PC Router bearings..

[spektr]

Did the guys having hot collets on rebuilt PC routers ever get to the cause of the problem, I'd like to know what you found.

Thanks
Scott

[gerald_d]

Why not post the question in the original thread (http://www.talkshopbot.com/forum/messages/26/3961.html)?

[paco]

Hey Gerald! You look to me as a VERY GOOD forum supervisor/administrator!!!

[spektr]

Hi Gerald. I put it here because until Jay Pollards post, after mine was posted I might add, NOBODY has identified a root cause of the problem. ALSO since the other thread has rambled between the slipping collet theory, the bad electrical component theory, the too small feed wire theory, the bad replacement bearing theory and a couple others, I thought I should post my question simply. What is the root cause of the problem. Scott.

[ron brown]

Having problems with a PC 6902 type 2 router. I have the Porter-Cable part numbers but would prefer to source the bearings locally. Does anyone know the bearing numbers so I can get the bearings BEFORE I open the router?

Thanks,

Ron

[Brady Watson]

Ron,
You can get the complete parts schematic for the PC6902 here (http://media.ptg-online.com/20040708103125_690lr.pdf)

Not sure I understand your request...If you have the part numbers...why are you asking for the part numbers?

-Brady

[ron brown]

Brady,

Nice blinking link. Parts numbers one would use to order from "Porter Cable". Bearing numbers are the numbers on the bearing and are actual designations used by bearing manufacturors and bearing suppliers. These numbers are the ones on the bearing found inside the little bag that has Porter-Cable's part number.

The bearings will be "standard industrial parts" that PC buys, marks up for profit and then holds the ignorant hostage on availabity, delivery and cost.

If I can source them "local", I can be back working. If not, I am down several days.

Ron

[bjenkins]

Ron,

I have a couple inputs, but no real help. First, you can order a set of bearings from PC and have them ready before you tear down-- if you can limp along. Second, the bad news is that companies the size of PC can have bearings made for them by major bearing suppliers. They may be customize slightly or simply made with custom numbers so people can't use industry standard bearings. Bottom line, they may not be "industry standard". With that said, you may well be able to use the dimensions of the bearings to find a perfect substitute for the PC part number. What you already know (and said) is you can find that out by tearing it apart, but then you are down.

[Brady Watson]

I know you wanted to do it without a tear down...but even if you come up short on the actual bearing number, I am sure that you can mic the ones in the router and order them up from a bearing dist going off of measurements and tolerances alone. You may even be able to upgrade them to a ceramic-type bearing like Colombo uses.

Bud, I doubt that PC special ordered a bearing. In most cases, engineers follow the path of least resistance (although when I look under the hood of my truck, I have a hard time believe it...) & with most tool designers today using CAD to build the tool, chances are they make the bearing land castings to fit an off the shelf bearing...not the other way around unless someone severely messed up on the design team.

-Brady

[anderson_r_l@rallstech.com]

Ron
Just thought I would let you know, the PC does use off the shelf bearings. I replaced mine about 6 months ago, but can't find the receipt and can't provide the numbers, sorry.

-Ron

[ron brown]

update-

About Midnight the router became past tense. The fine folks at the store were happy, maybe, to warranty the tool.

Thanks for the help and moral support,

Ron

[bjenkins]

Ron,

When you do tear it apart, I would be very interested in getting the numbers and dimensions that you find. I would like to have a set of bearings waiting for my turn.

Brady,

You are right... most of the time. I'm an engineer (or was before I turned to the dark side of management) and have 28+ years of experience in product development. It is amazing how often high volume products are made with other than off the shelf hardware. It sounds like PC did the right thing, though.

[ron brown]

PC 6902 Bearing:

Lower - # 6262RS - 35mm X 15mm X 11mm
Upper - # 608Z - 22mm X 8mm X 7mm

I thought the upper bearing dimensions sounded familiar. They were. Skateboards and Rollerblades use the same bearing size.

