Drilling holes in bamboo: Splintering prevention

[kudzu9]

The technique I've used with pretty good success is one that's commonly employed in general woodworking...masking tape. If you give the area you're drilling through several tight turns of masking tape and then go over them with your thumbnail or something hard to really adhere them, it wil usually minimize splintering at the exit hole. If you do have a few loose fibers, use a razor blade to slice them off, then carefully remove the tape.

[Mark Meckes]

Hiya Kudzu9,
yep, some things can be so straight forward that the hardest part of workin is in makin it fun!
Thanks for explaining it in such a way that DOES make me wanna go and try it out!

some thoughts about hole drilling...
... not all masking tapes are equal... some are a real pain to remove while others wont stick al all.

...the bigger the hole to be drilled, the greater the propensity to split or fray.

Other important considerations...
- type, and sharpness of drill bit, speed of drill, angle and momentum of approach...
- oh yeah, and all that stuff about differences in species, whether green or dried, and quality and consistency of materials etc... now it's gettin mind boggling!
Hey what! Hole drillin is a good exercise for evaluating the `substance' of materials at hand.
Nothin lost is nothin gained...HuH? well wut i mean is ...mistakes is a part of learning...though... Ouch! It really hurts to finish a piece of work to perfectos, and then ruin it by drilling a disastrous hole.
...so hey! here's a good piece of advice...
Drill your holes early in the making ... don't let it be the last task! That way it's easier to discard the piece and start again.

...back when I made lotsa windchimes, and drilled lotsa holes, this process (masking tape), would have been too time consuming for my likings...if for instance a chime required drilling of 40 double sided holes.
So I then relied on the tools, bits and techniques, and lots of practice, to drill without the need for masking tape ...though there would inevitably be a small percentage of fraying or splitting, especially if I'd wander away from the focus of necessary attention to the task at hand.

I also didn't drill right through the bamboo, but set up various jigs, and drilled a matching hole from both sides, as separate tasks.
Mark
...hoping someday somebody will come up with a two bit hole drilling jig that will automatically center the hole for any size culm dia, and drill a clean hole through both (out)sides at one time!

[kudzu9]

Mark-
I've used the masking tape method to drill holes up to 1-5/8" in dried culms using Forstner bits. Just make sure you use a decent quality tape with good adhesion (not masking tape for painting, which is less sticky).
I prefer Forstner bits because they slice through the fibers at the edge first and that also helps minimize fraying. I've even used these bits to cut a semicircular piece off the end of a large culm so that it matches the curve of another piece I'm joining it to. You just need to be careful in aligning the piece on your drill press table, and clamp it firmly and level. It helps if it's an end that has a wooden plug glued in as described in my other post `A couple of bamboo joint techniques' (http://www.bamboocraft.net/forums/showthread.php?s=&threadid=141) in the thread `Bamboo joints'. The little fraying I got with this drilling was easily cleaned up with a razor blade. The only thing to be aware of is that the glue you use to glue the plug in with can also cause a residue to build up on the outer circumference of the bit, so it may have to be cleaned off frequently with solvent if you're drilling several holes.
If I'm working with really big culms -- like 6" in diameter -- and I want to make really big holes I do the following. [I use this technique, for example, when making big bamboo water spouts for gardens.] First, I put down tape in an approximate circular shape that matches the size of the hole I want to make, and then mark it as best as I can in pencil. Then I drill a 1/2" hole inside the circle, as an entry point for my sabre saw. I use a long blade and go slowly, cutting all around the shape I've marked, but keeping the opening a little smaller than what I'll need. Once the hole is cut out, I put one of those little 1-1/2" diameter sanding drums on my radial arm saw accessory shaft and use the drum to clean up all around the hole. I'll just keep sanding away all around the edge, and doing test fitting, until the piece I want to insert fits right.

[sound world]

...hoping someday somebody will come up with a two bit hole drilling jig that will automatically center the hole for any size culm dia, and drill a clean hole through both (out)sides at one time!

I second that emotion! C'mon somebody!
Some kind of calliper drill would be interesting,drilling from both sides at once...

[asnor69]

Dear bambooseros,

I have not tried frosteners bit up to now, since hole saw do the job for me. The way I did it is choose the hole saw with lesser diameter of 1 to 2 mm. This gives allowance for the hairy bit as a result of using hole saw. Then use coarse sandpaper to sand out the hairy bit. In doing so, we can also shape the holes to the oblong bamboo. This way, we can get a perfect fit as well as a clean hole.

Happy Bamboo smithing.