William Sobral
March 5, 2023

FlipStep Automation - $200 Automatic Drillpress

At Crawford manufacturing we produce a product called the FlipStep -- a steel tailgate step for pickup trucks. We outsource about 25% of the parts by count, and make the rest in house. As we continue to produce product, we realize and alleviate bottlenecks to increase factory flow and profitability in a process of continuous iteration. Everything from cutting, measuring, welding, and transportation, we try to go faster and make the process easier -- as a manufacturing company does. One of our largest bottle necks that we’ve been dealing with for almost two years now is drilling. We do a lot of drilling, in fact we drill 11 holes per step. Which doesn’t seem like a lot, but if you look at it in production that's 1,100 holes per 100 steps. If each hole took 1 minute to drill that would be 18 hours of drilling for 100 steps. However, 100 of those holes are 11 gauge ¾” tube and 400 of them are solid ¾”. If you want a clean finish and respect your drill bits, there is no way you can drill one hole per minute. Additionally, this is a tiring process that involves constantly cranking down on the drill lever for hours on end. It was clear to us that this problem needed to be solved.

At first we went with an ultra low budget solution that made use of scrap parts. We called it the “hillbilly holemaker”. It consisted of multiple pulleys and a bucket of weights that would crank the lever. This solution had inconsistent results. Sometimes it would work, other times it would get stuck, or go too fast and create an off center hole. This solution also still required a bit of manual labor. Obviously this wasn’t going to cut it for production use, so it was back to the drawing board with a marginally bigger budget.

We had the idea to motorize and automate the drill. At first we weren't sure what kind of motor or configuration to use. We considered direct drive, belt drive, and even spring drive. All options had their downsides. Direct drive could be hazardous and potentially damage the equipment if something went awry. Belt driven was a good option as a built in failsafe if it didn’t necessitate a complicated design and consumable belts. The spring drive was also too complicated. I eventually found the perfect solution on eBay.com, a stepper motor linear actuator. It is inexpensive, has good torque, allows for slippage without damage, and has enough horizontal load capacity to actuate the drill lever. It requires additional components like a motor driver, power supply, controller and simple lever modifications, but all said and done the total cost of materials was less than $200.

To mount the actuator I made two brackets that attach to the aluminum extrusion using t-nuts, that also bolt on to the drill in which I drilled and tapped ¼-20 holes into the cast iron housing. Next, I made a custom drill lever that is driven by contact with a bolt mounted on the actuator carriage. To control the apparatus I used a stepper motor driver, an Arduino, and a few switches. There is an on and off toggle switch, an up and down springback toggle switch, and button for automatic drilling. Of course, stepper motors are stupid. It doesn’t know where it is in space so I added an endstop at the end of the actuator so it could home itself when it is turned on, and so it doesn't go too far and break something if it ends up skipping steps. As for power I got pretty lucky and found an old laptop charger that supplies both 5v and 12v, so I could power both the Arduino and the motor without a boost converter. The end product is marvelous. The drilling speed can be fine tuned for optimal performance and can be left alone while it completes drilling. It also retains all manual functionality as the lever isn’t permanently affixed to the actuator. Retraction speed is doubled after the drilling is complete so you can quickly remove your part and load a new one.

Finally to make the drill press require even less labor to operate, we made a water cooling system for lubricating holes to substitute the use of cutting oil. We used a small pond pump, a five gallon bucket, loc-line and band ade cutting fluid. This eliminates the action of manually oiling the hole multiple times periodically, yields a nicer finish, decreases cleanup, and extends bit life.

These are highly recommended modifications for limited production consumer grade drill presses. They are inexpensive and have some impressive labor saving benefits. The drill still maintains normal manual functionality, yet can be left alone to complete a drilling process. This is especially useful when a complimentary task like cutting is at hand, so one can simultaneously cut and drill parts.