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View Full Version : Update in 2008 - Porter Cable 7518 running hot



trakwebster
09-08-2008, 05:27 PM
There are a couple of threads from 2005 about Porter Cable router 7518 (or the motor 75182) running very hot, and the consensus is suggestive that (at that time) some really poor bearings were being sent out with Porter Cable.

For several years I've been running a smaller Makita router, but it began to somehow lose power and start bogging down, even with brand new cutters and using the same cutting speeds that used to work fine. I'd originally chosen the lesser-powered Makita because it's one of the quietest routers, and at that time there were neighbors in the same building.

However, now we have our own 1200 foot shop with its own shopbot room, so I figured it's time just to change to the often-used Porter Cable routers. I also had two of them sitting under-utilized in router tables, so I got one that had perhaps 5 hours of light use total, and installed it in the shopbot.

Immediately, the bogging down problem went away, plus we began getting cleaner cuts. However, the first time I did a bit change -- ouch! -- the collet (on the router side) was too hot to change bits using bare hands.)

Experiment showed that the heat was being generated from inside the router, not from the cutter, and that only a couple of minutes running (with no load) was enough to make it too hot to handle.

A search on talkshopbot found a couple of threads in the archives, and the same thing came up on via google search on some other forums.

In that shopbot thread, some recommended bearings were SKF made 6202ZZE/C3 & 6005ZZE/C3. The zz means shielded on both sides, and the c3 means extra clearance.

However, when I tried to buy these through my normal vendor (MSC at http://mscdirect.com) I had trouble getting the part numbers to match up. The helpy person at MSC did get SKF folks on the line, and SKF claims that they have a different designation that means the same thing. The manufacturer's part numbers in the MSC system show as 6202ZZJEM & 6005ZZJEM, and the claim is that the JEM means c3.

I've ordered them. We'll see.

The posts about this trouble were all back in 2005; however, that also happens to be about when I bought both my PC routers. Maybe it's no longer a problem.

There was also some suggestion that the Milwaukee 3.5 router was a better tool for the job, but I already have the two PC routers, so we'll first attempt to use the ones we have.

If anyone, now in 2008, has any additional info about this, please let me know. Thanks!

myxpykalix
09-08-2008, 07:57 PM
I too have the same problem however it is intermitent. Some times with just a few minutes running it is too hot to change then sometimes with hours of ruunng it is no problem. I have no idea why this is this way other than to know it is internal heat because the bit will be warm and the collet HOT.
I don't run it enough to figure out a pattern to the problem so when it dies i'll deal with it then.

woodman08
09-08-2008, 07:58 PM
I have just gone through the same scene except my 2 porter cable routers are brand new 2008 and after 30 min the collet was 65 degree c hot enough i could not change the bit and worried the next step would be router quitting.
I replaced the porter cable bearing (1 hr on the router --new) with the *****c3 bearing and today after a 3hour run at 19000rpm the router is just warm.Since porter cable has sold to black and decker ,the porte cable 7518 is not a router with a short duty cycle.Ver disappointing as I bought 2 new ones and i now have to fix them myself as black and decker say if they run they are ok

magic
09-11-2008, 03:19 PM
On the flip side, I've replaced the bushings in my router one time and I probably have 1600 hours on it. I also R&Rd a single cord from the router right into the control box. Most fires are caused by extention cords so I've replaced every cord in the shop with long ones that run from whatever tool it's coming from to wall sockets.

robtown
09-12-2008, 10:39 AM
I had a bad experience last year, I had to replace my second PC router (in 4 years) and bought a brand new one. It went bad in 14 days, took it back, and the next one did the same thing in about 28 days. Stone mtn power tools were very accomodating in exchanging the bad units. Thankfully that third PC router is still going strong.

curtiss
09-12-2008, 02:01 PM
Re: Ammeters
Seems like everyone needs one of these to keep track of how much load/ amps these tools are pullng.

This one goes to 400 amps, which would mean things are about ready to explode.

http://www.sears.com/shc/s/p_10153_12605_03482369000P

trakwebster
09-15-2008, 07:48 PM
Just a follow-up report about Porter Cable bearing-swap ...

The result, in brief: New bearings = cooler running.

My SKF replacement bearings arrived from MSC Industrial. The larger bearing had some engraving on the outer bearing edge that supported the MSC/SKF claim that the 'JEM' in part number meant the same thing as C3.

Neither my shop guy Patrick nor I had ever changed the bearings on anything, but I had an exploded view of the machine that came with the dinky user guide. We unscrewed a triangular bracket over the bearing on one end, a hex insert nut gets removed from end of rotor shaft, and unscrewed four screws that hold the black housing onto the cylindrical housing. It took some prying action with tiny screwdrivers, chisels, and then larger screwdrivers to separate the two parts, but apparently that *is* the thing to do.

Once done, the inner rotor was accessible on the end where black housing used to be. We could then place this assembly on a worktable, and my buddy used strong pliers over a protective coating made of multiple plies of duct tape to secure the end of this shaft against rotation, and the impact tool easily took the collet bolt off the other end, allowing the inner rotor to come out.

A bit of pressing and tapping removed the two old bearings, which we buried at sea with the proper ceremony.

A bit of pressing and tapping positioned the two new bearings, and we reassembled. Like dolts, we forgot about the brushes and basically bent their housings. Doh. So we took it apart again and put the brushes back where they would brush, and bent the housings back to approximately the correct position, which seemed to work. Once assembled, the shaft spun ok, and once plugged in, the router ran ok.

Reinstalled in shopbot and ran at slow speed without load, first for a few 30-second runs, then a few 1-minute runs, then a few 2-minute runs.

Previously, with old bearings, after two 40-second runs, the inner collet nut was too hot to hold, and after three 40-second runs, the inner collet nut was too hot to touch other than real damn quick.

Now, after three two-minute runs, the inner collet nut is warm, but I can hold it no problem, and it does not appear to get much warmer under operation.

Doctor, in spite of the surgeon's clumsiness, the operation appears to have been a success.

Costs and parts --

Impact wrench (1/2" drive) and 1 1/8" socket from Schuck's auto supply = $39.

SKF bearings from MSCdirect.com $10 and $18.
MSC part numbers 45667342 and 45666849
SKF bearing numbers 6202 2ZJEM and 6005 2ZJEM.

From earlier forum thread notes, the 2Z (or ZZ) means double shielded, not sealed, and the C3 or JEM means it has some additional clearance internally. Probably this internal clearance is what helps to keep heat down.