Ron

[dingwall]

I guess that's a hint at the upper rpm/speed limit of my skateboard

[gerald_d]

The 608Z bearing inside a 40mm wheel, turning at 20 000 rpm, turns out to around 95 mph

[ron brown]

... Jörg Schläfli of Switzerland set the 1998 world record for high-speed Inline skating
while being pulled ... Schläfli reached a top speed of over 145 mph

Pulled that from a "Google" cashe....

Probably 85mm or larger wheels

Ron

[stickman]

Ron,

On little pebble, boulder, or crack and he'd surely made other records...

Jay

[bjenkins]

Ron,

Thanks for sharing-- it will give us a chance to get replacements before the end. Have you noticed any change of heat after the change. My PC ran hot for the first few hours when it was new-- it would really heat up the collet! Eventually, it broke in and runs pretty cool. I'm wondering if I will see a change before the bearings go.

[dingwall]

"The 608Z bearing inside a 40mm wheel, turning at 20 000 rpm, turns out to around 95 mph "

My wheels are 60 mm :o

[dingwall]

I used off the shelf bearings on my 7518 router last time around. They were the highest rated rpm bearings my supplier had. I was a little concerned because one of them was only rated for 18,000 and the other 23,000. I broke it in gradually and it ran cool fairly quickly. Lately though something - probably cooked grease - is insulating the balls from the cage because there is no electrical contact between the collet and the router casing. The bearings are starting to sound in need of a replacement after only about 6 months of use. Next time, I'm going to just order in the PC ones.

[gerald_d]

Sheldon, you prompted me to look at my FAG catologue. Ron, I believe your big bearing is a 6202 as opposed to 6262. The 6202 is 35x15x11mm.

"Limiting" speed for a 6202RS is 14000 rpm (it has rubber seals). A 6202ZR (with metal shields) has a limiting speed of 20000 rpm.

[rjguinn@optonline.net]

Does anyone know if ceramic bearings are available for the PC 7518 & where they can be purchased?
Thanks,
Jeff

[ron brown]

What I have learned in the last few daze...

The quality motor rebuilder - retired, I know suggested "6202C3VV" rated for higher speed than the RS Bearing. He also sugested the "C3" suffix on the lower.

As I understand it, the "C3" is an "additional clearance" bearing. All in all, it makes sence to find a knowledgable person - IF you can, and heed their suggestions.

Ron

[gerald_d]

VV is used in some countries, while ZZ is used in others, denoting non-contact shields (low friction). Some suppliers will say 2Z as opposed to ZZ. Therefore VV, ZZ and 2Z are all similar.

Maybe you want to take another look at this post (http://www.talkshopbot.com/forum/cgi-bin/discus/show.cgi?tpc=26&post=15703#POST15703)?

[dingwall]

Thanks Gerald.

[dingwall]

I've got about .007" of vertical play in my Porter Cable 7518 bearings. Any thoughts on how to get it out? The bearings were replaced about 2 months ago.

[gerald_d]

Sheldon, is that .007" while your router is at normal operating temperature? My gut feel tells me that the vertical play is normal (and necessary) while the router is cold.

[dingwall]

.007" is a lot, I can hear it when it runs. At least that's what I attribute the extra noise to compared to when the bearings were new with no play.

I will check it today after 1/2 hr or so of use.

[dingwall]

I checked the play after the router had warmed up and it's still .007".

I've heard of people stacking an O-ring or wave washer on top of the top bearing race to compress it down.

[bruce_clark (Unregistered Guest)]

Sheldon,

Without actually disassembling a PC router myself, I would be hesitant to use rubber o-rings because of heat and friction.

What I WOULD use is something called a wavy washer. It is spring steel that has been corrigated to provide "thickness" but can collapse under a severe load (like themal expansion). Once things cool down or the load is removed, the washer goes back to its original corrigated shape.

I am sure that you can find them at most "good" hardware stores or bearing stores. Also some motor rewind shops have them as they use them a lot on electric motors (expecially stepper motors).

Good luck,

Bruce Clark

[dingwall]

With the help of my friend Byron Olsen, we were able to take the vertical play out of the router arbor today. The fix was simple, just loosen the set screw that expands the shaft inside the top bearing, push up on the collet while pushing down on the top bearing, hold that in place while tightening the set screw. It takes 4 hands, but it's quick and easy.