Pump Drill Technique

[Toddy]

A drawing pin works well for that
When we're demonstrating really simple stuff we use a couple of limpet shells; they fit inside the cup of the hand just perfectly

cheers,
M

 

[Stringmaker]

Good tip with the drawing pin.

I was aware of the limpet shell option but my part of the coast is the wrong environment to find them.

Iron Age bodyfiller it will have to be............although I can justify the drawing pin by saying it is Bronze!

 

[Stringmaker]

For those following my painful (but very educational) journey, I've gone back to first principles according to the "Earth Skills" article on pump drills.

I have now lashed up another garage scrap crosspiece using mismatched lengths of bamboo and masking tape, but the working length is 24". I have also re-geared the stroke so that there are 2 revolutions of the drill per stroke, and made sure that the bit is 1/2" in diameter.

The flywheel is a work in progress as I split and glued another section to the drill so it is close to the 2lb target. I should be able to test it again tonight but I'm not posting any photos as it is such a bodge unless anybody desperately wants to see it.

One immediate improvement I noticed is that by re-gearing the cord length and using the longer crosspiece, the cord now wraps properly and evenly. With the old set up the angle between the cord and the drill was too shallow, such that it was a good way along the drill before it beagn to wrap; again not very efficient.

More to come after the next test run (with photos instead of links this time!)

As W.C.Fields once put it:

"If at first you don't succeed, try again then give up. There's no point in being a damn fool about it!"

 

[Toddy]

Thomas Edison said he hadn't failed 15,000 times; he had succeeded 15,000 times in proving that a particular material didn't work

M

 

[Stringmaker]

Thomas Edison said he hadn't failed 15,000 times; he had succeeded 15,000 times in proving that a particular material didn't work

M

I like that.

15000 versions of my drill to beat then!

 

[Stringmaker]

I swear that the Gods of Fire are 'avin a larf!

I had a test run with the garage scrap bodge up MK3 earlier and it still didn't feel right after adjusting the crosspiece length and gearing. There was just no momentum in the drill.

"Right! That's it! It HAS to be the flywheel being too light!"

I was then on a mission to add weight and see if things improved; using whatever was to hand to test the theory.

After two additions of weight, it finally felt like it was running properly when this happened..........

http://imageshack.us/photo/my-images/851/pumpdrill003.jpg/

I knew the drill had a weak point as I'd whittled it down to size where the flywheel goes, rather than have a uniform section straight pole.

Just for information, the flywheel consisted of this lot:

Two sawn sections of Birch
The remains of a roll of lead strip
Two split sections of Ash
Two pieces of Sycamore (old table leg)

What was very interesting was that the total weight was 3lbs; the suggested working range in "Earth Skills" is 2 3/4 lbs to 3 1/2, so I'm actually quite pleased that by my own experimenting I arrived at the same conclusion.

I think I've now got the specification sussed; I just need to find decent materials to build a proper set and try it out.

Onwards!

 

[Toddy]

Hmm Unfortunate that.

From our experience I knew that that heavy whorl needs a lot of fixing......didn't think it'd break the shaft though

My whole house stank of smoke for weeks while we played around with it trying to get it right T'was fun though

cheers,
Toddy

 

[WolfCub]

Watching all your antics with interest

when you first posted I sent an email to my A.C.L. saying "Make me a 'pumpdrill' for camp ! Google it !"

with limeted info , he's made me two niether actualy 'work' as far as fire go ....

... but the Cubs and Scouts will have fun trying on camp ... keep some of them busy for hours !

so the 'prototypes' will achieve what I need for now ...

... but I do want to see you crack it ! Then I can get my bloke interested in putting one together that really works.

Keep up the good work !

 

[Stringmaker]

Watching all your antics with interest

when you first posted I sent an email to my A.C.L. saying "Make me a 'pumpdrill' for camp ! Google it !"

with limeted info , he's made me two niether actualy 'work' as far as fire go ....

... but the Cubs and Scouts will have fun trying on camp ... keep some of them busy for hours !

so the 'prototypes' will achieve what I need for now ...

... but I do want to see you crack it ! Then I can get my bloke interested in putting one together that really works.

Keep up the good work !

Thanks for that, you made my day!

I had no idea if anybody was that interested until Toddy began to comment, so to know that you've been following my sorry tale has spurred me right on to nail it. I can't work on it for a little while but I will definitely see it through now I know I have a readership.

