Making of encoder mounting plates requires several accurately drilled holes. I already made one plate and it seems to work, but I had some problems/issues with placing holes precisely.
The material is brass (it was a great idea to use brass).
I calulated all hole positions using a spreadsheet. See "Encoder Mounts" sheet here:To fit it over a 17mm motor shaft, I had to drill a 43/64 hole. (17.065mm).
I do not know of any way how I could drill that hole precisely, with a huge (comparatively) MT3 drill bit, as any drill bit would wander away at least somewhat, I think.
So what I did was, I drilled the 17mm hole aproximately where it should be. Then, with DRO, I located the center of the hole and then moved to what should be a point (0,0), based on the calculated position of the center of the hole. (kind of a backwards thinking process).
For smaller holes, all I did was start them with a center drill and then drill with a drill bit.
It actually seems to have worked, as the encoder works just fine.
When making that mounting plate, I realized that there is a lot to precision drilling, and want to ask now if anyone knows tricks for drilling precise holes. I have two more plates to make.
The required precision for locating encoder base is 0.01". (which is not that bad).
On a related note: to bolt the base to the motor, I had to drill four holes for the mounting bolts. How can I precisely measure the distance between holes. I tried using a caliper and it worked, obviously, but I can not be totally sure how accurate I was. I would measure the distance between two points in holes closest to one another, then farthest, and average the two. But it felt that there was a lot of wiggle room in those measurements. SEM has a manual for the motors in question and it specifies the distance, but based on what I drilled, the distance is slightly wrong. (the motors were made 20 years ago)., I was lucky that I drilled the holes slightly oversize. For the next pair of plates, I would really like to drill to-size holes in the right place.i i