Using the Gear Add-In

[TeccBoxx]

I am trying to use the Gear Add-In and I am not having any luck at all. The set of plans that I have includes the folowing info:

 

Outer Diameter

Pitch

Tooth Count

Depth of Tooth Cut

 

Anyone have any suggestions.

[Hardmill]

Can you be more specific. No luck meaning its

not working at all?

It works fine for me. Tell me what your trying

to input and I'll give it a shot.

 

PEACE

[TeccBoxx]

Sorry about that I should have been more informative on my situation.

 

This is the current info that I currently have on the gear

 

Outside Diameter: .708"

Tooth Cut Depth: .045"

Pitch: 48

Teeth: 32

 

This is how I am inputing all the info.

 

Type of Gear: External

Roll Measurement Method: External

Number of Teeth: 32

Number of teeth to create: All

Number of Pairs of Arcs in involute: 6

Pitch diamter: 6

Diametral Pitch: 48

Outside Diameter: .708"

Root Diameter: .663"

Pressure Angle: 14.5

Roll Diameter: .108"

Circular Tooth Thickness: .09817"

Roll Measurement: .708

Flank Angle: 0

Root Fillet Type: Specified

Root Fillet Radius: .003

Tip Fillet Radius: 0.0

 

And I get something that looks like an old TV antenna. I know I have something wrong but what I have no idea as I left some of it left as default. Hope this helps.

 

[ 07-13-2003, 05:20 PM: Message edited by: Tazzer ]

[kccadcam]

Tazzer,

You must plug in the pressure angle if it's other than 14.5

Look in the machinery handbook for all the info.

[TeccBoxx]

Thanks Kevin, I have been through the Machinery's hand book and three other books doing some calculations here and there. I have even tried the pressure angle at 14.5, 20, and 25 degrees. However every one I make comes out looking like a starburst or tv antenna or other geometrical circle.

 

On the positive side I have learned tons on gears, and even ordered a book on gear making to learn some more. Just when you think you are understanding something, another obstaacle pops-up. However that is a good thing.

 

I am about ready to ditch the add-in though and just create the gear with lines and arcs. Or just call up Boston gears and see if they have a gear this size.

[Hardmill]

quote:

---

Just when you think you are understanding something, another obstaacle pops-up. However that is a good thing.

---

You got that right. I've been at this for awile.

And I worked in a gear shop for about a year.

Im making a call tommorrow, as this has now

become a mission.

PEACE

 

[ 07-14-2003, 01:43 AM: Message edited by: Hardmill ]

[TeccBoxx]

Well still banging my head on the wall I had a lot of the numbers screwed up but there are a few items that I still have no idea what they are.

 

Can anyone explain what the following are and how to achieve them with a mathmatical formula.

 

Number of pairs of Arcs in Involute

Roll Diameter

Roll Measurement

Flank Angle

 

I have looked in the Machinery's Handbook, a couple of my school books, a engineering math book and I cannot find any information on the list above. All the entries below have been fixed and double checked and are correct.

 

Type of Gear: External

Roll Measurement Method: External

Number of Teeth: 32

Number of teeth to create: All

Pitch diamter: .66635

Diametral Pitch: 48.0226

Outside Diameter: .708

Root Diameter: .663

Pressure Angle: 14.5

Circular Tooth Thickness: .03271

Root Fillet Type: Specified

Root Fillet Radius: .0062470587

Tip Fillet Radius: 0.0

 

Inputing it this way and keeping the 4 unkonwn items I now get 2 full arcs. Anyone have any other suggestions.

[kccadcam]

Tazzer,

 

Look here for good info:

http://www.engineersedge.com/gear_formula.htm

 

 

As far as creating your gear in Mastercam:

 

No. of teeth = 32

hit enter

No. of teeth to create = all

Pitch diameter = .66635

hit enter

should automatically fill in all the right numbers for you.

click done and viola!!!

you should have a gear.

[TeccBoxx]

Hi Kevin thanks for the reply. I just have to say your my hero.

 

I wasn't hitting enter after putting in a field. It works perfectly now and I have the gear that I need. Thanks a whole bunch,

 

However if anyone still knows what the following things are I would like to know.

 

Number of pairs of Arcs in Involute

Roll Diameter

Roll Measurement

Flank Angle

 

 

Thanks again

[Dan_AKA_ROY]

Tazzer, when you input info are you sure "Number of teeth to create" is set to all? By default, it reverts back to one each time you go into the Gear parameter dialog box. That's why you may have gotten that antenna it's one tooth!!

[kccadcam]

Roll diameter is the dia. of the pins used to measure across the teeth.

Roll measurement is the distance across the pins

(like measuring threads)

Try inputting a flank angle no. like 10 degrees and you'll see what it does, has to do with the way 2 gears mesh.

[Hardmill]

You da man Kevin!!

 

PEACE

[CAM-mando]

No. of pairs is used to calculate how many arcs will be drawn to aproximate the involute.

 

Be aware that the roll measurement is across 2 pins 180° apart (or for odd spacing as close to 180° as possible). This is true even for ring gears (ID gears) or splines. Some drawings give a measurement of a pin tangent to 3 rolls (nested pins) in this case you must layout the 2 pin location and use that for the parameters. I think the problem is that you havent been given enough data to properly generate a true gear tooth.

 

Try asuming a pressure angle of 20 or 14.5.

 

Subtract the " tooth depth" from the OD and use that for the ROOT DIA.

 

Be sure to press Enter / Return after entering each field. When you change the DP you will see many of the fields re-calculate. Keep the recalculated numbers except the OD, Root, and count.

[TeccBoxx]

Thanks guys, I cannot thankyou on how much this has helped, I really appreciate everything, this thread has been printed and put in my book of things to remember. Thanks again

[KCollins]

i've used the gear program to generate teeth on many occasions....my suggestion is not to use anything less than 20 arcs per tooth if you plan on toolpathing the teeth....I"ve wired several gears this way and have been fairly happy with the results, using less often leads to a series of linear movements that you can visually see and not the greatest quality of gear. It sure would be nice if some genius would be figure out how to solve the involute function....

If you're only looking for a visual representation then 6 should be more than fine and save you a whole lot of regeration time.

Question for you. I've never seen depth of cut as a method of defining a gear. Is this simply the (majorØ - minorØ)? If so thats a new one to me...

Just another hint...the tab key between fields doesn't help you much with this c-hook....wont' recalculate the other variables....use the enter key....took me a while and about three monitors out the window to figure that one out.....

[CAM-mando]

KCollins,

 

Depends on the size of the gear. For Small (1/2") Dia splines, 6 pairs wire EDM'd looks and gages well. I agree for larger sizes more arcs will produce better results.