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...

Materials

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

Tools

T15 Torx driver

T10 Torx driver

Pliers

8" wire cutters

Another drill (you may borrow this from a friend)

Small hand saw, such as a coping or drywall saw

Utility knife

Dremel (optional)

Needle file

Sandpaper

Loosen the handle and foot screws about 1/2" with the T15 Torx driver.

Remove the red battery catch and spring and the black terminal cover. Set the terminal cover aside for later.

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.

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.)

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!

Cut the terminal cover along the red line shown. Smooth with a sanding block.

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.

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.

Insert the DeWalt battery once again, making sure it doesn't catch or snag and inserts smoothly into the contacts.

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...

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.

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.

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!

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.

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.

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.

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.

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.

With support installed all the way forward, drill pilot holes through the drill and support for two #4 or #6 screws. Install screws.

Your drill now stands proud, like it did 15 years ago. Hopefully DeWalt supports the 20V Max platform for a long time to come...