Broken Tonearm: Stock Restore or Custom Rebuild?!

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I've been reading with interest all the applicable current and past threads on diy/tweaked tonearms, especially making 12" or longer arms! Not wanting to hijack these threads or join in the recent "bumping" of four year old posts, I thought I'd seek some advice in a new thread.

For better or worse, I've recently acquired an older style Infinity Black Widow (IBW) with the double-wall black aluminum arm snapped off at the typical location ahead of the armrest. I've since scoured the archives of this forum and vinyl asylum and printed out quite a few pages of info. I am now getting close to starting my restoration/rebuilding.

First, with the end in mind, I'd like to either mount this on one of my customized Thorens TD165s or buy a TD125 to mate with it in the near future. I am, however, also toying with the idea of playing " Dr. Frankenstein" and doing something crazy like retro-fitting it onto a customized idler like a Dual 1219 or a DD like a Dual 701! (on larger plinth, new base, etc.)

Second, I've thought about constructing the new arm out of wood (rosewood and bubinga look great on my flyrods!) or using a graphite/carbon fiber tube like the later IBWs. I've located two custom fishing rod builders who said I could pick whatever I want out of their scrap bins for free. Finding a usable 12" to 20" section of a higher modulus graphite rod blank should be no problem.

Finally, the third issue I'm seeking advice on is arm length. Stock IBWs had an effective length of 227mm, but I believe I've got a world of possibilities open to me! I've already been playing around with calculating tracking error % vs. length! Perhaps increasing the mass of this arm by increasing the length wouldn't be so bad.

Are there any comments/experiences on arm lengths or materials I'm thinking of using? What about the tables I'm thinking of mounting it on? Has anyone ever messed around with one of the Duals I referenced above?

If there's interest, I'd like to post some photos of my progress with the rebuild. I've already shot a couple of pics during the disassembly.

Thanks in advance.

D
 
Custom rebuild...

really if carbon fibre offcuts are available, I'd try that. The arm tube is most likely glued to other bits, and the headshell of the tonearm. I know nothing of the Black Widow (other than reading about it and seeing examples on epay...)

have a look at the Mayware, aparently the Black Widow was a knock off. If you have the same Bulge" as the Mayware, then the replacement should be pretty straight forward.
 

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arm rebuild...

Hey Nanook - first I want to say you're an inspiration! I've reading some of your threads for awhile. In fact, your recent responses/posts on the AudioOrigami thread for the 12" arm Linn kicked my butt to do something with this arm! What kind of turntable do you have your 14" and 17.5" arms on in the photo?

Unfortunately, the IBW doesn't have the Mayware bulge. The 5mm or 3/16in dia arm tube goes back into a hollow silver-finished aluminum receiver that also secures the perpendicular knife edges for the vertical bearing.

FastEddy - thanks, I had been reading that thread with interest. In fact, I almost posted my questions there.

D
 
Broken Tonearm...

Hi Sjogren

I have a pair of Micro arms which had straight graphite wands and proprietary removable headshells. I originally had 3 headshells between the two arms and eventually, two of these headshells started wearing with loose connecting pins and worn mounting slots.

Earlier this year, I got fedup with the headshell problem and decided to make the arm into a 12" J-shaped type with an sme type socket for use on my 301's.

I looked around my workshop and found two landing sleds from an r/c helicopter. The curvature was perfect and after cleaning and polishing one of these, I also anodised it 'natural'. On my lathe I turned a sleeve from titanium to step up the dia (it was about 1.8mm smaller in dia). I also made all the internal fittings, as well as the step up sleeve for the arm end to the sme connector.

The new wand, the connector bit and sme-style headshells I can use now, made it necessary to increase the armweight behind the pivot and here I turned an add-on weight with a springloaded pin to engage with the armstub thread. This mod allows that the original VTF setting stayed as before.

I have a pic of the mod, if you'd like to see.

bulgin
 
Sjögren...

if the infinity black widow has a 5mm arm tube, replace the whole thing.

the turntable is my take on a DIY turntable. Actually a "re-plinth". An old Sugden Connoisseur BD-1. A hardwood cutting block 1-3/4" thick cut and spaced away from each other a suitable distance to mount the tonearm. Aluminum square tubing, and the original feet.

technically my 14" arm is 12" effective, and the 17.5" one is 15". I haven't finished the 17.5/15 one. I hacked up a high carbon plastic headshell from some beater turntable, but I do do my own headshells too.
 

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