Still digging into the FD bin for lenses to convert over, and I figured this one would be pretty straight forward. Other than being very careful with measurements (measure twice, cut/mill/turn once...), the toughest part was getting the shift leadscrew out. The endcollar lock screw on the leadscrew had a pretty strong adhesive on the threads, so the solvent of choice was MEK (be careful with that stuff...).
I started out with a backplate thickness of 5.82mm, so I milled it down to 2.50mm, and milled the M42-EOS adapter from 1.42mm to 1.20mm. The .12mm undercut ensures that infinity focus is maintained after heat/pressure bonding with J-B weld between the backplate and lens mount. Also, the joining ring and its\' mount needed to be shorted (because of the thinning of the backplate). I \"hexed\" the joining ring and burnished both female and male threads with a SS radial brush to help reform the threads...it worked perfectly. Everything threaded fine and tightened up very snug. The original spring for the rotation detent was replaced with a re-wound ball-point pen spring, and provides the same holding force as the orginal. The M42-EOS mount has a \"holding hole\" for it to reside in.
Finished photos will be posted Sunday afternoon, and hopefully some shots also. Last time I used this lens was on a T90, with Kodachrome 25...got to find those slides and get them scanned.
Still digging into the FD bin for lenses to convert over, and I figured this one would be pretty straight forward. Other than being very careful with measurements (measure twice, cut/mill/turn once...), the toughest part was getting the shift leadscrew out. The endcollar lock screw on the leadscrew had a pretty strong adhesive on the threads, so the solvent of choice was MEK (be careful with that stuff...).
I started out with a backplate thickness of 5.82mm, so I milled it down to 2.50mm, and milled the M42-EOS adapter from 1.42mm to 1.20mm. The .12mm undercut ensures that infinity focus is maintained after heat/pressure bonding with J-B weld between the backplate and lens mount. Also, the joining ring and its\' mount needed to be shorted (because of the thinning of the backplate). I \"hexed\" the joining ring and burnished both female and male threads with a SS radial brush to help reform the threads...it worked perfectly. Everything threaded fine and tightened up very snug.
Finished photos will be posted Sunday afternoon, and hopefully some shots also. Last time I used this lens was on a T90, with Kodachrome 25...got to find those slides and get them scanned.
Feb 26, 2011 at 04:45 PM
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