I’ve been trying to build a cartridge for a couple of years now. Getting pretty close to finishing it, but came to the conclusion that I don’t have a proper arm for it…
Have been using it on an old Lenco P77 I machined a new headshell for.
Having bought all the machinery (Small lathe and mill) for the cartridge, figured I might as well try my luck at a tonearm as well.
Had someone else’s 12” project arm I could use the bearings from, but it needed a new yoke, bearing house, armtube and counterweight.
Made a model in CAD, took some basic dimensions off of an Ortofon RMG and grabbed a couple of pieces of brass.
Everything fits together nicely. No loose parts, nice sliding fit on the counterweight and headshell connector. Used some thick walled aluminium tube of which I turned the inside diameter down to get to a nice fit for the connector. Also put a strip of balsa in the tube to dampen it a bit. Still need to shorten the tube, but wanted to see if everything would move as it should.
Still need to figure out the correct angle and length for the tube… The geometry is still a bit complicated for my simple brain. 🙂
Edit: design is largely influenced by the Old Ortofon arms.
Have been using it on an old Lenco P77 I machined a new headshell for.
Having bought all the machinery (Small lathe and mill) for the cartridge, figured I might as well try my luck at a tonearm as well.
Had someone else’s 12” project arm I could use the bearings from, but it needed a new yoke, bearing house, armtube and counterweight.
Made a model in CAD, took some basic dimensions off of an Ortofon RMG and grabbed a couple of pieces of brass.
Everything fits together nicely. No loose parts, nice sliding fit on the counterweight and headshell connector. Used some thick walled aluminium tube of which I turned the inside diameter down to get to a nice fit for the connector. Also put a strip of balsa in the tube to dampen it a bit. Still need to shorten the tube, but wanted to see if everything would move as it should.
Still need to figure out the correct angle and length for the tube… The geometry is still a bit complicated for my simple brain. 🙂
Edit: design is largely influenced by the Old Ortofon arms.
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Tried some cold blue on the brass parts. Doesn’t look half bad. Tried measuring some of the main points, pivot to spindle and overhang look promising. Can’t comment on offset angle yet, but with a set of angle gauges everything looks OK.
Base the main dimensions on an Ortofon RF297 because it should be a good match for the cartridge.
Base the main dimensions on an Ortofon RF297 because it should be a good match for the cartridge.
Very nice job on that TA. The bluing looks good. Vintage Ortofon/ESLs are among my favorite vintage TAs For their simplicity and quality. I hope the rest of your project turns out well.
Doug
Doug
Thanks Doug,
Hopefully by the end of the month I’ll be able to have everything working… Still remodelling my bedroom and guestroom/solderingroom. 🙂
I was thinking about adding the spring for dynamic balancing, but decided against it. Having owned both the RS-212 and an RMG-212, and found them both too finicky to set up. They do look elegant imho.
Hopefully by the end of the month I’ll be able to have everything working… Still remodelling my bedroom and guestroom/solderingroom. 🙂
I was thinking about adding the spring for dynamic balancing, but decided against it. Having owned both the RS-212 and an RMG-212, and found them both too finicky to set up. They do look elegant imho.
Very nice. You'll be wanting some bias compensation as well. Are you going to reveal details of your cartridge?
Leave it straight. There will be underhang instead of overhang, by how much depends on length. At least try before you build the offset.
It's controversial, but the only testimonials I've read against the concept of a straight arm are from people who've never heard one.
Nice job, BTW.
Cartridge will be a DST type. Finished a white headshell last night. Have been working on it on and off for the last two years…
Already have a made a couple of working “naked” versions, but never an integrated unit. Still figuring out how to do the ground strap.
Made all the drawings in CAD myself, based on the dimensions found over at LencoHeaven.
When finished the thing will weigh in at about 32 grams, but as you can see no problem for the arm.
Since nothing is stuck in place yet, I can always swap to a straight armtube. Interesting tip. 🙂
Already have a made a couple of working “naked” versions, but never an integrated unit. Still figuring out how to do the ground strap.
Made all the drawings in CAD myself, based on the dimensions found over at LencoHeaven.
When finished the thing will weigh in at about 32 grams, but as you can see no problem for the arm.
Since nothing is stuck in place yet, I can always swap to a straight armtube. Interesting tip. 🙂
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The DST-62 is a different beast. The inner works are very different. 🙂 Very tempted to give it a try as well.
