installing quil on mill drill

[spro]

I hope it is okay to note a certain point within a great reply. If the shaft is bent and the bearing is still tight, the bearing will rack to angle when pulled out. These bearings are cheap but the housings aren't and the race could fairly core out the housing by extraction. Not saying it will. Sets of feeler gauges used to be right inexpensive.

[elewayne]

i've been out of town for a few days. Are you talking about when I pulled the bearings and shaft from the cast housing? That might have done something to the housing hole? Would I check that with and inside dia, feeler gunge? I'm not sure yet, but I suspect any bend in the shaft is ahead of the bearings. Hopefully any bend is in the 1/2 dia end of the shaft. Its weakest part. Kind of wondering how I'll get those bearings and shaft pressed back in that hole, without damaging the casting somehow.

[Lewayne]

I got back in the shop today and pressed off the bearings on the shaft in question. Put it between centers. That should be the most reliable means of measurement, right? Checking it out the pictures shows the ares where it’s the most out and I’m hating a reading of about 2.5 thousands. Would you even try to correct that small an error or am I wrong, and that’s really a big error. I thought surely it had a lot more runout than that.

[Lewayne]

Picture of my set up.

[Harold_V]

Before you accept your readings, you should run the indicator on the tips of the centers. They may or may not be true. That said, if you're turning the shaft by hand, not rotating the headstock, it won't matter if that center runs true, or not, but the live center in the tailstock rotates with the part, so if it isn't true, or if the centers in the shaft are not concentric with the OD of the part (not uncommon), the readings you get may or may not reflect the true condition of the shaft. What reading do you get when you place the indicator at the very right side end of the shaft? Does it run true?

Where the bend is may play a role in the readings you get by this method. If it is bent abruptly at the shoulder (to the left of the contact in the picture you posted), when the left side is in alignment, the shaft that protrudes (unsupported, and, I expect, where the handle mounts) will display a lot more run-out, so, yeah, the couple thou you see may be in bad need of being eliminated. Look at it this way. It's straight, or it isn't. If the centers aren't the problem, in this case, it isn't straight.

One other thing you might think to check is if the hole in the handle is straight and concentric. If you place it on a close fitting shaft (like the one it came off) and spin it while the shaft is stationary, does it run true? If you see wobble, it may be part of the problem. It's not uncommon for parts to be made by folks who are not machinists (machine operators), and they often lack the necessary understanding to make things properly. I've seen a lot of that in items made in China. I'll also note that the import items have improved considerably in quality, in general.

H

[Lewayne]

So the worm gear, the black one, that’s what you call it right? Shows wear. Considering all the way around. It even has a burr Thad seems pressed into the teeth. Any thoughts on this being the real issue, for some reason?
I thought for sure I’d find a bent shaft, but that’s not materialized as the cause.

[Lewayne]

[attachment=1]D0C8D0B8-FC6B-4CAC-9219-84B300AB09B3.jpeg[/attachment
Sorry, posted it twice by accident

[elewayne]

thanks Harold. After checking, the tail stock center is very true. But the head stock center is about 5 thousandth off. So I kept the head stock still and just hand turned the tail stock center. that reads only about 1 thousandth off in the same place as the photo. not 2 thousandth. So I'm willing to say the shaft is pretty straight and not causing the binding as I suspected.

Sorry, I posted the photos from my phone, so things are a bit out of order and I posted the photo twice. still getting the hang of the photos on this site.

[pete]

For some reason your worm wheel is showing definite signs of bottoming out on the worm. That will cause binding as well. You need to investigate what's causing that. It's not impossible that area was relieved at the factory to provide clearance, but if not then you have a problem.

[Harold_V]

What pete said. If the relieved area on the gear was generated on purpose, there shouldn't be any signs of contact with the worm at the root of the worm. It shouldn't make contact there at all, not ever. Gears, like screw threads, should make contact at their pitch diameters, never at the roots or crests.

Assuming you can't see signs of contact on the worm (not the gear, which is the one that appears black, not brown), it's safe to assume that the parts do not make contact where they shouldn't. There will be distinct rub marks, maybe even some signs of galling and rounding of corners, if they contact where they shouldn't.

At this point, it appears to me that you should be checking the bore of the handle to determine if it is concentric and at a right angle. If it isn't, the handle will appear to wobble as it is turned, and it may well bind on the opposing face, especially if the face itself is not true to the bore in which the shaft rides.

In general, your entire problem may be caused by numerous errors in machining, not one single cause. That would not surprise me, not at all.

H

[spro]

I agree. This fine feed adjustment to the quill, is unlike my experience. Mine would be suspended by another bearing outside the worm. It appears that only a center point screw was to locate it.

[Lewayne]

Thanks for the observations. I’ll clean up the gears for better inspection and photos. I really can’t believe this mill has had this problem from the factory, you can’t even use the drill press handles to operate the quill. Something must have happened to cause a misalignment. Quite possibly something I did in the re-assembly process. I just don’t know what yet. But since the shafts seem to be okay, I’ll put it back together I guess. Then start looking further.