Shop Blog – Derusting and Restoring a Skil HD-77 Saw

Posted: June 15, 2014 in Shop Blog, Woodworking
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I’m a tool junkie.  For me woodworking is a hobby.  It’s fun, but woodworking doesn’t pay the bills.  So, when it comes to tool collecting, I tend to be frugal.

Okay, okay, I’m CHEAP!!!

I search for nice quality used tools at yard sales, on Craigslist and eBay.  To me, the hunt is part of the fun of the hobby.  Over the years I’ve learned a few things about restoring tools to their prime working condition.

My goal is not restoring the tool to like new condition.  My goal is to optimize the functionality of the tool and its usefulness in my shop.  That includes making sure working surfaces are rust free.  When I find a tool I want, a little rust doesn’t scare me.

I have wanted a Skil HD-77 worm drive saw for some time.  I recently found one on eBay and was able to purchase it within my budget.

Here is a little story of how I restored it for my shop.

First a few pictures of the saw fresh out of the package. That rusted blade will be the first thing to go.


Fortunately for me, when I plugged in the saw a pulled the trigger, the motor ran smooth as silk.  The oil was clean and fresh.  The brushes on the electric motor are in excellent condition.  That is always one of the biggest risks, when buying a power tool without the ability to test it first.


Rust on surfaces that will be in contact with my project pieces is definitely a problem.  This plate will need to be rust free, before I use this saw on my next woodworking project.


Disassemble the problem pieces from the saw and group parts for rust removal.

These parts are headed for the electrolysis bath, for aggressive rust busting.


I will soak these parts in a little vinegar to soften the rust and restore the surface appearance.


I found plans online to build my homemade electrolysis chamber.  Google “rust removal with electrolysis” for more information on building your own electrolysis kit.

The battery charger was a nice find at an estate sale for $1, a few years ago.  Electrolysis uses a combination of chemical (soda ash in water) and electrical reactions to neutralize rust on steel parts.

The reaction causes a mild boiling action in the water.  Electrolysis is one of those processes you can start and go do other tasks.  You really cannot over “cook” the parts.  These parts were in the electrolysis bath for almost eleven hours, while I did other things like cleaning off the old saw dust and gunk from the saw body (plus, running errands with my wife and mowing the lawn).


When you first remove parts from the vinegar bath, the surface looks black.  The acidic vinegar attacks the rust, but leaves a black residue (iron oxide) on the surface.  A little rubbing with some 00 steel wool will return the normal color of the parts.


Fresh out of the electrolysis bath, the rust has been neutralized leaving a black iron oxide residue on the parts.  A little rubbing with some 00 steel wool will remove the residue and restore the steel’s normal color.  Hint: Keep the surface a little moist during the steel wool scrubbing.

The foot plate will remain unpainted, so after the steel wool I dry the part completely. Then, give the part a brisk brushing with a copper pot scrubber (a Scotchbrite pad works nice, too).

The small parts wear originally painted black, so just the steel wool to smooth the surfaces for new paint.


Here is the nice shining foot plate, after a few minutes of 00 steel wool and a brisk brushing with the pot scrubber.  I’ll put a coat of paste wax on this plate, to help protect the surface and make it glide nicely when its back in use.  It is much easier to apply paste wax to the plate, before reassembly.


Here is a better comparison.

Electrolysis Process

These small parts were originally flat black.  All I had was gloss black in my paint supply.  Apply a quick coat of paint and these parts will be ready.  After the paint dried to the touch, I dulled the gloss by rubbing the parts with a terry cloth towel.

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I used a nylon brush, a brass wire brush and an air hose to loosen and remove the old saw dust from the saw body.

Rust is gone. Paint is dry. Saw body is free of old saw dust and debris.  Parts are on the bench and ready for assembly.


Here are a couple pictures of the reassembled saw, with a new blade.  It’s bright, shiny and ready to be put to work.

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All in all, I am really pleased with this little project.  I now have a nice new tool in my woodworking arsenal.

One last Before & After comparison:

Saw - Before & After

These saws retail for around $160 new.  A timely eBay find, a little know how and couple hours of hands-on labor I have this nice saw for less than a third the investment of retail.

Now, I’m ready to go make some sawdust.  Thanks for letting me share.

  1. robert putman says:

    a nice tutorial here tim, ive had my worm drive for around 20 years, its a jewel…enjoy your saw..


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