I recently bought a mini mill (LMS 3990) and needed a solid place for it in my detached garage. I was going to buy a heavy duty workbench, but instead, decided to design / build a custom solution myself and pick up a few tools in the process.
DESIGN. I had a few requirements:
1) I wanted it to be about 12 feet long, but also easy to move around. I split it into two 6 ft pieces and made them detachable (not permanently built into the wall).
2) The height was driven by typical items to slide under the bench (tool drawers, storage bins, trash can, etc). 35" clearance to the floor did the trick and made a decent working height.
3) I wanted to maximize tabletop space, and 28" depth seemed about right without making it difficult to reach anything on the wall. I ended up making the joists 23.75” (which saved on material cost since 2x4s usually come in multiples of 24”). With a 2x4 frame on from and back (3” total) and another 1.5" overhang for the tabletop, the total depth ended up being 28.25".
4) The design needed to be extremely strong for the mill and any projects I could throw at it. I used mainly 2x4s, one 2x6 and 4x4 posts which was cost effective. The table top is 3/4”.
BEFORE. Here’s the before shot, kind of a mess compared to my clean, attached garage. There’s a folding table to the right, a rickety old desk (with mill on top), and random items lying everywhere:
CAD MODEL. Before beginning, I created a CAD model. I was going to sketch it out on paper, but I’m glad I made the model. It helped work out details and better plan the material purchase. It only took about 2 hours or less. The final version had a few tweaks from what’s shown below. I added a 1.5” overhang to the tabletop on 3 sides, and I reduced the number of angled supports from 8 to 2. It just came out so strong, the supports were not necessary:
FASTENER SELECTION. I had a 10lb bucket of 3 inch, #9 sized Torx head construction screws which were primarily used. I also used a shorter and longer variant. The longer version was used solely for the post joints. They’re big screws — 4 inches and #12 diameter (.216”). Although self tapping, I did drill pilot holes to ensure screws went in straight. The Torx heads are the only way to go. Stripping then is nearly impossible:
UPPER FRAME. Here’s a shot of the upper frame being assembled, but not yet complete:
POSTS. The posts were fastened with the 4” screws mentioned above. To install them straight, I made a drill guide (not shown), and counterbored the holes. Luckily there was no wood splitting. Bolt pattern is 2.25” square:
TABLETOP. Not much to see here. I cut the 3/4” plywood tabletop with a circular saw using a 8’ level as a cutting guide. Both workbench tabletops were cut separately, but they came out exactly the same size to the ~1/32:
FITUP. At this point, it was about done. I positioned the two workbenches in place. After screwing down the tabletop, I filled the counterbores with wood putty and sanded the top using 320 grit and a palm sander:
SHELF. I really needed (and still need more) shelving out here. I had enough extra material to make a 6 foot long shelf:
MILL MOUNTING BASE. By this point, the workbench was done, but the mill was still on its shipping pallet. I made this base out of two plywood pieces. The 4 bolts are counterbored in the wood allowing the entire mill can slide anywhere on the top of the workbench:
CHIP SHIELD. I made a quick chip shield out of some 1/4" MDF I had lying around:
FINAL PRODUCT. Here's the final product, for now:
BUILD TIME. Building the workbenches took 2 days including the design and trips to Home Depot. The shelf, mill mount, sanding, and organizing everything took another days worth of work. Maybe if you're a pro you could have done it all in just a few hours tops (lol).
Not exactly a racing post, but the mini machine shop will no doubt be used for racing endeavors in the future.
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