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Talking Shop

FRICTION REDUCERS & RUST INHIBITORS

• Most woodworkers know that high humidity causes wood to expand. But here in Iowa, the high humidity during the summer creates other problems too: friction and rust. This friction makes a workpiece stick to a metal table instead of sliding smoothly — the same way your shirt sticks to your back.

I've used a lot of products to reduce friction. Car wax, talcum powder, corn starch, and furniture wax to name a few. But the problem is, they leave a residue on the wood, and they don't last all that long. Plus they do very little, if anything, to protect the surface of the metal from rust. So we use three different products in our shop: Kity Speed, TopCote, and Boeshield T-9. (See page 31 for sources.)

kity SPEED. I like to use Kity Speed for a long-lasting friction reducer. It gets a lot of use on the table saw, band saw, and drill press tables.

Part of the reason why it wears so well is what it's made from. Kity Speed is a special graphite wax with the consistency of tooth paste.

Mixed in with the wax are small silver flecks. These flecks are a molybdenum compound used for reducing friction. (At least that's what Farris Machinery Inc., the supplier, told me.)

The other thing I like about Kity Speed is how it's applied. It reminds me of waxing my car. You wipe it on. Let it haze over. Then buffit off.

This process takes a little time and effort. But it's satisfying to look back and see the silver flecks where I've put down a coat of protection.

TOPCOTE. Another product I use in the shop to help eliminate friction is TopCote. This is a product with a Teflon based formula that you spray on your tools. It reminds me of a vegetable shortening you spray in a pan to keep food from sticking.

Since TopCote is an aerosol, it's a convenient way of getting into a difficult-to-reacharea. For instance, I use it on the planer bed because the spray easily covers the whole surface, and I don't have to worry about missing a spot. I also use it on some of my hand tools (like my combination square) to prevent rust. It easily gets into all those nooks and crannies.

To use TopCote, simply spray it on and let it dry for a few seconds. Then for the best results, just rub it out lightly with a clean cloth. Although a second coat is recommended, I've found a single application is usually enough.

TopCote is easy to apply, and I'd use it exclusively — except for a couple of things. First, it's a little more expensive than a paste product. And second, it doesn't seem to last as long once it's been applied.

Shop Caution: When spraying aerosols like TopCote, the thing to be careful with is the overspray. If it gets on the shop floor it can become slippery.

BOESHIELD T-9. While Kity Speed or TopCote does provide some rust protection, there's another product better suited for the job: Boeshield T-9. It's designed to protect metal parts from moisture. So it's ideal for those shop tools that don't get used all that often.

Boeshield is an aerosal product product that's composed of a solvent and paraffin wax. By spraying on a light film and then wiping it off, it can be used to protect and lubricate the tools you use everyday.

But to protect your tools for a long stretch (like over the summer), simply spray a coat on and let it set — don'tbuff it out. This does leave a sticky film. So when you're ready to use the tool, simply wipe it down with a solvent.

ABRASIVE PADS

• You've mentioned abrasive pads in previous issues, and I've seen them in local hardware stores. Can you tell me a little about them?

Abrasive pads (like Scotch Brite, Bear-Tex, and Scuff-Rite) work well when you are smoothing out a finish between coats. If you typically use steel wool or 320-grit (or finer) sandpaper between coats, you might want to give these pads a try. Abrasive pads have some distinct advantages.

Unlike sandpaper, these pads don't clog up with dried finish. That's because the small abrasive particles are bonded into an open web of interlocking fibers, instead of being glued to a heavy paper backing.

And there's another benefit. Abrasive pads are flexible. So they can conform to the shape of the surface, which makes moldings and curved parts of projects much easier to work on, see photo at left.

Abrasive pads also have an advantage over traditional steel wool. Steel wool leaves tiny slivers behind, which is a problem especially when you're working with water-based finishes. The slivers can rust when the next coat of finish is applied.

On the other hand, the fibers that make up the abrasive pads are synthetic. As you rub the pad across the workpiece, the fibers wear away and expose fresh abrasive particles. The surface still needs to be wiped off, but any missed particles aren't going to rust and discolor.

Abrasive pads come in a variety of "grits" and are usually color coded. But since different companies produce different abrasive pads, they're not standardized, like sandpaper and steel wool. However, there's often a steel wool equivalent in the product information.

DOG HOLES

•In the last issue, we featured a workbench complete with holes for round bench dogs. But what if you want to add dog holes to an existing bench?

I've found that whether you add holes during the building process or after the top is complete, there are two steps: laying out the holes and drilling them.

layout. To lay out the dog holes, start by determining the distance between them.

At most, this distance should be slightly less than the opening capacity of your vise, see Fig. 1. However, when laying out the holes on my bench top, I wanted to avoid turning the vise handle a number of times when adjusting it to hold a piece. So I usually space the holes 3"- 4" apart.

Of course, you don't need a vise to use bench dogs. With the bench top I built in the last issue,

I used Wonder Dogs in addition to a vise, see Fig. 1. On a Wonder Dog, the screw is much shorter than on a vise, so the dog holes can't be much any apart than 4". (The length the screw on the Wonder Dog travels.)

LOCATION. Spacing isn't the only thing you need to consider. You also have to determine the specific location of the holes. In other words, there are some objects you need to avoid.

The most obvious obstructions are the parts of the vise. Avoid drilling holes in the vise screw, guide rods, and carriage.

