Delta 17-965 spindle question

[Steven J Corpstein]

I have been trying to figure out how to get the nut loose so I can remove the front pulley on my drill press in order to remove the bottom sheet metal pan. I need to put rubber washers between it and the cast head to eliminate vibration noise and one of the 4 screws is under the pulley.Haven't figured out how to hold the pulley without damage while I remove the 1 1/4" nut.

In the process of tapping the ratchet handle with a rubber mallet in an effort to loosen the nut using inertia, I must have tightened something because the up/down travel of the spindle is stiff now instead of smooth.

Is the nut I'm referring to at the top of the spindle, and seems to hold the pulley on, a jamb nut of some sort that adjusts the tension of the up/down motion of the spindle?

I cannot find any service manuals that explain the tear down, only parts diagrams. Anybody have a clue what I'm talking about?

[Dick Strauss]

Maybe a strap wrench meant for taking off oil filters from a car would hold the spindle or pulley while you loosen the nut...

[Jim O'Dell]

I'd try the largest bent Allen wrench I had chucked up and use it for a handle to hold the shaft while I or someone else loosened the nut. That is if I understand what you are trying to do.
On another note, I went out and looked at my 17-965, and the pulley cage is pretty secure. Is that the problem, that yours has just vibrated loose so it rattles? Hope my idea works for your. If so, I think I'd use some of the blue lock-tite on the screws to help hold them in place. Jim.

[Sean Tracey]

I don't know your drill press, but on the 17-959 the spindle pulley has left hand threads.

I unplugged the machine, put the drift used to remove the chuck arbor in the spindle, and unscrewed the left hand threaded nut.

The pulley bore is tapered and I had to use a great big gear puller to get it off. I screwed the nut back on but did not seat it to the pulley and put a spacer on top of the nut for the gear puller threaded rod to push against.

I don't really know your machine, so I suggest looking at the online assembly drawing on delta's web site. It may give you some insight.

Another way to get the pulley off the machine with the spindle that is much easier is to remove the set screw that holds the upper pulley spindle shaft in place. You back a jam nut off and use an allen wrench through a hole on the right side of the machine. The pulley and upper spindle assembly will slip right out. When you put it back in, you have to adjust the tension on the set screw carefully so the spindle doesn't move up and down, but also so tight that the spindle doesn't turn freely. You use the jam nut to hold that adjustment.

Again, that is on the 17-959L, not your machine.

If you hit a ratchet with a mallet, and the spindle is now stiff, you may have bent something.

My upper spindle shaft was bent in shipping. It doesn't take much of a hit to bend the shaft as it is hollow.

I hope the next words don't sound rude, but the parts you are working on spin with quite a bit of power and at some pretty good rpms right next to your face. If you don't get this right, you could be severely injured or killed by a pulley or other part hitting you.

To be fair, I had a bit of trouble figuring the thing out myself. First I turned the big nut on top counterclockwise and it got tighter. That's when I figured out it was left hand threads. I work on industrial equipment, so this wasn't too unusual for me. I am most concerned that you may have damaged the parts by hitting them. I have a machine shop, so when I pulled the spindle out, I found three problems. First, the pulley bore was painted which prevented proper seating on the spindle shaft, this really wasn't causing much of a problem. Second, the upper bearing was loose on the shaft which was a big problem and third the shaft itself was bent. The part is less than $12.00 and the bearings are less than $4.00 so replacing it is cheap.

[Steven J Corpstein]

Sean,
I did in fact take it the rest of the way apart using a puller. I was concerned about exactly what you said, bent shaft. What I found was the spacer between the 2 bearings on the tapered sleeve was damaged.

I've got parts ordered but am looking for some kind of a service manual so I can get the torques right, etc. The shaft goes up through the sleeve very smoothly when it is out of the head casting, I think the damaged spacer was causing the issue.

[Sean Tracey]

I am a little unclear on which shaft was dragging. I think your splined shaft was dragging inside of the tapered sleeve when you raised or lowered the quill.

I will describe my machine.

The upper spindle pulley sleeve tapered at the top and is threaded at the top for the nut that holds the pulley on. The nut has left hand threads. The bore of this upper spindle pulley sleeve (USPS) is splined so that it will drive the splined shaft. The bottom end of the USPS is turned down to accept two ball bearings of equal size. Between the two ball bearings, there is a spacer that has a v shaped groove in it. The v shaped groove goes around the circumference fo the spacer. There is a snap ring at the bottom of the USPS that keeps the two bearing and spacer from coming of the bottom of the USPS.

Now here is the important part as I think we may have had similar issues reinstalling everything.

The USPS is held into place by a single set screw. The set screw is pointed on the end and matches the v-shaped groove in the spacer. The set screw is removed which allows you to slip the USPS back into the bore. I tightened the set screw while moving the USPS assembly up and down slightly until I could not move the USPS assembly up and down. I then tightened the jam nut that fits on the set screw while preventing the set screw from turning. I found that if I tightened the set screw beyond the point where up and down movement could not occur, the spindle would have noticable drag.

There are several reasons why that might be possible.

You may be having the same issue and I can't say for sure as I only rotated the spindle and did not move it up and down when the spindle had too much drag on it.

One other point, the pulley on my machine had paint in the bore. I removed the paint from the bore and off of the USPS before reinstalling it. A little paint can prevent the pulley from seating properly on the USPS taper. This can cuase runout, vibration and even slipping to occur. I found the design and machining of the drill press to be good, but the painters were allowed to put paint on surfaces that were machined and the packaging was not up to the job.

