50 Tidbits
1. Cross checking your measurements with 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 is in 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 to not have trouble
31. Don’t pour cold coolant over a warm machine and expect to not 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
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 actually 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

Professional Instruments Company manufactures the world’s most accurate air bearing spindles and slides for customers who require millionth-inch precision, high stiffness, and zero friction. Since 1946, we have solved our customers’ problems in manufacturing, measuring, and scientific research. Anywhere ultra-precise motion or geometry is involved, there’s a good chance we have something to do with it.

In addition to our product line of air bearings, we provide a wide range of sub-contract manufacturing including tools, gages, precision cams, special machines, and prototype or production parts. Our highly skilled technicians combine a profound understanding of precision engineering with the experience of many years; we satisfy and delight customers around the globe. For prompt, personal service, please let us know how we might contribute to your high-precision project.