Thursday, February 20, 2020

Hand Drills, part 2

Last week I covered the once-common hand brace style of manual drill. This week I want to explore the geared manual drill, usually just referred to as a hand drill, the last form of manual drill invented before electric motors took over the hand tool market.
Sometimes called an eggbeater drill because it uses the same mechanism as a manual eggbeater, this style of hand drill shares most of the pros and cons of the hand brace but uses a gear and pinion system to increase the speed of the turning bit. That pesky law of conservation of energy requires that an increase in speed comes at the cost of torque or power, so a hand drill is not going to do large holes as well as a brace will. The now-standard 3-jaw chuck for holding drill bits was introduced with this style of drill, allowing more flexibility and standardization in the choice of bits. Working around explosives in the Army, I had to use an eggbeater style drill on rare occasions. I recall drilling out a couple of rivets, which took two days and a bunch of bits, but they were made of very hard metal.

Eggbeater drills are still in production and I recommend spending more for a quality tool rather than getting a cheap one. We usually link to Amazon for purchases, but after looking at what they had to offer I couldn't find one available in the US worth adding to a serious tool box. I did find a woodworking toolsite that has better quality, so I'll use their drills and pictures as examples.

To recap the pros and cons of a manual drill, with emphasis on the eggbeater style:

  • Quiet. With no electric motor, they are almost silent.
  • Precise. The lower speed and manual operation give better control over the drilling.
  • Cordless. No batteries or electricity means it will work anywhere, even after a power outage or underwater. Yes, I have seen them used underwater and they do work.
  • Durable. Fewer moving parts generally means longer life. As long as you choose a well-built drill, it should last a few generations.
  • Slow. When working on metal or stone, slow speeds will extend the life of your bits. I can't count the times I've seen someone with an electric drill ruin a bit by using too much pressure and too high of a speed. Blue bits don't cut and can't be sharpened; the steel has lost its tempering and is too soft.

  • Slow. Trust me, they're slow when used on metal.
  • Tiring. Instead of using a whole-arm motion like a brace, the eggbeater style only uses the lower part of your arm. You'll feel it in your elbow instead of your shoulder after a while.
  • Low torque. The eggbeater style won't generate the torque of a brace, so it is better suited for small bits (under 3/8th inch).

There are a few different styles of hand drills.

Instead of having a handle in line with the chuck and bit, a chest drill will have a flat or slightly curved plate perpendicular to the chuck. This lets the operator put his chest on the plate while turning the crank, giving him more downward pressure. Handy for working with larger wood bits and any size metal bit, but overkill for precision work. I have seen sets with removable handle/chest plate sets to expand the use of the drill. Picture from Highland Woodworking.

Single vs. Double Pinion
Cheap or light-duty drills will have a single pinion gear connected to the shaft that holds the chuck. The outside drive gear with the crank handle on it will engage this pinion gear and cause the shaft to spin. Having only the bottom of the frame for support, this style will not be as precise or as durable and a drill with two pinions.

Double pinion drills have pinions that engage the drive gear at top and bottom. Cheap versions will have the top pinon mounted to the top of the frame and a drive shaft that ends at the bottom pinion, while a quality drill will have a shaft that extends through the frame and has pinion on both top and bottom. Proper double pinion gears will provide a more rigid drive shaft and less tendency for the drill to twist or torque while in use.

Light vs. Heavy Duty
Light-duty is the standard, while heavy-duty generally means better bearings and stiffer frame with the addition of a second handle mounted in the center of the frame. The second handle will let you get more of a pistol style grip on drill, which is handy when using it in a horizontal position.

Adding a gear box and the ability to change gears, this style will offer a bit more flexibility in what you can do but adds a lot of moving parts.You can see the gear box on the breast drill above.

Extra-Light Duty
Fiskars is a craft and hobby brand of scissors and other hand tools. They make a plastic hand drill that is pistol-shaped, designed to be held in the left hand while the right hand turns a crank on the side. I've never used one, but I'd bet that it has plastic gears inside the sealed case. Plastic gears will not last as long as even cheap metal ones, so I would place this in the “toy tools” box.

Not everything a prepper can use fits in the EDC category. Having a well-stocked tool box will give you options to repair or build things that can make life easier. If you're looking at barter as a part of your preps, having the tools to create things opens up new opportunities and being able to repair stuff is a valuable skill.

1 comment:

  1. When very young, I was introduced to a tool called a "Yankee Drill". It's a form of hand drill, but is not cranked. It is a piston-style drill -- you hold the drill's bit on the spot where you want to make a hole, and press down. The outer portion with the handle moves toward the work piece, and engulfs a smaller in diameter portion. A spiral groove is either on the inside of the upper portion, or on the outside of the lower portion, and pushing the handle over the bottom part engages a pin in the groove and rotates the lower section, and the bit, against the work piece. When it is pushed in all the way, letting up the pressure causes an internal compression spring to push the upper section off of the lower section, which engages the grooves again, but in reverse, and rotates the bit in the other direction.

    A Yankee bit is not a spiral, it is an hourglass shape, with sharp edges. It can cut when rotated in either direction. So pushing in and letting up on the piston will cut the material on both the inward stroke AND the outward. The shape of the bit will naturally move the shavings up and out of the hole as it cuts deeper.

    A Yankee drill is EXTREMELY energy-efficient. It's a lot easier on your hands, and will fit into a tighter space. It doesn't need room for your hand on the side, and doesn't need room for a brace to fit. It basically looks like a cross between a piston actuator and a screwdriver. Some Yankee drills can be used as screwdrivers -- a control will stop rotating the drill either on the push stroke or the spring-return stroke, so it will rotate either clockwise or counter-clockwise as you push it in and out. This way, the screw or bolt will only be turned one way or the other, screwing it in or unscrewing it.

    Here's an article from MAKE about the Yankee Drill. (You can also look up "Yankee Screwdriver"):


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