1. Cross check your
measurements with a lesser accuracy gage
2. Always push on your indicator stand to see
if the needle comes back to the same spot
3. Don’t assume your grinder ways are worn out
when you can’t hold size anymore, it might be your tailstock that’s worn out.
4. Invest in taper stones to remove burrs and
scratches from center adapters and tool holders
5. Don’t necessarily believe the gage with the
highest resolution
6. Always wring up 2 stacks of gage blocks
7. How you hold on to a part is probably going
to be your greatest source of error
8. A 3 jaw chuck doesn’t necessarily bend your
part 3 lobe
9. 60 degree centers are a gift from God
10. Check to see if your indicator tip is loose
11. Look for flats on your indicator tip
12. Counter drill your tapped holes
13. Bigger screws don’t necessarily make for a
better bolted joint
14. Ground surfaces go together better than
lapped surfaces
15. Put light bulbs inside your machine base to
keep the base from getting too cold in the winter
16. Remember that you are a big source of heat
17. Make sure you soak your part long enough
before you measure it
18. Always stone your parts
19. Always stone your surface plate
20. If you want to do a very fine infeed try
bending your machine
21. A soft hammer works well to move a plain
way machine slide a very small amount
22. It is perfectly reasonable to level your
machine
23. Balance your grinding wheel
24. Most machines can be made to be much more
accurate by replacing the work spindle with a Blockhead air bearing
25. Don’t necessarily assume that your spindle
is bad because your parts are
26. Everything is rubber when you measure in
microinches
27. Get yourself a good used Mikrokator
28. Most machine tool slides are very well
made; the biggest deficiencies in most machine tools are their work spindles
and their tool/work holding
29. There is nothing magical about 20 degrees
centigrade; what you really want to do is avoid temperature gradients and fast
temperature changes
30. Don’t pour warm coolant over a cold machine
and expect not to have trouble
31. Don’t pour cold coolant over a warm machine
and expect not to have trouble
32. Check your gage calibration over the range
that matters to you
33. Electronic gages need good batteries even
when you have them plugged in
34. Invar’s coefficient of expansion is as far
away from steel’s as aluminum's
35. Worry about your material’s thermal
conductivity as much as you worry about its coefficient of expansion
36. Know what you are measuring; often what you
think you are measuring is different from what you are actually
measuring
37. Generally the more massive your indicator
mount is, the better your measurements will be
38. Make sure your screws are properly
tightened
39. Things bend when you tighten screws
40. Collets only work correctly when your part
is the right size
41. Your spindle’s drive is very often the main
source of spindle error motion
42. Air regulators are not created equal; get a
good regulator and consider cascading if you
want to do precision work on an air bearing spindle
43. Don’t necessarily believe your diamond
grinding wheel salesman; he might want to sell you a wheel that lasts a long
time and your parts might be better with a less durable wheel.
44. Running your grinding wheel at a slower
speed sometimes gives you better parts
45. Don’t run your wheel at your
machine’s natural frequency
46. Lessons learned from diamond
turning don’t always transfer to other kinds of precision machining
47. Donaldson Reversal isn’t a
very practical a way of separating spindle error from ball error
48. In spindle testing it is very
important to have your master sphere integral to its mount
49. Running your CMM slower can
increase its accuracy; the formula that tells you how accurately you can
measure with your CMM assumes fairly fast measurements
50. Granite Dents