Not Looking Good With New (Used) PRSalpha

[gerryv]

Feeling pretty glum:( The electrician just got our new (to us) 2009 PRS alpha wired up yesterday and things are not looking very promising for a machine that the previous owner advertised as having very little usage.

1. The biggest worry is the 4 HP HFC spindle. Without cutting, after the recommended warm up cycle and ensuring that the empty chuck nut was tightened it is about a half as loud as a PC router and worse, a lot of vibration being transmitted to all parts of the machine. Not much different with a good quality tool mounted. At some speeds the two yellow safety bars were acting like a big tuning fork, grab them and the noise changes. Tech support was very helpful but basically said take it to a good motor repair shop but don't hold out much hope. Any advise from anyone who has actually had one of these serviced successfully?

Finally, we decided to cut the 2" dia holes in the plywood base for the vac. system. Yuck. There sure is a problem with the spindle I guess.

2. This may just be us doing something wrong but on my good ol' PRT alpha and PRS standard Buddy, there were no surprises when we closed the keyboard command window (K). with this machine when we close it (by clicking the window close X, the spindle stops. Probably something obvious but having used the earlier machines very little and the command bar and settings very seldom am I overlooking the obvious?

3. I'm kind of thinking at this point that it might also be a good idea to clear all the previous users settings and go to whatever the current recommended actors settings are. Is there a simple way to clear these and default to factory settings before doing an update to the SB3 software and firmware?

Thanks much guys, feeling pretty "had" right now. Thank goodness it's not a machine with less than great tech support and user forum.

Best,
Gerry

[cnc_works]

Gerry, I have one possible cause. Are you sure the collet clicked home in the nut? My first run on my spindle I had symptoms much the same, but had read no directions that told me to seat the collet before tightening. Seated it and symptoms went away. Hope it is that simple for you.

[srwtlc]

Gerald,

For #2, if this is the first time for you with a spindle, it does turn off when the Keypad is closed. You can leave the keypad open and toggle switch 1 to turn it on and off. You can also change whether the closing of the Keypad will automatically turn the switch off under VD (KeyPad Switch AutoOff). The spindle however will always turn off when closing the Keypad. On your older system with a router, you may have been used to being able to turn the router on off at will.

For #3, issue a UR to reset. Follow the prompts and choose the default settings file for your machine.

On the spindle, maybe it's just the top bearing. Cheaper and easier to replace. Can you feel any slop at the collet end or any roughness?

[Brady Watson]

My advice would be to get a quote from SB on the spindle motor ONLY. You can keep the VFD & cable. I have heard nothing but horror stories and disappointmet from a number of people who had their spindle rebuilt by spindle distributors. They NEVER sound as quiet as a new factory fresh one, and by the time you add up all the costs, you can buy a brand new spindle motor for only a few hundred bucks more.

I rebuilt mine with help from a friend who has been rebuilding motors for 40 years...and his dad before him. There were a lot of little tricks in the disassembly and assembly that I didn't know about that have to be correctly executed. The bearings alone cost around $500-600 because they were ceramic hybrids in a matched set. Inner & outer races have to be clocked to each other properly...the correct grease has to be used (which they don't give you) etc. I know a few that had their 3HP Colombo spindles rebuilt and it cost them somewhere around $1200-1400. You could buy a new one with VFD and 50' cable for $2500...with wrenches, starter collets etc.

Put it aside. Buy a new motor. If you want to investigate later and look into rebuilding it yourself, start with the top bearing. If it works out, you have a spare. If not, then you probably learned something in the process. You could also buy a Chinese type spindle for several hundred, but you'd be on your own when it came to integrating it with the SB control.

-B

[Ajcoholic]

Sorry about the problems... That hurts when you expected things in good shape.

Before you buy anything, it might be wise to talk to a big Canadian machinery supplier, like Akhurst (where I bought 99% of my heavy equipment) who also deal in large CNC and parts & service, and all makes of spindles. They actually have a booth at the IWF here in Atlanta, I'll talk to the guys tomorrow.

[Ajcoholic]

Just spoke to a few of the guys from the HSD booth, for the series of spindle we use they recommend not overhauling, but replacement.

[gerryv]

Hi Andrew,
That does seem to be the prevailing wisdom . I really appreciate you're taking the time to ask.

Too bad tool changers cost so much, this would be the time to upgrade. Ah well, I'm going to review all the good feedback I got and then do what needs to be done in the next couple of days. I've got nearly $20k into it now so can't leave it idle.

Donn, Scott, Brady & Andrew, Thanks so much.

Donn, if that's what it turns out to be I'll be asking you what your favorite restaurant is!

Scott, Glad to know about the keypad difference - one less thing to worry about. I'll be looking into your other suggesting as soon as I'm back to the shop. Christian at SB say's it almost sounds as if they might have dropped it in a bad way and bent the shaft.

I guess that would explain why they said it had not been used in a few years. Hmm... Do these things dry up if left unused that long in their vertical position?

Brady, thanks for the heads up on repairing, that would be a real downer that I don't want to risk. If I'm not lucky enough to escape with Donn's check, I'll be calling Shopbot for a new one. Their tech support has been there for me so it's fair that I call them first.

[richards]

Unfortunately, a "spindle" us usually considered to be a "throw away item", meaning that when it stops preforming as expected, it is just thrown out and replaced with another spindle.

When I upgraded my PRT-Alpha to use a spindle, I always worried that "someday" I would have to replace the spindle; however, I carefully warmed up the spindle everyday and I carefully programmed the cuts so that "drilling" was minimized. When I sold my PRT-Alpha, the spindle seemed to work just as well as it worked the first day that I installed it.

One of the things that MUST be done, if you're using your machine to make money, is to include in your expenses the cost of everything that will need to be replaced. Adding a dollar or two per hour to your basic charge would cover the cost of replacing the spindle every few years. Be sure to run a spreadsheet to see how much you should be charging to keep your shop running for as long as you want to stay in business.

In my other life, as a computer programmer and "efficiency expert", I required my customers to run a spreadsheet and to allocate all expenses properly so that they knew the true cost of producing each "widget". Those who think that their only cost is the cost of materials and the cost of "cutters" will loose their business. Those who account for all overhead, including the cost to maintain and repair each piece of equipment, will always have a "top-notch" shop with all equipment running as if it had just been installed.

One very successful business owner told me that he amortized all equipment using an 18-month schedule. He said that if a piece of equipment could not be justified using an 18-moth amortization schedule, then that piece of equipment was too expensive for his shop. He dealt with photo equipment costing well over $100,000 per piece. I've always considered him to be wise.

Most people seem to think that a piece of equipment will last forever. The Shopbot comes close to doing that, but it does need an occasional repair. If you talk to an accountant and properly depreciate your equipment, you will have a price structure that will sustain your business for as long as you care to be in business.

[gerryv]

Much truth in that Mike. Unfortunately, the unsustainable pricing offered by folks who don't take these factors into consideration often has a detrimental effect on others trying their best to make a living. Thanks kindly.