Worm Gears

[gbritnell]

The threads per inch of the worm is 16 therefore the pitch is .0625. The pitch diameter of the gear is .216 so the circumference is .67858. .0625\.67858=.0921. TAN angle is 5.26 degrees.

 

[SmithDoor]

Are worm gear ratios calculated the same as spur gears ie: 20/40 teeth = 2 to 1 ratio ?.

This may be a little off subject.
I have seen manufacturers use acme thread for a worm at point you finish with acme tap the worm gear. You buy acme bolts or all thread, it is cheaper than a worm gear cutter.

Dave

 

[timo_gross]

This may be a little off subject.
I have seen manufacturers use acme thread for a worm at point you finish with acme tap the worm gear. You buy acme bolts or all thread, it is cheaper than a worm gear cutter.

Dave

Has the tap some clearance? It should have. Never checked this, but a tap must be a little larger in diameter than the matching bolt or not?
I used a M6 tap to make a small model worm gear. At that small size not easy to see, the cheat.
It is similarish to a 0.3 module gear with 30° instead of 20° pressure angle.

 

[TonyM]

It means :
ratio = 1/n
1 revolution of the shaft of the worm
n = the number of teeth on the worm wheel
Right ?

Right.