Bill Jones's tenth reading seat runout gauge
    I had used several other runout gauges that I had bought or borrowed and I didn't like any of them---except Sunnen had one that was about $1000 that I sort of copied the design
-I built this thing myself and I've changed several things about it along the way.
-basically the pilot goes in the valve guide hole----then the part that is knurled installs with the knurled part at the top as shown in the assembled state--the top two photos.
-the 3rd photo shows there is a rounded head pin sticking down out of the bottom and back side of the aluminum of the dial indicator mount.
-This pin sits on top of the flat part of the knurled wheel---and this knurled wheel has an adjustment containing a teflon ball---the adjustment allows for different seat diameters---and the teflon ball rides on the seat.
-I chose teflon because if you used a steel ball and happened to drop that piece onto the seat it would leave a dent in the seat---and that was very easy to do.
-As you rotate the knurled piece the teflon rides around on the seat and if the seat is not concentric it will raise the knurled part up and down slightly---which in turn the rounded head pin lifts and drops the dial indicator and mount assembly
-This causes the needle on the dial indicator to move up and down out at the large gray plastic end I have attached to the dial indicator stem end.
-This large gray plastic end is needed because it rests on the face of the cylinder head and sometimes there is water holes there---so the plastic is like a big foot that will span most water holes I have come a crossed.
    The adjustable feature where the teflon ball is installed----I have totally changed that to where I now use teflon cones where the cones are down and same angle as the seat---say a 45º.
-Then I machine about 350º of that cones edge back about .060" so that there is a very narrow width strip of teflon that rides on the 45º---and this is usually about 1/8" wide x 3/8" long so it can accomodate a small variety of seat diameters without needing any adjustment.
-Then I make up a series of these teflon pieces to suit the different size valve seats (and seat angles) I am working with.
    As far as price---it's probably worth more than the very best you could find on the market which is probably the Sunnen gauge that was valued at somewhere around $1000 about 16 years ago when I built the runout gauge.
-The dial indicator alone is something like $187---it reads in ten thousandths and has a .050" total range.
-the dial indicator mount was made out of aluminum and needs to be a fairly snug fit to the pilot shank---but I has a bolt sticking out the back that actually has a spring loaded ball bearing that keeps the pilot snug against the inside of the aluminum pieces guide pilot hole.
-I seriously doubt that I could be persuaded to build another ---even for $1000.
-I probably spent the better part of a week building the thing--and then have spent some time over the years--eventually changing the adjustable teflon ball section over to the teflon cones which is much quicker to use.
    The actual hardest part and the most critical part of this contraption is the knurled part that rotates.
-It has to be super hard where the rounded head pin sits ands rubs against that rotating piece.
-then this knurled piece has to be press fitted to a piece of 5/8" x 3/8" steel tubing---and I silver soldered these two pieces together.
-since I use Sioux pilots that are .385" diameter I had to precisely ream the hole and then hone it to a nice tight but a slip fit to fit my pilots---and that meant measuring every pilot I had and making sure they all would fit.
    Once I got the knurled piece and the tubing bored to perfect size I took a Sioux pilot and loctited the knurled piece to the pilot---then I chucked up the pilot using a tail stock on the one end for support---diai indicated and got the pilot runout perfect---then set up a die grinder on t/my lathes tool post and ground the top surface perfectly perpendicular and 90º flat to the shank.
-Then I warmed up the loctited pieces and disassembled them---ran a wire brush thru the bore hole to remove the residual loctite.
Bill Jones

Bill Jones' Photo Gallery Page 9

Valve Seat Runout Gauge