sync. gap

<BODY BGCOLOR="#FFFFFF" TEXT="#080000" LINK="#0000CC" ALINK="#800299" VLINK="#663399"> <div> <I>sync. gap</I></div> <div> <IMG SRC="0c8fabc0.jpg" border=0 width="250" height="188" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"> <IMG SRC="0cafabc0.jpg" border=0 width="250" height="188" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></div> <div> my gap started life as a blower asembly, i took the motor off and tore into it after much looking, thinking, cringing, asking, sweating and more looking?</div> <div> <IMG SRC="0ccfabc0.jpg" border=0 width="250" height="188" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"> <IMG SRC="0cefabc0.jpg" border=0 width="250" height="188" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></div> <div> after mesuring and finding my 1/3 diameter, i marked it out, the calipers really helped to get the two flats parralell, 180 from each other. i ground the flats with a paper flap wheel on my 4" grinder, then i finished the flats with a flat file and sandpaper wraped around a ruler. every one was right, it isn't that bad and at first i thought i messed up, after emailing the moderator of the "tesla coil mailing list" and a few others that don't mind too bad when i bug them, i tried running the motor under a florescent light without the flat pully on it. bingo, there in front of me was the allen head of the set screw showing up in the 60hz flash of the tube! as i turned the motor 15 degreas(?) either way, the bolt head would disapear. this ashured me that the motor was in sync. with the 60 htz line voltage.</div> <div> i then started on the rotor disk for the flying electrodes. i have a piece of G10 board that is 1" thick, but since this is my first atempt at a sync. gap, i opted for some 1/2" lexan that i have. i cut two 8" circles out of it with a jig saw, i placed eqaly spaced screws around the 3" bolt circle to screw the two disks together to make a 1" lexan rotor. i was going to turn this true on my metal lathe but it's old and belt driven, and the drive belt broke! how to true this up? all my machinest buddies had there lathes at work tied up for weeks on jobs so it was up to me.</div> <div> my solution? i made a jig out of wood with a 3/8" bolt countersunk in the board, i used this for the pivot point of my motor shaft.</div> <div> <IMG SRC="0d0fabc0.jpg" border=0 width="250" height="188" ALIGN="BOTTOM" HSPACE="0" VSPACE="0">using a carbide edger i just "bumped" the disk jig over untill it contacted the cutter and slowly turned it untill all the high spots were gone. after this i bolted the rotor to my motor and brought it up to speed and filed and sanded the edge smooth and true for a very nice disk.</div> <div> <IMG SRC="0d2fabc0.jpg" border=0 width="250" height="188" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"> <IMG SRC="0d4fabc0.jpg" border=0 width="250" height="188" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></div> <div> since this is a 3600 rpm motor i only needed two electrodes, but i drilled four holes just in case i wanted to try 240 bps, or if i wanted to bolt it to a dc motor for other bps's?</div> </BODY>