Checking Valve Refacer Chuck Runout 

Valve Grinder Chuck Inspection

Chuck accuracy is critical to producing a quality valve job.

Most O.E.M.'s require a valve face run-out to be below .0015. To accomplish this, the chuck in a valve grinder must not only run-out below .0015, but must repeat this every time.

High performance engines require even greater accuracy. In some cases run-out must be below .0005.

How do you determine the accuracy of the chuck in your machine? There is basically one easy method that can be used which provides an accurate evaluation.

Start by finding a known round and straight part. A valve seat pilot, carbide if you have one will work very well. If you do not have one, use a section of drill rod that is straight and round. This will be your test piece.

1) Insert the test piece into the chuck so that it is gripped correctly and has at least two inches of protrusion past the face of the chuck.
2) Install a dial indicator (.0000 reading if possible) so as to have the plunger contact the test piece one inch from the face of the chuck.
3) Turn the machine on and observe the indicator as the chuck is rotating. The reading at this point should not exceed .0015.


If the reading is in excess of the .0015, you can first disassemble the chuck and clean it thoroughly. (Follow directions given in the machine manual). Examine the ramps on which the ball bearings ride, if wear is evident (grooves), the chuck will require placement. Kwik-Way provides new chucks that have less than .0005 run out and for the standard SVSIID and a Hi-Performance version with less than .0002 run out.

If you have any questions in regards to chuck performance, or if you need a replacement chuck, contact;

Kwik-Way Tech Services at 800-553-5953.

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