 

[Stringmaker]

For those of you kind enough to admit that you've been following this story, I shall be back in the garage very soon.

I am now confident(!) that I know the build specifications in terms of drill length, crosspiece length and flywheel weight, but I was stumped until recently to come up with a means of making a flywheel heavy enough but small enough. I don't have any soapstone, and I wanted to make a kit that can be completely taken apart if needed, so I am going with leather lashings to hold it all together.

I plan to make the flywheel from the remains of my first one, wrapped in lead roofing sheet then lashed to the drill. I should get some lead by the weekend and then it's back to the build stage again. For the period I am working in, lead is a good "cheat".

There will of course be photographic evidence of Pump Drill MK4 in due course.

Thanks for reading (I hope).

 

[Stringmaker]

Right,

I gave up trying to find straight poles from my limited stash, so bought two broom handles for my latest effort. At least I'll know that the balance should be right.

This is what Mk4 looks like:

http://imageshack.us/photo/my-images/18/pumpdrill004.jpg/

The flywheel is exactly 2 3/4 pounds, as arrived at last time, but as you can see it is a lot more compact thanks to two pieces of lead sheet rolled around two offcuts then lashed against two flats on the spindle. It is stable and doesn't move, and also feels like it's got both some inertia to overcome, and therefore some momentum when it's rotating.

So does it work?

Sort of.

I was losing interest by now, so the test run was just lashing the hazel bit into place with masking tape, so it wasn't too tight. I also don't think even now that the crosspiece is quite long enough, but I can report that there was consistent momentum and brown dust with smoke! In the interests of bodging, I also used old washing line for the cord again which doesn't quite wrap as well as paracord.

For the next effort I will make a slightly wider hazel bit, get yet another longer broom handle for the crosspiece(!), cut a proper notch and use paracord. If that doesn't work then it's back to matches!

Thanks for reading.

 

[Stringmaker]

Yes folks you read that right!

Not 30 minutes ago I was inwardly whooping for joy as I stared at a beauty of a fat smouldering coal at the first real attempt using the "tweaked" set up.

I bring you...........the Stringmaker Pump Drill MK4 (a)

http://imageshack.us/photo/my-images/703/pumpdrills006.jpg/

And just to prove it:

http://imageshack.us/photo/my-images/546/pumpdrills007.jpg/

Apologies for the harsh flash but you can clearly see the coal smoking away.

If you read the last post then you remember that I was struggling with getting the friction bit to secure and wasn't convinced about the dimensions. I was pondering this when the solution hit me; use the drill itself as the friction bit!

I know that it will wear out, but I now also know that a broom handle makes a great drill and bit, so I'll just buy a new one. As I'm planning on using this set with kids, I wanted something which I have confidence will work, rather than go through all the pain of trying to build something on-site which probably won't.

To say that I'm well pleased with myself is an understatement; this has been a real voyage of discovery and learning by experiment.

Oh, and I also knocked out a cracking coal with my bow drill setup too!

 

[Toddy]

Very well done
Persistance pays off

It's one of those really good tools when it works, isn't it ?

cheers,
M

 

[mountainm]

Brilliant! Anyone tried an achimedes drill?

 

[Stringmaker]

Very well done
Persistance pays off

It's one of those really good tools when it works, isn't it ?

cheers,
M

Thanks.

Yes, I was also patting myself on the back for sticking with it; nearly a month in all I think.

The breakthrough was when I started adding weight to the flywheel; it got to the point where the "feel" was right as soon as you started to drill. I now want to make another one with a flint bit for drilling green wood.

It's early technology projects like these (I don't like the term "primitive") that connect you to the past in a way that nothing else can.

 

[Stringmaker]

Having kept the project leader of my volunteer group posted on my progress, he suggested I bring my kit to our meeting last night and do a "show and tell".

No pressure there then.

By the time we'd finished our main meeting it was getting a bit gloomy (we had the meeting on-site in the woods), so I could barely see if I was getting an ember.

After a few seconds gentle hand wafting there was a nice red glow appearing which turned into a corking coal; especially in the dim light.

Phew!

I now plan to build another larger one to see if it scales up well for two or three kids to work as a team. If I do, I'll post it up.

 

[Linker]

i got to building one of these yesterday and made a quick video this morning -was alot of fun http://www.youtube.com/watch?v=pCpNVN00zPM