Mk IV Carp - Compound Taper

[CrayCane]

Yes I agree completely Alan.

Pete

[Nigel Rainton]

The graph above shows the plot of the Richard Walker MkIV taper from Rod Building for Amateurs. A straight line (red) has been included to highlight the changes in taper. The data is plotted against distance from the tip. The bottom left hand corner of the graph shows the taper of the tip and the top right hand corner shows the taper of the bottom section. That is, its upside down !

The thickness of the tip is .021" more than a straight taper at its thickest point. The thickness of the bottom section is .019" less than a straight taper at its thinnest point. None of this data includes the handle.

[Nobby]

Am I getting this right? You're saying that the tip is thicker than a straight taper, making it heavy and stiffer, and the butt is thinner, making it springy and flexible???


Perhaps this is the mysterious 'hinge' I have heard so much about?

Not so much a hinge, that pivots in one place, more of a top heavy tip to bend the butt more.....


Fascinating stuff. Thank-you.

[Nigel Rainton]

Yes, exactly. I don't know if the rods follow this data. It would be interesting to measure an early Mk IV and see. I don't have either an early Walker rod or a micrometer :-)

[SeanM]

Here you go:



The graph shows the taper from Rod Building for Amateurs and plots it against the Chapmans Mk IV variants.

As I understand it the hinge is the levelling out of the taper between 84 and 90 inches. You can see that the Chapman rods follow the rbfa measurements pretty much exactly in the tip section, but that their Mk IV has a slightly beefier butt.

[Nigel Rainton]

SeanM, Thanks for that.

Is that from measuring rods or from data supplied by Chapman ? I don't have a micrometer and have never used one, is there a modern digital gizmo that gives readings in inches and millimetres ? I find it very hard to believe that a natural material could be worked by hand to a tolerance of .001". A machine might achieve that using a man-made material such as plastic or metal but surely not by hand on bamboo ?

[Ryeman]

Hello Sofa Surfer, I know that this can all get confusing but firstly, if you are saying that the tip of the Mk4 is thicker than if it was a straight taper and the butt is thinner than if it was a straight taper, then I'm afraid you have it the wrong way round and need to look again at the measurements. The measurements suplied by Cray Cane clearly show that the tip gets thinner and the butt gets thicker.
Secondly, I don't know why you are not including the handle. This is the butt, after all. Walker specified using beech dowel of three-quarter inch diameter under the corks, into which a hole is drilled to take the half inch thick cane. This, clearly, is a big increase in diameter, though the rate of increase in taper is also built into the cane just above th handle.
Thirdly, I wouldn't get bogged down with measurements as small as a thousandth of an inch. A micrometer is an accurate measuring device and measuring to the nearest thou is just what it does. A thick layer of varnish will probably account for a few thou! And cane rods of equal diameter can easily vary quite a bit in actual stiffnness depending on the quality of the cane, whether or not some of the outer layers have been removed during manufacture, and whether the cane was baked or not, or how sucessfully it was baked.

Alan

[Nigel Rainton]

Hi Ryeman,

I entered the data supplied by CrayCane (measured in 6" steps) from the tip to butt because that's the way it was listed. I didn't include the handle because there was no data.

The data from SeanM is presented the other way around. The two graphs show roughly the same thing. I agree about the varnish.

I'm interested in finding out if any manufacturers bothered to build compound tapers or if they just built straight tapers to save time and money. Hence my suggestion about measuring an early MkIV Carp.

[Ryeman]

Hello Sofa Surfer. I'm afraid I can't help with information about commercially made Mk. 4 rods. There must be people on here with them who could run a micrometer over them for you. All I know is that Walker listed compound tapers for his Mk 4, I built mine with compound tapers, and I'll tell you this. It might be a nice rod but in forty five years I've never caught a 44 pounder with mine....Maybe I've got the tapers a few thou out!!
Hope someone comes up with what you want to know.

Alan

[Nigel Rainton]

Ha Ha . . . . are you from Rye ? :-)