What key machine operators often forget is if the depth adjustment is off by as little as 1-1/2 thousandths of an
inch (.0015”) they will accumulate generations. In as little as five generations the key probably won’t work in the
lock.
In reality, generation cutting is a representation of the entire key cutting process (key machine, operator, and
adjustments) and the results you get are either good or bad – but you don’t learn the reason why you are getting
good or bad results. Your results do not indicate the quality of the key machine, the quality of the operator, or the
quality of the adjustments made to the machine. All questions remain unanswered.
There is only one way to get good results on a consistent bases. Buy a quality-built heavy-duty key machine,
don’t abuse it, and keep it well maintained and adjusted at all times. Keep an eye on cutter sharpness, the integrity
of the stylus, the fit of the vise jaws, the fit of the key gauge shaft to the carriage, and the fit of the cutter shaft to
the bearings. Any situations in these areas will decrease the performance and accuracy of the machine. When
parts start to wear – replace them.
In addition to a quality machine and its maintenance you need an accurate measuring tool such as a dial caliper or
key micrometer (preferably mechanical digital).
Measuring True Key Machine Accuracy
The proper way to measure key machine accuracy is to take the key you are going to duplicate from and measure
it. Measure each cut from the back edge of the blade of the key. Measure each cut several times and record their
average. Compare the results. There is really no substitute for the procedure if you want to make accurate
duplicate keys. Generation cutting will not give you meaningful results like this procedure.
19.
TROUBLESHOOTING
Machine Always Needs Adjustment
There are several things that can cause your machine to need adjustment.
1.
Cutter wheel may be dull. This can cause the key to try to “float” and not cut deep enough in the deepest
cuts. Replace or resharpen the cutter.
2.
Carriage spring may be weak or adjusted to light. Replace the spring or adjust the spring.
3.
Stylus may be worn. Check it carefully, if there is a groove worn in the stylus you may get deep and
shallow cuts on different brands of keys. For example when cutting Ford double sided keys the ignition
key will be cut high on the stylus and the door key will cut low on the stylus – Schlage C keys are cut
more in the middle of the stylus. This may seem like an extreme case – but it happens every day.
Replace the stylus.
4.
Carriage shaft and bearings are worn. Check for excess “wobble”. Replace the carriage shaft and bronze
Oilite ® bearings.
5.
Cutter shaft bearings are worn. Check for any “wobble” or in-out play. Replace the cutter shaft
assembly.
6.
One key cuts fine and the next doesn’t. You adjust and readjust all the time. The problem may be the
carriage depth over travel adjustment is set too high. This results in the machine’s inability to cut the
deepest cuts on a key – but shallower cuts are fine. This symptom is more common than you think.
Fix the problem by readjusting the Carriage Over travel Depth Adjustment.
7.
Again – one key cuts fine and the next one doesn’t. This time it may be the key gauges. Sometimes key
machine operators don’t flip down the full-function key gauges all the way down and the left-hand key
gauge CRASHES into the stylus holder and knocks the key gauges out of position. The key they’re
cutting is O.K. but the next key they duplicate won’t work in the lock. If you ever CRASH the left-hand
key gauge into the stylus holder – fix the key gauges right away. See Key Gauge Adjustment for how to
do it.
Keys don’t always work in the lock when gauged off the bottom shoulder stop. This is a common problem caused by the
key blank manufacturers. In recent years many of the key blank manufacturers have stopped paying attention to the bottom
shoulder stop on most key blanks since they are seldom used by the lock cylinder.
15
