Mark Meckes
28th June 2001, 02:45 PM
The `rebar'(reinforcement bar) is a great tool for
knocking out node diaphrams (also referred to as septums, or stops) of lengths of bamboo to make a hollow tube.
In the past it may have been accomplished using a stout, hard heavy wooden stick, but steel has the weight, keeps a good `cutting edge`, and is cheap and easy to find.
Also a steel tubular pipe works good too.
The bottom circular edge can be sharpened with a file to better facilitate smoothing of the inner node ring.
Watch out for those curved culms! ...you may just have to split your bamboo open to get your stuck bar back.
Shorter tubes can be `reamed' by punching the diaphram, and chipping off the edges as you work your way down.
The pole can be held upright, or at an angle when doing this.
If you need to make a lot of long tubes, and you have
reasonably straight culms, here's one way:
(I haven't tried this on anything more then 2 1/2inch
diameter poles)
For a 10 - 20 ft pole I'll use a 4 - 8 ft length of rebar which I start by popping out the first few nodes (have the the base of the pole against something sturdy)
Once the rebar is in the top I'll turn the pole upright and tap the base on a wooden block.
With a hard TAP,the rebar will often drop down fast through the node diaphragms... POPPOPPOPPOP.
I try to tap gently , and, using up and down motions, steadily bounce the bar down through the nodal diaphragms, which chips away any edges the bar works it's way down.
Making the hole through the node diaphram is the easy part compared to chipping away and smoothing the inner walls at the node.
One method is to use a rebar that's about twice the length of your culm, and slide and rotate the pole (horizontally) back and forth, working away at that inner edge.
While doing this, the hands soon learn to sense the inner workings, and you get a feel where the rough edges are inside.
Drilling a hole through the node diaphram is no problem.
I use a regular -small to large- twist drill bits.
You can fine-tune inner node rings with a round or curved wood or metalworking rasps, files and sandpaper.
This is an important process in making some types of musical instruments etc.
~ Mark
knocking out node diaphrams (also referred to as septums, or stops) of lengths of bamboo to make a hollow tube.
In the past it may have been accomplished using a stout, hard heavy wooden stick, but steel has the weight, keeps a good `cutting edge`, and is cheap and easy to find.
Also a steel tubular pipe works good too.
The bottom circular edge can be sharpened with a file to better facilitate smoothing of the inner node ring.
Watch out for those curved culms! ...you may just have to split your bamboo open to get your stuck bar back.
Shorter tubes can be `reamed' by punching the diaphram, and chipping off the edges as you work your way down.
The pole can be held upright, or at an angle when doing this.
If you need to make a lot of long tubes, and you have
reasonably straight culms, here's one way:
(I haven't tried this on anything more then 2 1/2inch
diameter poles)
For a 10 - 20 ft pole I'll use a 4 - 8 ft length of rebar which I start by popping out the first few nodes (have the the base of the pole against something sturdy)
Once the rebar is in the top I'll turn the pole upright and tap the base on a wooden block.
With a hard TAP,the rebar will often drop down fast through the node diaphragms... POPPOPPOPPOP.
I try to tap gently , and, using up and down motions, steadily bounce the bar down through the nodal diaphragms, which chips away any edges the bar works it's way down.
Making the hole through the node diaphram is the easy part compared to chipping away and smoothing the inner walls at the node.
One method is to use a rebar that's about twice the length of your culm, and slide and rotate the pole (horizontally) back and forth, working away at that inner edge.
While doing this, the hands soon learn to sense the inner workings, and you get a feel where the rough edges are inside.
Drilling a hole through the node diaphram is no problem.
I use a regular -small to large- twist drill bits.
You can fine-tune inner node rings with a round or curved wood or metalworking rasps, files and sandpaper.
This is an important process in making some types of musical instruments etc.
~ Mark