Woodworker's Journal 2009-33-1, страница 18
Questions & Answers -▼- Determining Dovetail Differences THIS ISSUE'S EXPERTS Chris Marshall is field editor o/Woodworker's Journal and author of several books on woodworking. Rob Johnstone is editor in chief o/Woodworker's Journal. Betty Scarpino is the woodturning columnist for Woodworker's Journal. Some of her turnings are in the Smithsonian collection. Ken Horner is a retired organic chemist, woodworker and author of the Woodworkers' Essentials three-book series. Contact us by writing to "Q&fl," Woodworker's Journal, 4365 Willow Drive, Medina, MN 55340, by faxing us at (763) 478-8396 or by emailing us at: QandA@woodworkersjournal.com Please include your home address, phone number and email address (if you have one) with your question. Ql'm confused: what's the difference between "half-blind," "through" and "rabbeted" dovetails? David Sawyer Palm Bay, Florida A The names of these three dovetails give you a hint as to how they work: On a half-blind dovetail, the end of the tail board is imbedded in the pin board, so the joint is only visible on the side. From the front, the joint is "blind." For through dovetails, you see the ends of both the pins and tails, since the parts pass right through each other. Rabbeted dovetails are really just modified half-blinds. The tail board sets into a deep rabbet on the pin board instead of being flush with its end. They're useful for building overlay-style drawers where the drawer box front is also the drawer face. The projecting tongue of the rabbet forms a lip to cover gaps around the drawer opening. — Chris Marshall QI was reading about aligning a tabletop with biscuits at glue-up, and the author advised to not glue the biscuits in — arguing they only serve an alignment purpose. Why wouldn't you want to use the biscuits' full potential and glue them into the joints? Mark MacMullen Carrollton, Texas A Deciding whether to glue biscuits in place or not depends on the type of glue joint you are making with them. Gluing up a tabletop usually consists of edge gluing (technically a butt joint) a few prepared boards together. Done correctly, the butt joints will be so strong that the actual fibers of the wood will break before the glue joints fail. Biscuits certainly make the job of aligning the boards much easier, especially if the pieces are "longish" (over 24" as a rule of thumb). Gluing them in place will not increase the strength of that type of butt joint in any way that makes a difference. There is also a very slight chance that if you do glue them in place, it may exacerbate the possibility of the biscuit's shape telegraphing through to the surface of the tabletop. So in this case, why glue them in place when there is no strength advantage and you might hurt the look of your piece? With that said, if you are using biscuits to join stiles and rails, breadboard ends or miter joints — all examples of end grain joinery — in these situations biscuits absolutely add strength to the joints when glued into their slot mortises. For those tasks, keep Frank Grant's mantra in mind: "Glue is your friend!" — Rob Johnstone QI recently received a detail gouge as a gift and was wondering why the grind looks and feels rough. Do I have to run it through a light grind to smooth it before I start turning? I thought I could just grab a new tool and start turning. Amy Nielsen Maple Valley, Washington A Turning tools do not necessarily come out of the package smoothly sharpened, although some are better than 18 Half-blind Dovetail Through Dovetail |
