I have been following the Nanook 219 tonearm build thread on diyaudio. It is a very simple unipivot tonearm, with the arm tube usually made from an aluminium arrow shaft, the tip of a Parker ball pen refill cut off and used as the male bearing, and various types of female bearing arrangements - from simple brass pieces to jewel bearings - having been used by various builders. In its rawest form, it is just the basic arm tube, bearing arrangement as mentioned above, a suspended counterweight to lower center of gravity, and some sort of headshell arrangement ranging from the elaborate to really simple ones.
But the central idea behind this build is to utilise easily available parts to make a good sounding tonearm. The original build costed $ 2.19, hence the name Nanook 219, Nanook being the diyaudio user name of the Canadian gentlemen who adopted and improved the Altmann "joke" arm.
I have spent lots of my evenings and weekends planning how to go about this build. The biggest challenge for me at the outset was to figure out what to use as the female part of the bearing. The male bearing was easy as I happened to have a couple of Parker ball pens.
The next decision was whether to use aluminium or carbon fiber arrow shaft as arm tube or make something out of wood. Aluminium is the most commonly used among builders of this tonearm. Each has its advantages and disadvantages. Aluminium or carbon fiber arrow shaft would not need any shaping as they're already tubes, close tolerance ones at that. Both would need some amount of internal damping. I knew that I won't get ready-made wooden rod of my required diameter. And even if I got one from somewhere, there is the question of how to drill a hole all along the length of the arm tube.
I chose to go with wood as wood is usually known to have good sonic properties (different types of woods are used by builders as tone wood in tonearms). Plus wood has adequate damping property. And I am more familiar with woodworking than working with metals. I have zero working experience with carbon fiber. Moreover I didn't exactly set out to build a very light arm. It was my intention to have a medium to heavy mass arm so wood seemed like the best choice for the purpose.
So here's where I am at now, temporarily rigged up with a counterweight borrowed from another tonearm and suspended from the counterweight "stub" with a thickish solid core copper wire:
Top view, temporary setup to check trackability. There is no wiring yet. After setting the tracking weight and fixing it at the correct mounting distance (I am using 294 mm pivot-spindle distance), it tracks beautifully without jumping or skipping. I didn't bother with correct offset angle yet, though I had offset the headshell by rough estimate (I am guesstimating approx 18 degrees):
Right now the two halves of the arm tube are tied together with cable ties, and need to be glued together. Since I didn't have a chisel that could cut away a semi-circular section, 5 mm wide, I had to improvise my own chisel by sharpening the pointy end of a metal file (the end that usually goes into the handle). But the metal I used was not tampered and therefore quite soft. It needed constant sharpening on a sharpening stone.
Some more build pictures below. Except for some parts, it isn't difficult to build an adequately working model. Fit and finish perhaps is where the skilled will come away looking good. And if my fit and finish leans on the agricultural on the aesthetics scale, you know just where I stand on the skill divide:lol: But it has been an immense learning experience for me.
This is the starting point: D section wood decorative moulding, 13 mm diameter, machined teakwood. It is dirt cheap - Rs 53 for a six and half feet length. Buy the full length, as you need to cut off at least two straight segments of 15 inch each. More often than not, these mouldings are hardly arrow straight. Also one needs to choose good looking grain structure. Buy something with the least blemish (and the straitest, of course).
The groove for passing the tonearm wire is manually carved out:
In the picture above, the extended part on the right hand side of the picture (topmost piece) was an afterthought. After making two of equal length, I was suddenly faced with the problem of how to make the headshell. I thought one might as well make the headshell an extension of the arm tube itself to avoid the complication of joint, and also to maintain as much structural rigidity as afforded by this piece of wood.
More build pics to follow
But the central idea behind this build is to utilise easily available parts to make a good sounding tonearm. The original build costed $ 2.19, hence the name Nanook 219, Nanook being the diyaudio user name of the Canadian gentlemen who adopted and improved the Altmann "joke" arm.
I have spent lots of my evenings and weekends planning how to go about this build. The biggest challenge for me at the outset was to figure out what to use as the female part of the bearing. The male bearing was easy as I happened to have a couple of Parker ball pens.
The next decision was whether to use aluminium or carbon fiber arrow shaft as arm tube or make something out of wood. Aluminium is the most commonly used among builders of this tonearm. Each has its advantages and disadvantages. Aluminium or carbon fiber arrow shaft would not need any shaping as they're already tubes, close tolerance ones at that. Both would need some amount of internal damping. I knew that I won't get ready-made wooden rod of my required diameter. And even if I got one from somewhere, there is the question of how to drill a hole all along the length of the arm tube.
I chose to go with wood as wood is usually known to have good sonic properties (different types of woods are used by builders as tone wood in tonearms). Plus wood has adequate damping property. And I am more familiar with woodworking than working with metals. I have zero working experience with carbon fiber. Moreover I didn't exactly set out to build a very light arm. It was my intention to have a medium to heavy mass arm so wood seemed like the best choice for the purpose.
So here's where I am at now, temporarily rigged up with a counterweight borrowed from another tonearm and suspended from the counterweight "stub" with a thickish solid core copper wire:
Top view, temporary setup to check trackability. There is no wiring yet. After setting the tracking weight and fixing it at the correct mounting distance (I am using 294 mm pivot-spindle distance), it tracks beautifully without jumping or skipping. I didn't bother with correct offset angle yet, though I had offset the headshell by rough estimate (I am guesstimating approx 18 degrees):
Right now the two halves of the arm tube are tied together with cable ties, and need to be glued together. Since I didn't have a chisel that could cut away a semi-circular section, 5 mm wide, I had to improvise my own chisel by sharpening the pointy end of a metal file (the end that usually goes into the handle). But the metal I used was not tampered and therefore quite soft. It needed constant sharpening on a sharpening stone.
Some more build pictures below. Except for some parts, it isn't difficult to build an adequately working model. Fit and finish perhaps is where the skilled will come away looking good. And if my fit and finish leans on the agricultural on the aesthetics scale, you know just where I stand on the skill divide:lol: But it has been an immense learning experience for me.
This is the starting point: D section wood decorative moulding, 13 mm diameter, machined teakwood. It is dirt cheap - Rs 53 for a six and half feet length. Buy the full length, as you need to cut off at least two straight segments of 15 inch each. More often than not, these mouldings are hardly arrow straight. Also one needs to choose good looking grain structure. Buy something with the least blemish (and the straitest, of course).
The groove for passing the tonearm wire is manually carved out:
In the picture above, the extended part on the right hand side of the picture (topmost piece) was an afterthought. After making two of equal length, I was suddenly faced with the problem of how to make the headshell. I thought one might as well make the headshell an extension of the arm tube itself to avoid the complication of joint, and also to maintain as much structural rigidity as afforded by this piece of wood.
More build pics to follow
