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# Caliper to measure diameter of bamboo clum

Brooksville, FL(Zone 9a)

Does anyone know where I can find a caliper for measure diameters of trees or bamboo?

Any help with a web site to order from would be appreciated very much.

Jan

Everett, WA(Zone 8a)

1.
Wrap a piece of paper tightly around the culm and mark where it overlaps.
(To be fussy, push a pin through both bits of paper and measure dot-to-dot.

Measure the length of the piece of paper (circumference).

Diameter = circumference divided by Pi (3.14)

It's probably easier to measure and divide in metric (millimeters),
then convert to inches (one inch = 25.4 mm).

This has the advantage that any error in meaurement is divided by three, so it's as if your ruler had three times the resoluton it really does.

2.
Use a Xerox machine to copy a ruler onto some paper at 100% size. Now you can read the circumference right off the paper (you still have to divide that by 3.14.

Or use a fancy Zerox machine to blow that ruler up by 314% and read the diameter right off the paper.

3.
Or use any crescent wrench on the culm, then slide it off and hold it on top of a ruler to read the diameter directly.

4.
If you're doing a LOT of these measurments, make some "GO - NOGO gauges" from cardboard or sheet plastic.
Cut them to the sizes you're interested in, say every 1/8th inch from 3/4" to 2". The smallest one that slips over the culm is the size.

I got my digital calipers from Harbor Freight, but the Google search "amazon micrometer" gave several options.

Does anyone know if quoted diamters tend to reflect the thckest bulging part of a joint, or the narrowest part in the center of a section?

Corey

Dahlonega, GA

And I flunked algebra !

Brooksville, FL(Zone 9a)

I know how, I just would like to have the caliper, which I found after posting on ABS's face book page. thanks

Jan

Dahlonega, GA

Hi again, Jan . Honest , I'm not following you around . LOL

Brooksville, FL(Zone 9a)

we will just follow each other...LOL

Jan

Brunswick, GA(Zone 9a)

I've seen outside calipers at HD, now that you've reminded me i think i will check there again in the morning. Lowes may also have them.....

Everett, WA(Zone 8a)

If you have a pipe wrench or crescent wrench, you have an outside caliper.
Or even a screw-clamp.

Tighten the jaws until they press against the culm.
Pull it off, take it indoors.

Read the gap with a ruler.

But are they measuring the narrow spots, or the bigger O.D. of the joints?