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Post by AJR on May 13, 2013 6:56:20 GMT -7
I have been trying to find the pitch of the gears. Cannot find anything definitive on this. Does anybody know what the correct answer is. Thanks in advance.
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Post by pceng on May 13, 2013 9:57:13 GMT -7
Hey JJ, think that pitch refers to the angle between gears. Or the degree of angle needed to make gears mesh properly when drive and axle (for our cases) are not 90 degrees in relation to one another. Don't know if your familiar with angle-winders ......oops showing age now. Can motor would be turned to an angle in relation to axle, and crown gear would have teeth laid back so to speak so it would mesh with pinion on angle. Or now that I'm thinking about it. Might just be the angle of the face of teeth in relation to gear shaft hole. Flat gear like a plate gear would be 0 degrees, a crown like we use 90 degrees.
Saw post earlier, but was in hurry to get to PO. ............. Hope this helps (hope I'm right...lol)
................................................ Peter
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Post by AJR on May 13, 2013 16:30:55 GMT -7
Thanks for the quick response Peter. I was really looking for the number. I've read in a couple of different places that it is 48 or 64 pitch, but nothing for sure. I'm kind of surprised that I can't find it.
Jeff
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Post by chriswfo on May 14, 2013 9:35:06 GMT -7
I've always thought if pitch on a gear as coarser or finer. It is a ratio of the size of the gear and the number of teeth. A standard Aurora and 4 Gear crown gear each has 15 teeth but the 4 Gear has a smaller diameter and a finer pitch.
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Post by pceng on May 14, 2013 12:45:36 GMT -7
Hey guys, think somehow you might have been mislead. Checked with a couple of people since it's been some time since thinking about this. Pitch, when refering to a gear is measured in degrees and is the difference in the angle the gear teeth are facing in relation to the plane the gear is ment to operate on. The shafts used to contect whatever type of drive to axles we use (NTRA) are 90 degrees in relation to one another. So the pitch of the gears equal 90. Flat gear (like plate) 0, crown 90. Could have that backwards. If both gears conected at right angle have a beveled edge (a cone shape) and have the same picth - 45. Different could be 30-60. Or something that adds up to 90.
The coarsness or number of teeth used in a given size, is just that. The number of teeth used by a given manufacturer to achieve desired affect. Alot of that depends on the desirerd ratio wanted between gears (the number of times one gear turns in order to achieve one rotation of next gear). An inline with 7/21 gears would be a 3 to 1 gear ration. Also the space between gears makes a difference. Fine teeth on gears will give a more precise function of whatever it might be, like Swiss watches. As long as desired ratios are met, number of teeth is a design thing. Some combinations won't work together, some do (fine and coarse that is).
..........................Hope I helped, Peter
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Post by 440gtx on May 14, 2013 13:10:30 GMT -7
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Post by AJR on May 15, 2013 6:08:56 GMT -7
Thanks guys! A lot of information there. I answered my own question....it's 48 on those gears. I appreciate the feedback for sure.
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Post by pceng on May 15, 2013 7:24:15 GMT -7
Hey guys, first, thanks for posting the Dr's. info. Looks like I've been wrong for a long time. After reading over the Dr's. page a number of question come up. The bigest question is how the gears used in our cars work? If gears have to be in the same family of pitches to work, like 12:24, 4:8, 12:36 (think those were numbers given). Each has to have a whole number ratio. So, how does a 14t gear drive a 15t crown gear or 24t plate gear. Or a 7t, 8t, or even 9t pinion drive a 20, 21, 22, 23, 24, and 25 tooth crowns? OK, the 7/21 and 8/24 combos work. But don't the rest of the numbers contradict this.
Could just be my warped way of looking at things .......... Peter
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Post by pceng on May 15, 2013 14:49:12 GMT -7
OK, this has been bugging me all day. What unit of measure is used to descibe pitch? Thought it was degrees. Measuring 48 degrees between the same point on each tooth would give you 7.5 teeth on a gear. One rotation of a gear being a 360 degree turn that is. Do not get it. This boat must have left yesterday on me.
......................... Peter
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Post by 440gtx on May 16, 2013 4:29:27 GMT -7
the example above shows the circular pitch. Circular pitch is the distance from a point on one gear tooth to the corresponding point on the next gear tooth, measured along the pitch circle. When you see a gear referred to as a 48 or 64 pitch gear they are using Diametral Pitch. Diametral pitch refers to the number of teeth given per inch of a gear's pitch diameter. Diametral pitch is the most common method of classifying gears. I measured a t-jet idler gear at the pitch diameter, which is roughly in the middle of the tooth. It measured about .373". If you divide the 24 teeth by .373 you get 64.343 which would be a 64 pitch gear. To confirm this I mated it up to one of my 64 pitch gears for my 1/24 cars and it was a perfect fit. |
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Post by AJR on May 16, 2013 5:46:57 GMT -7
Excellent explanation 440gtx. That is very good information....thank you. I guess I could have looked this info. up in the beginning, I just thought somebody might have that number already.
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Post by pceng on May 16, 2013 8:47:40 GMT -7
Thanks Matt, kinda like threads on a screw. Got it.
Just wondering now what gears with angled teeth are called. Or how they are described.
.................... Peter
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Post by 440gtx on May 16, 2013 13:59:05 GMT -7
Thanks Matt, kinda like threads on a screw. Got it. Just wondering now what gears with angled teeth are called. Or how they are described. .................... Peter You're welcome. Is this what you mean by angled teeth?  |
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Post by pceng on May 17, 2013 9:26:05 GMT -7
Beveled, yep that's them. Thanks!
......... Peter
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