Harbor Freight Roller Cabinet Mod, Part 2: Wheel Upgrade and Structural Enhancement

toolcab3I know it has been a while since I’ve worked on the roller cabinet, but I’ve finally managed to find some time to finish the upgrades. So let’s get straight to the modifications!

The stock Harbor Freight cabinet comes casters and hardware to attach the cabinet to the bottom of the cabinet. The bolts are threaded into rivet nuts on the inside of the cabinet. Those are the little gold cylindrical nuts on the inside of the cabinet on the image on the right. We won’t need those since we want to install some beefy aluminum channels to reinforce the floor of the cabinet. The method that I decided to with was to drill them out. You could effectively use a die grinder, but I didn’t have one around at the time. Drilling out the rivet nuts was a bit of a pain, insanely messy, and very tedious.

After this was done, all that was left were some relatively over-sized holes (see the image below). One other issue that may not be apparent is that the sides of the cabinet, towards the back, have a square tubing that runs up the cabinet. It offsets all of the drawer glides to be flush with the opening. Not only is the tubing there to offset the drawer glides, but it provides some level of structural stability to the cabinet. I didn’t want to mess with cutting out clearance at the bottom for the aluminum channels. Instead, I decided to notch out the aluminum channels, to allow for the new set of bolts to attach to. This was mostly because the side walls on the aluminum channel material was rather thick, and if I didn’t notch out the sides, the holes would’ve been drilled into part of the channel walls. That would’ve been no es bueno!



My next dilemma was to determine a way to notch out the 6061 aluminum. The ideal way to notch out the side wall of the channels is with a large milling machine. Unfortunately, I don’t have one of these fancy machines, but I do have a plunge router. My insane idea was to use a 1/2″ diameter end mill bit to route away the aluminum. My large Makita plunge router can accept up to 1/2″ shanks, so that’s why I went with the 1/2″ end mill bit.

Once I determined that I was going to use my plunge router, I also decided that I wanted to keep the cuts clean. I didn’t want to freehand the cut. I decied to purchase an acceptable router bushing guide kit for my router model. Once I sorted that out, I wanted to have the router bushing follow some straight edges. So I jointed the edges of some walnut planks I had lying around. Walnut, being a piece of hardwood, was my go to choice. I would’ve gone with hard maple, but I had long planks of that material and I didn’t want to waste them by cutting them up for this quick exercise. I used the jointed walnut planks as parallel guides, and with the correct bushing attached to the router, I could follow the edges of the walnut planks. As you can see to the image on the left, I had my set up on some medium duty saw horses, and I went crazy with the clamps! As a woodworker, you really can’t have too many clamps.

I made sure that the aluminum channels were facing each other, and made sure I used screw-type clamps. The trigger-type clamps don’t have a strong enough grip than the clamps that have a screw handle. The reason why I made sure the aluminum channels were facing each other, was because I had indicated on the bottom of the aluminum channels the amount of material I needed to notch out. One of the key things to this setup was that I made sure the work piece was clamped to the saw horses (I didn’t want the work piece to rock side-to-side when the weight of the router was resting to one side of the walnut guide set up), and I made sure the walnut planks had appropriate spacers and clamps hold the planks to the work material AND the saw horses.

In the image below, you can see how I used the walnut planks as parallel guides that I use the bushing on the router to follow. The best way to route the aluminum is to take very, very, VERY shallow passes, and to set the RPM low. A plunge router is the best way to make these types of passes, although a standard router could work as well, because the notched cuts are from end-to-end. If we were to start the routing in the middle of the work piece, a plunge router would be the idea tool-of-choice.


As you can see below, I screwed up the very first pass by not moving the router at a consistent speed. That’s why you can see the swirling bit marks that were left behind. This was the very first time I was attempting this, so you can’t fault me for doing some trial and error. I also went too deep at first. Shallow cuts are the key! I wasn’t worried about the finish at the moment, since this was the first shallow pass of many to come.


But eventually, I got to the final depth and the finish came out great after I got a good feel for the setup. I did a bit of sanding with an orbital disc sander, to smooth out any jagged burl or sharp edges.


IMG_1207So what’s this nonsense about the notches that I keep talking about? Well, on the right, you can see the test fit of the piece I made. I wanted to set the aluminum channels to the sides of the roller cabinet as much as I could, without taking too much material off. This allows for clearance for the washers, nuts and bolts that I’ll be using to attach the casters to this new reinforced structure!

What I did was I made a ton of measurements as to where this new hole would be. I had made a mock up template on a piece of hardboard (sorry, I didn’t take a picture of it!). Once I was sure the test template would fit and make clearance for the hardware, I went straight to the aluminum channels. I had the bottom facing up, and used some black sharpie to indicate where the holes for the casters would roughly be. Using a caliper, I made some score marks, which you faintly see on the aluminum channel, below. The black sharpie dots that I made can be used as a surface “dye” to allow for making marks to indicate where to cut or drill. Machinists use Dykem to do the same thing, but I don’t have any so the black sharpie works just as well!

Sidenote: I think one of the greatest things about doing some of these types of projects is that you don’t need expensive equipment to build what you need. Sure, I’m not using cost-effective hand tools to cut and drill the aluminum, but I’m also not using expensive milling machines or drill presses (although I do have a drill press, but it’s currently in a freezing cold workshop that has no heat).


