- Joined
- Feb 13, 2017
- Messages
- 2,138
Gear calculations are tabled in the Machinery's Handbook, in your case in the metric section. There also are a couple of good videos by "This Old Tony" on the subject. There are many others, I happen to like ToT for his "half bubble off plumb" sense of humor.
The basic calculations are as follows:
OD(Outside Diameter) = number of teeth + 2 X the modulus. ie. for a M1_24 tooth gear ~ 26 X 1 in mm
DoC(Depth of Cut) = 2.25 X module ie. 2.25 X 1 mm
This is a ballpark figure, the fit and tolerance may well need adjusting depending on usage of the gear. Those adjustments are in Machinery's Handbook.
Now, to dogs: There are times I use "store bought'n" dogs, other times I use a ground rod clamp. For small (well, large for me) work, it's a good fit on 5/8 rod. The screw will get smashed up some, but not where it counts. I also use cable clamps and the like. But I have a good supply of electrical parts. . . In all probability, you will want to do finished work between centers.
However, a chuck should have been included with the indexing head. Transferring the work from the lathe to the indexer chuck is just a matter of indicating to your specs. It might be a piece of shimstock in one jaw or maybe getting a 3 or 4 inch 4 jaw if things are really important.
An important consideration is true horizontal (90 Deg) of your head. You don't need a surface plate, a milling machine table will do fine. Your lathe ways are probably too small. Measure the height, indicate, close to the chuck, and then at the end of the rod. A foot or more is preferable, if you have space. When the two readings are the same, set the pointer for 0*. Or 90*, whichever is appropriate. You probably can trust the degree tics, the pointer is the problem most times. Once the divider is trued, set the tailstock to match.
It's a long story behind the flanges where we won't go. The bottom line is table saw blade flanges are available in 1/2, 5/8, and 3/4 sizes. I use the 1/2 inch ones regularly. Thread half the mandrel to 5/8 fine, screw on a hardware store nut til it's there to stay. Then turn the mandrel to 1/2 inch facing the 5/8 nut as you go. Thread the mandrel 1/2-20 and the only facing then is the 1/2 nut. The saw flanges aren't really "machine shop" quality, but are quite easy to make and learn on. Or easy and cheap to find. . . And a 127 tooth 4 inch dia gear with 12mm bore isn't really that stable without them.
The cutting boards I've seen at Wally World were 1/2 inch, more likely 12mm. I have a sheet of 5/8 plastic salvaged from a pizza joint that I work from. Whenever I can stop Wife from stealing a chunk. . . I suppose 8mm (likely) stock would work well enough for light gears but would be a bear to work. Too thin for change gears, for sure.
In the long term, tooling will cost as much, or more than the machines. Any tooling you can make cuts that cost down significantly. I have an Atlas shaper, an Atlas (benchtop) milling machine and an Atlas (Craftsman) lathe. And several grinders and drill presses. Being the cheap old buzzard I am, I waited 'til I found the machines at a price I was willing to pay. Took several years to acquire them all. But tooling is a different issue. Until I retired time was precious, so I bought tooling as I needed it. Usually at full retail. . . Now that I'm retired, I had one stroke too many and now am confined to a wheelchair. Ce'st la vie, stuff happens. Go it while you can.
.
The basic calculations are as follows:
OD(Outside Diameter) = number of teeth + 2 X the modulus. ie. for a M1_24 tooth gear ~ 26 X 1 in mm
DoC(Depth of Cut) = 2.25 X module ie. 2.25 X 1 mm
This is a ballpark figure, the fit and tolerance may well need adjusting depending on usage of the gear. Those adjustments are in Machinery's Handbook.
Now, to dogs: There are times I use "store bought'n" dogs, other times I use a ground rod clamp. For small (well, large for me) work, it's a good fit on 5/8 rod. The screw will get smashed up some, but not where it counts. I also use cable clamps and the like. But I have a good supply of electrical parts. . . In all probability, you will want to do finished work between centers.
However, a chuck should have been included with the indexing head. Transferring the work from the lathe to the indexer chuck is just a matter of indicating to your specs. It might be a piece of shimstock in one jaw or maybe getting a 3 or 4 inch 4 jaw if things are really important.
An important consideration is true horizontal (90 Deg) of your head. You don't need a surface plate, a milling machine table will do fine. Your lathe ways are probably too small. Measure the height, indicate, close to the chuck, and then at the end of the rod. A foot or more is preferable, if you have space. When the two readings are the same, set the pointer for 0*. Or 90*, whichever is appropriate. You probably can trust the degree tics, the pointer is the problem most times. Once the divider is trued, set the tailstock to match.
It's a long story behind the flanges where we won't go. The bottom line is table saw blade flanges are available in 1/2, 5/8, and 3/4 sizes. I use the 1/2 inch ones regularly. Thread half the mandrel to 5/8 fine, screw on a hardware store nut til it's there to stay. Then turn the mandrel to 1/2 inch facing the 5/8 nut as you go. Thread the mandrel 1/2-20 and the only facing then is the 1/2 nut. The saw flanges aren't really "machine shop" quality, but are quite easy to make and learn on. Or easy and cheap to find. . . And a 127 tooth 4 inch dia gear with 12mm bore isn't really that stable without them.
The cutting boards I've seen at Wally World were 1/2 inch, more likely 12mm. I have a sheet of 5/8 plastic salvaged from a pizza joint that I work from. Whenever I can stop Wife from stealing a chunk. . . I suppose 8mm (likely) stock would work well enough for light gears but would be a bear to work. Too thin for change gears, for sure.
In the long term, tooling will cost as much, or more than the machines. Any tooling you can make cuts that cost down significantly. I have an Atlas shaper, an Atlas (benchtop) milling machine and an Atlas (Craftsman) lathe. And several grinders and drill presses. Being the cheap old buzzard I am, I waited 'til I found the machines at a price I was willing to pay. Took several years to acquire them all. But tooling is a different issue. Until I retired time was precious, so I bought tooling as I needed it. Usually at full retail. . . Now that I'm retired, I had one stroke too many and now am confined to a wheelchair. Ce'st la vie, stuff happens. Go it while you can.
.