Porter Cable 75182 repair, or just trash it?

[Ted D]

My ShopBot was 10 years old when I bought it 5.5 years ago. I don't know if the router motor (3.25 hp Porter Cable 75128) was 10 years old or not, but I've used it regularly for the last 5.5 years. This week it was noticeably louder and I could see blue sparks through the vent holes in the housing. I swapped it out with a spare from my conventional router table and it's obviously smoother and quieter.

My question: Is it worth trying to rebuild the old motor or just scrap it? I assume it needs new brushes, but is there more to it than that? Even rebuilt, will it be worth using or is it likely worn to the point that it has excessive run out?

If anyone has had one professionally rebuilt I'd appreciate contact information and an approximate cost.

I've ordered a replacement already and if anyone's interested I got it for $285.99 delivered from "Factory Authorized Outlet". There's a $20.00 discount until the end of the year and free shipping. They didn't collect tax for me, but YMMV on that. I bought the one I just put in the ShopBot for $255 or so back in 2011. I guess $30 isn't too bad over 4 years.

Thanks.

[John David]

It probably ( most likley) just brushes on the router. I have changed mine 3 or 4 times.it easy todo and cheap to replace . Could be a good choice for a backup router.

John David

[cowboy1296]

MY router eats brushes for breakfast. I do mainly 3-d so i am sure thats what causes that. the sparks are a good indication that the brushes are bad. Chances are they will always spark a little but when a little turns into a lot.............

[jTr]

Recently bought one of these motors with an Excalibur router table, and found excessive run out- as in you could see the wobble as it idled down. Researched on line and found this is normal- mine measured .004" and there are examples showing that up to .006" run out is common.

I followed advice posted by precise bits .com, picked up their ER style nut and collet set for the Porter Cable, and things are much smoother now. Not a cheap kit, but incessantly pounding your bits, workpiece and the motor itself is senseless.

Kit included ER-style nut and matching wrench, 1/4 and 1/2" collets plus some cotton applicators and collet care sauce. A thorough dissertation on collet care and use is included, so I'll be more attentive to the spindle on the shop bot as well. Not bad for under $100.

So- while tending to these motors, I'd recommend you take a look at their offerings.

jeff

[cowboy1296]

oh yeah i use their collets and have 3 different sizes.

[Brady Watson]

Keep your old PC router & rebuild it. It is better than the newer ones.

Replace the bearings and brushes yourself. There are videos on how to do this on YT.

-B

[Ted D]

Thanks everyone. I found a video and got the brushes out, they're obviously worn. The top end has a lot of slop in it, but odd it doesn't seem to be the bearing itself, but the bearing is loose in the housing. When you shake the whole unit you can hear it clunking as it goes back and forth. The bottom seems relatively tight, but doesn't sound very good. I didn't find a video on bearing replacement for this exact model. I did find a three part series on a B&D, which is probably similar. It's about 30 minutes though and I don't have the patience to sit through that. Maybe I can find a written tutorial.

I looked at the collets at PreciseBits.com. So is the recommendation just to get the collets and nut rather than the full blown ER conversion?

Honestly, I cut 3/4" baltic birch into parts with relatively low tolerance 99% of the time. Certainly I would like things to run smoother, but I'm not building rocket ships.

[jTr]

Ted,
Took me a few minutes of browsing there to realize you could buy just the nut and collet set for an entry-level upgrade. While it is tempting to go all the way and convert to what I believe they referred to as an ER-16 system with shaft and all, I was not ready to double the investment in my router motor for a simple router table. Price to performance comparison, the low-grade upgrade was just right for my needs and budget. The fact that you do not have to tear it down may be one of the most appealing aspects of the collet/nut set.

Were I using this on the CNC, I'd likely spring for the $300+ primo kit, but think it is wisest to do so with a fresh motor, as opposed to during a re-build. $600 in the heart of the cnc for spindle-like accuracy is very reasonable, considering the thousands saved over a spindle investment.

I was truly stunned to see the motor so heavily used on Shop bots had such run-out, and wondered how good it could be for 3-D carving. I assume many others using the PC motors have upgraded via precise bits, but thought I'd bring up the topic in case some were not aware of this option.

jeff

[Ted D]

The motor I just put in has relatively low hours on it as it's been in a traditional router table with little use. I have a brand new one on the way to replace it and act as backup for the CNC, which is what I bought it for in the first place. It sat in the box for a couple of years before I bought the table and lift to make some use of it. The motor with bad brushes will be the second line back up, or to use if I have some really rough work to do with a router (I have a base around here somewhere).

