Project Failure: Pump Drill
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[edit] Pump Drill
The pump drill is a fire-by-friction device consisting of a hearth board, a spindle, a counterweight, and a crosspiece. A hole is drilled through the crosspiece so that it can pump up and down on the spindle. The crosspiece is then attached to the spindle with a piece of cordage and twisted up. It is quickly pumped down and allowed to rise back up. The untwisting cordage spins the shaft and the counterweight provides the momentum to wind it back up. The friction of the spindle against the hearthboard creates a glowing coal as the wood is ground to dust and heated to extreme temperatures.
While the pump drill is less portable and takes longer to make than a bow-drill it is said to start fires faster and with less effort. Therefore it makes a valuable addition to any more permanent primitive camp. Many original pump drills featured a single flat round stone or heavy piece of wood drilled through the middle as the counterweight.[1] However, sandwiching two weights between crosspieces has become popular among modern practitioners, probably due to the initial difficulty shaping and drilling through stone.[2] Ironically, once the pump drill is built its main use other than starting fire is to drill holes in stone, bone, shell and other hard materials. This is accomplished by affixing a point to the end of the spindle that is harder than the substance to be drilled. The Native Americans made their wampum beads with a pump drill.
[edit] The Project
[edit] In The Beginning
The idea of building a pump drill first arose when I promised to do a public presentation to go along with my paper Ethnobotany of the Iroquois. This is how the Iroquois started their fires and I thought, what's a good presentation without a little smoke? Well the presentation never materialized but the pump drill did. There is not very much information on the construction of pump drills on the Internet. Tom Brown Jr. gives some specifications but does not go into great detail about the building process in his Field Guide to Living With the Earth. For guidance I relied heavily on an article called "Pump-drill Fires" by Anthony Follari in Primitive Technology: A Book of Earth Skills.
[edit] Getting Started
Nick had just cut down an ash tree in his back yard, so I went up to see if there were any usable pieces. I cut out several promising-looking chunks with a crappy saw. It kept binding no matter what I did. Then I went in search of another dead tree. I forget why. I guess the first one didn't have enough straight parts. I found a dead ash. The saw was not working on this tree at all, so I went back inside and traded it for a little hatchet. I was having a really hard time with the hatchet too until I figured out, wow, I really have to angle the thing and make it look almost like a beaver cut this tree. Later, around dusk, I went searching for a good hearthboard among the aspens but all the dead wood I could find was either rotten or not thick enough. Finally I found a suitable piece.
The next day I began measuring out the pieces. Part of the process required splitting one 30-inch piece into several long and flat pieces for the pump and sandwich pieces and I was unsure of how to proceed especially since the piece I wanted to use was dry and not green. Would I be able to control the split by bending the pieces as the article suggested? Well it turns out that I didn't have to worry about this because Nick did it for me and he did a pretty decent job, though I ended up replacing one of the pieces later.
[edit] Mistake One
The first diversion I took from the instructions, rarely a good thing, was that the spindle piece I selected was not as wide in diameter as suggested...but I persevered. (Actually this mistake was eclipsed by later mistakes and didn't matter so much after all). I took the sandwich and pump pieces inside and drilled them using an old-fashioned hand drill that I had only used once before to tap maples. I had to figure out how to change the bits in the hand drill and that took a minute. Most girls just don't grow up using tools. I wish I did.
The next step was to drill a hole in the bottom of the spindle for the fire plug to fit in. Sure, you could just use your spindle tip to start the fire but most people don't because the pump drill is a rather permanent apparatus. It is meant to be used over and over again and they don't want to have to replace a good straight spindle every time it burns down too far.
[edit] Mistake Two
Did I use it because it looks totally rad and primitive? No, it was the only thing around.
The hole drilled in the bottom turned out to be slightly off-center. Oh well, we'll carve it even or alter the plug to fit the hole. Ha! yeah right. Anthony's method of attaching the fire plug involved splitting the wood around this newly drilled hole, wedging in the plug and tying it all tight. I had brought a yucca stalk from home in anticipation of making the pump drill and I split off a piece with the help of my "whomping stick" and carved it. Well, because the thickness of the walls differed around the uncentered hole the wood began to give more on one side than the others causing the plug tilt. Not good. The the splits began to split themselves right up the shaft farther than desired.
