Woodworker's Journal 2010-34-1, страница 12
Questions & Answers No-Slip Shop Tips THIS ISSUE'S EXPERTS Bill Hylton is a Pennsylvania woodworker and author of several woodworking-related books. He is a long-time contributor to Woodworker's Journal. Chris Marshall is field editor of Woodworker's Journal and author of several books on woodworking. Rob Johnstone is editor in chief of Woodworker's Journal. Michael Dresdner is a nationally known finishing expert and the author of The New Wood Finishing Book. Contact us by writing to Q&A," 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. Q While routing half-blind dovetails, the bit slid down onto the jig after the third drawer. I cleaned the collet and started again. After about two more drawers, the bit had slipped again. I had to reset the bit after about every other set of drawers. I needed eight. The router is an older one, but it has never given me a problem like this. Any help on what the problem might be? Ron Wagner Citrus Heights, California A The likely cause of your problem is a worn collet. But start with the bit. Measure its shank with a machinist's caliper; its diameter should be spot on, but two or three thousandths undersize is acceptable. That is, a 1/4" shank should be 0.250" in diameter; if less than 0.247", replace it and see if the problem is solved. If the bit shank is accurately sized, the culprit is the collet, and you need to replace it instead. An obvious follow-up question is: "If the problem is the collet, why doesn't it occur with all my bits?" The dovetail is a harbinger. As a collet wears, it doesn't grip a bit tight enough to ensure it spins at the same speed as the router motor. Under load, the bit slows down, but we don't notice that happening. Scoring or galling on the shank are signs of this, but again, we don't always notice. Eventually, the grip deteriorates to the point that bits begin to work out of the collet. Ah, then we notice! Because a dovetail bit is designed to pull itself into a cut, trying to burrow deeper, and because the dovetail shape traps the bit in the cut, it's more prone to be pulled out of the collet by the resulting tension stress. — Bill Hylton QWhat is the easiest way to make case parts square for parts that won't fit between the miter gauge and the blade on the table saw? As one solution, I'm considering building an infeed table (a reverse of the outfeed table in the February 2009 issue.) Is it safe to make an infeed table for the table saw? Am I missing another method or something very obvious? Using the table saw on bigger parts, I can make great parallelograms by just using the fence, but perfect squares are another story! And there really isn't much room between the miter gauge fence and the saw blade. John Weaver El Cajon, California AWhile adding an infeed table to your saw seems plausible, I don't advise it for a couple of reasons. First, adding a table in front of the RECALL NOTICE Recalls are in effect involving the following items. If you need more information, visit "More on the Web" at woodworkersjournal.com. • Model number G0640X Grizzly 17" Metal/Wood Band Saw; (800-523-4777). • Model number R4511 Ridgid 10" Table Saws with date codes between CD0829 and CD0837; (866-539-1710). • Model number 27017 Rockler LED Magnifying Light Kit and model number 26429 Rockler LED Spotlight Light Kit purchased between 3/27/09 and 10/25/09; (800-260-9663). • Model numbers D3038 and D3346 Shop Fox Dust Collection Remote Switches; (800-840-8420). 12 February 2010 Woodworker's Journal |
