The Bottom Line
That being said, the versatility of the jig and the exceptional clamping system make this dovetail jig is a very good value for its middle-of-the-road price.
- Very sturdy, well-built aircraft aluminum base
- Clamping system with sandpaper wood grabs work quite well
- Versatile - cuts numerous styles of joints
- Difficult to fine-tune, and must be fine-tuned each use
- Manual is in need of improvement
- The unit is very sturdy and strong, and the clamps securely hold the workpiece without marring the finish.
- Adjustments should be made in tiny increments. Even a quarter-turn can turn a tight joint into an overly loose one.
- When opening the box, be certain to remove all of the styrofoam, as the bits and guide bushings are beneath the packaging.
- Be certain to fine-tune the jig each time you use it. Reliance on the previous session's settings could be disastrous.
- The router bits for this unit are not standard sizes, so you'll likely have a tough time finding third-party replacements
- The dovetail bit & straight-cutting bit require different collars, so when changing bits, don't forget to change the collar.
Guide Review - Porter-Cable 4212 Dovetail Jig Review
While the 4212 does do a fine job on all of the dovetail styles mentioned above, it does take quite a bit of massaging to get there. And don't rely on the manual to a huge help with the job. Instead of walking one through the features and functions, including how & why the jig or depth guides should be adjusted in a specific manner, the subjects seem to be covered in a rather haphazard manner. For instance, I never did read at what depth to set the depth gauges for any particular thickness of stock. I figured it out through trial and error with a few test pieces. The pictures helped more than the text.
Aligning the jig & cutting the tails of my through dovetails seemed easy enough. Simply insert a backer, center the workpiece, adjust the offset guide (for repeatability), install the dovetail bit & collar on the router at the desired depth and cut the tails. Next, flip the template, change the workpiece, switch to the straight-cutting bit (and a different collar) and cut the tails. Now, test to see if the pins & tails fit.
In my case, they were quite tight. So, I adjusted the template what I thought was ever so slightly (1/4 turn on the adjustments) & re-cut the pins and tails. The resulting joint was so loose that it had to be discarded.
After trial and error, I was able to get the fit just right, but switching bits & collars took a long time. I then noticed that when I loosened the knobs that hold the template, I was also loosening the adjustment knobs behind the template. Unfortunately, this appears to be a design issue, preventing consistent repeatability.
As such, be certain to always run a test piece before cutting your project workpieces. Better safe than sorry!