norvalwilhelm
Well-known member
I have 2 methods of drilling rotors. The easiest for me is a rotory table that has degrees marked on it, the rotor is clamped on this table, you eyeball where you want the first hole to be, drill it and then rotote the table a certain number of degrees and drill again. If you choose a number that divides into 360 degrees that works.
Example you want 18 holes around the outside, 18 into 360 is 20. So every 20 degrees you drill a hole.
Reduce the diameter of the circle and start over drilling more holes.
This is the easy way BUT my rotor had 32 vanes and 32 doesn't divide into 360. Well it does but that is 11 .25 between holes and this gets tricky since the table is marked in degrees but reading 1/4 of a degree get tricky and you need to constantly watch the mather.
The other way open to me is by using a computer printout. NC controlled milling machines divide the rotor into 10's of thousands of addresses. The entire surface of the rotor is marked with an address. Think of a big parking lot, one with no lines, there is no order to parking. NOw lets mark parking spaces everywhere, this gives order if people park in a designated spot. Now give the parking spaces address like row 34 parking spot 67. This is an exact place to park and if sent to it you could have a disignated spot. This is an address.
Now divide my disc into an imaginary parking lot with address, a computer program does this. I just tell it the diameter of the circle it is working with.
Now I tell it I want 32 holes around a 12 inch circle, in a few seconds it spits out the addresses for these 32 holes. I then say give me some more for a 11 1/2 inch hole, out comes the addresses. It will do any number of holes and spit out the addresses.
Degrees mean nothing to it, nor number of holes.
Anyway the rotor is clamped to a table that has left to right movement, X axis and at the same time back and forward motion, Y axis.
The printout calls dead center in the rotor as address 0,0. or home
Using a dial inticator I find this zero and set the digital readout to read zero.
Now all I have to do it go to the addresses printed on the computer printout by turning the x and y handles on the table so the digital readout matches the address.
Drill a hole and move on to the next address.
Simple but reading 4 digit numbers all afternoon get tireing.
I did both discs in 4 1/2 hours
I did drop every second hole so ended up at 16 to the circle, 3 circles for 48 holes per side plus 18 in a circle for mounting the hat.
If you look at one of the pictures I planned it so no hole in next to another without a vane a heavy 1/4 inch vane is seperating it from the next to prevent cracking.
Each of the sets of 3 holes is in 3 different spaces between vanes.
This is a shot of the rotor clamped to the table in the process of being drilled
I was careful to drill between the vanes, each hole is separated by a vane making cracking more difficult. Even if the holes look close together they are separated by a vane.
.
Address, printout beside digital readout
Finished drill rotor. The holes are ¼ inch and chamfered . The small holes around the center, 18 of them are to be threaded and this is how the hat mates to the rotor.
Example you want 18 holes around the outside, 18 into 360 is 20. So every 20 degrees you drill a hole.
Reduce the diameter of the circle and start over drilling more holes.
This is the easy way BUT my rotor had 32 vanes and 32 doesn't divide into 360. Well it does but that is 11 .25 between holes and this gets tricky since the table is marked in degrees but reading 1/4 of a degree get tricky and you need to constantly watch the mather.
The other way open to me is by using a computer printout. NC controlled milling machines divide the rotor into 10's of thousands of addresses. The entire surface of the rotor is marked with an address. Think of a big parking lot, one with no lines, there is no order to parking. NOw lets mark parking spaces everywhere, this gives order if people park in a designated spot. Now give the parking spaces address like row 34 parking spot 67. This is an exact place to park and if sent to it you could have a disignated spot. This is an address.
Now divide my disc into an imaginary parking lot with address, a computer program does this. I just tell it the diameter of the circle it is working with.
Now I tell it I want 32 holes around a 12 inch circle, in a few seconds it spits out the addresses for these 32 holes. I then say give me some more for a 11 1/2 inch hole, out comes the addresses. It will do any number of holes and spit out the addresses.
Degrees mean nothing to it, nor number of holes.
Anyway the rotor is clamped to a table that has left to right movement, X axis and at the same time back and forward motion, Y axis.
The printout calls dead center in the rotor as address 0,0. or home
Using a dial inticator I find this zero and set the digital readout to read zero.
Now all I have to do it go to the addresses printed on the computer printout by turning the x and y handles on the table so the digital readout matches the address.
Drill a hole and move on to the next address.
Simple but reading 4 digit numbers all afternoon get tireing.
I did both discs in 4 1/2 hours
I did drop every second hole so ended up at 16 to the circle, 3 circles for 48 holes per side plus 18 in a circle for mounting the hat.
If you look at one of the pictures I planned it so no hole in next to another without a vane a heavy 1/4 inch vane is seperating it from the next to prevent cracking.
Each of the sets of 3 holes is in 3 different spaces between vanes.
This is a shot of the rotor clamped to the table in the process of being drilled
I was careful to drill between the vanes, each hole is separated by a vane making cracking more difficult. Even if the holes look close together they are separated by a vane.
Address, printout beside digital readout
Finished drill rotor. The holes are ¼ inch and chamfered . The small holes around the center, 18 of them are to be threaded and this is how the hat mates to the rotor.
