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Any reputable machine shop could do it. The holes would not have to be an exact mirror image of the holes on the right side or ear as you say. The arm you choose (and how its mounted) would dictate where they need to be I would think for ease of set up.If the arm you choose is fixed in place with a nut from underneath such as a rega an others it would not matter. If it is screwed in place to the arm plate then those holes would be critical.Have you also conscidered that because two arms was not part of the original design if your heading for problems?Remember now the arm would be parallel to the front and back and not the sides of the sub chassi as the original arm. Curious though, where would you place the motor then and have you conscidered the resale after doing so? Cheers
I run a machine shop.
The first step is to dissassemble the base, and remove it from the other parts. Then carefuly cover the edges in blue painters tape to prevent scuffing damage.
Hold the mount in place, and mark one hole. Then centerpunch that hole, and drill it. Now use one mounting bolt, and secure the base lightly. You can swing it on this bolt to get the pivot of the arm the exact distance from platter center.
When its right, mark the othe two holes through the base. Remove the base, and punch and drill the remeining 2 holes. Deburr the holes with a countersink.
Depending on the arm you use, you may need a larger fourth hole in the center for the phono leads.
I took a quick look at my Gyro SE this morning and I'm assuming you plan on using a second Michell armboard in the spot where the motor is located. Moving the motor outside the "ear" shouldn't be a problem however there is another issue you might want to consider if you plan on doing this. First yes the holes need to be precisely positioned, but the biggest problem I see is that on the underneath of the "ear" where the armboard is mounted from the factory the casting is much thicker and allows the holes for the armboard to be threaded. The "ear for the motor is not like this and is only about 3/16" thick so even if you tapped them to accept the mounting screws it wont be very secure (in my opinion) and could easily be stripped by overtightening! I would thing you would want to bond some appropriate nuts on the underneath of the casting to accept the mounting screws. Personally that's the biggest problem I see and would be a deal killer for me, also the reduced resale value.
Michell actually had a version for two arms at one time (pictures), though I never saw it offered for sale. I am guessing you plan on bypassing the suspension? The TT has a 1Kg. wt. limit for an arm+base so I am guessing that limit has to be split pretty evenly for a 2 arm set up. I read where the two arm units had to have the densodamp removed from under the second ear to mathch the weight of the 2nd arm. I don't really see it working too well if the suspension isn't bypassed. I'd send an email to Artech and ask for details. I've always gotten good advice from them.
I was contemplating the same move and I be interested to see what you do. Keep us posted or drop me an email.
Just want to share some info I was able to dig up over the weekend. From what I was able to gather, the original design was intended for two arms. But Michelle never officially made that announcement. And they stopped offering post-sale services to drill holes on the second "mouse ear" around 2002.
Some had suggested to just blu-tak the second armboard to the mouse-ear, and remove the weight underneath the mouse-ear. That looks plausible, except I am afraid of a freak accident where the whole assembly may get yanked off the table. So I am thinking of doing the blu-tak method and adding a few plastic ties to prevent the arm assebly from accidentally flying off.
Someone asked about where to locate the motor. My understanding is to measure the distance from the spindle to the center point of the pulley while it is still sitting inside the mouse-ear. Place it anywhere outside of the mouse-ear, but make sure that the distance between the center of the pulley and the spindle stays the same.
Will report in this time next year if this works. I am in the process of dismantling my system as my house will be going under a major remodel. That's why I was hoping to get the subchassis drilled while the turntable is out of commission.
Thanks for everyone's help.