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Drill Press Runout

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abrace

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#1
All,

I measured the TIR of my drill press and it is .005 about 1" below the chuck. Jumps to about .010 about 6 inches down. This is with the quill all the way up...didn't have a chance to take a reading with the quill down because the washing machine died right in front of me while I was working so I got a little distracted.

I am thinking of popping the JT33 chuck off and checking TIR against the taper, but I am not sure it is worth the effort. This is a RIGID drill press, nothing fancy, and I don't wanna waste a bunch of time if this amount of runout is expected. I know it is a DP and not a mill, so I wanted to get some opinions before I tear into this.
 

Bob Korves

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#2
I assume from your post that there is not an additional Morse taper in the drill press spindle to mount a JT33 adapter. If there is a Morse taper, then the spindle, the Morse taper, the spindle to chuck adapter, the chuck, and the test bar can each introduce runout. It is not necessarily additive runout, one can also work to help negate runout somewhere else in the chain. Without a Morse taper, then the possible culprits can be the spindle, the JT33 taper (which is part of the spindle), the drill chuck, and whatever you are using as a test bar to indicate. Start with your test bar, whatever it might be. Check the runout, write down the amount and mark the direction of the high spot on the chuck, then turn the bar 90 degrees in the chuck and try it again and see what you get. Repeat at 180 and 270 degrees, and write them down and mark the high spot for each position as well. If the runout and its location changes, following the rotation, you might be testing with an inaccurate test bar. If the test bar passes, then your runout must come from the components above. Remove the chuck, and reinstall it at 90 degrees on the JT taper. Keep proceeding to map each component at multiple clock positions so you can see what is really going on with your stack up. You can then replace or repair anything that is introducing runout, or you can attempt to cancel it out by putting the high spot of one interface opposite the high spot of another interface. With .006" runout one direction and .004" runout on another interface that is facing the opposite direction, your net result is .002" runout. You are gaining. This is long winded, and I hope you get the idea. It is not quick to do this kind of work, and it can get confusing at times, but with a careful and systematic approach you can greatly improve the runout, often without buying any new parts or tooling and without bending or grinding or machining anything.
 

Nogoingback

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#3
I have a Jet DP (Taiwan) that I bought about 20-25 years ago. The runout on mine was horrible, but I put up with it for years. I finally threw the old chuck in the trash and replaced it with
a quality keyless chuck about 10 years ago. It was a completely different machine after that.
 

mikey

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#4
I think Rigid is one of the few drill presses with a threaded chuck. You might check to see if yours has a Jacobs taper or is threaded on. If it is threaded on, then run out is going to be an issue unless the chuck has a spindle register of some kind.
 

abrace

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#5
I have not removed the chuck yet. I have wedges on order to do so.

I have had it for 10+ years and bought it new. My memory at the time was that it was not a morse taper and was not threaded. The spindle has a JT33 taper on the end and the chuck press fits onto that.

Bob, thanks for your detailed writeup. I will do what you suggest and rotate the test bar (I am using a 1/2" drill bit) and see if the high spots change. Good idea.

It sounds like from everyone that this runout is excessive even for a DP and I should continue my investigation. Correct?
 

Bob Korves

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#6
Drill presses are often not considered precision machines, especially the cheap ones. As a machinist, I do not consider .010 runout acceptable, but that is how many machines come from the factory. For a lot of work it is acceptable, but not for accurate work. The good news is that it is addressable. Near perfection can take a lot of effort and money to address, and a drill bit is still not a tool for making precision holes...
 

mikey

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#7
Okay, just wanted to point out the possibility of a threaded spindle. I've also heard of a Jacobs taper on Rigid drill presses so I'm sure you're right.

As Bob said, a drill press is not a precision machine but mainly because the quill floats in the bore in the head; it only has a rudimentary screw that runs in a slot in the side of the quill to take up play. The spindle and drive sleeve can be made to run quite accurately within that quill but the play in the quill is the issue. This is not necessarily a bad thing because it allows the drill to center in the hole.

