mynameisusername
Plastic
- Joined
- Oct 16, 2015
I finally got around to attempting Forrest Addy's suggestion to convert a Porter Cable 444 Profile Sander into a light-duty power scraper. I put about $80 CDN into this project, but found the results disappointing. The data, however, is useful for the ongoing community effort to find an accessible alternative to Biax power scrapers.
In essence, the linear mechanism isn't sufficiently rigid to allow the scraper to dig in and then shovel off material. The rigidity of the blade tang was not an issue. The cutter was salvaged C2 carbide ground to the usual specs: -5º rake, 100mm radius.
Addy suggested modifying the plastic adapter to receive scraping blades while retaining the sanding functionality. I don't recommend this because it's already too flimsy. I machined a holder out of aluminum to gain rigidity, as well as make a more robust clamping surface. I would recommend machining away much more material than I did because the resulting holder may have been too heavy. The plastic holder, with profile inserts, weighs about 120g, but my aluminum holder weighed 210g. Trying to adjust the counter-weight didn't help. The sander is extremely unpleasant to hold in use (I'm a cabinetmaker and have tried numerous sanders, and the Porter Cable 444 is the worst I've held), but the additional balance error made it a bit worse.
This same balance error also increased the strain on the plastic housing mounts. Within 10 minutes of use, the plastic housing had cracked at the anchor point for the linear motion mechanism. I did not attempt to correct the balance error because the idea does not seem worth pursuing further.
At the time of posting, I haven't received the speed controller to reduce the tools RPMs by at least half. I'll update the thread after I'd tried it.
In essence, the linear mechanism isn't sufficiently rigid to allow the scraper to dig in and then shovel off material. The rigidity of the blade tang was not an issue. The cutter was salvaged C2 carbide ground to the usual specs: -5º rake, 100mm radius.
Addy suggested modifying the plastic adapter to receive scraping blades while retaining the sanding functionality. I don't recommend this because it's already too flimsy. I machined a holder out of aluminum to gain rigidity, as well as make a more robust clamping surface. I would recommend machining away much more material than I did because the resulting holder may have been too heavy. The plastic holder, with profile inserts, weighs about 120g, but my aluminum holder weighed 210g. Trying to adjust the counter-weight didn't help. The sander is extremely unpleasant to hold in use (I'm a cabinetmaker and have tried numerous sanders, and the Porter Cable 444 is the worst I've held), but the additional balance error made it a bit worse.
This same balance error also increased the strain on the plastic housing mounts. Within 10 minutes of use, the plastic housing had cracked at the anchor point for the linear motion mechanism. I did not attempt to correct the balance error because the idea does not seem worth pursuing further.
At the time of posting, I haven't received the speed controller to reduce the tools RPMs by at least half. I'll update the thread after I'd tried it.