[ssutton]

Found out today that I have worn out another set of bearings on my 1617. I do cut a lot of aluminum so I expect to lose some bearings now and then. Bearings seem to last about 75-100 hours of operation before failure. Anybody with high time routers cutting heavy loads that have held up, Porter Cable, Dewalt, etc., looking to see if I should switch to another router. Not ready to go the route of a spindle yet.

Thanks
Scott

[freecncplans]

The bearings are easy to replace if you get a bearing puller. I have gone through probably 10-12 of these routers in the past 4-5 years and I am now starting to rebuild them, but we only cut wood with ours. I think we get about a year out of them running them 40-60 hours a week. They work good and Amazon has about the best price on them.
Sean

[dmalicky]

The first question is what factor is limiting their life. In your case it sounds like heavy loads, possibly made worse by high speeds which increases temperature (vs, for example, simple contamination).

Routers use industry-standard deep-groove ball bearings. For better life, first I would look for a router that uses a lower bearing with a higher "dynamic load rating". The 1617 uses a 6004 (as do many routers in that class) which has a dynamic load rating of 9400 Newtons or 2110 lbs:
http://www.podshipnik.ru/docs/nachi_dgbb_10-25.pdf
For ball bearings, the first two numbers designate how 'heavy duty' the bearing is: 60=extra light, 62=light, 63=medium. The last two numbers designate the bore size: 04 = 20mm, 05=25mm, etc. For example, a 6205 would be 'light' and 25mm bore, and has a dynamic load rating of 14,000 N, 3150 lb.

E.g., this Makita uses a 6205 (but it's not as easy to mount in a CNC): Makita RP2301FC Parts List and Diagram : eReplacementParts.com

Even better, possibly there is a router out there that uses a double-row angular-contact bearing; those part numbers start with a 5, e.g., 5204. These have much higher load ratings: a 5204 is 20,000 N.

You could also try a 6004 bearing that
- is from a top manufacturer (SKF, NSK, FAG...): they will likely have better QC. There are lots of good 6004s on ebay.
- is a higher precision ABEC class #: runs cooler, probably lasts longer. Routers are probably ABEC 1. ABEC 3, 5, 7 are next.
- has more internal clearance: runs better when hot, but a bit more runout if not. I think routers use a C3 clearance; C4 is next.
- has ceramic balls: runs cooler, faster, under more load, for $$.
- is full ceramic: $$$

Or, now that you know how long it lasts, get a bunch of 6004s and replace them on a schedule.

[ssutton]

Good information, thanks to both of you. I do run a full RPM when cutting because I use single flute aluminum bits and they run better wide open. Also this necessitates that I move as fast as possible so I do not build up heat in the bit, a lethal bearing combination I am sure. I use an industrial bearing supplier at work, I will contact them and see what they have/recommend for this app.

Thanks,
Scott