In my experience, excessive run out can come from excessive wear in the drive sleeve at the top, the spindle itself, the bearings that support the drive sleeve and spindle, the arbor and the chuck. Typically, the drive sleeve has to be really knackered before it affects accuracy because it simply transfers rotational motion. If it is excessively worn enough to be a problem, you will see the wear in the splines on the inside of the drive sleeve.

Wear in the spindle can occur but, again, this is not usually the source of the problem unless the user removes and replaces stuff on the end of the spindle frequently. The spindle can be bent or the chuck can be installed improperly at the end of the spindle; the latter case is most likely.

Far and away, the most common cause of excessive spindle runout on a drill press are the bearings. The Chinese use cheap, shielded bearings that don't last long. If you get more than a few years of good service from these bearings, you're lucky. I think your best bet for improving run out on your machine will come from changing the drive sleeve and spindle bearings to deep groove bearings from Nachi. Deep groove bearings can take heavy axial and radial loads and can be found in the permanently lubricated and sealed 2RS versions. I've done several drill press overhauls and the bearings, far and away, make the biggest difference. My personal drill press has Nachi bearings and has 0.0005" TIR at the spindle; it has remained that way since I rebuilt my press in 2006.

If you change the bearings, you can then measure the run out at the spindle taper. If it is acceptable then mount the chuck and check run out again. I suspect it will be very near to what the spindle run out is.

Good luck with this. A drill press can be made to run pretty accurately. I cannot visually see radial movement of a drill held in the chuck of my press. With 0.010" TIR, you would definitely see the bit wobble.
 

Nogoingback

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#8
It sounds like from everyone that this runout is excessive even for a DP and I should continue my investigation. Correct?

Maybe one way to look at this is ask yourself, how far are you willing to go to improve it? In other words, what's the budget? And, how much better do you want it to be?
Bob is correct: there is only so much accuracy that can be expected from a DP. If it's in the machine (i.e.. spindle), the solution may be a better machine, but that still is only
going to improve things to a point and the cost is high. If the chuck is bad, that's a fairly easy fix as I found on my Jet, and in my case the improvement was huge. But
it still cost $$$. What kind of work do you use your DP for?, and does that amount of runout cause problems for the work you do? In my case, the chuck was so bad
that normal drilling jobs were difficult to do properly, and since I changed the chuck I've had no problems.
So, I guess what I'm suggesting is, instead of thinking about numbers, ask yourself if the machine does the job you want it to? If you want to do really precise work,
a DP isn't the right tool.
 
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abrace

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#9
Thanks, everyone. Good feedback. Once the chuck wedges arrive I will pull the chuck and see what I see. Could be I didn't clean the taper well before mounting the chuck back then. I don't know what I am doing with this stuff now, and I know a lot more than I did years ago when I bought this...so it could be cosmoline on the taper for all I know!
 

Ken from ontario

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#10
Thanks, everyone. Good feedback. Once the chuck wedges arrive I will pull the chuck and see what I see. Could be I didn't clean the taper well before mounting the chuck back then. I don't know what I am doing with this stuff now, and I know a lot more than I did years ago when I bought this...so it could be cosmoline on the taper for all I know!
Please let us know how you take off the chuck, the Ridgid DP of the old with greyish color had the JT #3 chuck ,as far as I know and as you mentioned, you'd need wedges to separate the cuck from the arbor,( hope mine is not screwed on) but for the orange Ridgid you'd need a drill drift,I have the old Ridgid that was built by Emerson ,mine just like yours has a visible runout but it's not as bad ,just enough to bug me each time I start it.

I already have the wedge set but have not attempted to remove and clean the chuck yet,maybe if you post your progress it'll give me the push that I need to measure the runout and see if I can reduce it.
 

abrace

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#11
Mine is the orange Ridgid and has a JT33 (according to the markings on the chuck). Exact model number I have is the DP15501.

Manual says to just tap on the chuck with a mallet to get it off. I haven't even bothered trying that, I am going right for the wedges.

