drawing an involute spline

[JDF]

I need to come up with a drawing of an involute spline profile for a school project and am having a hard time with the numbers. Machinery's Handbook doesn't seem to go into nearly as much detail about splines as it does gears. Do some of the numbers and formulas for spur gears work for splines as well? The other problem is that the pressure angle is 27.5 deg, which I can find no data for.

The splines will be wire EDM cut, and the shop is just waiting on the drawing.

Thanks in advance!

[PSD KEN]

Maybe this will help:
http://www.omnigearandmachine.com/in...ions_30_pa.htm

[This message has been edited by PSD KEN (edited 03-18-2004).]

[CCWKen]

All of the formulas should work except Dedendum, Whole Depth and Clearance. These are the only ones that have constant values in the formula. I wonder if your 27.5 PA would be the same as 25? The 20 and 25 are the same.

Edit: What I mean is the variables are the same for 20 & 25 PA.

[This message has been edited by CCWKen (edited 03-19-2004).]

[Spin Doctor]

A while back we had to come up with the spline profile for a job to do on a wire EDM. We resorted to drawing one tooth in AutoCAD and doing an array command to get the whole form. as long as we knew the tooth width at the top, pitch line and root we just dropped a spline through the three points. then we broke up the tooth profile into a series of lines about .005" long as I recall to get so the machine would cut it.

[Ironland Spline]

Hey,

We cheat! We use involute simulation software. There are a few good ones out there that convert the basic involute tooth nomenclature to shop usuable (form radius, form spread, form height, etc. . . .) info without all the complicated calculations.

Mark Smaha wrote a classic used by many broach manufacturers, so has Jim Laydon. Check out "Involute Pro 2.0, or the following link for "Involute Simulation Softwares Inc".

http://www.geartechnology.com/copage/involute.htm

Howard

[Ironland Spline]

Here's the link to Jim Laydon's site on his involute software:

http://www.laydon.com/

Jim's software will even calculate involute spline form compensations for grinding back taper into a broach cutting tool.

What's back taper? The fastest way to relieve the splined form on a broach, so that it will cut better (just having the front of the tooth come in contact with the part) is to grind the splines with backtaper. When we put back taper into a broach spline form we tilt the broach axis a prescribed amount, and then we grind in the splines. Sometimes as much as .0003" per inch, per side. On a broach that's 50" long in the cutting section, that's alot of back taper, and therefore alot of form compensation is needed for the part to come out right when the tool is pulled parallel to it's axis (when you turn a circle just a little you now have an elipsis).

Jim's software can even accomplish this for us. It tells use where the contact diameters are in the involute form for various gage pins to contact for qualifying the form, even with a prescribed amount of back taper. I don't know how it works, but it does, and well.

Howard

[JDF]

Thanks for all the replys. Finally just looked up the formulas for a circular involute, used excel to generate about 50 points along the tooth profile, and dropped the points into autocad. Simple matter of drawing max/min diameters and root fillets after that. Of course no sooner than I got this done, the shop decided to just buy cutters rather than use the wire machine. Oh well, learned something usefull anyway!

Thanks again!

[John Stevenson]

<font face="Verdana, Arial" size="2">Originally posted by Ironland Spline:
Here's the link to Jim Laydon's site on his involute software:

http://www.laydon.com/

</font>

What a crap web site!!
Half of it tells you absolutly nothing about the gear product and the other half offers you web design

Sorry but it really infuriates me when you go to a site like this where they have gone to the trouble of setiing it up only to find no information.
I have even been to some that offer an email address and no phone number.
It is a business after all.
&lt;rant off&gt;

John S.

[Ironland Spline]

Oh come on now John!

There is a great illustration of the involute profile there, which would help anyone not familiar with the concept to better picture it in their minds.

There's also an explanation of a broach cutter tool.

And it contains Jim's contact info. Maybe someone is interested in the involute software. Or would want to talk with him about it.

Howard

[macrobee]

hey bro you only need to fill this simple form and thy will solve your problem and give you the good quality tools. visit broachindia

[Spin Doctor]

Well, I think this gets the prize for thread resurection.

[Zahnrad Kopf]

ack. justnoticed the necro thread.

[oldtiffie]

For what its worth, try John Stevenson who may be able to generate the entire involute spline on his Gearotic software on his computer.

He may be able to get the enquirer a copy of the involute spline gear form.

[John Stevenson]

For what its worth, try John Stevenson who may be able to generate the entire involute spline on his Gearotic software on his computer.

He may be able to get the enquirer a copy of the involute spline gear form.

After 11 years ?????????????

[ironmonger]

If you want data to be 'permanent' you'd better have your own copy... try to access any of the web sites in the old thread

Definition of "knowledge is ephemeral"
-no boot sector on internal hard drive

Bumper sticker from an old floppy disk drive manufacturer
'On a clear disk you can seek forever'

paul