gear measurment

[Fralex_francois]

I would need to do a gear and to inspect it. Is there a micrometer to check and if yes, do I have to check the pitch like thread???

 

thanks

[specprogrammer]

When I went to school, they had a "gear tooth vernier caliper". It measured the addendum and I believe the chordal height. The pitch was determined by how many teeth on a certain dia. I haven't cut any gears in 14 years, so I really don't know for sure.

[John Summers]

You put a roll in opposite teeth, and measure over the rolls with regular mikes. The c-hook GEAR.DLL offers a roll size, but you can change it if you have different size pins. GEAR.DLL gives you the dimension over the roll size you select.

[jspangler]

HI

Wow, how do you find this kind of info?

Is this something that is listed in the machinists handbook, or something you have to learn from experience??

 

Thanks

 

John

[pip]

I learned from experience, both with "gear tooth Vernier" and over pins. If uneven amount of teeth then you have to use 3 pins. It is all in the "Machinery Handbbok"

[John Summers]

You don't have to use 3 pins. You can use the measurement over 2 pins for an odd number of teeth.

Machinery's handbook has a lot of information. Sterling Instrument supplies free handbooks that have a lot of good gear information.

[Fralex_francois]

no need to by the gear caliper???

[crazy^millman]

Nope never used one here just always used gauge pins and a micrometer.

 

HTH

[specprogrammer]

How do you determine if your addendum is wide or if you teeth are to deep using the pin method

[Harryman]

You'll know your addendum is too wide or your teeth are to deep by observing the ages of women that look at you.

 

I cut some bevel spur gears and checked them by making a fixture with axle pins at known positions. It's not the same as measuring, but I know if the gears will work.

[crazy^millman]

Well if you are using a shaped cutter then if the PD is right then everything esle is right. If doing it 3d then you have to have a little faith otherwise you in all honesty should problay be checkign them with a CMM if you need to know every face and angle and space needs to be 100% on the money.

[John Summers]

When you make a gear with GEAR.DLL, you also specify the circular tooth thickness. When you change that from the default, the dimension over rolls also changes, so you simply use the dimension over rolls that GEAR.DLL gives you.

[Fralex_francois]

Thanks everyone for all this hint...

gonna give some news on that after i made it.