[Steven J Corpstein]

You've pretty much nailed exactly what is going on. The only part that's different, I don't find a set screw at all. My bore has a snap ring at the bottom to keep the USPS from coming out the bottom, there is a semi-hard plastic spacer between the bearings, but no groove in it. I don't have a set screw that I'm seeing, I have an additional snap ring at the top so after you insert the USPS into the bore, you add the second snap ring at the top to prevent it from coming up.

What I found after disassembling it completely was during the discovery procedure (not realizing it was left hand thread which makes sense if you think about it) I think I damaged the spacer enough to throw things slightly out of alignment. Once I got it apart, I noticed the spacer was squished out to one side. I can place the USPS over the spindle and it slides up and down with no effort now that I pushed the spacer back in place. I've ordered a new spacer to replace the damaged one.

The part I'm leery of, is that I had to take a wooden dowel and drive the USPS upward to remove it and I'm trying to figure out a way to reinsert it after I replace the spacer, without pounding. I didn't have to use much force, but I don't want it going in at any angle whatsoever and don't want to take a chance of damaging the spacer. How did you hold the spindle/USPS so you could tighten the pulley nut?

Here is the URL for the schematic at Service Net in case you're interested. I really appreciate you taking all of this time to help out. That's why I love this board. I owe you.
http://www.dewaltservicenet.com/Products/DocumentView.aspx?productid=43213&typeId=10067&documentId=29493

[Sean Tracey]

Now that drawing makes sense. Snap rings at the top and bottom of the bore keep the bearings centered vertically in the bore. Your spacer is a plastic disc whereas mine was a steel disc with a groove and my bore has no snap ring grooves since the set screw replaces them.

First a few things. The USPS on my drill was bent due to shipping. But the problems didn't stop there. The bearings should be tight on the shaft meaning you can't rock them and would need a puller to remove them. The top bearing on my USPS was so loose on the shaft that it could be rocked. Since the bottom bearing was tight, and both bearings are the same size and bearing races are ground to tight tolerance, this meant that the bearing fit area on the USPS was cut with a taper with the smallest end being at the shoulder. This might occur due to the cutting tool deflecting the part less at the shoulder end and therefore removing more material.

Because the upper bearing was loose, the USPS could run out more at the top. I am not a fan of the design because the bearings are so close together. I could have bought a new part but I ended up knurling the bearing fit and remachining it to proper size.

You should first check to make sure the bearings are tight on the shaft. If so, you are good to go, although you will have to use a puller to remove the bottom bearing to replace the spacer. It is probably a good idea to replace that bearing since you will be pulling on the outer race to remove it and it is easy to damage it without knowing. The bearing is probably only a few dollars anyway.

You will install the new spacer and when you install the new bearing, you will want to use a bushing that only pushes on the inner race. It would be handy if you have a little press and maybe the right size deep socket that will clear the shaft and only press on the inner race. It is always better to press bearings on rather than tap them with a hammer.

If both bearings are tight on the shaft, this will minimize the chances of smashing the spacer when installing the assembly into the bore.

Now for the tricky part. Typically, a bearing is designed to be tight on the shaft and slightly loose on the bore. This allows for thermal growth. If the bore is too loose the bearings might spin on the bore and damage it. Your bore is tighter than mine was because mine just slipped into the bore. It sounds like a light tapping was all that was needed to remove your assembly, so I think you are okay. The trick is to start the part as straight as possible. To help with this, try lowering the quill down so that the splined spindle is out of the way. Find some rod material that will just fit in the bore of the USPS and use that to help you see how straight you are holding the part. The longer the rod the more it will amplify your angular misalignment. You are eyeballing the straightness, so make sure no objects are in the background to give you an optical illusion. It would be really great if you had some sort of steel cylinder with a hole in it slightly larger than the rod you could then slide the steel cylinder up and down on the rod and use it like a slide hammer to tap the assembly home. The reason for doing this is because the rod will ensure a straight blow and not a side blow that will cock the part as you tap it home. The slightest amount of cocking will dramatically increase the force necessary to drive the part home. If you do get the part cocked very slightly, you can sometimes straighten it out by tapping the other side. The USPS is kind of delicate since it is hollow and splined and there isn't much surface area to tap on. You may be able to screw the pulley nut on the top to give you a larger surface area to tap. Don't bottom it out on the thread though, stop just shy of that point because the bottom of the threads will often cock the nut. Before you do any of this, check the bore for a bur and remove carefully with a fine file but don't dig a hole.

One other trick that might make it a little easier to put togther. Move the drill press out into the sun. On a good warm day, steel tools will often get to 140° in the sun and you can hardly pick them up without burning yourself. Put the assembled USPS in the freezer for a few hours. The difference in temperature may be enough to reduce the force required to tap the part into place. Alignment is still critical as it is possible to cock a part with clearance. Generally 0.002 to 0.003" clearance is a slip fit. From 0.001 to 0.002" clearance you need a steady hand to slip parts toghther. Below 0.001" clearance you may have to tap the part on.

Make sure the bore of the USPS has a fair amount of grease in it to lube the splined shaft.

Once the assembly is installed, let the quill go back up and turn everything by hand to see if there are any tight spots. It should be smooth and free all the way around. If you have a dial indicator, now is the the time to put it on the top of the USPS and check run out. Mine was running out about .002 to just shy of 0.003". The drill is pretty smooth with that amount of run out. The run out was over 0.012" before I fixed it.

In order to tighten the nut on the pulley, I turned the spindel by hand untill I could stick a drift in the slot in the spindle and quill. This will keep the spindle from turning so you can tighten the nut.

Don't go nuts like I did because you forgot the nut is left hand threads.

I would tighten the nut with a torque wrench primarily so you aren't tempted to hammer on the wrench or ratchet. I really don't know what the appropriate torque is either, so I kind of set it to what it felt like coming off.