Gene Isn’t this simply a case of doing the maths for at a small section of the shaft/hub? So imagine you have steel incline with an aluminum mass on it with a vertical force exerted on the aluminum mass. The reaction against the slope induces a force in the horizontal plane. the only thing that stops the aluminum mass (your hub) from moving along the slope is the coefficient of friction between steel and aluminum.
So put simply the angle where you will have equilibrium (i.e. the point at which the shaft becomes self locking) = arctan(coefficient of friction between the two metals) obviously to make it self locking you would deduct a couple of degrees from this and to make it self releasing add a couple of degrees to this to account for variation in materials. A quick google found me a table of coefficients of friction of various combinations of brake materials http://www.engineeringtoolbox.com/friction-coefficients-d_778.html <http://www.engineeringtoolbox.com/friction-coefficients-d_778.html> I would use the greasy oily column. In fact steel on steel in this case gives arctan(0.16) which is approximately 9 degrees for the point of equilibrium (neither self locking or self releasing) subtract a couple of degrees to ensure it is self locking and the result is as you predicted. Eric > On Jun 16, 2015, at 5:03 AM, Gene Heskett <[email protected]> wrote: > > Greetings; > > Building on an idea Andy suggested earlier today. > > Somewhat entending a thread on tapers I started a couple years ago, now I > would like to be advised on the taper angle to use, where the tapered > ring being wedged in to the hub is steel and the hub is moderately hard > alu. > > I've done quite a bit of googling, and read the older threads here, but > the closest I've come is an included angle in the 14 degree area, or 7 > degrees off axis in cnc terms. No one has discussed the effect of > dissimilar metals that I have noted in skimming about 65 old messages or > in the google outputs. > > My copy of #27 is out in the shop, and the weather is wet and noisy and > I'm still pretty well crippled up. I could get there, but it would > likely cost me another painful, sleepless night. > > Is it in there (#27), or are there some general rules of thumb that > govern this to a "first pass that will work well enough" accuracy? > > Thanks everybody. > > Cheers, Gene Heskett > -- > "There are four boxes to be used in defense of liberty: > soap, ballot, jury, and ammo. Please use in that order." > -Ed Howdershelt (Author) > Genes Web page <http://geneslinuxbox.net:6309/gene> > > ------------------------------------------------------------------------------ > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