IMG_1243Back to the project. Since I’m using a cordless drill to drill these holes, I wanted to make sure that the drill bit didn’t “wander” on the work piece. Because the work piece is made out of aluminum, you’ll want to create little divots on the work surface where you are planning to drill your holes. In comes the center punch! Probably the greatest tool when you plan on drill holes through any surface. It creates a great starting surfacing for pilot holes.

Once I center punched each location of where I wanted the holes to be, I used my smallest drill bit to drill the pilot holes. I find this the best solution at the end of the day, because the pilot holes create a small hole to allow you to align your larger drill bits with. It also allows your drill bit to follow the path of the hole. As long as the pilot hole was created perfectly perpendicular to the work piece, then your final hole sizes will be straight!

As you can see below, I drilled out pilot holes for each hole location. I didn’t manage to to take any pictures of the 3/8″ diameter final hole sizes, but you get the point (haha! Get it? The point…drill bits? Points?…whatever….).


The new casters.

Before I went any further, I decided to work on the casters. Back on Part I, I had purchased some Moldon polyurethene wheels. Just the wheels were replaced, because the bolt pattern on the casters were funky and atypical of the normal casters on the market. The part number for the wheels is 5.00005.925. I would suggest that you order these wheels from a brick-and-mortar industrial equipment store, as they usually cover shipping costs. I purchased these from a vendor that I found online, and I had to pay for shipping, making these wheels a lot more expensive than I’d like ($44 for 4 wheels, but shipping jacked the overall cost to $64). It sports a pedestal precision ball bearing (PPBB), which really reduces the noise when rolling the cart around. They say there’s no maintenance involved, but they do have a grease fitting on them which is a huge plus, for any future maintenance. These wheels are capable of up to 750lbs each, so they can handle over a ton and a half of weight. We aren’t using these bad boys on a light weight sports car, so they’ll be more than enough to handle the weight of the tool cart!

I made sure they were the same diameter as the 5″ stock caster wheels, because I wanted the old hardware to work with the new wheels (specifically the spinning casters that had the lock on it!). I had to purchase a 1/2″ drill bit, since my drill bit kit maxed out at 3/8″. I went with a 1/2″ drill bit because I had to upgrade the nut and bolt for the caster axles to a 1/2″ bolt. The stock nut and bolts for the axles of the old wheels were too small. I drilled out the the caster frames where the new bolt axle would fit, as well as the cam and stopper pieces on the spinning casters. Caution to those that do this…were some long sleeves and mechanics gloves, because hot metal shavings that fly onto your bare arms and hands tend to hurt a bit. I ain’t chicken, but they were definitely unpleasant. You can see the final product below.


Putting it all together.


I fitted the aluminum channels into the bottom of the roller cabinet, and tested with a finished caster wheel assembly. With one bolt in, I made sure that I had clearance for all of the other bolts to attach the finished casters with. I was really lucky that I didn’t screw up any of the hole locations on the aluminum channels for the casters. The hole locations on the aluminum channels were spot on. They say you should measure at least 37 times before cutting once. Come to think of it, I think I made one measurement on my template, drilled some holes, and checked the template fitment. Once I saw the fitment was good, I didn’t really measure anything afterwards on the final aluminum pieces…other than copying my dimensions that I had written down on the hardboard template. I mean…I technically didn’t measure it. But in practice, you should measure a few times before making your final drilling/cuts.

You can also see the clearance issue I was referring to earlier in this article/build/posting. For all of the nuts and bolts that are towards the sides of the roller cabinet, I had to notch out the aluminum a bit to allow for that clearance. Even with the notches, the clearance was still a bit close, but it was enough of a clearance to fit a washer and nut on the each bolt on each caster. Mission success in my book!


I did a test on the whole roller cabinet, after putting all of the drawers and top drawer unit back on. The entire roller cabinet was very stiff and solid. There was a very slight sway when I pushed the entire assembly from the top, but I suspect that it was most likely from the drawers being relatively empty. Once I load up the drawers with my tools, I highly doubt there would be any sway whatsoever! Another awesome thing was that the new wheels are completely quiet and it glided so smoothly along the floor. I was really shocked at how smooth these wheels were! Was the wheel upgrade really necessary? Not really. The stock wheels are ok for the job. But these wheels really put a smile on my face when I’m moving the cart around. Effortless and quiet. I’m a fan of mobile equipment and having these wheels move so easily and quietly was very satisfying.

I’ve provided a breakdown of the overall costs to the rolling tool cabinet. Overall, I spent about $472 on this tool cabinet, which is still considerably cheaper than multi-drawer cabinets on the market. Don’t let the low price fool you, though! The drawer glides and construction of each drawer is VERY solid. These are chunky and heavy duty, and with a bit of modifications to the casters and structural integrity of the floor pan of the cabinet, I dare anyone to find a smooth, quiet, effortless tool cart for less than that price (with the same number of drawers, or more, for a 26-inch cabinet)!

Harbor Freight Roller Cabinet $334.00
Aluminum Stock Channel $59.00
Moldon Polyurethane Wheels $64.00
Hardware (nuts and bolts) $15.00
Total $472.00