Wood Router as Spindle

This just goes to show that those accountants who control the quality of products are worth every penny they're paid. Sadly, it's the destruction of a good name. They (manufacturers) just don't GAF anymore.

You could (I know, I've seen examples of your work) machine the router housing end/bearing support section out of aluminum and make the part so the bearing can be swapped almost effortlessly (well simply), and use quality bearings intended for high speeds (not 10-for-$1 skate bearings).

"Wild_Bill" fired this volley in news:ogyBq.176105$ snipped-for-privacy@en-nntp-07.dc.easynews.com:

bad stuff....

Bob, et al,

I have a friend who owns a 5x9 CNC flatbed router. He chose from the beginning to spend $2200 on an Italian high-speed head and VFD.

He's got >12K hours on the machine now (seven years plus, 8 hours a day), and nary a glitch. It's still probably good for another 5 years, according to the manufacturer's specs. FWIW, it doesn't "sing" any more than it did the day he plugged it in.

LLoyd

Are you driving them harder? ie, have you optimized production to the point where they work harder and die sooner, or are the programs /feedrates the same and they really are just making them worse and worse (believable, just asking...)

Not familiar with the Bosch colt, but if the design hasn't changed much since I bought mine, there's a reasonable amount of metal (and replaceable parts) in a good old PC690 - which I use as the spindle in my CNC, but it's wood CNC, mostly, so....if you are not maxing the power on a (web says) 5.6 amp colt, an 11 amp PC690 should be plenty of power, and likely costs somewhat less than an 890... No plastic in the nose of a 690, as far as I recall.

I just started looking at high speed spindles on eBay. What drive do they need? I need to spin a 1/32" x 6" cut-off wheel to trim wire filled end brushes.

"Tom Gardner" fired this volley in news:raSdnW0E5rRQJUvTnZ2dnUVZ snipped-for-privacy@giganews.com:

Tom, most of them want a 0-400Hz VFD. Just match to the wattage of the motor.

LLoyd

They use a VFD. Single phase in and 3 phase out at variable frequency from

0-400 hz. There are a couple outfits who sell them as packages with spindle and VFD control. Most of the VFDs can be controlled off Mach 3 or EMC 2 with just a little figuring out.

No, I have definitely changed the way I machine over the last year. I tend to cut deeper at a much slower feed rate. My end mills last longer, and I remove more material per hour that way. It is possible that I might by pushing them too hard when I run a .125 end mill, but I would think the smaller ones would be more likely to break than put too much load on the spindle bearings. My calculations still show low fractional horsepower requirements.

I believe they are not using as good of bearings. The ones I replace the bearings on BEFORE they cook I get much longer run time out of.

I have been looking at the PC 890, but atleast one person reported that they had more runout.

I looked at the 690 too. I'll have to change my relays though for any larger router. I have 10 amp 48 volt relays controlling my spindle and coolant pump.

Thanks for the feedback.

I considered making an aluminum insert to replace the nylon one so its metal to metal which will transfer heat better. I also thought about making my own spindle cartridge with an off board belt drive, but figuring out which bearings to use is a real bear. Also weight is an issue for me. Neither of my smaller machines can really handle a 15 pound spindle assembly. Its one of the reasons I'm not running the stock spindle (that and the 10K top speed) on the Taig.

I appreciate the confidence, and the feedback.

Bob

Looking at a PC (computer) radiator and pump if I go that way for cooling my spindle(s).

How about putting better bearings in a brand new one, and logging the hours with a running time meter? If you can get a good idea of bearing life, change them as preventative maintenance when they hit around 75%. It's also possible that the nylon insert deforms, and makes the bearings gun hotter.

I had considered that. Time and distance is built into Mach 3.

and that I was trying to do, but they kept failing quicker and quicker.

I had not considered that.

Failure analysis was part of my job at several companies so I try to find the reason why we saw common failures.

If the problem lies with the plastic why not just machine an aluminum replacement. I would bet that since most of your failures are bearing related that if you made a replacement housing out of metal the bearings would last longer due to better heat dissipation and alignment.

That is one of the things I am considering. I haven't got my mind around the problem entirely yet. Making the entire bottom end would be way to time intensive and difficult, but if I can get the insert out and press in an aluminum replacement it might be worth the time.