[Horseman]

Well I just burnt up the bearings on another Bosch 2.25H router. I only had this one for 1 week and only ran it for about 12 hours total. I had a couple jobs that took a couple hours, but I was really careful to make sure it was not overworked or running too fast for too long. That is my second Bosch router since I got the Gorilla CNC router in October. I am going to look at getting a different router. Maybe try the Porter Cable 7518 and see if it lasts.
Any one else have any suggestions?

[Andre' B]

smart ass answer(nuts)
http://www.fischerprecise.com/pdf/spindles/SD-4084.pdf

Just for kicks I got a rough quote on one of these a short while back.
spindle, drive, and chiller about $35,000

[ger21]

http://cgi.ebay.com/WATER-COOLE-MOTO...item56376f0bf7

[stevespo]

The bearings are shot after 12 hours? I'd call Bosch. You should get many hundreds of hours of use out of that router. We had several of those in the shop for hand held use and they always struck me as well made, durable routers. What are you cutting, what feed rates, and what type of tooling?

I've had a couple of PC 890 series on my CNC. They have held up pretty well, although most of my work is pretty light duty. The bearings on the last one had a break in period where they ran really hot for a while, then after some time (MANY hours) they started running cool. This was not what I expected, but according to PC tech support is correct behavior for the new bearings they are using.

I've switched over to a Chinese spindle, and I'm very happy.

Steve

[cheetahcnc]

Porter Cable 7518 is a good router. How is your dust collection?

[Horseman]

I have it hooked up to my shops dust collection unit and there is very little dust. I have been doing some V-carving in plywood. 0.2"deep, 70in/min, 16,000 rpm, with a 3/4" v-bit. Also some solid alder cabinet doors for some 3D animal cut outs running a 1/4" mill bit at 100in/min, 16,000prm, and then a 1/4" roundnose bit. These cuts took about 6 hours total. Other than that it has been small 3D and v-carve jobs that took around 20 min. each.
I need a router that fits a 3.5" clamp. General Tools told me if I modify to go to a bigger router that the weight may cause some deflection and mess up the gantry. I am still in contact with General and they are trying to help me out. I have been using routers for over 12 years and never seen them die so fast. It has to be something with the way they are worked on the CNC. But I was really carefull to not over work this last one.

[ger21]

The 7518 is over 4" in diameter. I've been using an 892 for a few months now with no problems.

[stevespo]

From your description, that's very typical work. Was the 6 hours continuous or total time for the carving? What specifically are you seeing with the router? Noise in the bearings? Excessive runout? Lots of heat?

What are you running for acceleration values? Bumping that down might put less strain on the bearings.

What's the weight difference between the 7518 and the 1617? Maybe 3-5 lbs? If that much extra weight is going to cause problems with the gantry then maybe the problem has to do with the rigidity of the CNC machine. Make and model?

Steve

[wildwestpat]

I use both Elu and Trend routers with no problems for many hours of continual cutting. Suggest you contact Bosch as they may have bought a batch of duff bearings or changed their assembly process in either case you should be in line for free replacement routers.

Good luck with getting Bosch to come clean and sort out your problem.

Pat

[woodman08]

I have a lot of experience running both the bosch 2.25hp and the porter cable 7518.
The bosch is a good router and you shouldn't be having problems i switched to the 7518 and black and decker have taken over porter cable and i feel they have gone to a cheaper bearing .
I have done a lot of bearing changes and it boils down now that the porter cable runs fine at 12000rpm and a bit of 16000 rpm but if you run it higher you will go through bearings temp at the collet @16000 rpm for 2 hrs is at 97 degrees f @ 12000 is just warm ,so cut back on feed but run slower in rpm.
Soindles are good but who is going to fix a chinese spindle ,but a router lots of people can replace the bearings ,i do my own now with jigs i had made to ensure a proper bearing replacement

[Bugsy36]

Woodman hit it right on the nose! The bearings in the routers are not intended for continuous running. As a matter of fact, most router bearings are rated at 12k. The manufacturers call it "calculated risk" because most units will not run for extended periods as on a CNC.

I run a new but older PC7518 but rarely run over 10k (adjust and compensate with feeds instead). I have a spare set of ceramic hybrid bearings (rated at a true 23k) sitting in a drawer for the day the bearings bit the dust.

No matter what you buy, you ought to plan an upgrading the bearings from the get-go (IMO). The darn thing will also run quieter too

[woodman08]

Its was a real shocker when black and decker came back to me during all my bearing problems and said the 7518 was not for continuous use ,there is not another router on the market .
i have looked and i did find one close in HP it was red the store owner asked what i had and told me to go home and keep fixing the7518 as the router i looked at they stretched how they talk about hp.
So slow it down and keep fixing it ,mine at 12000 rpm runs 8.56 amps,i monitor the current and temp (have 30

[ger21]

The red one was probably a Milwaukee. Those are the only two fixed based 3+HP routers made.

[woodman08]

yes it was a Milwaukee and the tech said not to replace the 7518

[ger21]

I've read lots of posts from people who prefer the Milwaukee. But I have a 7518, so I can't tell you the difference.

[Horseman]

The 1st router started to smoke and get very hot. This one so far has just started making a lot more noise and start to get hot before I shut it down. The one job was about 6 hours total with a few stops for bit changes and stock changes. I am going to try running the router again today to see if it will start to smoke or not. I will slow the router down and make sure the table is running at Constant Velocity.

[CNCMAN172]

Horseman,

I also run the same Bosch router and the bearings died in about 12 hours of use. I was shocked to see it die so fast. I got a replacement one because I figured I got a lemon, but think the bearing can not handle the speed. I dialed mine down to about 12K and have only been cutting maybe 3 hours on the new router. I also made sure I did not restrict the air flow out of the nose of the router. I had been using a deverter to help keep the air from blowing the chips all over the place and this might have cased excess hear to build up even though I did not block the vents. I also purchased a 4HP water cooled spindle from Ebay with a VFD, which I will be putting on shortly. I need to build a mount because they did not have them on ebay. I am going to make something similar to the ones you see offered my K2CNC, I even sent them an email as they recently started selling mounts that fit the 2.2KW 80mm water cooled spindles. The spindle is heavy duty and uses Germany bearing according the the ebay ad. I have read on the zone others are happy with the water cooled units and run them for extended periods without any issues. I did read one post where a guy finally killed a water cooled unit and it needed bearings not sure if he got those fixed or not. Anyway, I think it is clear the Bosch can not hold up to hours of continuous use on a CNC machine without some kind of upgrade in the bearings. By the way I pulled mine apart and wrote the bearing numbers down and searched ebay and found the bearings on ebay from a store called something like USA bearings & ??? anyway they bearings were cheap actually made in China and had about .012 runout when I put them on the bosch. I then ordered the real ones from Bosch which are expensive about $15 each and they worked good and the runout dropped to .002. So what did you actually do? thx

Russ
CNCMAN

[Horseman]

I have just slowed everything down. I keep the router speed slow around 12K and try to keep my feed rates at a point that the router will keep up with. So far I have been having no further router problems running the machine this way. I also have the constant velocity button turned on now too as was recommended by Steve Stevenson from General. I have been using the router a few hours each day for last couple months now without issue.

[bsteers]

A great replacement bearing is the NSK 6004VVC3E. These are rated to run at a much higher speed than the ones that come in the bosch.