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# dimension between pins

## dimension between pins

(OP)
i don't have much experience with splines so i was wondering if anyone can help me with understanding the formulas for calculating the dimension between pins for a 30 degree flat root side fit 14 tooth 12/24 internal spline.  i'm not sure how to calculate the pressure angle at pin center mostly.  thanks in advance

fyi, i do have ANSI B92.1 in front of me on page 96

### RE: dimension between pins

What is the problem?
I do not have that standard on hand, but as far as I know, you should be able to calculate the

inv(of the pressure angle at the pin center)

From it the pressure angle can be calculated.

### RE: dimension between pins

The method for internal gears or internal splines are the same so if you have a handbook for internal gears, the method will be defined there.  You have to use a pin size that does not bottom out in the root.

### RE: dimension between pins

The method is the same, the math/formulas behind it is for certain parts of calculation different. The calculation of the involute of the pressure angle to the center of the pin is one of them.

### RE: dimension between pins

Gearguru
the calcs are the same I use the same program I wrote to verify splines or gears.

Rfacatguy

If this is a one time issue it's easier just to use software all ready written.

This is a good book to start with Spur & Helical gear problems. Invo spline Company.if you can find it ?

### RE: dimension between pins

I do not want to go into details here. The calculation/formulas can be the same, but only if you (or your program) is using the DIN method of entering the number of teeth for internal gears/splines as a negative number.
I also have couple of my calculations for the over/between pins/balls and . In VB, as a spreadsheet, as a htm file (javascript).
I agree that using a ready made calculation is OK, but I also believe that to understand how the formulas work and what they geomtrically mean is very important.
RFACATguy can learn a lot doing his own calculation "from scratch".

### RE: dimension between pins

RFACATguy,

From ANSI B92.1-1996, page 104:

measurement between 0.1440 dia pins for max actual space width on a class 5, 14 tooth, 12/24 pitch, internal involute spline: 0.9609 inch.

A few years ago, a company called Van Keuren that makes gauge wires published a very nice reference book that gave you hundreds of tables for over/between pin dimensions of splines and gears.  Don't know if the book is still available though.  Try contacting them or looking on ebay.

http://www.vankeuren.com/tmw.aspx

Regards,
Terry

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