Drill Press In Need Of Help!

[NorthByNorthWest]

Hello everyone, I'm new to the site; I've been out of machining for awhile, but have recently been tooling up. I just added a 20" Rong Fu VFD drill press to the shop and it arrived a little worse for wear. The depth stop handle was broken off, as was the electrical box holding the VFD. I reamed and tapped the motor casting and reattached the VFD; I got a new kipp handle and repaired the depth stop; I also fitted a used Jacobs 14n into the press on a new arbor. Thought I was ready to go, but here's where it gets squirelly. If the spindle is turning, lowering the quill causes vibration and it seems to meet resistance on the way down and back up. After removing the belts, they check out fine. The pulleys are all running smooth. I marked the spindle pulley and found that the quill only retracts properly on about 1/3 of it's revolution. If the chuck is turned into the other 2/3 of its revolution, there is resistance and the quill stays down due to some internal friction. The return spring is adjusted properly. Does this sound like a bent spindle? I do not have the setup to check runout at this time, but it's minor if there is any. Can anyone help diagnose this? Maybe the low price on this machine wasn't such a good deal after all...

 

[mikey]

There is a screw, usually on the left side of the head just forward of the quill return spring, that runs in a slot machined into the side of the Quill. The purpose of the screw is to prevent rotation of the quill. It also allows you to reduce side play in the quill to a minimum. Typically, this screw is slotted and has a jam nut on it. Try loosening the jam nut and backing out the screw a bit to see if this improves the binding issue. Sometimes the head of that screw can be deformed and cause it to stick, or it may simply need to be adjusted properly. To adjust it, run the screw in until it just contacts and run the quill up and down until it just runs freely, then lock the jam nut down.

The spindle itself runs inside the quill and a bent spindle will manifest as excessive runout but it will not cause the binding you describe.

 

[dlane]

Take apart , Clean and oil

 

[francist]

Bar Z Industrial just posted a video within the last few days on removing and lubing the quill splines on a drill press. Not saying you absolutely need to do this, but if you get to that point and do want to take it out it might be worth watching the video first.

-frank

 

[NorthByNorthWest]

The screw on mine is located on the front of the machine, underneath a plate that houses the DRO. I completely removed it to rule out that possibility, then adjusted it. Everything is clean and greased, however I have not pulled the quill or spindle (and I will check out that video if it comes to that). It just seems weird to me...very little runout (though untested), everything operates smoothly, but if you lower the quill while running you can feel the resistance and vibration through the handles.

 

[mikey]

If you consider what could hang up the quill like this, there are only a few possibilities. One is that quill screw but yours is fine.

Another is a damaged rack or pinion gear to which the handle is attached but if that were the case then it would hang up regardless of the position of the drive pulley so that can't be it.

When the handle is lowered the upper end of the spindle moves up and down inside the drive sleeve. The location of the drive sleeve is fixed and the splines of the spindle mate with splines inside the drive sleeve. As the quill is lowered it moves the spindle down through the sleeve. If the splines of the spindle are damaged somehow then when that part hits the drive sleeve it might hang up. I've never seen damage occur to this part of the spindle as it is well protected by the drive pulley but anything can happen, including chips or some debris getting caught up in there. What is confusing is why this resistance is noted only during 2/3 of the rotation of the pulley.

The only other thing that I can remotely imagine is that the drive sleeve bearings are so bad that they allow radial movement of the spindle enough to cause resistance. If this were the case then that would be some really bad bearing damage.

There really isn't anything else in there. Well, there are the two spindle bearings but they only control the radial movement of the spindle and are not involved with the vertical movement in any way.

I think if this were me I would pull the quill and drive sleeve and inspect for damage. I would change the two drive sleeve bearings and the two quill bearings for quality aftermarket bearings. If there is a problem it should become clear with your inspection.

Edit: If there were some hardened grease stuck in the splines of the spindle, I guess that might possibly cause your symptoms.

 

[dlane]

Depth stop handle broken off ?. How dose it feel not running ,Got a pic of that and the press ?

 

[NorthByNorthWest]

I made a little video to give you guys a better view of what's going on. Mikey, I really appreciate the step by step breakdown posted above...where might a guy find aftermarket bearings? The depth stop has since been replaced, but I note in the video where it was sheared off...to be honest the handle that broke was crap...pot metal at best. I replaced it with a slightly larger kipp handle. Thanks for the help so far on this! Just to let you guys know, I'm going on the road tomorrow and will be out for a couple weeks. When I return, it sounds like a disassembly may be in order. Here's a link to the video:

 

[mikey]

The video really helps to clarify what is going on. Since the quill moves smoothly when the pulley is clocked to a certain position but not at others it suggests that something is bent or out of position. I'm wondering if there is some way the drive sleeve might be cocked somehow. Unless this press is built different than most other drill presses out there, that's the only thing I can think of that would do that. Bad bearings will give you excessive runout but you said the runout is fine. That also suggests the spindle and quill are also fine. That only leaves the drive sleeve.

I would personally drop the quill out and check everything. If you decide to change the bearings (although they seem fine if your runout is low) then you can get them from any bearing supplier, either locally or online. The bearing info will be stamped on one side of the stock bearing. Every Asian press I've seen has shielded bearings, which are fine except for the lower spindle bearing. I would replace it with either a sealed 2RS deep groove bearing (handles higher radial and axial loads) or even better, a double row sealed angular contact bearing if you can find one to fit.

 

[Eddyde]

I agree with Mike, the problem is probably with the drive sleeve/pulley interaction with the spindle. Does the problem occur through the entire down travel of the quill or just in the upper region? Also it would be good the check the actual runout with a dial indicator, as it can sometimes be hard to see by eye. If you don't have an indicator, you can take a 5"+ - piece of straight drill-rod ¼-½" d. and chuck it up (I like to tighten the key in all three holes of the chuck), run the machine, any runout will be magnified at the end of the rod. See if it gets worse or better dependent on the position of the quill, if so, it's probably a bent spindle. Either way, I would take the whole quill apart and see whats going on in there.