Modding a Porter-Cable PCB420SA bench sander?

[Brandon Thill]

I'm trying to find a hobbyist bench sander and of course at <$150 they all appear to be rebranded versions of the same one, the most popular probably being the Wen. But the Porter-Cable PCB420SA seems to be a bit of step up: more powerful motor, direct drive vs plastic! gears. It does have some common complaints, but I'm wondering if they would be mostly solvable by modding? For example the dust impeller seizes, but I'll be using DC so I'll just disconnect that. Possibly a starter cap issue, perhaps a replacement with a quality part from Mouser/Digiikey would solve that? (anyone know specs?) And the other is the motor burning up which is either related to the cap issue, or drag. So maybe break it down right away and make sure everything rolls smoothly and is well lubricated?

What do you guys think?

[Marc Jeske]

Where are you located?

There may be other options.

Marc

[Brandon Thill]

Denver. I don't ever see anything terribly impressive on craigslist here.

[Marc Jeske]

Bingo !

This is what I was hoping to find for you.

9" disk 6x48 belt.

I highly suggest you look into this.. I have had two of them over the years and they are a great bang for the buck.

No plastic gears or plastic anything, all cast iron, and says USA on it.

Night and day compared to what you are currently considering.

The guy is asking a fair price.

Marc

https://fortcollins.craigslist.org/tls/d/craftsman-disk-belt-sander-on/6486973343.html

https://www.youtube.com/watch?v=5SI_9xUiD74

https://www.youtube.com/watch?v=AXHra0LzDkI

https://www.youtube.com/watch?v=Ml4L3oXnApE

[Ole Anderson]

That Craftsman on CL is the one I have. I used the heck out of it sanding aluminum when I ran a business out of my basement. For what I was doing, it was a bit short on power so I installed a 1 hp TEFC motor on it. I didn't like the disc, and seldom used it, had it been solid steel, I would have kept the disc option on it. I made a fence so I could use it as an edge sander. Still one of my go-to machines.

[Brandon Thill]

Does that Craftsmen have good DC?

[Marc Jeske]

I seconds 29-35 in the link below you can see the DC nipple on backside of disc housing.

https://www.youtube.com/watch?v=AXHra0LzDkI

It is by memory AFAIK approx 1 1/2".

Otherwise, no... but certainly something can be easily DIY made at the bottom of the belt, on backside.

BTW - The belt also tilts up to plumb.

Very solid machine... GREAT bang for the Buck. Marc

[Ole Anderson]

Does that Craftsmen have good DC? Probably 95% the way I have it set up. I added a pic in Post #5.

[Brandon Thill]

I went back and forth on what to do, and in the end bought the PC. I wanted a true compact bench sander that didn't take up it's own floor space. It will be mounted to a spin-o-rama bench I'm working on that will have a couple other tools mounted. Here are some of the mods I've done.

First, to reduce drag I pulled the impeller out of the housing and detached the belt drive:

https://i.imgur.com/738TEjW.jpg
https://i.imgur.com/ye7noNB.jpg


Then to solve the capacitor and most probably the related motor issues I replaced the caps with much better ones. Here are the OEM parts, start cap and run cap, respectively:
https://i.imgur.com/r7DrNmu.jpg
https://i.imgur.com/eN3bL9e.jpg

A 20uF film and 100uF electrolytic. I replaced them with Class A and B lifespan film caps from mouser: https://www.mouser.com/ProductDetail/EPCOS-TDK/B32332I6206J81?qs=sGAEpiMZZMv1cc3ydrPrFyAEDdQ02CGe ReMknfQRF8o%3d and https://www.mouser.com/ProductDetail/KEMET/C870CG36100AA0J?qs=pqRVuuzkf6aojq2BqdFF2w%3d%3d

The 100uF is pretty big, preventing installing the metal bottom plate. Lot of ideas you could do here, but since this thing is not ventilated very well (another cause of motor failure?) I attached a good HVAC filter with metal duct tape to cover the bottom while providing ventilation:

https://i.imgur.com/Jdd3yYI.jpg

I also detached the belt and checked that the motor spun freely. Felt real good so I put it all together and ran it for 10 minutes and adjusted the belt. I also widened the dust collection slot a bit on the belt guard, really limited here by dimensions though. Next project will be to smooth the tables and flatten the belt frame.

Anyway, these were all cheap and easy mods, that I *hope* will prevent all of the known issues with this otherwise nicely built budget sander.