Miter Gauge Moves While Tightening

algale · Post by **algale** » Sat Jan 14, 2012 2:58 pm

When tightening the knob that secures the protractor head of the Shopsmith miter gauge, the rotation of the knob is moving(rotating) the miter gauge several beyond where it is intended to be set. I noticed this when setting the gauge back to 90 degrees. Pushed the pin in and rotated the protractor up against the 90 degree set screw. As I tightened the the knob, however, the gauge moved about 2-3 degrees past 90. There is a washer under the knob which I assume is there to prevent the knob's rotation from being transferred to the protractor head, but it isn't doing the job. The stop pin and set screw are no help at the 90 degree position, moreover, because the rotation swings the head and stop pin away from the set screw. Any ideas for a solution (other than buying the Incra) are greatly appreciated.

JPG · Post by **JPG** » Sat Jan 14, 2012 3:10 pm

algale wrote:When tightening the knob that secures the protractor head of the Shopsmith miter gauge, the rotation of the knob is moving(rotating) the miter gauge several beyond where it is intended to be set. I noticed this when setting the gauge back to 90 degrees. Pushed the pin in and rotated the protractor up against the 90 degree set screw. As I tightened the the knob, however, the gauge moved about 2-3 degrees past 90. There is a washer under the knob which I assume is there to prevent the knob's rotation from being transferred to the protractor head, but it isn't doing the job. The stop pin and set screw are no help at the 90 degree position, moreover, because the rotation swings the head and stop pin away from the set screw. Any ideas for a solution (other than buying the Incra) are greatly appreciated.

Make sure the mating surfaces are flat and square. Lubricate(sparingly) between the knob and washer(only).

Gene Howe · Post by **Gene Howe** » Sat Jan 14, 2012 3:16 pm

I turn the gauge over and slide it against the table, then tighten the knob. May not work if yours is a "T" slot. I it is a "T" slot, set an accurate square against the gauge head and the blade. hold it there and tighten. For other than 90, I use draftsmen's plastic triangles against the gauge head and blade. Make sure the triangle misses the teeth on both sides of the blade.
Might be that a new washer would solve the problem....dunno.

reible · Post by **reible** » Sat Jan 14, 2012 3:32 pm

"There is a washer under the knob...."

You should have two washers under the knob.

Ed

Ed in Tampa · Post by **Ed in Tampa** » Sat Jan 14, 2012 3:34 pm

algale wrote:When tightening the knob that secures the protractor head of the Shopsmith miter gauge, the rotation of the knob is moving(rotating) the miter gauge several beyond where it is intended to be set. I noticed this when setting the gauge back to 90 degrees. Pushed the pin in and rotated the protractor up against the 90 degree set screw. As I tightened the the knob, however, the gauge moved about 2-3 degrees past 90. There is a washer under the knob which I assume is there to prevent the knob's rotation from being transferred to the protractor head, but it isn't doing the job. The stop pin and set screw are no help at the 90 degree position, moreover, because the rotation swings the head and stop pin away from the set screw. Any ideas for a solution (other than buying the Incra) are greatly appreciated.

My guess the knob has been over tightened at one time or another and either the casting on the miter gauge, the washer, or the knob/knob shaft are bent, grooved or otherwise damaged. I would take it all apart and inspect each part. Making sure all mating surfaces were true and nick free, that nothing was bent or otherwise out of shape.

dusty · Post by **dusty** » Sat Jan 14, 2012 3:58 pm

reible wrote:"There is a washer under the knob...."

You should have two washers under the knob.

Ed

I don't know if I am missing washers on both of my SS Miter Gauges, Ed, but I do not have two washers under the knob. I have only one on each of the two miter gauges. Both washers are .064" thick]The illustrated parts drawings that came with my equipment does show two washers Part number 120392 (269).
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This is one of those situations where I wish the parts breakdown contained component specifications. I believe these miter gauges to be in original configuration but I have had these for a long, long time and my memory just does not serve me well over that long period of time.

Is there a technical reason why there would be two washers. If the top one was a lock washer, I would understand but not two face-to-face flat washers.

dusty · Post by **dusty** » Sat Jan 14, 2012 4:02 pm

JPG40504 wrote:Make sure the mating surfaces are flat and square. Lubricate(sparingly) between the knob and washer(only).

Won't lubricating it better enable the knob to work loose? Yes, I know that the locking pressure is between the threads in the knob and on the threaded shaft.

algale · Post by **algale** » Sat Jan 14, 2012 5:02 pm

reible wrote:"There is a washer under the knob...."

You should have two washers under the knob.

Ed

Ed, nice pick up. The exploded view clearly shows two washers under that knob. http://www.shopsmith.com/ownersite/part ... xpview.htm There's only one washer under my miter gauge (like Dusty is finding). I know I have never had it apart, so either it didn't come with one or the previous owner lost one.

Whether the second washer will make the difference remains to be seen. If one washer reduces he transfer of rotation directly to the protractor, then two may be twice as good, or not. I'll put a washer in (after the football games are over) and give it a try.

Thanks all who have responded. I will document any "findings" I may make when I take it apart.

Am I crazy for thinking that Shopsmith could have solved this problem by reversing the 90 degree stop pin and set screw location?

algale · Post by **algale** » Sat Jan 14, 2012 5:09 pm

Gene Howe wrote:I turn the gauge over and slide it against the table, then tighten the knob. May not work if yours is a "T" slot. I it is a "T" slot, set an accurate square against the gauge head and the blade. hold it there and tighten. For other than 90, I use draftsmen's plastic triangles against the gauge head and blade. Make sure the triangle misses the teeth on both sides of the blade.
Might be that a new washer would solve the problem....dunno.

Yep, it is a T slot and yes I am using an accurate square against the head and blade. Still not easy to keep everything 90 degrees. Even moderate tightening of that knob rotates the miter gauge a little bit. I am going to try that second washer and see if it helps.

algale · Post by **algale** » Sat Jan 14, 2012 5:10 pm

Ed in Tampa wrote:My guess the knob has been over tightened at one time or another and either the casting on the miter gauge, the washer, or the knob/knob shaft are bent, grooved or otherwise damaged. I would take it all apart and inspect each part. Making sure all mating surfaces were true and nick free, that nothing was bent or otherwise out of shape.

Good advice. I will take it apart and document anything wrong.