The Care and Feeding of Bamboo Fly Rods Part 2

Last week we got started on 18% nickel silver tubing, and how it is made into ferrules for bamboo fly rods.  A few photos showed some pitfalls experienced when fitting 18% nickel silver ferrules.  Checking the male ferrule for roundness, as well as taper,  prior to fitting, is a necessary step in bamboo rod making. 

Of all the dimensions important to the bamboo rod maker, out of roundness is probably most important.  We are trying to fit a male ferrule into a female ferrule, and basically want the inside diameter of the female nickel silver ferrule to be the same dimension as the outside diameter of the 18% nickel silver male ferrule.  If either male ferrule or female ferrule is out of round we run into problems.

Indicating spindle 1

If your lathe runs true, it’s easy to check your male and female 18% nickel silver ferrules.  These images show the TIR as the spindle revolves.  The indicator measures to one 10 thousandths of an inch.

This spindle has about .0002″ TIR.  Good enough. Way good enough.

When a collet is placed in the spindle and a precision gage pin is placed into the collet, the runout is again checked.

Indicating gage pin 1

Indicating gage pin 2

Indicating gage pin 3

A Hardinge decimal collet is used, based on the outside diameter of the 18% nickel silver tubing. These images show TIR to be about 2 to 3 ten thousandths of an inch.  That’s good.  Very Good.  Things are running true.

Now we put a commerically available female ferrule in the collet, and check the inside diameter for roundness.

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As is seen in the images, the ferrule is out of round by some .001″ TIR.  This is only the female.  If the male is out of round by as much, then the problem starts to become evident.

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Posted by on February 17th, 2009

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