I gave up on the plug for a moment and set about trying to figure out how to put on the string. I was really confused at first about what to do. All the pictures showed the string wound up. How was I supposed to attach it to the spindle? Was I supposed to wrap it around some special way? How long was it supposed to be to make the thing spin? What the hell makes this thing spin anyway? Did I mention I failed the mechanical aptitude part when they conned us into taking the ASVAB (military placement) test in high school. Well as you can see in the first photo the attachment of the unwound string is pretty simple, but I fumbled for a good while that night tying and retying and trying to understand the mechanics. It wasn't until days later that I found Anthony's suggested string measurements and pump piece length at the very end of his article.[3]
[edit] Mistake Three
After I figured out how to make the thing spin, I had to attach the rocks. I had already picked out some rocks at home and weighed them on a scale. They must be as close as possible to the same weight. The article had recommended around three pounds of weight. I didn't have two rocks that were big enough, so I had to use four: two on each side. This turned out to be a double mistake. One because I erroneously thought there was to be three pounds of weight on each side rather than three pounds total, and two because sandwiching multiple rocks--especially round rocks--on top of each other was a total pain in the ass. I finally attached the rocks and set the thing spinning but it seemed slow and ungainly and not like anything that would ever produce fire. I went to bed.
The next day I cut off the old part of the shaft with the hole in it and sharpened the tip so it would spin smoothly on the floor so I could practice with it, even if it wouldn't start a fire. I spent a good deal of time attaching rocks and having them fall off.
Finally, I gave up on the four stones and replaced them with two equally weighted, squishy sand balls like the type you use to exercise your wrists and hands. Those stayed in place much better, though they slipped out a few times too.
The next problem I encountered (now that I could pump for longer periods of time without something flying off) was that the sting, just a piece of jute cord, kept breaking. After two breaks, Nick gave me a scrap of thick leather to use for string. I cut it into a spiral. This string had a new problem. Being thicker, it was harder to tie to the top of the spindle. It kept rolling down, and when I put a notch in the top of the spindle to hold it, the spindle began to crack and split from the downward pressure. Shit. This string also broke eventually, but that's getting ahead of myself.
[edit] The Saga Continues
I took the thing home and tried again the next day. I finally found Anthony's suggested measurements for the string and the length of the pump piece[3] and realized the suggested weight was around three pounds total--not three on each side. I put rocks back on, one on each side this time, wrapped in washcloth so as not to slide around so easily. I cut the pump piece to size and drilled some holes in the ends to secure the string there instead of wrapping it around and having it tend to roll towards the middle. I used a band saw for a lot of things from this point on just because I am lazy.
I no longer had access to the hand drill, so I actually had to use power tools in that case. I found a battery-powered drill and took a wild guess at what sort of drill bit of the various kinds in the basement was supposed to go in that, but it was too weak to drill the hole. On to the scarier drill press. I stuck another random bit in there (am I sounding dangerous to you or are these things all interchangeable? There is the kind with no numbers that looks like a corkscrew with a dull tip and a kind that has dimensions such as 7/8 and a sharp point on top of a squarish blade). I figured out how to adjust height and things on the drill press and drilled my holes successfully. Then I found a way to attach the string to the top also without causing further splitting or slippage...most of the time. With that all set I began pumping, but it started to become evident that the device was too wobbly-my spindle was probably not straight enough.
[edit] Beginning Anew
The days blur into one another here. I'm not sure what happened when, but next I decided I might try to straighten my spindle rather than replace it entirely. I heated it up over the electric burner on the stove and bent it into shape. It seemed to be working until I used my shoe to help and crack, it snapped. I taped it back together as a last ditch effort but of course that was never going to work. I scarcely expected it to.
Days, perhaps weeks passed. At some point I replaced the old shaft with a 3/4 inch commercial wooden dowel I found in the basement. No more crooked spindle problems. Then I noticed my pump piece was spinning up crookedly and tending to jam at the top because the original split ash piece that was just too warped. I first attempted to adjust it but eventually gave up and replaced that too with a nice straight piece of lumber. This involved more drill problems, as I now had to drill a new hole for the spindle to fit through, and the drill press only went up to 1/2 or maybe exactly 3/4 of an inch. Well, that's the size of the hole they offer you in the platform to drill through so I just drilled carefully from one side and then from the other until it the hole was through making sure not to jam the drill bit into the metal platform. Now that I think about it, though, I could have simply placed another piece of wood underneath to drill into.
[edit] New Problems
With each improvement I was able to pump faster and for longer periods of time which resulted in new issues from the increased stress.
The main issue was the weight and sandwich pieces refusing to stay in place on the spindle and trying to keep spinning around it which ruins the moment of the drill. Plus the weights kept slipping downward towards the tip of the spindle. On a truly primitive pump drill this is not so much of a problem because generally a branch tapers at one end and if you make the hole just the right size you will be able to slide the sandwich pieces on so it is impossible for them to drop any farther. My dowel, however, was all the same size. It would be difficult to taper. Even if I did taper it, I would have to make new sandwich pieces with smaller holes.
