drawing an involute spline

[oldtiffie]

Originally Posted by oldtiffie View Post

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 ?????????????

You are quite right John - my apologies - I should have checked for more recent dates of previous posts.

[Zahnrad Kopf]

Admittedly, I got sucked in, not noticing the thread's resurrection until after I hit "reply". Since it is being gawked at in the present I'll go ahead and re-post what I had originally written in the hopes that it might help someone along the way.

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!

I realize that you have the issue remedied and have moved on, so this is offered that maybe it will help in the future. Maybe not. If you are WEDMing your Involutes ( of any type ) and need any manner of higher than hobby or school level accuracy, make sure that the software that drives the WEDM machine can actually handle the task accurately. Seems almost every software I have come across actually approximates and simplifies the complex Splines to the point that higher accuracies are compromised. Many times, if the scale of the part is large enough this can even be seen by the naked eye and looks like the surface is "faceted" instead of smoothly curved/blended. The obviousness disappears as the parts get smaller, but the condition exists just the same and can be seen through microscope, et al. ( Just because you can't see it doesn't mean it isn't there. ) None of the companies admit this freely and most all deny it, point blank. But it is there and when pressed, one or two will actually admit it and admit that they haven't fixed it. Caveat Emptor. Good luck.

[dp]

Probably a response bot that found the thread on google.co.in

[Rosco-P]

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

An ancient thread, you resurrect it and post a link to a company on the Indian sub-continent with your personal seal of approval? Current employer or perhaps you have a controlling interest in them?

[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

[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 ?????????????

[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.

[Zahnrad Kopf]

ack. justnoticed the necro thread.

[Spin Doctor]

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

[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

[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

[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.

[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!

[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

[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