Drill press runout question

[Louis Brandt]

A friend gave me his used Ryobi (I know, it's not the top of the line) DP101 10 inch bench top drill press, and I’ve never had a drill press before. It appears to be in excellent condition, and my question concerns runout (which I’ve seen mentioned many times in postings).
I just finished drilling a few test holes with the drill press, and based on what I‘m observing, there doesn‘t seem to be any runout at all with this press. The holes look perfectly clean and accurate. But maybe I‘m too much of a novice when it comes to drill presses, so I’m wondering whether a top quality (one of the more expensive brands) drill press is supposed to be perfect with absolutely no runout. Maybe if one of you used this press, you’d say that it has runout and that I’m just not experienced enough to know runout when I see it.
Is there a way for me to measure whether this press has runout? Is there some kind of test that I could do to determine it?
Thanks,
Louis

[David Romano]

There probably several of ways to measure it. The most relevant method is to measure the diameter of a drill bit and the diameter of the hole it drills. Be sure to secure the work piece well. You'll need a good set of calipers. Repeat the test on several holes and measure the bit and the holes across several axis to detect any roundness issues. Also use several bits and rotate the position of the bits in the chuck. You need to isolate the runout of the drill press from the straightness of the drill bit. It's also possible that the chuck is either not seated well on the spindle or the chuck is not centric. (think of all the contributors) After drilling your holes, measure them veray carefully. If the diameter of the hole is larger than the drill bit, you effectively have run out. I say effectively because vibrations could also cause the enlargement, but regardless of the cause, the size and shape of the hole is what you really care about.

Another way is to put a length of drill rod in the chuck and measure the deviation as it spins using a dial indicator. The disadvantage to this is that you have to turn the chuck by hand and that the rod might not be straight (but your drill bits may not be straight either).


David

[John Thompson]

I had that drill press once upon a time and sold it to a gentlemen that restores old muscle cars at his work-place. He wanted it for home.
David gave you how.. but if it isn't broken, don't worry about fixing it.

I found it to be the best BT drill press at that time (they changed to a Chinese manufacturer latter with the same blue-print) as I returned a Delta that would not keep a chuck on. The run-out was fine on the Ryobi and frankly.. I wish I had it back to drill small holes in metal as it seemed to excel.

Sarge..

[Louis Brandt]

John,
Well, mine does say DP101 on it, but it also says "made in China", so it may not be the same one that you had.
Louis

[Tom Veatch]

Runout might be a problem if you're working to tight tolerances in metal. Working with wood, drill a hole, remove the bit from the DP and use it to check the hole. If it's not sloppy, you'r good to go. Spend your effort making sure the table can be set square with the quill/spindle axis. It's a rare drilled hole in wood that needs the kind of precision/tolerance that would require great concern about DP runout.

Don't forget, the hole diameter and shape are going to be different anyway as soon as the temperature/humidity changes, so if it ain't broke, don't fix it.

[glenn bradley]

Just cause it's a little guy doesn't mean it has to be problematic. You could take a 1/4" or larger brad point bit, drill a hole through a piece of 3/4" material. Take your calipers to the bit and then to each end of the hole. If they are all the same (within the capacity of your measuring tool) then life is good. If the DP seems fine to you then i would say it is fine. Don't get too hung up on the numbers.

[Pete Bradley]

One way to measure it would be to chuck in a piece of precision drill rod (not all drill rod is created equal) and measure the runout with a dial indicator. However, typical small amounts of runout are irrelevant for woodworking. If you're getting good holes, there's no need to mess with it.

Pete