Degree wheel

Depending on the type of spindle encoder you are using for your ELS setup, you might be able to use it to set a particular spindle rotation.
 
The encoder I have 4096 PPR, is not very good for this application. 1 count is 0.087890625 degrees. Kind of useless... I can't hit 36 degrees for instance... 409 counts is ~ 34.95 degrees, 410 counts is ~ 36.035 degrees. Think you would need some sort of magic numbers for the PPR, like multiples of 360 perhaps? 1440 PPR gives 1/4 degree steps.
 
paradox_pete said:
I haven't used a cog, but I have used the change gears from the lathe for indexing on the lathe. Mounted on an expanding mandrel that fits the back end of the spindle. I've found the 60 tooth gear particularly useful as one can index 2,3,4,5,6,10,12,15,20, 30 and 60 hole patterns with it. Works great. See Below...
View attachment 429997

Granted the bungee cord is a little crude, but it works.

Would I do this rather than use a rotary table or dividing head on the mill? The obvious answer is that I did not have a mill, rotary table or dividing head at the time.

There are still situations in which I might find that approach preferable. I've encountered situations where I would prefer to produce a bolt circle at a specific point in the order of operations, but would also like to keep the part on the lathe to ensure concentricity for subsequent operations....

-Pete
Click to expand...
Simple,primitive,"crude"........in other words EFFECTIVELY SMART.

When it works,it works.
 
WobblyHand said:
The encoder I have 4096 PPR, is not very good for this application. 1 count is 0.087890625 degrees. Kind of useless... I can't hit 36 degrees for instance... 409 counts is ~ 34.95 degrees, 410 counts is ~ 36.035 degrees. Think you would need some sort of magic numbers for the PPR, like multiples of 360 perhaps? 1440 PPR gives 1/4 degree steps.
Click to expand...
Depending on the accuracy needed your 4096 ppr encoder may suffice if you consider surface distance traveled per count. Assuming the part has a circumference of 10" the distance traveled is .0024" per count. The 1440 ppr would travel .0069" per count. The possible error of a 3600 ppr encoder would be as much as .0027".

That 4096 ppr encoder may indeed be quadrature, in which case you get 16,384 counts per revolution. Or .0006" resolution on the 10" part.
 
Chip Hacket said:
Depending on the accuracy needed your 4096 ppr encoder may suffice if you consider surface distance traveled per count. Assuming the part has a circumference of 10" the distance traveled is .0024" per count. The 1440 ppr would travel .0069" per count. The possible error of a 3600 ppr encoder would be as much as .0027".

That 4096 ppr encoder may indeed be quadrature, in which case you get 16,384 counts per revolution. Or .0006" resolution on the 10" part.
Click to expand...
The encoder is 1024 quadrature. So it really is 4096 ppr. It's great for an ELS, but not good for exact degree indexing. Advantage of it was that it was pretty inexpensive and met the needs for an affordable ELS.
 
WobblyHand said:
The encoder is 1024 quadrature. So it really is 4096 ppr. It's great for an ELS, but not good for exact degree indexing. Advantage of it was that it was pretty inexpensive and met the needs for an affordable ELS.
Click to expand...
OK well, just don't let your parts exceed 1/8" diameter and you should be good to go. :)
 
I saw "bicycle sprocket" and it reminded me of a move my father pulled back in '80.

At the time, Dad was a self-employed engineer, with a specialty of designing centrifuges and rotors. One project he was contracted for was a rotor to spin and test discrete electronic components. The rotor insert that held the components for testing was a 1/4" thick disc of Delrin that had radial cut slots (for the leads) and a circular groove (for the device body). The challenge was that he needed 17 slots, evenly spaced. His divider plate did not accompodate that number or any multiple, and his rotary positioning table was loaned out.

There I am in 10th grade English, the school secretary opens the classroom door, points to me to follow her to the principal's office. There, I find my father. I immediately panic thinking there's horrible news. Nope, he needed me to go home and disassemble the gear cluster on my racing bicycle so he can use the 17 tooth sprocket as a guide for slot cutting.
 
imagineer said:
Nope, he needed me to go home and disassemble the gear cluster on my racing bicycle so he can use the 17 tooth sprocket as a guide for slot cutting.
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Disassembling a bicycle gear cluster is a MAJOR undertaking (without damaging all the other gears).
 
SLK001 said:
Disassembling a bicycle gear cluster is a MAJOR undertaking (without damaging all the other gears).
Click to expand...
This was before the cassette style cluster. Back then you needed a pair of chain whips to unscrew the small gear.
 
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