I've been playing with cnc straight flank cutter gear "shaping" and I was wondering what the stepover is for these shapers? It seems like I can get decent results from 14 steps on a module 1 gear however I don't have a good way to test. I"m also wondering about the geometry of shaping a bevel gear, so if you have any references you can point me to that would be great.
Jesse: To make accurate true bevel gears takes complex shaping machines. Perhaps a wire EDM machine can do it with proper programming? An easier bevel gear is the so-called parallel depth tooth bevel gear, which can be machined on a horizontal mill with standard cutters and dividing head. A true bevel gear cannot be produced this way without additional hand work with filing.
@@BasementEngineer from my understanding the difference between a gear shaper and a straight flank cutter should not be significant, it is a matter of setup and "gearing" the relative movements of the cutter and the work. There are plenty of videos of regular shapers being used to cut gears. You can also do this with an A axis and a regular cnc machine with a straight flank cutter. I've written a gcode generator to do this, it works great. It isn't perfect, but if you compare the curves it is a very good approximation to a mathematically perfect gear. I made several videos on this and I have also shared the code on github. I've not yet done bevel gears but I don't see why it wouldn't work, it works great for straight tooth and helical gears. LSCAD has a great video that walks through all the math and setup for bevel gears.
@@JesseSchoch Well, suck it and see if it works. A true bevel gear tooth tapers in two directions: The chordal thickness decreases from the large dia. to the small dia. of the tooth. Further, the depth of the tooth also decreases from the large dia. to the small dia. Mechanically this was achieved with a tooth shaping machine consisting of two rams such that one tooth was formed completely at a time. These rams had two adjustments to produce the angles described above. Then of course the cutters had to follow the flank profile; not sure how this was accomplished. I suppose a copying type of arrangement using a large template might do this. This is the reason why quality bevel gears are expensive. Almost 50 years ago I had a pair of bevel gears made to repair the cross slide feed on a very large lathe. These gears were perhaps 5" or so in dia. and cost $4500 for two at that time.
Need to correct my bevel gear narrative above. Bevel gear shapers do not need a template to produce the tooth flank profile as this is generated the way it is accomplished with a spur or helical gear: The gear blank is rotated while the shaping tool transverses tangentially across the gear blank. Videos are available on YT; these are very clever machines; my hat's off to the designers.
Good job
this mill is how much?
I've been playing with cnc straight flank cutter gear "shaping" and I was wondering what the stepover is for these shapers? It seems like I can get decent results from 14 steps on a module 1 gear however I don't have a good way to test. I"m also wondering about the geometry of shaping a bevel gear, so if you have any references you can point me to that would be great.
Bevel gear cutting method is deffrent from machine to another one
Jesse: To make accurate true bevel gears takes complex shaping machines. Perhaps a wire EDM machine can do it with proper programming?
An easier bevel gear is the so-called parallel depth tooth bevel gear, which can be machined on a horizontal mill with standard cutters and dividing head.
A true bevel gear cannot be produced this way without additional hand work with filing.
@@BasementEngineer from my understanding the difference between a gear shaper and a straight flank cutter should not be significant, it is a matter of setup and "gearing" the relative movements of the cutter and the work. There are plenty of videos of regular shapers being used to cut gears. You can also do this with an A axis and a regular cnc machine with a straight flank cutter. I've written a gcode generator to do this, it works great. It isn't perfect, but if you compare the curves it is a very good approximation to a mathematically perfect gear. I made several videos on this and I have also shared the code on github. I've not yet done bevel gears but I don't see why it wouldn't work, it works great for straight tooth and helical gears. LSCAD has a great video that walks through all the math and setup for bevel gears.
@@JesseSchoch Well, suck it and see if it works.
A true bevel gear tooth tapers in two directions:
The chordal thickness decreases from the large dia. to the small dia. of the tooth.
Further, the depth of the tooth also decreases from the large dia. to the small dia.
Mechanically this was achieved with a tooth shaping machine consisting of two rams such that one tooth was formed completely at a time.
These rams had two adjustments to produce the angles described above.
Then of course the cutters had to follow the flank profile; not sure how this was accomplished. I suppose a copying type of arrangement using a large template might do this.
This is the reason why quality bevel gears are expensive.
Almost 50 years ago I had a pair of bevel gears made to repair the cross slide feed on a very large lathe. These gears were perhaps 5" or so in dia. and cost $4500 for two at that time.
Need to correct my bevel gear narrative above. Bevel gear shapers do not need a template to produce the tooth flank profile as this is generated the way it is accomplished with a spur or helical gear: The gear blank is rotated while the shaping tool transverses tangentially across the gear blank.
Videos are available on YT; these are very clever machines; my hat's off to the designers.