-
Welcome back Guest! Did you know you can mentor other members here at H-M? If not, please check out our Relaunch of Hobby Machinist Mentoring Program!
Order of operations
- Thread starter richz
- Start date
- Joined
- Mar 17, 2018
- Messages
- 1,400
If you are using a rotary table or an indexing head I would do all operations together. If not, finish the holes one at a time.
- Joined
- Dec 27, 2014
- Messages
- 4,093
It depends on your tooling. If a drill press, do all center drills first, then drill, then tap.
If you're on a mill, without a rotary table, that's a lot of cranking to do each hole center drill then drill, etc.
With a rotary table, just like the drill press, spin that table. Ideally you'd have a super spacer with twelve notches.
If you're on a mill, without a rotary table, that's a lot of cranking to do each hole center drill then drill, etc.
With a rotary table, just like the drill press, spin that table. Ideally you'd have a super spacer with twelve notches.
- Joined
- Feb 1, 2015
- Messages
- 9,994
Using your PM932 with a DRO, I would calculate the coordinates of the twelve holes. The calculations for a twelve hole bolt circle a quite simple. Four of the holes are at the quadrants so +/- 2.5, 0 and 0. +/-2.5. For the remainder of the holes, you have 30-60-90 triangles The relationship between the sides is 1.25:2.165:2.5 (the 2.165 is 2.5/2 x sq.rt(3) from the Pythagorean theorem). Those numbers will provide the remaining coordinates; i.e. .5,2.165; 2.165,.5; etc.
With the locations determined you now have two choices. 1. perform an operation on all twelve holes then move on to the next operation, and so on or 2. perform all operations on a single hole and move to the next hole and repeat.
Which way to do this depends upon the relative complexity of the operations vs. the work involved with moving. My preference is to do one operation on all the holes and then set up the next operation and repeat.The reason; tapping twelve holes involves spotting the hole, drilling , and tapping. That involves a lot of tool changes.
In contrast, moving from hole to hole for each operation only involves three tool changes. There is a lot more cranking involved but the distance moved from one hole to the next are less than 1/2" on each axis. There is an increased chance of operator error but with a DRO and some care. that should be negligible. If I didn't have a DRO, I would do the first way as the chances of making an error are much greater and backlash would have to be taken into account.
With the locations determined you now have two choices. 1. perform an operation on all twelve holes then move on to the next operation, and so on or 2. perform all operations on a single hole and move to the next hole and repeat.
Which way to do this depends upon the relative complexity of the operations vs. the work involved with moving. My preference is to do one operation on all the holes and then set up the next operation and repeat.The reason; tapping twelve holes involves spotting the hole, drilling , and tapping. That involves a lot of tool changes.
In contrast, moving from hole to hole for each operation only involves three tool changes. There is a lot more cranking involved but the distance moved from one hole to the next are less than 1/2" on each axis. There is an increased chance of operator error but with a DRO and some care. that should be negligible. If I didn't have a DRO, I would do the first way as the chances of making an error are much greater and backlash would have to be taken into account.
- Joined
- Aug 3, 2017
- Messages
- 2,437
Your DRO likely has a bolt-circle mode, I'd just use that and do all of 1 step at once. I have done it both ways and swapping tools constantly gets REAL time consuming.