Dividing a circle by 359

[stuartw]

The hard part of compound indexing
Is when you find index number is not found on the chart .

yes, thankfully forums like this exist to point people in the right direction. I had not even considered compound indexing, and in truth, I've never had to divide a circle before now using a dividing plate. I didn't know what to even search for. the book i found on the subject didn't mention it (or i missed it)

Compound infexing is found in books dating back to 1900
You find this old machinest Hand book as late as the 1950's

perfect, thanks. I am going to try to find a copy along with the treatise of gear wheels and a couple others. It seems the old timers methods are still applicable today for the hobby user, even if it's not as relevant to current industry.

 

[stuartw]

After reading your explanation a couple of times, I am starting to grasp the concept of what you're doing. I'm not into astronomy, a couple of steel mills too close. Light polution........ It seems to me you don't need to go all the way around, simply a quadrant would suffice. That could be driven by a couple of stages of worm and pinion, adjusted to a clock. As in move "x" degrees in "y" minutes. Final speed adjustment would be as simple as a servo motor with a good power supply. The other possibility is that I am so far off the track that I just want to answer and can't really help.

The solution is pretty much just as you've described, a worm and pinion: a low speed motor connected to the worm, and the x, y connected to the pinions and a feedback loop that adjusts the rpm as needed. In terms of tracking an object, from the position you found it, you probably would never go past 180 degrees. I think some commercial work as you've described with a more limited range of motion since you can't track objects past the horizon.

 

[stuartw]

vtcnc sent me a sample using a couple of tracks and it gave me some inspiration to apply the information learned here in a similar manor. the standard dividing plates on the rotary table are about 100mm/4" in diameter. I used that as a constraint and came up with this:

Each group A-F is spaced 90.25 degrees apart. So, starting at A-1, rotate left through 270.75 degrees, after you get to the last position for A-1, when you come back up to 0, you use the next track, A-2, this repeats until you hit A-15 @ 270.75 degrees, at this point you come back up to B-1 and repeat the sequence until you get to F-15, stopping one rotation short for 359 divisions. You can see with the blue lines that what would be A-16 lines up with B-1.

EDIT:

I have attached the original rhino3d + dwg and dfx in the dplate.zip file if in case anyone would like to take a look.

 

[Karl_T]

Looks like you got a great plan.

This is such a neat project, I'll make you an offer.

Make and send me a blank plate. Give me a listing of all the holes in this format:
(X0.000 Y0.000 is center of plate)
X#.### Y#.###
X#.### Y#.###
X#.### Y#.###
...

I'll center drill then drill them on my CNC. I am not offering much, this is trivial on a CNC mill.

 

[Smithdoor]

The hard part of compound indexing
Is when you find index number is not found on the chart .

yes, thankfully forums like this exist to point people in the right direction. I had not even considered compound indexing, and in truth, I've never had to divide a circle before now using a dividing plate. I didn't know what to even search for. the book i found on the subject didn't mention it (or i missed it)

Compound infexing is found in books dating back to 1900
You find this old machinest Hand book as late as the 1950's

perfect, thanks. I am going to try to find a copy along with the treatise of gear wheels and a couple others. It seems the old timers methods are still applicable today for the hobby user, even if it's not as relevant to current industry.

It found very old book by Brown and Sharp in early 1900's

I do have draws on the settings up on compound indexing

Dave

Sent from my SAMSUNG-SM-J320A using Tapatalk

 

[stuartw]

Make and send me a blank plate. Give me a listing of all the holes in this format:
(X0.000 Y0.000 is center of plate)

Thank's for the offer, for the now, I would like to try to do the layout myself and vtcnc has offered to laser cut the disc. If anything changes, would you be okay if I messaged you then?

 

[Smithdoor]

Make and send me a blank plate. Give me a listing of all the holes in this format:
(X0.000 Y0.000 is center of plate)

Thank's for the offer, for the now, I would like to try to do the layout myself and vtcnc has offered to laser cut the disc. If anything changes, would you be okay if I messaged you then?

Good luck
Dave

Sent from my SAMSUNG-SM-J320A using Tapatalk

 

[Karl_T]

no problem

 

[vtcnc]

Stuart,

Here ya go! It cut beautifully on the laser...

View media item 97331
And here is the finished product:

Stuart's Dividing Head Plate

• vtcnc
• Jun 26, 2018
• dividing head laser cutting

359 spacing - 4" O.D., 430 SS, 16 ga., Laser Cut on 3kw laser cutting machine (Trumpf 2030)

PM me your address and I'll drop it in the mail tomorrow

 

[Smithdoor]

Stuart,

Here ya go! It cut beautifully on the laser...

View media item 97331
And here is the finished product:

Stuart's Dividing Head Plate

• vtcnc
• Jun 26, 2018
• dividing head laser cutting

359 spacing - 4" O.D., 430 SS, 16 ga., Laser Cut on 3kw laser cutting machine (Trumpf 2030)

PM me your address and I'll drop it in the mail tomorrow

The link did not work

Sent from my SAMSUNG-SM-J320A using Tapatalk