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.
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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.
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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.
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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.
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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.
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Bill Jones
Bill Jones' Photo Gallery Page 9
Valve Seat Runout Gauge