Spindle wear & tear

[beacon14]

I've been using my HSD 2.2 HP spindle for a little over a year and a half, and I suppose I push it pretty hard compared to some. I've probably cut around 1,000 sheets of material, mostly melamine, some plywood and MDF, plus hours of solid wood machining. I may have even banged into a few things over that time but would rather not get into specifics.

Lately I noticed a slight change to the sound produced when the spindle was first turned on. Once warmed up it sounded and cut fine and was still producing more than acceptable cuts. But I've always wondered in the back of my mind how many sheets can I expect to get from this small spindle?

So I was going away for 2 weeks and figured it would be a perfect time to send the spindle in for a bearing replacement/preventive maintenance. Not being able to locate any kind of US based service for HSD I sent it to Precision Drive Systems in North Carolina. They sell and service Columbo spindles but their web site advertises servicing all makes and models and a phone call verified they would work on my unit.

Apparently they had a very hard time getting the case open - they spent several days alternating between the freezer and the oven (?!?) to get the locking ring/retaining ring/some similar gizmo to come off. Then they sent me a quote for $700 to replace the bearings, which I approved.

Finally heard back from them this morning and he tells me the spindle is "dead". They've put two sets of bearings in and can't get it to run without overheating! I told him I was a little shocked since the spindle was working just fine when I sent it to him for preventative maintenance.

He (the manager) seemed a little surprised to hear that it was working when it arrived (the paperwork clearly stated "bearing replacement/preventative maintenance"). He said he'd tell the tech's to give it one more try to get it working and get back to me tomorrow.

So if you're still with me, do they owe me a working spindle? Had I basically used that one up? Is it normal to have so much trouble dismantling or servicing a spindle? I thought I was doing the right thing by sending it out before it self-destructed. I know nothing lasts forever but I thought replacing the bearings would put it back like new.

I'm keeping an open mind since he still has to get back to me but just wondering what people's thoughts are. Meanwhile it looks like I'll be putting the old PC back on the machine to get a few parts cut this weekend until this gets sorted out.

[coach]

David,
they spent several days alternating between the freezer and the oven (?!?)
That would be a concern for me. Can you actually put a spindle in the oven? What other abuse did it take?
I would get a detailed bill and see if they put the oven and freezer operations in writing. Then I would figure they wrecked it.
If you heat metal it changes the structure and I bet it even changed the actual dimensions of the case. Maybe not much but maybe enough...(how hot I would wonder?)...I welded aircraft engine components for years and I know heat treat operations were critical.
David

[bcammack]

Wow. That's not the sort of story I expect to hear about PDS.

Did ShopBot have no recommendations regarding a service center for the HSD spindle? If they're offering them on their product, I'd be shocked if they didn't have support info on them at least to the point of telling you where to have them repaired.

[beacon14]

He did not actually say oven, but he did say "freezer", "heat up" and "several days going back and forth". I guess that's a trick they use to get stuck parts loose without beating on them. I suspect they also put it in a vice and beat on it to some extent. He mentioned something about "milling down some high spots" on the bearing seating surface, and that there might still be a couple of flat spots from when they took it apart.

I had called ShopBot and they said they just sell them, I'd have to go to the manufacturer for service. I did a web search but HSD is in Italy and I could not find any USA based support or authorized service.

Anybody at the show this weekend care to stop by HSD and ask them where to get service in the US?

[Brady Watson]

David,
I don't let anyone work on my spindle (after hearing numerous horror stories from others in the field). I did get some assistance from a friend that rebuilds industrial motors for a living, but other than this, I rebuilt my Colombo myself. I feel that most 'mechanics' these days really don't love what they do...and I don't want that energy (or carelessness) going into the heart of my main money making machine.

You can get parts for your HSD (AND service!) from http://www.ekstromcarlson.com/ (Click here for HSD page) I bought my Colombo bearings from them in the past. I'd put money on the small top bearing being the noisy culprit with your spindle. The 2 bottom bearings are usually OK. The top bearing is nothing fancy - It's most likely an ABEC-7 version of a GM alternator bearing, like the one in my Colombo.

