General Tools & Instruments 840 Pro Doweling Kit
- Six Dowel Sizes in a Single Jig
- Placement not Limited to Center
- Soft Metal Jig
- Single Hole
- No Spacer for Multiple Holes
Don’t waste your money on this tool, it is fatally flawed with almost no redeeming qualities.
The particular jig that I am reviewing is about 30 years old. After looking at new ones in the store, it is clear that little has changed.
- The jig can be placed at a customizable distance from the face of the board.
- The current kit includes:
- 3 brad point drill bits: 1/4, 5/16 and 3/8
- 30 dowel pins: 10 of each 1/4, 5/16 and 3/8
- 3 drill stops: 1/4, 5/16 and 3/8
- 6 dowel centers: 2 of each 1/4, 5/16 and 3/8
- 1 hex wrench
- Craft Glue
Spending around $30 on a doweling jig is a pretty good deal. The single size non-adjustable Rockler Doweling Jigs run about $20. Paying $10 more for multiple dowel sizes and the ability to easily adjust the hole location is more than reasonable.
Ease of Use
Positioning the jig at a specific location is difficult. There is an index line for positioning the jig along the length of the board. However, there is no index line for determining how far away from the face of the board the hole will be placed. Instead, the jig relies on a ruler stamped into the guide rail. As you can see in the image to the right, it is difficult if not impossible to determine how to read this ruler.
This is unfortunate, as the ability to define the distance from the face of the board to the hole is a feature of this jig. Self-centering jigs by definition limit you to placing the hole in the center. Similarly, simple jigs like the Rockler Jig come predefined with a set distance from the face and require modifications to use customized distances.
Additionally, the only means by which you can index subsequent holes is using a tape measure and the indexing mark on the jig. Some nicer jigs include a bar or spacer that offsets subsequent holes a fixed distance from already drilled holes.
Here is where the Jig really suffers. Whatever metal or allow is used for the drill jig is absurdly too soft. In my case, the jig didn’t even last a full project before I broke the 1/2 inch hole. As you can see in the image to the right, the 1/2″ hole is no longer round. The oval cut is on the underside of the jig and was caused by hitting a hard knot in the wood. I stopped drilling as soon as it happened, but it was too late. I will keep the jig around for the other sizes, but the 1/2″ size is unusable on my jig now.
As noted above setting the depth from the face of the board is highly inaccurate. Additionally, the index line on the jig is so wide that I would say at best accuracy is +/- 1/32″. Finally, there is a small but significant amount of movement in the jig that results in further inaccuracies.
Given the lack of durability, accuracy, or any means to index subsequent holes off of the first hole, I don’t have much use for this jig. Luckily I didn’t pay for it, but I would feel bad for anyone who did.