- Joined
- Dec 20, 2021
- Messages
- 896
Having got my hands on a few ground/polished hardened pins of various sizes I'm in the process of making a few cylinder squares. However, the OD needs to be lapped just a bit (~0.0001" to .00005") to make them perfectly parallel.
I've got some diamond paste coming, and some aluminum to make some OD laps from. However, studying some pictures of round OD laps, it appears that some have different size holes for the flexures that are drilled parallel to the lap bore. Starting with larger holes near the adjustment cut/screw, progressing to smaller holes near at the opposite end. My guess is that is to counter the effect of the lap tending to egg out when adjusting the lap if even size holes were used all the way around.
Has anyone else seen this, or are any of your aware of the calculations necessary to pick the spacing and hole sizes to keep the bore from distorting when snugged up? I might be able to beg a buddy to run an FEA to see how these flex when snugged up, but if there's an old school way to get that might be preferred.
Dan
I've got some diamond paste coming, and some aluminum to make some OD laps from. However, studying some pictures of round OD laps, it appears that some have different size holes for the flexures that are drilled parallel to the lap bore. Starting with larger holes near the adjustment cut/screw, progressing to smaller holes near at the opposite end. My guess is that is to counter the effect of the lap tending to egg out when adjusting the lap if even size holes were used all the way around.
Has anyone else seen this, or are any of your aware of the calculations necessary to pick the spacing and hole sizes to keep the bore from distorting when snugged up? I might be able to beg a buddy to run an FEA to see how these flex when snugged up, but if there's an old school way to get that might be preferred.
Dan