Going forward, if you need another brain to sort things out & make a decision, give me a ring. While there are some important things that you have to pay attention to (like correctly aligning the bottom bearing pair to each other) - it's ain't rocket science. I'm confident that YOU can do what needs to be done.

-B

[harryball]

On this topic... is it better to proactively replace bearings or just wait until they begin failing? Not flying apart but cuts not acceptable and play in the bearings.

Are there any numbers on how many hours a spindle can cut?

My 4 HP HSD has begun to sound slightly different but otherwise runs without a problem. Cuts are good, no play, solid running.

/RB

[tmerrill]

Robert,
I don't have any experience with spindles, but after spending my career in maintenance at power plants, one of the worst things you can do is let electric motor bearing go until failure. To predict failure, the electric utilities have implemented a very comprehensive preventive maintenance program consisting of periodic vibration and sound measurements with computer analysis - far beyond what a ShopBot owner could do. So in my opinion it is best to be proactive. I think David did excellent by looking ahead, seeing a two week window and arranging for his service.

I might add that as any bearing fails, you loose tolerances and gain friction and heat, which increases the rate of failure. To the tolerances that spindles are constructed, I would want to be very proactive in getting one serviced. I very much agree with Brady - if you can do it yourself you are going to get a better job. I could tell you many similar stories as David's, some with shops we had done business with for years, where the skilled people moved on or retired, their replacements lacked skill and caring, and all of a sudden we had a multi-thousand dollar motor that was junk.

One recommendation would be to obain a stethoscope designed for listening to machinery. Grainger and MSC used to carry them as possibly Harbor Freight and other smaller suppliers would. Find out where on your spindle you can hear the bearings best. Mark these places with small pieces of electrical tape and get into the habit of listening to your spindle on a routine basis. Try to keep the conditions the same, such as rpm and operating time. You will be amazed at what you can hear and should be able to pick up on increased noise pretty well.

Tim

[tmerrill]

David,

Found this reference for HSD USA. Not sure if you were able to find it or if it helps at all at this time.


3764 SW, 30th Avenue
33312 Fort Lauderdale
Hollywood - Florida, USA
Phone +1 954 5871991
www.hsdusa.com
supporthsdusa@hsdusa.com

[ron brown]

It is far better to change bearings a bit early. Bearings will start heating a long time before showing any other signs of wear, in my experience.

As Brady said it isn't rocket science. I will also say some folks are just not mechanically inclined. I've never had a problem or fear of tearing into machinery. I have family members who have trouble changing the oil ... at the quick lube shop down the street.

Ron

[beacon14]

Well, miracles do happen. He called me back to tell me that somehow they were able to get it running within spec, and it's on it's way back to me. He said they had ways to fix things within a few microns, and they did some more tweaking of some sort. I'm certainly relieved.

Brady, thanks for offering to help but I'm not sure I want to get into that kind of repair. I've always been better at engineering than mechanics. I can usually figure out why something isn't working but I've always considered car repairs (for instance) way beyond my pay scale. Without at least some specialized equipment, considerable knowhow, and reasonable experience, or at least "a friend that rebuilds industrial motors for a living" I think it's more cost-effective for me to outsource this sort of maintenance and repairs.

Tim, thanks for the link, I probably saw that page and missed it, it's in pretty small print. I'll call them first next time.

Just to close the loop, the guy I spoke with confirmed that the upper bearing was "half burned up" and had apparently overheated at some point. I do have a problem with my cooling fan sticking and not turning on until I poke it with something. On occasion I've cut a couple of sheets before remembering to check it. Hmmm...

Thanks for all the input. I do think preventative maintenance is worthwhile (I take the car to Jiffy-Lube every once in a while). I also think in a perfect world I'd be using a larger spindle to do what I do, but I'm limited partly by the electrical requirements. I think I'll start putting a couple of bucks in a jar for each sheet I cut, to get ready for the next time.