I have had to replace the switch on my Sears Craftsman radial arm saw several times.  I use a pushbutton single pole, single throw (SPST) switch from Radio Shack.  It is stock number 275-671.  The retail price is $ 5.99 US plus sales tax.

(The red rectangle is a label with my name.  To be cautious about Internet security I made it illegible for this photo.) 

Step 1: My Radial Arm Saw

This Instructable applies to Sears radial arm saws that look like this one (The photo is from an earlier Instructable.)  This series of saws was made from the late 1940's through the early 1970's.  My saw was made in 1972. 
As always, your Instructable is very well done, Phil. About the last step, I suggest you to do a little bigger the hole of the little wooden block, diameter of your finger, and then stick it (the block, not the finger) covering the start button. Thus, in order to turn the saw, you need to deliberately introduce a finger into the hole to press the button, which is very hard to do unintentionally. I think this is safer than the removable locker. Congratulations for the idea, I do not have occurred to me a so necessary safety arrangement.
Thank you, Osvaldo. I have been using this for more than 25 years without the safety lock. I simply was very careful to keep my hand away from the switch button, unless I wanted to turn the saw "on" or "off." I like having the button exposed so I could slap at it with the palm of my hand if I ever had to turn the saw "off" quickly in an emergency. But, thank you for the idea. There are a lot of saws like this sitting in home workshops. It may be that someone has not used his saw very much. When his factory switch stops working, he will need some ideas about how to replace it. This Instructable was designed to help in that situation.
Phil, please read my response to photohippie.
I never suspected you were from another part of the universe. Do you come in peace?
Oh, yes, but humans are delicious...
Do you know the comedian, W C Fields? He liked liquor, but not children. Once someone asked him how he liked children. He said, "Fried." (He is no longer living.)
I prefer the exposed switch for the exact reason that Phil gave. If there is any problem what-so-ever it would be more likely for the slap of a hand on the top of the machine to turn it off rather than a dexterous finger poke. The change I would make is to only have a cut out on one side of the wood block instead of providing access to the switch while it is resting in the "off" position. Small young fingers tend to poke and pry at things they should not be.
Thanks, photohippie. I'm talking from outside, without knowing well the subject. My excuse is that this is a very common attitude among the earthlings...
I was only picking a side and defending it. I can very easily see your side also.
I remember once the saw blade bound up in a long piece of wood and pulled the motor down to a growl. It was not that the saw presented a danger. I just wanted to cut the power to it as soon as possible. (It does also have thermal overload protection.)

About This Instructable




Bio: I miss the days when magazines like Popular Mechanics had all sorts of DIY projects for making and repairing just about everything. I am enjoying ... More »
More by Phil B:Easy Monitor for NordicTrack Skier Uses for Spent K-Cups Make a Conduit Bender 
Add instructable to: