Chuck and bearings runout question

astjp2

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So I picked up a Duracraft DP1214 drill press for cheap. It has a 5/8" MT2 chuck, so I bought a couple of MT2 threaded adapters for some smallerjacobs chucks that I have. Right now the run out is between .0025- .003" Would this be acceptable for all 3 chucks? It also has a growl, I am thinking that either a belt or bearing is bad, is it worth tearing down to put new bearings and belts on or should I just run it to failure? Tim
 
When you say you have 0.0025 - 0.003" TIR, how and where are you measuring this? I ask because dynamic run out that is checked while the machine is running is fraught with inaccuracy and tells almost nothing about what is doing what.

It sounds like this machine has an MT2 socket and it might be a good idea to check static concentricity inside the spindle to see what that looks like; this will give you a baseline so you'll at least know what the spindle is doing. If you then install a chuck and have a large increase in static run out then you know that it is the arbor, the chuck or the way the arbor was install in the chuck.

I don't know anything about Duracraft machines but from a quick search on the net, it is a Taiwanese machine. Typically, these machines were made to a price point and it is a good bet they use cheap shielded bearings on the spindle and drive sleeve. When these bearings go bad you will see run out increase and hear excessive noise when it runs. They will also run hot. If you wish to get it running as accurately as you can, change both the spindle and drive sleeve bearings with good sealed bearings. This makes a huge difference in accuracy.

Drill presses are not intended to be precision machines, just as drills are not precision cutting tools. However, I can tell you that 0.003" TIR at the arbor is enough to see 0.006" TIR at the end of a drill and that much run out is visible as a wobble. If you see that, its time to assess the machine.
 
I put a TDI inside the spindle and it was the same as when I put in a dowel pin in the chuck. It looked to me that the arbor was running true in the spindle but the spindle was not running true. I guess I will pull the spindle bearings and get some replacement belts from Motion. It is a way heavier machine than what I had before. I guess I will have to mill a socket to make a spanner socket to get the spindle nut off.

I need to get my Delta DP220 cleaned up and rebuilt too. That one needs the chuck fixed and new bearings, I can turn the spindle on it and feel the grit in the bearings.
 
If you replace the spindle bearings, replace the drive sleeve bearings at the same time. If one pair is shot it's a good bet that the other pair have failed as well. Both contribute to run out. Good luck!
 
If you replace the spindle bearings, replace the drive sleeve bearings at the same time. If one pair is shot it's a good bet that the other pair have failed as well. Both contribute to run out. Good luck!
drive sleeve?
 
The spindle rotates inside two bearings at either end of the quill; these are the quill bearings and there are two. The spindle extends up through a sleeve with internal teeth that match those at the top of the spindle. This is the drive sleeve that runs inside two more bearings separated by a spacer. The top of the sleeve has a taper that mounts the drive pulley. As the pulley turns, it turns the drive sleeve that, in turn, drives the spindle. That is how power is transmitted to the chuck.

When you change bearings, you should change all four - two quill bearings and two drive sleeve bearings. Pull the bearings and buy the equivalent bearings but I suggest you use sealed bearings, not shielded ones. The grease in sealed bearings last longer. I also suggest you buy deep groove bearings from Nachi or NSK. Deep groove bearings can sustain high axial and radial loads and quality Japanese bearings are worth the small extra cost.

My 30 year old Craftsman drill press has Nachi bearings that are at least 8 - 10 years old by now and it still holds about 0.0005" TIR at the spindle despite frequent use. Most folks worry about how accurate their drill chucks are but the primary source of accuracy in a drill press are in the bearings, all four of them.
 
Sealed bearings have the rubber seals, shielded ones have a thin metal cover with a tiny gap that can let debris in. Nachi makes good, reasonably priced bearings, it's a Japanese company.
Mark
 
So I got the drill press apart, it is missing a few small items like thumb screws but it is intact.
I pulled the spindle, it has a 6205 and a 6203 bearings in it, the grease was old and stiff but not gritty. With the spindle in the vise, runout was .0002

There was an intermediate slow speed pulley that seems to be causing most of my problems, there seems to be a manufactures defect in one of the sheaves, and the 6202 bearings were gritty. It also has belts that were too tight and cracked. So the only thing I have to do yet for tear down is to get drive sleeve off once I find a spanner socket. I dont like using a punch to take them off if I dont have to, it makes it hard to get the proper torque on bearings.

Tim
 

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The spindle rotates inside two bearings at either end of the quill; these are the quill bearings and there are two. The spindle extends up through a sleeve with internal teeth that match those at the top of the spindle. This is the drive sleeve that runs inside two more bearings separated by a spacer. The top of the sleeve has a taper that mounts the drive pulley. As the pulley turns, it turns the drive sleeve that, in turn, drives the spindle. That is how power is transmitted to the chuck.

When you change bearings, you should change all four - two quill bearings and two drive sleeve bearings. Pull the bearings and buy the equivalent bearings but I suggest you use sealed bearings, not shielded ones. The grease in sealed bearings last longer. I also suggest you buy deep groove bearings from Nachi or NSK. Deep groove bearings can sustain high axial and radial loads and quality Japanese bearings are worth the small extra cost.

My 30 year old Craftsman drill press has Nachi bearings that are at least 8 - 10 years old by now and it still holds about 0.0005" TIR at the spindle despite frequent use. Most folks worry about how accurate their drill chucks are but the primary source of accuracy in a drill press are in the bearings, all four of them.
Mikey, do you happen to know the dash number for the high precision deep groove bearings? I found the Nachi 6203-2NSE and 6203-2nse9, but I am not seeing in the naichi catalog what the 9 means, they also carry them for the 6205 and the 6202
 
I don't know what the "9" means, sorry. There is a seller from Turkey selling the 6203-2NKE version with free shipping. This is the rubber sealed, non-contact version of your bearing that will take more heat. The 2NSE version is a contact seal type which is fine for a drill press, though.
 
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