed was around 2400 rpm and the feed was 7.5 ipm.

sneak peek! hot shop styles for 2012

This new milling machine creates a lot of tiny shards of aluminum. And apparently those are not good for a toddler to eat, so I’ve had to take steps to reduce the amount of aluminum chips I drag into the house from the shop. I think my solution is pretty stylish…

shop coveralls G0704 CNC mill

3D-printed shop vac adapter

Believe it or not, 3D printing can be used for more useful things than clip-on mustaches… I have a miter saw with a missing dust bag, so whenever I use it I fill the immediate area with a fine coating of sawdust. I always thought a shop vac attachment would be more useful than the bag anyway, so I bought a 1.5″ to 2.5″ adapter that didn’t work at all. So I simply measured both ports and sketched up a quick elbow adapter.

I then modeled it in CAD, converting inches to mm and fine-tuning some of the dimensions and details.

A couple of simple sweeps and shell features, plus some details for hose clamps (a backup, in case the friction-fit doesn’t work):

The print took about 8 hours and required copious support material (which in turn took copious cleanup) but it came out perfect.

And fit perfectly too (no hose clamps required)!

I’ve uploaded the part to Thingiverse… enjoy!

CNC mill to-do list

Making progress (finally) on the mill upgrades, including full enclosure, flood coolant, oiling system, and ball screw conversion. Stay tuned!