68 - Our All-New Router Jig, страница 24
JIGS & ACCESSORIES
Look through any woodworking catalog and you'll find pages and pages of hardware — fasteners, handles, knobs, and hundreds of other items. The nice thing is they're an inexpensive way to make a jig better and easier to use. Here are a few of my favorites.
One piece of hardware that's easy to overlook is a simple carriage bolt. When combined with a knob, it's a simple way to hold two parts of a jig together, as in the jig in photo M.
Since carriage bolts come in a wide variety of sizes, you can easily find just the right one to suit your needs. (I keep VV'-dia. and 5/i6,Ldia. bolts in various lengths on hand.)
Carriage bolts work great when the bolt can stay in one spot. The advantage of a carriage bolt is that the square shank below the capped head keeps the bolt from turning.
But carriage bolts don't work as well in soft materials. The material around the squared part of the head can round over or the head can pull through the material. To get around this, you can switch to a different type of hardware—T-nuts and inserts.
T-NUTS & INSERTS
T-nuts are metal fasteners with large flanged heads. Located on the flange head are raised points to spear the wood and keep the T-nut from turning. (Some T-nuts have small holes for installing brads.)
NOTE: THREADED SHAFT IS EMBEDDED IN KNOB
STUDDED r KNOB
T-NUT ALLOWS STUD TO LOCK STOP BLOCK IN PLACE
Since the flange is large, the T-nut won't crush the wood. So they work well in soft materials and plywood. But they also work great when you need a countersunk, low-profile "nut" for a stop block, as shown in photo N and the detail above.
Insert - An alternative to a T-nut is an insert. Ifs a small piece of hardware with double threads. On the outside are coarse threads to hold the insert in the wood. And on the inside are threads that fit a bolt or screw.
What makes them unique is they can be used to exert downward pressure. The sanding block shown in photo 0 above is a good example. A T-nut would
simply back out as you tightened the screw. But an insert wants to "thread" itself further in. So ifs more secure.
But inserts do have their limits. I typically don't use them in plywood. The outer threads don't grip the plies as well as I'd like. And they can be difficult to screw into some solid woods like maple.
Sometimes it's the last thing you add to a jig you've made that makes it even more useful — knobs. They come in so many different sizes and shapes, there's probably one for just about any need you can come up with. Once again, there are a few I keep on hand that are used over and over.
Captured Knob - Any time you lock down part of a jig, ifs easy to rap