DoubleGroove™ Close Fit Bench Dogs
A perfectly engineered complement to the Parf Guide System
To create the most accurate 20mm worktop, you need the best fitting 20mm dog. That was our design intent when we set out to create the CF-Dogs or "Close Fitting" Dogs. Most 20mm dogs on the market feature a 19.90mm body, which fits well in the Festool MFT/3 but can result in needless play when used with the Parf Guide System or a 20mm worktop made with precision by CNC router. Instead, our CF-Dogs feature a 19.98mm body providing a near zero clearance fit when inserted into a 20mm bench dog hole.
A Smart Add-On to the Parf Guide System
Watch Peter duplicate 20mm holes with precision using 20mm bench dogs for drill guide registration in Part 2 of his Parf Guide System video.
The introduction of Peter Parfitt's Parf Guide System (PGS) now provides the everyday woodworker a means to create highly accurate 20mm patterned worktops to near-CNC accuracy. This system relies on a drilling jig that is indexed to the table via two 20mm bench dogs. Because our CF-Dogs fit into this drill guide and indexing holes with near-zero clearance, you will achieve more accurate hole positions compared to using a traditional 20mm bench dog. This is why our DoubleGroove™ CF-Dogs are the perfect add-on for those using the Parf Guide System.
The usefulness of our DoubleGroove™ CF-Dogs is not limited to those using the Parf Guide System. Many woodworkers are creating custom 20mm tops with CNC routers capable of machining holes accurate down to ±0.002” (0.050mm). With this kind of accuracy, many discover that their traditional 20mm bench dogs now fit with too much play; a problem that can be solved with DoubleGroove™ CF-Dogs.
DoubleGroove™ CF-Fit Dogs are available in two sizes: small (the product on this page, ideal for use with the PGS) and tall (for use with our Dog Rail Clips).
So Exactly What's Different Here?
DoubleGroove CF-Dogs are distinguished by their slightly larger body diameter, 0.003" (0.08 mm) to be exact. While this change may seem minute, it makes all the difference in eliminating any unwanted play that may be present when a standard 20mm dog is inserted into a precision cut 20mm hole. A CF-Dog can be easily identified by the addition of a single annular groove in its top surface.
Not Ideal for All 20mm Work Surfaces
For everyday use in a typical work table such as the Festool MFT/3, our CF-Dogs can be less than ideal. Manufacturing variances present in the MFT/3 can result in a frustratingly tight fit, making them challenging to remove even with their handy collar ridges. For this reason, we recommend using our general-purpose DoubleGroove™ Dogs available in sizes Small, Medium, Large and Tall. Every dog in our DoubleGroove™ family can be underside clamped with an M8 knob such as our SpeedKnobs™ to ensure perpendicularity and a wobble-free fit.
Don’t Confuse Accuracy with Tolerance
All DoubleGroove™ Dogs are manufactured to the same extremely high 0.001” tolerances. They are all equally precisely made. The distinction is in the diameter of the body; the CF-Dog's larger diameter body results in a closer fit when inserted into a 20mm hole.
Looking to the Future
Many woodworkers are migrating to high precision tools such as CNC routing or the Parf Guide System to cut their next work top. While general purpose 20mm dogs will serve most well for some time to come, DoubleGroove™ CF-Dogs and Super Parf Dogs will increasingly become the dog of choice for precision woodworking.
- Easier to Use: Twin grooves running along the collar make DoubleGroove Dogs easier to remove than other dogs on the market; no more stuck dogs!
- A Special Fit: Precision machined to exacting tolerances, with a diameter of 19.98mm to fit snugly in precision-machined 20mm holes.
- Ideal for High Precision Custom Worktops: If you've made your own perforated worktop based on the 20x96mm standard and aren't quite sure if your tolerances are perfect, you'll likely find our general purpose DoubleGroove Dogs to be a better choice. But if you've made your work surface using a CNC router or a high precision method such as the Parf Guide System, these CF-Dogs should provide a better fit.
- Clampable: Each dog includes an M8x1.25 threaded hole, perfect for use with our SpeedKnobs to secure the dogs inside your 20mm perforated worktop. (If you already have the knobs from Festool's 488030 Clamping Elements, those will work too, but you'll find our SpeedKnobs to be much faster and easier to thread.)
Dimensions for "Close Fit" Bench Dog, Small Size