Introduction: Convert Porter Cable Model 884 Drill to DeWalt Lithium-Ion Battery
The Porter Cable 19.2V cordless drill was one of the first to truly rival a corded drill in power and performance. I bought mine in 1999 and have used it for all manner of DIY building and maintenance projects. Its size and heft, combined with excellent balance, make it excel at driving deck screws and even lag bolts without torquing one's wrist around. However, Porter-Cable abandoned the platform in 2002 and parts are hard to come by. With one dead battery, one half-dead and a charger that's getting flaky, I replaced it last winter with a DeWalt budget cordless. While the new drill has more power, is half the weight and half the cost, it likes to twist around when turning screws and its clutch is barely firm enough for deck screws, much less lags. Apparently DeWalt wants you to buy an "impact driver" now...Not wanting to spend another $90 for a driver that won't stop once the screw head is flush, I thought to myself, "What can be done to bring my old drill back to life?"
Like today's lithium-ion tools, and unlike most tools in its day, the P-C 19.2V batteries insert along a slide carriage. I noticed the slide rails and terminal position of the DeWalt battery were remarkably similar to the old P-C...and the polarity was identical. I thought, This could be a really easy mod, and since I'm using the existing slide mechanism, it should hold up well. So here's a way to resurrect your old P-C 19.2V tools...
Step 1: Materials and Tools
One Dewalt 20V Max lithium-ion battery. 3.0 Ah or larger is preferred.
1/4" x 1-1/4" lag screw
1/4" flat washer
Two #6 x 1/2" flat head screws
4-6 oz. ballast weight (optional)
Construction adhesive, such as Liquid Nails
T15 Torx driver
T10 Torx driver
8" wire cutters
Another drill (you may borrow this from a friend)
Small hand saw, such as a coping or drywall saw
Step 2: Loosen Screws
Loosen the handle and foot screws about 1/2" with the T15 Torx driver.
Step 3: Remove Catch & Terminal Cover
Remove the red battery catch and spring and the black terminal cover. Set the terminal cover aside for later.
Step 4: Relieve the Slide Rails
Re-tighten the handle screws. Each slide channel on the drill body must be deepened about 1/8" to allow the DeWalt battery to slide in. The rail must also be thinned slightly near the entry point. Carve away the plastic using a saw & utility knife or a Dremel. As you work, test-fit the battery often to ensure the movement is not too tight and not too loose.
Step 5: Check Insertion Depth
Continue carving and test-fitting until the battery contacts can slide forward to the terminal mount, and the battery catch is pressed against the foot plate. (The picture shows a corner cut away from the terminal mount; you do not actually need to do this.)
Step 6: Modify Electrical Contacts
Note: Beyond this point the mod is not reversible. You will be converting the drill's female clip to a male plug, essentially.
For reference, position the drill's terminal clip over the DeWalt battery contacts. The clip's outermost contacts neatly line up with the battery's B+ and B- (positive and negative) terminals. The inner contacts are superflouous and will be clipped off. Use the clipper to score the inner contacts close to the contact base, then break off with the pliers. Then, use the pliers to straighten each outer contact. Work each contact until it lines up perfectly straight with the clip inside the DeWalt battery. Take care not to bridge the contacts with any metal tool!
Step 7: Trim Terminal Cover
Cut the terminal cover along the red line shown. Smooth with a sanding block.
Step 8: Re-assemble Electrical Terminal
Once again, loosen the handle screws. Insert the little circuit board with the copper terminals into the original groove on the holder, then re-seat the holder in the drill. Tighten screws.
Step 9: Trim and File Contacts
Snip each contact back so that each extends 5/16" past the terminal cover. Use the needle file to round off the sharp edges. You want them to look like the contacts on the P-C battery or a DeWalt drill, rounded so that they don't wear the battery clip.
Step 10: Insert Battery
Insert the DeWalt battery once again, making sure it doesn't catch or snag and inserts smoothly into the contacts.
Step 11: Squeeze the Trigger
The drill has power and will run! Yippee! You can stop here if you wish, but there are a couple things you will want to do to finish the tool:
1) Add a catch to keep the battery from falling out
2) Add a front support and optional ballast weight.
Let's start with the battery catch...
Step 12: Mark and Cut Drill Foot
Mark the inner edge of the yellow battery tang on the drill body. Cut away the plastic with the hand saw. The tang should fully extend with the battery inserted.
Step 13: Drill Pilot Hole
Drill a 7/32" pilot hole at the base of the handle, as shown. The seams in the plastic create a natural start point. Angle the drill 15-20 degrees as shown so that the lag screw head will mate with the battery's yellow tang.
Step 14: Insert 1/4" Screw
Insert the lag screw until there is a 1/4" gap between the head and the cut-away body. Test fit the battery. If the battery's tang doesn't have a good grip on the head, add the washer. Glue the washer in place with strong construction adhesive or super glue.
Insert the battery and tweak screw depth until you get a good fit. The catch is complete!
Step 15: Front Support: Remove Battery Screws
These last steps cover the front support. I decided to make this out of the dead P-C battery's case.
Remove the six case screws with a T10 driver. I didn't have a T10 driver so I used an Allen wrench and, when that stripped, a small flathead screwdriver. You, however, should use the right Torx driver.
Step 16: Remove Battery Cells
Lift off the battery cover and dump out the cells inside. Dead Ni-Cd cells must always be recycled and never thrown in the trash. Re-seat the cover and replace the end screws. Leave the two middle screws out.
Step 17: Mark Cut
With the DeWalt battery inserted, place a Post-It note slightly forward of the battery. This marks where the battery case is to be cut. Remove the Dewalt battery, insert the empty P-C battery case and transfer the mark.
Step 18: Cut the Case
Cut completely through the case at the mark. A table saw gives a nice clean cut but pretty much any saw will work. You will keep the smaller of the two pieces.
Sand the keeper if necessary. Slide onto the drill to check fit.
Step 19: Optional: Add Ballast
The new battery is lighter than the old, despite having considerably more capacity, and sits further back on the drill body. Adding weight to the front support helps restore the original tool's weight and balance. I found five 3/4" flat washers (the biggest Home Depot sells) did the trick. Secure these with construction adhesive.
Step 20: Secure Support
With support installed all the way forward, drill pilot holes through the drill and support for two #4 or #6 screws. Install screws.
Step 21: You're Done!
Your drill now stands proud, like it did 15 years ago. Hopefully DeWalt supports the 20V Max platform for a long time to come...