Monday, October 5, 2009

Radial Arm Saw Fix for a Scary Problem

Yesterday afternoon, in the middle of constructing cold frame lights, my Radial Arm Saw stopped working. This saw is the central machine of my shop: I use it to do just about everything from ripping to chopping to mitering. And though replacing it would be possible, it would hurt—in more ways than one.

Before I turned it off, the saw worked fine through all the cuts I performed, and it did not slow or stop until I turned the switch. There was no smoke or hot smell, and the cuts were not through overlarge or dense material. But when I turned the switch again the saw just buzzed; the blade moved almost imperceptibly in the wrong direction but did not turn at all. After a few tries with the saw still buzzing—turning off, turning on; unplugging, replugging; pressing the reset button, and poking the blade with a stick (probably a dumb idea as I think on it)—there was a little click and the saw no longer reacted to the switch at all.

Perhaps everyone in a situation like wonders if they caused the problem somehow. I wondered, because this once, for the first time, I had turned the switch in the opposite direction from usual. It had to be just coincidence that the two events occurred together. But it was the only thing I could think of that might have caused the saw to stop.

I took out the switch, checked the connections, and reassembled it. Still nothing. My saw is wired with a plug and socket between the switch and the motor so the motor can be easily taken out of the arm and taken elsewhere. I thought "Maybe I can plug in something else and test the switch?" but the plug was on the switch side and the socket on the motor side. So I swapped the two and was ready to test the "broken switch" theory. I plugged in and ran a shop lamp and then the shop vacuum: the switch was definitely OK.

It was in the motor. Again I pressed the red reset button several times and tested the saw with no result. It seemed I was going to have to open the motor to get this fixed, but I'd been in the shop for much of the day and I was frustrated: I decided I wasn't going to get it fixed that day.

Later I had a chance to talk with my friend Sean, who suggested I visit the Old Woodworking Machines forum to look for (or ask for) help. Sure enough, I found a comment string that suggested some possible actions that didn't involve taking apart the motor.

Back in the basement I pressed the reset button harder. There was a promising click. I plugged the saw back it and it was back to buzzing (but still not turning). I was making progress! On to step 2. I rapped on the motor housing—especially near the reset switch—with the handle of a screw driver. Believe it or not, after that the saw worked.

So for the moment, all is well again.

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Monday, August 31, 2009

Building a Cold Frame for the Winter

Last winter I read a great book on winter gardens called Four Season Harvest. According to this book, one of the keys to having garden vegetables year round (or at least during an extended season) is the use of a cold frame.

The book describes how to build one of these mini greenhouses in detail, but the width was too great for our garden beds. So after measuring to be sure (3' 3" maximum) I sat down to draw out new plans in Sketchup on Sunday morning. Then I cataloged what I had on the wood rack and what I needed to buy. The whole list looked like this:

Base:
  • 2 sides 3' 3" x 11.25" x 1.5" to be tapered to 7.25" at one end
  • 1 back 7' 9" x 11.25" x 1.5"
  • 1 front 7' 9" x 7.25" x 1.5"
  • 2 long sacrificial bottoms 7' 9" x 1.5" x 1.5"
  • 2 short sacrificial bottoms 3'3" x 1.5" x 1.5"
  • 1 cross brace 3' 4" x 1.5" x 1.5"
Light (x4):
  • 2 light sides 3' 3" x 1.5" x 1.5"
  • 2 light ends 21" x 1.5" x 1.0"
  • 2 stops (to hold the glass in) 3" x .75" x .5"
  • 1 piece of tempered glass 1' 10.5" x 3' 1.5"
Notched prop sticks: (to hold the lights up and vent the frame during warmer days)
  • 4 prop sticks 2.0" x 1.5" x 16" (two inch notches with one inch of material in between)
Other:
  • 50 Kreg self-tapping 2.5" pocket screws (everything is screwed together)
  • 16 Kreg self-tapping 1" Pocket screws (or some other 1" screw for holding the stops on)
A trip to Home Depot and Lowe's later I had all the supplies, including the 1/4 router bit I needed for milling the grooves the glass will sit in. Sunday afternoon was dedicated to milling most of the parts for what will become two cold frames. Many of the parts were cut down from larger lumber. The 2 x 2 stock, for example all started as 2 x 4 or larger.

To cut the tapered ends, I marked the end points of each side (minus about 4" for clearance and support), screwed a piece of pine from one mark to the other, registered it against the front edge of my Radial Arm Saw table, and set the saw blade even with the longer end. I was ready to make the cut, but first I set two combination squares to the depths of those marks. On each of the other three ends I just marked the length from the combination squares and screwed down the same piece of pine as a straightedge. It worked perfectly.