I think for my purposes the "entry-level upgrade" will be more than adequate. I'd like to do some 3D carving, but just don't have the time right now.

Thanks to everyone for the advice.

[Ted D]

As a side note, over the last two days I've been surfacing a very warped walnut slab that's 30" at it's widest by 10' long. I took from 1/2" to 3/4" off of it in no more than .08" passes with a 1.5" bit. About half way through is when I decided the router motor wasn't going to survive the job and swapped it out. I reset my home position several times in the process as my table is only 4'x8' so I was moving the slab back and forth in the X to reach all of it. After I finished I checked my X/Y zero and X was only off 0.015" and Y was still at 0.000". I recently upgraded the controller and motors and this kind of repeatability is amazing to me considering what I had before.

[cowboy1296]

after all of the years of abuse that i have put my router through i just went to amazon to order one. I will put the old one on the shelf for back up. they had just reduced the price to 279 but when i went to check out there was a 20 dollar promo discount, so i got it for 259, plus free shipping.

[cowboy1296]

If you need to call precise they have always been very helpful and will spend the time with you that you need.

I do primarily 3-d and have never had anything other that a porter cable router. I dont know if a spindle would give me better quality or speed, but i do find it hard to believe that it would.

But here are some 3-d's to look at that were done by the pc router.http://www.talkshopbot.com/forum/attachment.php?attachmentid=26775&stc=1http://www.talkshopbot.com/forum/attachment.php?attachmentid=26776&stc=1http://www.talkshopbot.com/forum/attachment.php?attachmentid=26777&stc=1http://www.talkshopbot.com/forum/attachment.php?attachmentid=26778&stc=1

[Ted D]

That's the third time this month I bought woodworking stuff a week before the price went down! Amazon collects sales tax from me so it would have been $275 and change so I only lost about $10.00 this time. Frankly I'd rather give some company $10.00 more than let the yahoos around here waste the $20.00 in tax I would have paid.

It's hard to argue with the results. Nice work.

[Ted D]

I found a pretty good tutorial on bearing replacement here http://reproductionwoodworks.blogspot.com/2011/12/how-to-replace-bearings-in-porter-cable.html I DID NOT remove the brushes or mess with any of the wiring like he says though. I only pulled the brush springs back and the brushes themselves and left everything in place.

After getting everything back together it runs again. However, it still has the "rattle" in the top end. The brand new router motor I bought as first line back up does not rattle when you shake it. I think the top bearing housing (cast aluminum) is just worn out. EReplacementParts.com (my source for brushes and bearings) doesn't list this part. When I have time I'm going to try to add some shims between the bearing and it's housing.

[cowboy1296]

Anyone ever have this happen with their brushes. I put my last brushes to the test and when i checked them, i am surprised that the router was even running. So i broke out some spare brushes and back in business. The new set had very little use when I finished a 3-d carving this morning. When i went to start a v-carving tool path the router would not even start, even doing the F1 command it would not start (i may have listed the command wrong but it is suppose to start the router). I tapped the housing with a hammer and boom the router started. I could see all kinds of sparking in the housing a good indicator that the brushes were bad. I removed the brushes and they looked almost new. I re-installed them and started my v-carve file and the router is running just fine with no sparks. Now can anyone explain to me whats going on?

[jTr]

Take a look at the area of the armature that the brushes ride on. Replacing brushes can make a huge difference, but there is a limited amount of wear the armature can take. If you've had multiple sparking/arcing incidents, this contact area may be worn out. Seems to take longer for brushes to break in as this surface wears over the years. You may simply have dislodged some debris by removing and replacing, hence the better performance.

You should at very least clean that surface each time you replace brushes. Best to use a pencil eraser, as it will gently pull burned/scorched soot off, revealing more clean copper surface for brushes to ride on and optimize conductivity. If deep gouges are present, the motor may be past its usable life span, as it looks like about $185 is going rate for a replacement armature.

jeff

[cowboy1296]

Thanks and i never thought about the pencil eraser and will use that next time. My first motor was still performing well, but i did get a new one and put the old one on the shelf not that long ago

[Tom Bachman]

My repair place completely rebuilt my 7518 for 187.50. When I took it in for them to put together I asked and she said that the "worst case scenario" would be $187.50. So no matter what was wrong with it that is the most I'd pay. By the way, when I took them this router motor, is was completely torn apart, as the guy I bought the router from though he could fix it, tore it apart and gave up, and bought a new one.

[cowboy1296]

That pencil eraser advice might very well be good advise. I just tried it and quiet a bit of black material came off on the eraser. Now each time i change my brushes i will user the eraser as well.