Chris Schwarz's Blog

Moto-Saw: Now in a New Cordless Model

My co-workers branded me with a nickname in the 1990s after I took apart our shop’s Bosch plunge router and replaced the brushes on its commutator.

After reassembling the Bosch and putting it back in the tool cabinet, I returned to my desk for an exciting day of editing comma errors. The next day a fellow editor grabbed the Bosch. When he pulled the trigger, a shower of sparks (and he claims, flames) spit from the router’s vents.

As a result, I was referred to as “Sparky” whenever my power-tool acumen came up in conversation.

Last week, I earned my nickname anew when messing with the Dremel Moto-Saw I bought off eBay. I plugged the saw in to the power strip in my office during a staff meeting to demonstrate its vibro-massage function. I pulled the trigger. The saw shorted, my desk light flickered and the saw scorched my hands and jeans.

Hilarity ensued.

Today I vowed to fix the saw. I purchased short, pin-ended blades for the saw from Sears that fit quite well once I bent the saw’s spring back to its original position (thank you, patent drawings).

The short was caused by frayed wires at the end of the handle. So I disassembled the handle to replace the cord. It was going smoothly until I got to the place where the power entered the saw’s electromagnet. Like lots of 50-year-old tools, the insulation around all the components had turned to dust. I gingerly lifted one of the wires to blow out the insulation and the wire’s connection to the magnet disintegrated.

In fact, the connection was so far gone I couldn’t even tell how the wire was originally connected. I inspected the wire on the other side of the magnet. It was almost kaput as well. I pinched it and wiggled it. It popped off.

The Moto-Saw was now like all my other coping saws , cordless. I installed the blade anyway and decided to cut some 1/2″ cherry.

Hilarity ensued.

- Christopher Schwarz

19 thoughts on “Moto-Saw: Now in a New Cordless Model

  1. Dan Aycock

    I have a version of a Sears scroll saw that appears to be only one evolutionary step above your tool. It operates(ed) in the same process. It also suffered the same age related issues. It now resides, cordlessly, on the "antique" tools shelf in my shop. I found the broken/frayed wire connection on the armature a mere instant prior to applying power.

  2. Joseph Sullivan

    HMMMM

    The fully manual version sounds very much like the Minnesota version of a Norwegian chain saw — a hacksaw body with some chain blade fastenen whee the hacksaw blade would normally go, and a spark-plug welded on top

    Joe

  3. Kerry Doyle

    I had a dremel moto tool I purchased in 1966 that I recently discarded because the internal wiring had finally disintegrated and fixing wasn’t an option. They sure made those tools to last.

  4. Jon Johnson

    Maybe if I attach a handle to the arm of my Dremel Moto-shop and hold it upside-down…..

    On second take, maybe this is why Mr Dremel had second thoughts and invented the MotoShop which uses the same pin blades!!!
    The difference is that the oscillator is a motor & bellcrank design (like many modern scroll saws) in place of the vibrator.
    Dremel (and others) used vibrator actuators in other tools too. A 1950′s Dremel pad sander my dad had comes to mind. Many shavers and hair clippers too.

  5. Will Matney

    I would venture a guess, that Mr. Dremel, got the idea for this saw from the old "vibrator’s", that was used in the old tube-type automobile radio’s of his time.

    The vibrator was a reed type relay that ran off a solenoid. The armature actuated a switch that caused the magnet to switch on and off, thus causing the armature to vibrate.

    The armature has a natural frequency, and this was adjustable on the saw by the armature adjustment. However, there is a switch where the armature will break the electrical connection when in the down position, and it could be dangerous if any of the insulation is missing.

    Back in those days, safety was not as big of a concern as it is now, as can be seen by the open wiring on the tool. If the saw body happened to become shorted to one of the line leads, and you tipped a ground somewhere, (Water Pipe), you could be electrocuted.

    The saw could still be fixed, but I would leave it to someone experienced in this type of work, as new insulation will need to be made for several pieces of the saw.

    Will Matney

  6. Jonas Jensen

    As you have quoted in one of the earlier copies of Woodworking Magazine:
    "think about it, everything with a cord ends up in the landfill eventually"

  7. Chuck Nickerson

    Stirring varnish with a drill press? Somewhere, my Dad read that was the thing to do, so he tried it with his Shopsmith in 1969. There are still paint spots on that Shopsmith.

  8. Troy Bonte

    Hi Chris,

    Do you think the magnet can be rewound? We have an electric motor guru on staff. He might rewind it in exchange a couple of your prized imports.

    Troy Bonte
    Capital University – Columbus, OH

  9. John Cashman

    Seriously? A drill press to stir varnish? A guy who advocates using hand tools used a drill press to stir varnish? Were they filming a Woodworker’s Edition of Candid Camera?

    You are beginning to damage my calm.

  10. Mike Siemsen

    Chris,
    Judging from the photo of the blade holder on your Moto-Saw you have cured you blade rotation problem. It doesn’t look like that one can change position easily. This is obviously the tool gods telling you to eschew power tools and use hand tools only.
    Mike

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