To compound everything, a third problem was my rocks kept wiggling their way outwards, away from center, throwing things off balance and making the drill wobble. I bound all of these parts several times, but they just wouldn't stay. The spinning motion was very powerful and very effective for loosening anything I tied on. You know how sometimes you don't think a ring will come off but you just have to twist it? That's what was happening here. I first resorted to the glue gun to secure the string that was wrapped around the spindle in order to thicken it and keep the weights from slipping down. Later after pounding shims into the too big holes of the sandwich pieces and having them loosen and twist out immediately, I just filled those spaces with glue. I had to do that part twice, though, because the first time the sheer force of those stone wanting to keep spinning cracked the glue, and it came loose.
At some point I also sawed a notch in the end of the spindle in preparation for the next step. Whatever wood the dowel was made of was very hard, and I did not think drilling a hole in the end and splitting it would work well, so I went with more of notched tip similar to the one pictured in Tom Brown's book.[4] I used a folding saw due to its thickness. It was pretty hard to get the saw started into the grain like that, but eventually I did.
[edit] Getting Closer
I brought the now straight and relatively secure apparatus back to Nick's house and started work on the fire plug. I carved one that fit pretty well and tied it in there with string, but it kept wanting to tilt. Plus I was drilling in earnest now on a narrow fireboard that I had prepared from aspen, and the whole apparatus kept slipping off it. Attempts were made to flatten the hearthboard to eliminate any unhelpful wobbles and to deepen the starting hole, but there was still that "wobbly bit" problem. I suppose more of a squared plug that joined flush with the flat tip of the drill would have helped rather than my slightly wedged plug, but I wasn't sure how to accomplish that with my knife without splintering the fragile yucca. I gave up.
[edit] What Now?
Which brings me today. First I started carving again at the old plug trying to improve it. I realized, though, partway through that if I finished it was going to be so short that it wasn't going to be useful for very long; so I made a new one. Not taking any chances, I secured this one with gorilla glue and clamped it to dry for a few hours. I know this kind of defeats the purpose of having a replaceable bit, in fact all this use of power tools, hot glue, duct tape, etc. rather defeats the point of a pump drill, but then again what is the point? I just wanted to make the thing work. I like to make something the "easy way" first to get a good understanding of the process and make it again primitively later. Though, if this article is any indication, the easy way is not always so easy. As with the primitive spindle which naturally tapers, perhaps the proper primitive tools would work better than there modern counterparts.
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[edit] Almost There
Now Nick was helping, and we could drill pretty fast without any tipping or wobbling or things falling apart...except wait, the rocks were starting to make their way out towards the edges. Damn that centrifugal force!
We wrapped duct tape around that whole section and tried again. Smoke! It took a considerable amount of effort, at least as much as a bow drill, but smoke! We cut a notch in the hearthboard, tried a few more times, still no coals. I looked at the powder. It didn't look right. Too many large splinters, light pieces. Hmmm.
On a whim Nick tried drilling on a piece of treated pine that happened to be in the vicinity and had a hole started in it that the pump drill tip happened to fit in. I looked at the powder. Much better. Weird. Neither treated wood or pine work are supposed to work well, but it was. But there was no way to cut a notch near this hole and even if the hole were near the edge the board is much too thick. While I wouldn't expect my first drill to be too successful all reports indicate that a coal should be obtained with minimal effort and in as little as 15 seconds. In the videos I have seem of people drilling, they seem to be pumping much faster than it is possible to pump this drill.[2]
Which brings me to the present moment. Readers, what should I try next? I'm leaning towards a third piece of wood for the hearthboard, willow perhaps, or perhaps lighter weights to let the drill spin faster, but that will require cutting the current rocks out of their tape-string-washcloth cocoon.
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[edit] Updates
Stay Tuned
[edit] Sources
Wiki Authors
Web
- http://collections.nysm.nysed.gov/morgan/images_finished/all_images/full/r24.jpg
- http://wildwoodsurvival.com/survival/fire/pumpdrill/index.html
Books
- Tom Brown's Field Guide to Living With the Earth
- Primitive Technology: A Book of Earth Skills edited by David Wescott
- "Pump-drill Fires" Primitive Technology: A Book of Earth Skills by Anthony Follari
References
- ^ Iroquois Pump Drill Drawing http://collections.nysm.nysed.gov/morgan/images_finished/all_images/full/r24.jpg
- ^ a b Pictures and Videos http://wildwoodsurvival.com/survival/fire/pumpdrill/index.html
- ^ a b Anthony Follari, "Pump-drill Fires", Primitive Technology: A Book of Earth Skills
- ^ Tom Brown, Jr., Tom Brown's Field Guide to Living With the Earth
