DIY tone arm vs rega?

[staggerlee]

Thanks,

Googling it came up with some commercial products, so it is good to know what I can use that is already on my shelf. In the states methylated spirits is called denatured alcohol. I was using mineral oil, because I had it next to me at the time. Needless to say it didn't work very well.

Originally posted by Stuey
I'm not sure about such small holes, but I think for drilling aluminium methylated spirit is the recommended lubricant. Not sure what this is called in North America.

[cygnus x1]

I was planning on drilling the larger of the two tubes (from outside-in), using the idea of a pilot hole and then the tape and pin hole. I would then clean up the ID. Mount this in a square aluminum box section to make the manifold and seal the ends to complete. Just theory, but should work and resemble stock linear air bearings that I've seen.

[valveitude]

A point to consider..a small hole through the material won't have the same geometry as the "tape on aluminum" approach. I believe (as in I don't know for sure) the larger opening after the air metering hole allows the air to "spread" providing a better coupling to the sled, and reduces noise as the volume increase causes a velocity decrease. Personally, I would use a starter bit to "funnel" the exit.

Casey

[tobydog]

Originally posted by Stuey
I'm not sure about such small holes, but I think for drilling aluminium methylated spirit is the recommended lubricant. Not sure what this is called in North America.

Used to use paraffin for machining aluminium when I was an apprentice toolmaker many years ago.

Regards,

Mick.

[Trower]

I have a question in reguards to Nanook's unipivot design, I've tried searching but haven't really found what I need. What is the mounting distance from the center spindle to the pivot point? Thanks for any help, Nick

[Nanook]

the mounting distance is moot, as the base is movable....

Please see post #24 of this thread for a sketchup with the dimensions...

In the case of my original (and subsequent) tonearms(s), the distance is approximately 305mm (approximately 12") + an inch or so. I use no anti-skate, and the headshell offset is something like 20 degrees. Again, I don't actually know, because I use a "straight" headshell that allows for the cartridge to be rotated. I then use an alignment protractor and adjust the cartridge until I get good alignment with a grid at 57.5 mm from the spindle centre--not really "standard" alignment, but it works. Use whatever protractor alignment distance you prefer. The Oracle setup procedure suggests a spindle to alignment point of 65.5 mm.

I know this seems a little contrived, but I really don't know the complete specifications, as I got good alignment almost immediately (again because the complete base can be moved around the plinth). Obviously if you have a suspended deck, then the arm will not move with the suspension unless some kind of rotating arm board is made and attached to the suspension sub-chassis at the stock location.

Hope that helps.


stew

[graeme uk]

The tiny holes for the ladegaard arm are easy to drill in aluminium.

Mark out where the holes are going. Then drill most of the way through with either a 2mm or 3mm bit, dont go through!

Now, get a 0.3mm drill bit, you'll probably need a few, i get about 7 holes from each bit. These drills are tiny, i believe they are the smallest drill bits available, but may be wrong.

if you put these in a power drill they will just break. You need an archemedies (sp) drill.

Drill a 0.3mm hole in the middle of the big hole you just made.

Ill go get some pics to explain.

[graeme uk]

here we go.

As i say, you need to drill a bigger hole first. A 0.3mm hole right through doesnt work as well as a 0.3mm hole feeding a bigger hole.

http://aolsearch.aol.co.uk/aol/image...hemedies+drill

[k9vap]

For those contemplating a DIY tube arm....the whole tube is not necessary.

This guy made his arm out of the same piece of tube, split a piece of the tube for the slider & just opened it out.

Airbearing Tonearm

Personally, I think the Ladegaard approach is more efficient. Certainly the latest inverted design uses air flow of less than 200lph to float as opposed to other cylindrical designs which need 900.

Users of the cylinder type airbearing often complain about audible hiss. The inverted Ladegaard....AKA Terminator is effectively silent.

Ladegaard also chose to split the vertical & horizontal components to conduct experiments in their respective inertias. He concluded the best combination was a high lateral inertia & low vertical. The link has already been posted elsewhere in this thread.

The original posting of the inverted bearing Ladegaard can be found here:

Terminator Prototype

Finally, I wouldnt dismiss the simplicity & effectiveness of the blade bearing without hearing it in this context.