On Sunday 11 September 2016 13:46:06 Chris Albertson wrote: > Gene, > > I would not use JB Weld on a part that roads and vibrates and has oil > around it. If you need a piece of metal to index trigger with, I've > seen lots of simple ways to do it. I'm planning on adding this to my > lathe and mill some months from now as I'd like the ability to cut > threads. > > 1) Drill a small hole in the shaft, You should see a trigger on both > edges of the hole. Note that this is the same as making a "bump" of > 355 degrees length > > 2) use an existing keyway just like #1 above > > 3) Replace a small allen head set screw in a gear with a larger hex > head bolt and index off the bolt head > > 4) Paint stripe(s) on the shaft and use an optical encoder (an IR > transmitter/Receiver sees the change in reflectance.) > > 5) Drill a small hole in the gear and have the sensor look through the > hole, looking parallel to the shaft. Or (5b) place a small bolt and > nut in the hole and index off the bolt head. > > 6) don't like this but,... cut a piece off one of the gear teeth. The > "missing" pulse is your index > > 7) I found some really good optical encoders on eBay for $15 to $20. > They look like motors with a cylindrical body and a shaft and lead > wires coming out of the body. They have 100 to 600 pulses per > revolution. I think they were intended for servo motors. > > On Sun, Sep 11, 2016 at 9:13 AM, Gene Heskett <ghesk...@shentel.net> wrote: > > Greetings all > > > > When making the alu mount for these hall devices, I see ack the > > specs they aren't that sensitive for distance from the gear as long > > as its under 3mm's. So I am contemplating cutting out a mount whose > > face is curved to match that huge but only 60 tooth according to > > what parts lists I have, gear that is the backdrive gear on the > > spindle when the backgear is engaged. And milling a flat spot wide > > enough and deep enough that one of these hall devices would sink > > into, and that would protect the hall device should temp effects > > result in the gear actually touching the alu of the mount. If they > > are close together but half a tooth out of time, it doesn't seem to > > me the arc vs gear accuracy would be all that critical. An arc, > > something in the 6 inch diameter range looks about right. Is there > > a proximity effect when two of these are less than an inch apart? > > > > If I can mount it offset, effectively putting the center of my 1/2" > > thick concoction on one edge of this gear, can I jb weld a piece of > > ferrous in line with a gear tooth, and file it flush with the tip of > > the tooth? > > > > The question about the jb weld is driven by this gear having a 65+ > > yo coat of dried, or wet oil on it, so the jb weld might fall right > > off. > > > > So would a good washing with acetone be good enough, or do I pay > > hazmat fees to get some mek into my possession? Or grind/file the > > end of that tooth shiny and then wash well with acetone? That > > sounds easier if I can keep the filings cleaned up. > > > > That ought to work as an index generator if there is room in the > > bowels of the head casting to clear one tooth 1/8" wider than the > > rest. And it would be an all in one piece setup. > > > > Thanks everybody.
All good ideas Chris, making me think. Thanks. The goop is curing now, but if this blows up, they are all suitable substitutes. The drilling a hole idea, but move it to the edge of the rim and bend the leads of one of these to make it face the side of the gear should also work. Thanks. > > 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 > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users 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 Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