The only hand work was cutting angled notches in the front and back. Here I learned that crosscut really can make a difference, and since the first notch was started with a rip saw and finished with a crosscut saw the fit of the cross brace was a little sloppy. The second one was nice and tight, just like I would have wanted. In the picture below, the blemish is a knot hole.

I nailed the sacrificial sections to the bottoms of all the sides (these can be removed and replaced when rot starts to become a problem), and took one set of parts out into the yard to screw it together with Anne's help. It came out well. With luck, I'll get the lights done next weekend.




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Wednesday, October 22, 2008

Featherboards for Ripping Window Stock

The Radial Arm Saw (RAS) adjustments are completed—I expect to write about that soon—and it is almost time to start building the storm window to replace the old rotted one I willfully destroyed. This is a project on which I will definitely use machinery, and the RAS will play a key roll.

Research revealed that my prior belief that poplar would be better than pine for outdoor applications was wrong. In fact, consensus amongst online woodworkers and the Wood Handbook from the U.S. Forest Service agreed that pine was usually better, but not by much. So ignore my earlier intimation in the Replacing a Rotting Stair Riser post that poplar is any good for rot resistance: it isn't.

Among the contenders for stable outdoor woods: cherry, walnut, cedar, white oak, and mahogany. What a bummer: the beautiful woods are apparently also the ones to use in painted applications outdoors. There is a small silver lining in this: about two years ago I said "yes" when a friend offered me part of a bargain pile of mahogany offcuts, all 4/4 in random widths and 5 foot lengths. This stock is perfect for building the storm, and I selected window stock from this pile:
The thinnest piece will become a simple triangular molding designed to stop water from flowing easily into the window joints. I plan to post the storm window plans in a future entry. Especially because the molding stock was so thin, I wanted to have it seated firmly against the fence of the RAS (yes, I am going to rip stock on a Radial Arm Saw; and no, I am not any more afraid of this than I would be with a table saw). I wanted feather boards.

To start, I ripped a scrap of pine into thinner sections to make two feather boards:

Then I turned the arm to 45 degrees and cut a fresh kerf in the fence:

Using the newly cut kerf, I could line up precisely with the marked 45 degree cut and know that the cut would be exactly on the line. This kind of precision isn't necessary for the feather boards, but it was good practice for when it would be:

With the angles cut onto the board, I turned the saw back to the rip position and started cutting fingers on the board. I ripped to the marked line, turned off the saw between cuts, and repositioned the rip. Unlike a table saw, where the blade is stationary and the fence moves, on the radial arm saw the fence is stationary and the blade and motor are repositioned:

Many people have cautioned me about the dangers of ripping on a Radial Arm Saw (including my father and a friend who attended the North Bennet Street school), and while I agree that any exposed blade rotating at high speed can be a danger, in practice I believe a well adjusted Radial is as safe or safer for ripping than most table saw settups. Take a look at this:

Notice that the body of the motor blocks access to the side of the blade, and the blade guard, once properly positioned, sits directly between the feeding hand and the blade. Through all of this ripping, I felt perfectly comfortable with the safety precautions on the saw. And because I had adjusted the heal/toe position properly, there was no tendancy to kick. The process went quickly and when I tested the newly cut feather board it worked perfectly:

The only thing I didn't like about the feather board was the long point just waiting to catch me in the hip. So I cut the other side to a 45 degree and rounded the tip before starting in on another. At the end of the night I had two feather boards completed:

With that done, I'll soon be ripping window stock.

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Friday, October 10, 2008

More Radial Arm Saw Adjustments


It has been years since the radial arm saw came into my shop, and I have not used it at all because it was not set up accurately. I've been working on fixing this over the last two weeks, and I'm getting quite familiar with the settings.

The thing that took me longest, was getting the table to be nearly perfect in its alignment with the saw arm. I had spend hours trying to get this right, and I was getting nowhere until I learned the trick from a book called Fine Tuning Your Radial Arm Saw, by Jon Eakes. The secret was to adjust four reference points on the table and use a crescent wrench as a lever for fine positioning. This simple trick was a huge revelation, and once I learned it, adjusting the table was done in under an hour. I'm sure I could do it in under 30 minutes now if I needed to do it again.


I'm now most of the way through testing and adjusting the saw. I hope to finish tomorrow and start ripping stock for the storm windows I need to build. I guess I just needed a big project (ripping and chopping the stock for 5 storms) with a deadline (winter) to motivate me to get this machine working. There was no way I was going to rip all that stock by hand.

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