But there are other things that can get in the way. The base that the bench top sits on, any drawers, or even a cabinet underneath the bench are all obstructions that can prevent you from getting a bench dog seated fully in its hole — or back out if

Distance between dog holes should be less than opening capacity of vise

Distance between dog holes should be less than opening capacity of vise

Wonder Dog
NOTE: Spacing allows full reach of Wonder Dog

the dog is pushed in too far.

DRILLING. When the holes are laid out, the next step is to drill them. If you are building the top, this isn't a problem; you can drill the holes before the top is assembled.

But when the top is already built, it's too big to use the drill press, so you have to drill it by hand. The trick here is keeping the holes perpendicular and finding a drill bit long enough to drill all the way through the top. But there's an easy solution. You can use a hand drill guide and a spade bit to drill the holes, see photo. Note: For more on the spade bit and drill guide I've used in the past, see page 32.

When drilling the holes, you want to prevent the bit from "blowing out" the bottom side. To do this, I set the depth of the guide so just the tip of the bit breaks through the bottom, see Fig. 2. Then flip the bench top over and complete the holes by drilling from the opposite side.

To complete the dog holes, I also rout an V&" chamfer around the top and bottom edges.

Spade bit t_

FIRST.

Drill till point of bit breaks through bottom face

CROSS SECTION

CROSS SECTION

SECOND: Flip top over and complete drilling hole

-Top

HORSEPOWER RATINGS

■ Recently, I've been looking to buy a table saw, and I've run across advertisements that say a saw "develops three horsepower." What does this mean and how can I find out how powerful a motor actually is? When a motor is pushed to its limit, say by cutting through a hard knot, the motor draws more amperage than under normal conditions. Just before it stalls, the motor will be drawing the most amperage and producing its maximum horsepower. The most it can develop. Of course, it will only be able to maintain this for a short period of time before the motor stalls or the circuit breaker kicks off.

This is what manufacturers mean when they say a motor "develops 3hp." (It can also be referred to as a motor's "peak horsepower.") Technically, the manufacturers are right. But in my opinion, it's misleading. They're trying to get you to compare apples to oranges.

Most table saw motors use a continuous-duty horsepower rating. This is the amount of power a saw produces under normal use — it's the power you will work with most of the time.

To compare motors, check their identification plates. You can look at the horsepower rating, but often it's left off of saws that advertise their developed horsepower. But you can still compare them by checking the amperage ratings.

Generally speaking, the higher the amperage the more power the motor produces. So if one motor develops 3hp and another is a continuous-duty lhp motor and both draw about the same amperage, you can be pretty sure that both motors produce about the same power.

READER'S JIG

Assembly Jig

A simple locking system holds large pieces of stock without any clamps. Now you can assemble a project all by yourself.

Most woodworkers could use a little help from time to time, especially when assembling big projects. For example, trying to join two pieces of plywood together can be nearly impossible unless someone is around to give you a hand.

Since I probably won't grow a "third hand," the assembly jig sent in by Roger Balling of Santa Ana, California, is a welcome addition to the shop. It can be used to keep your V4"-thick workpieces aligned until your bar clamps are in position. Or if you make four of them, they will hold all of your large case pieces (one at each corner) so you can nail or screw them together.

This jig is so simple to make, you can almost build a set of four as easily as building one. That's because it consists ofjust a few parts. There's an i^shaped base. A thick, square block glued to one corner. And bolted to the base is a pair of circular disks.

These disks have an offset mounting hole that gives them a "cam action." So it's quick and simple to wedge the workpiece tight against the block. Just turn the disk.

BASE. Since all of the pieces of the jig are

All pieces are W-thick stock (except spacer)

Corner block

Wing nut

All pieces are W-thick stock (except spacer)

Center hole on width of base and 23/n° from corner blocks

Wx2m Carriage bolt

Rawing nut

Center hole on width of base and 23/n° from corner blocks

Wx2m Carriage bolt

Rawing nut

Disk

Spacer

attached to the base, I started with it first.

The base consists of two 6"-wide pieces that are 12" long. Each piece has a 45°

angle cut at one end, so when these base pieces are glued together, you end up with an L-shapedbase, see Fig. 1.

CORNER block. Sitting on top of the base is a corner block. This is just two more 6"-square pieces glued together to form a 1VS"-thick block. When glued in place, the corner block covers the miteredjoint on the base to strengthen the jig.

The extra thickness of the block is like small fence that supports your workpiece when the clamping disks are tightened. The only thing critical about making the corner block is getting the corners square (90°). If they're not, the corners on your project won't be either. Once it's glued up, simply glue and clamp it to the base.

disks & SPACERS. Also attached to the base are two 4" disks. They are the heart of the jig. They wedge your workpieces tight

Corner block

Wing nut

against the corner block to hold them tight for assembly. For this to work, the mounting hole in each disk isn't drilled in the center. It's offset by Vi", see Fig. 2. That way, the harder you twist a disk, the tighter it wedges the workpiece.

Mounted under each disk is a W hard-board (Masonite) spacer, see Figs, la and 2. It raises the disk up off the base to make it easier to grip. Unlike the disk, the mounting hole for the spacer is centered. Both the spacer and disk are attached to the base with a carriage bolt and a wing nut. Don't overtighten the wing nut. It should be snug yet allow the disk to turn freely.

USING THE JIG. Once the spacers and disks are attached, the jig is ready to use.

Simply set your pieces in the jig against the corner block and twist the disks to hold them in place, see Fig. 3. □

PROJECT SUPPLIES

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