It's what they call in engineering terms a "sliding fit", the thumbwheels shaft diameter is a couple of thou smaller diameter than the hole.
Remember, it has to have free rotation to be adjustable. But the tolerences still have to be fairly tight, otherwise you can get a missalignment from the thumbwheel on top and the center of the magnet housing on the bottom plate, and that's asking for an arm that wont work correctly. Also I use just a dab of anti-sieze in the hole around the shaft. Brass and Aluminum get a bit too friendly after a while, this thing called electrolicic reaction, don't ya know.
JD
Remember, it has to have free rotation to be adjustable. But the tolerences still have to be fairly tight, otherwise you can get a missalignment from the thumbwheel on top and the center of the magnet housing on the bottom plate, and that's asking for an arm that wont work correctly. Also I use just a dab of anti-sieze in the hole around the shaft. Brass and Aluminum get a bit too friendly after a while, this thing called electrolicic reaction, don't ya know.
JD
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@Frank: What is the purpose of that extra wheel found on the counter weight of the reference arm ? How does that function ?
@JD: Your suggestion on the anti skating wheel really helped in clearing the doubts that I had in my mind. Can we use wood instead of aluminium for the top and bottom plates (Just a thought) ? Please comment...
Best regards,
Bins.
@JD: Your suggestion on the anti skating wheel really helped in clearing the doubts that I had in my mind. Can we use wood instead of aluminium for the top and bottom plates (Just a thought) ? Please comment...
Best regards,
Bins.
Hi Bins,
The knurled wheel/screw can be added to all my arms, ot just the Reference model. It allows(you screw it in or out...) for ever so slightly changing VTF without the risk of altering azimuth when attempting to slide the main counterweight forward or backwards by a tiny amount.
One full turn alters VTF by ~ 0,03gr.
Best,
Frank
The knurled wheel/screw can be added to all my arms, ot just the Reference model. It allows(you screw it in or out...) for ever so slightly changing VTF without the risk of altering azimuth when attempting to slide the main counterweight forward or backwards by a tiny amount.
One full turn alters VTF by ~ 0,03gr.
Best,
Frank
Hi ,
The arm tube is not fully made up of wood. The rear end of the arm wand is of Aluminium. I think Christian is right. I too was thinking in the same line. But, will that affect the eddy currents generated in the aluminium tube ? In that case, the best place will be the head shell.
@Frank: What is your suggestion ?
Best regards,
Bins.
The arm tube is not fully made up of wood. The rear end of the arm wand is of Aluminium. I think Christian is right. I too was thinking in the same line. But, will that affect the eddy currents generated in the aluminium tube ? In that case, the best place will be the head shell.
@Frank: What is your suggestion ?
Best regards,
Bins.
So does copper and aluminum. You need to do something to prevent galvanic corrosion.
I am speaking from very bitter experience.
Nice project though.
Magura
I brush on a nice coating of "Anti-Seize" compond from a company called SAF-T-EZE,(STL Compund Corporation).which contains nickel and graphite in it's lubricant, around threads and movable mating surfaces.
The stuff is easily found in hardware stores and automotive supply shops.
Machine oil, imo, just doesn't offer enough protection in the long haul and has a habit of running off over time, The Anti-Sieze is tenacious and stays where put.
JD
The stuff is easily found in hardware stores and automotive supply shops.
Machine oil, imo, just doesn't offer enough protection in the long haul and has a habit of running off over time, The Anti-Sieze is tenacious and stays where put.
JD
So does copper and aluminum. You need to do something to prevent galvanic corrosion.
I am speaking from very bitter experience.
Nice project though.
Magura
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then you need to put some shielding into the wooden tube, e. g. a small carbon tube or metal foil which then is connected to ground. You could also use shielded tonearm cable in the tube, then no further shielding is necessary.
perhaps if you twist pairs + and - for each channel, then the external ground/shield would not be neeeded, as twisted pairs have a shielding effect.
So there would be two twisted pairs from the cartridge clips, through the arm and out to the rca's ( or whatever interface. (I'm using a Lemo connector on a junction box with a pair of RCA's to the "outside" world. THe junction box is connected to the turntable ground. This works very well in a modified SME/Thorens TD160 I've been using for a while now... Only 4 wires through the arm to the RCA's and no hum.... and the armtube is NOT grounded.
JD
So there would be two twisted pairs from the cartridge clips, through the arm and out to the rca's ( or whatever interface. (I'm using a Lemo connector on a junction box with a pair of RCA's to the "outside" world. THe junction box is connected to the turntable ground. This works very well in a modified SME/Thorens TD160 I've been using for a while now... Only 4 wires through the arm to the RCA's and no hum.... and the armtube is NOT grounded.
JD
That what I, talking about.
4 wires twisted and one wire around 4 signal wires.
Regards zeoN_Rider
+ thin metal plate above head.