Rockler Clamp-It Corner Clamping Jig Review

You might have seen the Rockler Clamp-In Assembly Square before, a handy right angle fixture that can be used to assemble cabinets and other types of work. It’s rigid and made from high impact polycarbonate for strength, durability, and accuracy.

If you’re wondering how the Clamp-It is used, just consider the name. If you clamp two boards or panels to something that is nice and square, they will become nice and square to each other.

Now, there’s also the Rockler Clamp-It Corner Clamping Jig, which is a new add-on product to the Clamp-It Assembly square. While you can use Clamp-It squares with many different types of clamps, the Clamp-It Corner Clamping Jig is a quick and low-profile one-piece clamping solution.

The combination of a Clamp-It square and Clamp-It Corner Clamping Jig is meant to securely hold 2 panels or boards at a 90° so you can fasten them together, without the need for additional clamps or accessories.

The jig has two Acme-threaded clamping screws with soft non-marring pads. With the Clamp-It square in place, they combined fixture can handle material up to 1″ thick. Once nice touch is that the glass-filled polycarbonate base is raised 3/4″, so you can use a 1x dimensional scrap pieces for additional workpiece support.

I had already purchased one Clamp-It square back when Stuart sent me on a $200 shopping spree, and Rockler was kind enough to send over a Clamp-It Corner Clamping Jig to test out. In addition to 2 Clamp-It Corner Clamping Jigs, Rockler sent over two more Clamp-It Assembly Squares to use for the review.

Unboxing the Jig

First things first, I had to get rid of the annoying sticker applied to the base of the jig. It wasn’t just going to peel off, they stuck it on good. With a judicious application of heat to soften the sticker, it peeled right off. Then I just used a little isopropyl alcohol to remove any sticky residue left.

You don’t have to remove the decal, but I wanted to.

There were 2 screws protruded from the bottom of each base, and I wondered what they were for. The screw heads caused the clamping jigs to rock a little bit on a flat surface, forcing me to think about their purpose.

Before I removed the sticker, I first needed to remove the screws from the base. It was then that I realized that the base had threaded inserts. So I looked at the packaging, and sure enough the screws are intended to be used to secure the Clamp-It Assembly Square to the base, so it becomes a solid one-piece assembly.

When the screws are used properly to hold the Clamp-It Square in place, they don’t protrude from the bottom.

The only reason not to screw down a Clamp-It Square is if you want to move between the Clamping Jig and separate clamps very often.

Using the Clamp-It Corner Clamping Jig

Overhead Storage Project

I previously discussed building a storage rack above my bench in the Rockler Tapered Countersink review. I used the two Clamp-It Corner Clamping Jigs to assemble the rack before I hung it from the ceiling. I learned that, despite the implied ease of use, it can take a little bit of adjusting to get the boards clamped in place properly.

I found that if I’d try lining up and clamping both boards at the same time, the joint wouldn’t line up correctly. After practicing on a few corners, I discovered a procedure that seemed to work well:

First clamp the board being butted up against in place, and then bring the other board into place and clamp down. Finally, unclamp the first board and readjust it so the corner is flush.

I also found that it is important to make sure the boards rest flat on the base. Downward pressure helps to keep them there while you turned the screw clamps. If you don’t do this, the top and bottom of the joint might sometimes go out of line.

I may be making it sound like these clamps are difficult to use, but once you figure out the above techniques, it becomes second nature and the corner clamps actually make assembling corners much easier.

You don’t have to use the jig on a tabletop surface either, it works just as well unsupported, as you can see above where it’s holding a cross member in place while I drilled holes and drove some screws.

Little Library Project

I also used the corner clamping jigs to assemble the other project I mentioned in the Rockler countersink review, the unofficial Little Library.

I assembled the house in two steps, first I clamped it together so I could drill the countersunk holes, and then I re-clamped it so my daughter could glue and screw it together. While I could have just done it in one step, this allowed me to setup the project in the shop on my own time so that when my daughter came down to help, I could keep her busy assembling the house.

I tried a few different configurations to test the clamps. For drilling holes in the back, I attached both sides to the house with the corner clamping jigs and rested the assembly on the two sides so I could drill the holes downwards using the table. This only required one extra clamp to span the back and hold the tops of the sides in place.

To try something different, I stood the house upright and attached the two sides to the house on the bottom with the corner clamping jigs and I used my extra Clamp-It Assembly Square to secure one side on the top.  The assembly was rigid enough that I only needed one small clamp to keep the second side in line.

Final Thoughts

There’s not much I could find to dislike about the Clamp-It Corner Clamping Jig, except maybe the price. One Rockler Clamp-It Assembly Square will run you $13 and one Clamp-It Corner Clamping Jig costs $28. So to just to clamp one corner you’re talking $41. That’s a lot of money for a specialty clamp, especially if you need four to form a complete square.

Another option is to use just a pair of these Clamp-It Squares and Corner Clamping Jigs. Clamps always seem to work better in pairs.

It comes down to whether you clamp enough assemblies to justify the cost. While these Rockler Clap-It squares and Clamping Jig do make assembling boxes much easier, there might be better ways to spend the same money, such as on good parallel jaw clamps.

But if you already have a well-stocked clamp rack, and the budget, there is just one another reason why you might not want to buy this, and that’s if you mostly work with stock that’s more than 1-inch thick.

Buy Now (Clamp-It Corner Clamping Jig)
Buy Now (Clamp-It Assembly Square)

Thank you to Rockler for providing the review samples unconditionally.