KO LEE Surface grinder questions and pictures

zaaephod

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Hello again everyone,

I picked up this K. O. Lee CO. Surface Grinder, the badge is missing, but looking at images online, I think it's a S718 6" x 18" ? It is hydraulically and manually controlled. It's VERY dirty, but pretty much rust free.

I'll start with my question first: Is there any oiling provision for the spindle on this type of machine? I sure don't see any.

So far, everything has been very stuck, it has clearly been sitting for a while. We hooked up a 3 phase 220v VFD to the hydraulic pump motor, and eventually got it to spin. The oil is in dire need of replacement. At first, the X and Y axis would only move in one direction. We eventually pulled off the cover, and removed the valve assembly for the Y axis. The two valves were not rusty at all, but stuck in the bore. A bit of percussive maintenance freed them up, and after reassembly, the Y axis now moves as it should. I'm sure something similar is the case in the Y axis, but I haven't opened that part up yet. The Y axis rack has been destroyed, as well as the X axis half nut, but those are things I can make or purchase. Back to my question, the spindle turns free, and I'm ready to test the motor, but I'm afraid to run it before knowing if the bearings need oil. I'll post more pictures I took from under the cover later on.

Thanks!


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If you cannot find a place to put oil, then it probably has a ball bearing spindle, greased for the life of the bearings. Test if very carefully, feeling and listening for gritty feeling or noise. There should be ZERO noise or grit, or the spindle is probably toast. If the motor drives the spindle from the rear directly, then there is probably a Lovejoy type coupling between motor shaft and spindle shaft. If there is backlash noticeable when turning the spindle alternately and quickly in opposite directions, then you need a new coupling. They are cheap, so it might be smart to change it "just because." If there is a very slight amount of cogging when turning the spindle by hand, then keep turning it over every time you go past it, and see if it improves or gets worse. To get a spindle professionally rebuilt is BIG buck$, and doing it yourself is fussy business and not recommended, but it is an old machine, and if it is already bad, then what do you have to lose by trying? Sometimes just new bearings can cost big money ($500+), but, again, there are workarounds, and if the parts are already bad? I rebuilt the plain bearing spindle on my SG, and it now works fine...

Tell us about the ways (and maybe show some pics) when you take the table off, it likely lifts right off...
 
Thanks for the reply, Mr. Korves.

We found some time between work today to take the X and Y axis apart. One good thing about terribly greasy things is, they usually aren't rusted solid. So far, everything came apart without incident. I can't read tea leaves, nor machine ways, and I don't have the equipment to measure them, but I'd say that visually, they're not terrible. If there's one I'm worried about, it's the one marked "20190811_201127.jpg", it seems like it's got scoring, but I don't see any evidence of it on the saddle way. It seems like it's on both sides of the bottom V groove, as if it's intentional for oiling. It looks terrible on the picture, but you can barely feel it.

I think I do see some wear on the extreme ends of the Y travel. The X traverse rack is toast, but I thought that if I could find a replacement rack, I can mill down the old one and make something work. If all else fails, I'm pretty sure I could make a complete replacement. This one is cast iron, and, my guess is, the reason it's ruined is the cylinder that should keep the hand wheel in place worked free, so the pinion gear wandered into the teeth a little at a time, eventually chewing up the whole thing.

The Y axis has what I'm going to call a hydraulic decoupler. When the hydraulic pump is engaged, fluid pressure disengages a spring loaded bronze(?) half nut that keeps the hand wheel from engaging the threads on the hand wheel shaft. The bolts on this have come loose, and it has been just bouncing around on the hand wheel shaft threads. I forgot to take a picture of this half nut, but at first glance, it seems relatively okay. You can see the top of it in the pictures. The threads on the hand wheel shaft however, are pretty sad, as you can see. I'm thinking of making a replacement shaft; I have experience single point turning threads, but never an acme thread, which I believe this to be (flat top teeth, not rounded like a Whitworth thread?).

One other thing of note, I see oil passages along the X axis ways, but I have never seen oil come out of them when the hydraulic pump is running. I was under the impression that the hydraulic oil was also the way oil, and I have no evidence to the contrary, since the machine doesn't seem to have any oiling provisions, Gits oilers, nor a one shot oiler. I haven't fully delved into the inner workings of all the hydraulic system yet, as we were chased off by a thunderstorm.

Anyway, on to the pictures. I'll get back to the spindle soon*.
 

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The table ways (X axis) seem to have lots of wear, the "X" shaped scraping marks were probably put there to deal with a stick slip issue, but now they are largely worn through. Yes, the Z (in/out from the column) lead screw is toast. You could buy some Acme threaded shafting and then make a nut to fit it, does not need to have high precision Z axis travel for most uses in a hobby shop. You could just put it together and see if it meets your accuracy needs on real projects. If not, tear it down again and do some more...
 
Thanks again for your input on this project. It's a tough choice, there's a LOT of cleaning to be done if I wanted this machine in my shop, but I'm hesitant to do all of that without being able to do some test grinding. Of course, that would mean dismantling the machine again, but now that I've done it, it's relatively easy. If I can get the X axis ram going both ways, I may just put it back together and run it purely on the hydraulics, just for testing. I'll ponder my options and post back later.
 
McMaster Carr sells rack and pinion stock. I replaced mine on my Boyer. It was a exact fit minus the mounting holes. They have the gear too.
 
McMaster Carr sells rack and pinion stock. I replaced mine on my Boyer. It was a exact fit minus the mounting holes. They have the gear too.
Thanks, I think I could make that work. The gear seems fine to me, it's just the rack that's destroyed.
 
<I thought that if I could find a replacement rack, I can mill down the old one and make something work. If all else fails, I'm pretty sure I could make a complete replacement. >

Looking at a S718 with an obvious rack/pinion issue, before I buy, curious as to what you did for a replacement rack. Specs? Source? Thanks
 
Post 6 McMaster Carr sells racks and the pinion gears. Fairly cheap just need to match them up.
 
I replied to dep5 in a personal message, but just to put the info out there, my machine is still sitting in storage, I've had other projects that need to get done first, however, my plan is to mill off the existing worn teeth, drill and tap some holes, and mount an off the shelf replacement rack, probably from McMaster as Cadillac suggested.
 
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