I am pretty sure I didn't use enough care cleaning the taper and chuck when I installed them. I know better now. I didn't then. Will see if I can clean it up a bit.
 

mikey

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#12
Tap it with a mallet? Very convenient ... nice way to damage the chuck, spindle and bearings, all at the same time.
 

abrace

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#13
Yup, but they did use the word carefully! :eek:

REMOVING CHUCK
See Figure 30.
 Unplug the drill press.
 Open jaws of chuck as wide as they will go by turning chuck sleeve.
 Using a downwards motion carefully tap on the chuck with a mallet while slowly turning the chuck with your other hand.
 Remove the chuck
 

abrace

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#14
All,

I got some more time to work on this...and also got a heaver magnetic mount stand for my indicator. The other one was a small Noga and seemed like it would fall over easily with a dial indicator on it....worked fine with my DTI.

Anyways, I followed the above advice and marked the high spot. I rotated the drill bit in the chuck and tested again. The high spot moved seemed to follow the drill bit. This tells me the bit itself has most of the runout? Am I correct?

What should I test the runout with? I was thinking of turning a piece of aluminum in the lathe and using that as a test rod, but I m not sure if that would institute additional testing issues.
 

Bob Korves

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#15
All,

I got some more time to work on this...and also got a heaver magnetic mount stand for my indicator. The other one was a small Noga and seemed like it would fall over easily with a dial indicator on it....worked fine with my DTI.

Anyways, I followed the above advice and marked the high spot. I rotated the drill bit in the chuck and tested again. The high spot moved seemed to follow the drill bit. This tells me the bit itself has most of the runout? Am I correct?

What should I test the runout with? I was thinking of turning a piece of aluminum in the lathe and using that as a test rod, but I m not sure if that would institute additional testing issues.
First indicate the chuck itself. Do it on the body of the chuck, the piece that has the holes for the chuck key. If that is spinning true. you can forget about everything above it. If not you will need to see what part(s) of the drill press have problems, as discussed above. If the chuck is spinning true, put a KNOWN accurate cylinder in the chuck. A new hardened steel dowel pin is cheap and suitably accurate, and is usually available at hardware stores. Check the runout of the pin close to the chuck jaws, and also farther away. If the chuck body is spinning true, issues with the chucked part are usually caused by worn or damaged chuck jaws, and/or from dirt and swarf in the chuck. The chuck can usually be disassembled to clean and lube it. The only real fix for damaged or worn jaws is to replace the jaws or the chuck. It will work a lot better if you can mount your indicator stand to the drill press head rather than to the table, more rigid setup. Steel attracts magnets better than cast iron does...
 
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retrojoe

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#16
If a drill press has especially bad runout and the bearing and chuck aren't obviously the cause odds are it's the quill to head fit. The set screw on the slide is only there to prevent the quill from turning, so its fit to the slot in the quill isn't a factor.

I have a cheap little Craftsman benchtop drill press for my basement (I have a floor press out in the shed) that is a combo drill + oscillating spindle sander. Because of the latter "feature" there's a lot of built in slop in the quill to head fit. Runout was not only visible but audible; I could lock the chuck up tight and and click the quill against the side of its bore in the head. It's the only press I've ever seen that could drill a hole both oblong and at an angle.

But I fixed it! I cut a thin vertical slot from the point where the quill enters up 0.5" past the final cast in ring that forms the bore; adding a 0.25" hole at the end to prevent cracking. I drilled a hole perpendicular across the head between these two cast in rings, being careful to keep the hole from passing into the plane where the quill would be (a slip for 1/4-20 bolt). With a hex cap screw slid in and a lock washer + nut on the end I could very carefully take up the slack. After reassembling the drill I slowly tightened up on the nut until the well oiled quill would just slide up and down smoothly. My oblong holes are now quite round and drilling is noticeably easier and more quiet. If anyone is interested I'll post a photo of the finished set-up. FWIW, I started the slot with a hacksaw but finished with a DeWalt 20v saber saw and a fine tooth blade (wish I'd started with it).

I didn't measure runout before (TIR=Horrible) and haven't measured it since because I'm planning on putting a nicer keyless chuck on it anyway. But I was very close to pulling the motor, pulleys and chucking the rest but now I'll keep it and am using it for important work. A lot of older premium presses had split heads for a quill lock but many also had the same takeup bolting arrangement.
 
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