Some gear cutting stuff

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Thanks guys. Selecting cutters has been the part I end up scratching my heard over. I cannot use Marv's program as I do not use PC's at all.

I'm assuming the actual cutting using a pre-made tool would go like Dean demonstrates. Other than making the tool.

Yes, it works the same way, Mike. Multi-tooth cutters get the job done faster, of course, and not so much "whacking".

Referring to:

mklotz said:
In addition, there are separate cutters for each of the common pressure angles. Older equipment will often use a pressure angle of 14.5 deg while newer will tend to use 20 deg. (Don't trust that obvious generalization very far.)

Is your program specific to a pressure angle, or does the pressure angle only affect the individual tooth geometry.

The equations implemented in GEARSPUR are independent of the pressure angle.
I was wondering how to use Marvs program.
I copied the code that was given earlier but there are no equations in this code.
Jdaniel343 said:
I was wondering how to use Marvs program.
I copied the code that was given earlier but there are no equations in this code.

You have to download the program from Marv's web site and install it on your computer.
Please, read the instructions at the beginning of the web site. It will answer most of your questions about running any of the programs. These are NOT Windows type programs, they run in DOS! VERY IMPORTANT DIFFERENCE!

Link to Marv's web site:
There's a spreadsheet "gearcutterstemplateupdateddec292012.xls" in the downloads area, excellent piece of work, for making cutters by the "two buttons" method, although I'm not sure it does all gear types - take a look?
I have a copy of one that I downloaded *somewhere*, can't remember where, though! There's still the need to make multiple cutters for different DP and tooth counts, and although the tooth profile isn't an exact involute making a geartooth-count specific cutter will probably be closer than a bought cutter at the extremes of its range...

The usual two-disc method of cutter making is fairly easy to extend from single to four tooth (making cutting quicker and a little kinder to the machine) by offsetting the cutter blank equal amounts in the direction of each jaw of the 4-jaw chuck and gashing the cutting edges at the resulting "corners" - this gives a 4-tooth form-relieved cutter that's relatively easy to sharpen and retains the correct form too...

With a stretch of the imagination I can see this extended to higher tooth counts, but it would be a piece of work to produce a home-made 12 or 16 tooth cutter...

Single-tooth cutters usually need to be set on an eccentric arbor, but do a good job of cutting fairly accurate gears, albeit a bit slowly :)

Dave H. (the other one)

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