Posts
24444
Joined
4/1/2008
Location
US
Edited Date/Time
10/7/2014 6:07pm
I needed to drill the swingarm pivot holes in my PK Racing XR75 mono shock frame from 10mm to 12 mm. The guys that built these back in the day had a pretty archaic approach to how not to make a swingarm pivot properly and safely for a fat guy so I decided it needed to be upgraded to use a1974-78 CR125 pivot bolt, dust caps and pivot bushing. First off, since this is a frame we are working with, the first piece of tooling required is a frame machine to sit this all on.
One frame rack, check.
Special drill fixture from my friendly machinist with a cut down drill bit for centering and alignment of the new hole to be reamed, check.
Low speed air drill is the best I could do on short notice. Clamping my Smithy home lathe to the frame rack was going to be a bit troublesome. First reamer up, check.
Once that hole was opened up I stepped up to the larger one for a nice precise and straight 12mm hole. Second hole punch up, check.
Once drilled, a little polishing roll finishes things up for a perfect fit of an original CR swinger bolt.
I gotta admit, I probably could have done this with a unibit drill bit, but the fancy tooling made for a truly professional job. What I couldn't have done without though was the frame machine as it was a necessity for working on the frame. All that special tooling and fixturing, well I'm done with it so it just got tossed in the trash.
All hooked up.
One frame rack, check.
Special drill fixture from my friendly machinist with a cut down drill bit for centering and alignment of the new hole to be reamed, check.
Low speed air drill is the best I could do on short notice. Clamping my Smithy home lathe to the frame rack was going to be a bit troublesome. First reamer up, check.
Once that hole was opened up I stepped up to the larger one for a nice precise and straight 12mm hole. Second hole punch up, check.
Once drilled, a little polishing roll finishes things up for a perfect fit of an original CR swinger bolt.
I gotta admit, I probably could have done this with a unibit drill bit, but the fancy tooling made for a truly professional job. What I couldn't have done without though was the frame machine as it was a necessity for working on the frame. All that special tooling and fixturing, well I'm done with it so it just got tossed in the trash.
All hooked up.
The Shop
XRs are very cool!
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