Tonearm

Moving to tonearm, Graham Elite is one of my very first serious tonearm. "Serious" means its not cheap. Since I am using Air Force 1, the one that naturally fits is the 10 inch arm. The standard arm comes in aluminium. I would describe the sound as dynamic, exciting and explosive. The bass is very vibrant to the extent that it is almost out of control at times.

Techdas actually offers a titanium wand upgrade. It does cost an arm and is beautiful. But I have placed an order for over 1 year and still has not received yet. So I gave up in the end.

Looking at the structure of the arm, it seems that one can DIY a version of it for fun. One reason titanium is a good option is because of its stiffness. Recently, the forged carbon technology has become available to home DIY use. A combination of titanium body with a forged carbon coat has come to my mind. And that is exactly what SAT is doing with their top model arm. My aluminium arm is 41.5g and the titanium version is 50.0g. So about 9g extra. Hopefully, the forged carbon fibre design can keep the same stiffness without adding extra weight.

Titanium tubing is actually not difficult to come by. The TA2 pure industrial titanium can come in at a very reasonable price. The only problem is machining. If the selling can cut it for you, then there is no issue.

Reverse engineering is actually an interesting hobby. it takes a lot of research in material technology and machining. Learning to use CAD is another challenge. But thanks to Google and Youtube, nothing is impossible.

You can see the original SAT arm photo and my reversed engineered headshell. I am pretty happy with it.

Now I have to make a mould to create a forged carbon headshell plate. The following picture is the mould I created with Fusion 360. If you want to learn more about forged carbon fibre and compression moulding, you can find it here. The aluminium headshell will have to "contract out" to my local miller for further processing

This is the first prototype. There are sufficient clearance without the shaft rubbing on the LP surface. If you read Grahams design principle. He places the center of gravity of the tone arm at the same level as the pivot point. My DIY tone has the same principle in mind.


While I am waiting for the mould parts, the titanium tubings have arrived. I need to fix it with the DIN5 connector that is placed inside the tonearm shaft, so I have designed a part that fits everything together. Since it is extremely difficult to machine this part out of titanium, it can only be made in aluminium.

The titanium shafts is 140mm long with an outer diameter (OD) of 8mm and inner diameter (ID) 7mm. It snug fits into the aluminium housing which will then be used to house the DIN5 connector. This DIN connector is just a standard tonearm connector. To make sure the 2 materials bonded together, first I made the inner diameter of the housing exactly the same size of 8mm. So, naturally, the titatium tube will not fit as it is also 8mm. So I use hot air gun to expand the aluminium so they fit. Once the aluminium is cooled down. The fitting is so tight that structural integrity is mantained. To provide extra support, I also use super glue.

After 1 week the mould for the headshelf finally arrives. It seems to match the CAD design very well. After coating the interior with mould releasing agent, I started the process of forged carbon. You can see that the mould is now filled with 2mm carbon fibre. I calculated that 2.7 grams of carbon fibre is needed to get the 60:40 ratio. And it seems to fit the mould well. The photo on the right is with all locked in place the clamps the 2 parts together.

This is straight out of the mould without any polishing. The surface looks much better after polishing and with the defects filled.

The CNC milled headshell mounted on the 3D printed prototyped arm. Noticed I have made too small indentions on the headshell to allow a more secure attachment with the carbon fibre plate

This can be considered to be an alpha version of this wand. The forged carbon head is glued to the aluminium head-shell with acrylic resin.