As always, impressive. I have a older Swedish dividing head but it just make my head hurt, I'm going to have at it again after watching this. Thanks Mr.
Most people don't need differential indexing - I'm doing it for a set that I want to make. The other use is to produce a 127t gear for metric conversions. Other than that, it's pretty esoteric.
The satisfaction of exercising true gearhead intuition is a great gift. Which I don't have. I tip my hat to those who have a feel for that part of mechanical arts, and you can have my seat at the bar. Even change gears for my lathe were a complete pain for me, so I built (a design by someone smarter than me) an electronic lead screw. SO worth it, in my case. The next CNC-ish thing I build will be an electronic rotary table / dividing head for my mills, to sidestep my personal anxiety regarding all but the simplest of gear trains. Carry on your usual fine work, sir! Discourse like yours may someday cause the required neuron in my brain to fire, and the lightbulb over my head will go on.
keys Michael,, that is a good tip . i still don't fully understand all this but really enjoy watching it. one day i do have to make gears for my Victoria mill knee. cheers.
Think of it this way - normally when dividing, the pointer indexes around a set number of divisions on the (fixed) dividing plate. With differential indexing, the dividing plate is not fixed but geared to the spindle, so as you index around, the dividing plate moves just a little bit more. In comparison to normal dividing, the pointer (that moves the spindle via it's handle) has moved in absolute terms slightly more. From memory, I think the standard set of gears that comes with a dividing head can all be made on a semi-universal head so you are safe!
I would use CAD to create a template and glue it on to the workpiece, or center punch the centers of the teeth. You'll know right away if you've fallen off the trolley.
Traditional texts on cutting gears with a dividing head say to go around once with a light cut to check the divisions - bit like that first skim pass when cutting a thread. Trouble is, that takes time, especially for a larger gear. Centre punching or using a pen or something would take time too. If you think 15 seconds per mark, that's still around 15 to 20 minutes for a gear this size. I haven't got the patience.
Sorry. I tried to explain it as best I could. Think of it as normal indexing but instead of going a fixed number of divisions, you go a number plus 'a bit'. That bit is dictated by the gearing that feeding back.
@@occasionalmachinist after rewatching it twice! I think I get it. Basically if you want to do more than 50 holes or a prime number of holes, then as long as you have the relevant charts and gears you can do it on the say 50 hole plate and the head will compensate?
@@paulrayner4514 More or less! Which division plates you use and the gearing that works requires calculation (but in the tables/ chart). For the 77 tooth gear I was using a plate increment (10 on a 20 hole ring) that would have given me 80 divisions - but because of that gearing, it dropped back to 77.
As always, impressive. I have a older Swedish dividing head but it just make my head hurt, I'm going to have at it again after watching this. Thanks Mr.
Most people don't need differential indexing - I'm doing it for a set that I want to make. The other use is to produce a 127t gear for metric conversions. Other than that, it's pretty esoteric.
The satisfaction of exercising true gearhead intuition is a great gift. Which I don't have. I tip my hat to those who have a feel for that part of mechanical arts, and you can have my seat at the bar.
Even change gears for my lathe were a complete pain for me, so I built (a design by someone smarter than me) an electronic lead screw. SO worth it, in my case. The next CNC-ish thing I build will be an electronic rotary table / dividing head for my mills, to sidestep my personal anxiety regarding all but the simplest of gear trains.
Carry on your usual fine work, sir! Discourse like yours may someday cause the required neuron in my brain to fire, and the lightbulb over my head will go on.
I must admit I like cutting gears - there is something I find very soothing about it.
Thx for the vid.
keys Michael,, that is a good tip . i still don't fully understand all this but really enjoy watching it. one day i do have to make gears for my Victoria mill knee. cheers.
Think of it this way - normally when dividing, the pointer indexes around a set number of divisions on the (fixed) dividing plate. With differential indexing, the dividing plate is not fixed but geared to the spindle, so as you index around, the dividing plate moves just a little bit more. In comparison to normal dividing, the pointer (that moves the spindle via it's handle) has moved in absolute terms slightly more.
From memory, I think the standard set of gears that comes with a dividing head can all be made on a semi-universal head so you are safe!
@@occasionalmachinist thanks for taking the time to reply,, cheers
I would use CAD to create a template and glue it on to the workpiece, or center punch the centers of the teeth. You'll know right away if you've fallen off the trolley.
Traditional texts on cutting gears with a dividing head say to go around once with a light cut to check the divisions - bit like that first skim pass when cutting a thread. Trouble is, that takes time, especially for a larger gear. Centre punching or using a pen or something would take time too. If you think 15 seconds per mark, that's still around 15 to 20 minutes for a gear this size. I haven't got the patience.
ermmmm. i'm confused or thick!
Sorry. I tried to explain it as best I could. Think of it as normal indexing but instead of going a fixed number of divisions, you go a number plus 'a bit'. That bit is dictated by the gearing that feeding back.
@@occasionalmachinist after rewatching it twice! I think I get it. Basically if you want to do more than 50 holes or a prime number of holes, then as long as you have the relevant charts and gears you can do it on the say 50 hole plate and the head will compensate?
@@paulrayner4514 More or less! Which division plates you use and the gearing that works requires calculation (but in the tables/ chart). For the 77 tooth gear I was using a plate increment (10 on a 20 hole ring) that would have given me 80 divisions - but because of that gearing, it dropped back to 77.