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Pump Drill (Read 1922 times)

Jackcordial

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Pump Drill
Nov 17^th, 2005 at 9:29am

Okay, MammotHunter here. Apparently, I am about all bloody useless at producing fire. I've been trying to make a pump drill, and I can't get it to work. Now, it doesn't seem that complicated, really. I'll give you all my specs on the pump drill I have, and maybe someone who has made one can tell me what I'm doing wrong?

Spindle: 3/8" diametre, 22" long. Notch carved in top to hold string. I cut a notch for easy replacement of the bit should this one break, not work, or I want a boring bit instead of a firestarter bit.
Handpiece: 5.5" long tube from failed fire piston with holes drilled in ends to accomodate braided rawhide cord and one in centre 1/2" diametre.
String. No final length yet. I've made the knots slightly loose beneath the handpiece so I can adjust the length of the cord to find an optimal length. I'm thinking maybe about 10-12" of cord on either side of the spindle on a 22" shaft would be good.
Now, as of yet, there is no flywheel, and maybe this is where I have gone horribly wrong, but I can't even get the drill to spin, really, or pump. Is there supposed to be some sort of twist in the cordage at the top of the spindle through the hole or some other special arrangement? From the pictures I've seen, there doesn't appear to be, but this fire drill should not be beyond me. What causes it to pump up and down and how can I get mine to spin?

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slingbadger

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Re: Pump Drill
Reply #1 - Nov 17^th, 2005 at 12:31pm

First, you really do need the flywheel. It adds mass at the end and its momentum helps the process along.
When you put the crosspiece and cord on the main shaft, the crosspiece needs to be spun around on the shaft. This twists the cord, which helps give it extra springiness, and " bounce". You have to experiment with how many twists, as its different for each cord.
And yet the Ancients did all this without computers, and we call them dumb.

The greatest of all the accomplishments of 20th cent. science has been the discovery of human ignorance The main difference between genius and stupidity is that genius has it's limits.-Einstein I'm getting psychic as I get older. Or is that psychotic?

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MammotHunter Interfector Viris Spurii Offline Give me a rock, a sling, and give me some room Posts: 1020 virginia, for now Gender:	Re: Pump Drill Reply #2 - Nov 17^th, 2005 at 12:47pm Yeah, I've got the spinning of the cordage around the spindle down pretty well, and I can get it to spin one way, but not the other on the return. My thoughts are that most of my problem lies in lack of flywheel.
Back to top	Foolish is he who frets at night,&&And lies awake to worry'&&A weary man when morning comes,&&He finds all as bad as before&&-Excerpted from "The Havemal" IP Logged

Curious Aardvark Forum Moderation Offline Taller than the average Dwarf Posts: 13965 Midlands England Gender:	Re: Pump Drill Reply #3 - Nov 18^th, 2005 at 10:41am that's a pretty good description - as I'd never heard of a pump drill but from reading your description jackcordial I can actually envisage one and how it works :-) Just thought I'd mention it :-)
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bigkahuna

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Re: Pump Drill
Reply #4 - Nov 20^th, 2005 at 6:01am

You really do need that flywheel or it will not turn properly. Also be sure to provide a bit of lubrication to the top of the spindal so it turns freely. Usually just by rubbing it along side your nose works well enough. Also try using a softer wood for your fire board. This might make it alittle easier. Or you can just use a bow drill type of arrangement. That is a little easier to work. Any way, good luck Cheesy

Give a man a fish and he will eat for a day. Teach a man to fish and he will sit in a boat and drink beer all day.

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MammotHunter

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Pumped Up
Reply #5 - Nov 22^nd, 2005 at 4:03pm

Alright, I'm riding high and feeling really "pumped" right now! ( I know that was a bad pun, I don't care) I just finished my pump drill, and it works magnificently! I gave it a few test spins on my floor, and before I knew it, I had drilled through the carpet, and the end of the spindle was feeling a wee bit warm. I just bought a hugely overpriced table leg bottom made from a pinewood bun for the flywheel, and it made all the difference in the world. MammotHunter has discovered fire!

Foolish is he who frets at night,&&And lies awake to worry'&&A weary man when morning comes,&&He finds all as bad as before&&-Excerpted from "The Havemal"

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bigkahuna past-moderator Offline Posts: 3894 Delaware, USA Gender:	Re: Pump Drill Reply #6 - Nov 24^th, 2005 at 12:57am I think we're still safe as long as we don't tell him about explosives!
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