Dewalt GA Refurb and Mod (Pic Heavy)

[Tapper]

Hello All,

I've always wanted a Dewalt medium arm radial saw ever since I sold my old Craftsman many years ago. I found this Dewalt RAS on Ebay some time ago. It sat in my garage for at least a couple years, in the queue behind other projects.

The Saw

Dewalt GA, medium arm (24" crosscut), 3 HP, 3 phase. Serial # says it was born in 1958. When it arrived it looked to be in "decent" shape for its age. Had been used in a commercial shop for some time. My only concern was the condition of the ways. Seller had told me on the phone that when he pulled the carriage there was no "bump." He was truthful, fortunately for me.

Below are a couple of photos of the saw as it looked when it arrived. Table was trashed and someone had used a nail to substitute for the tapered pin that secured the elevation handle.  All the parts were there as far as I could tell. My plan was to disassemble the saw entirely, clean everything thoroughly, replace worn parts as necessary, and reassemble. Saw was completely disassembled, all rollerhead bearings were replaced as well as the motor bearings. All parts were cleaned thoroughly before reassembly.

I decided to do a refurbishment and not a restoration. The painted parts were cleaned and three coats of wax applied for protection. No painting was done.

   

   

   

The Elevation Motor

As the saw sat, I was surfing Ebay one day looking for something else and ran across this previously owned DC motor for sale on a "Buy It Now." Got me to thinking about the possibility of a motorized elevation device.

   

   

This is a Swiss motor with a German drive. I consulted with a good friend who has a technical background. The question was would the motor be strong enough to lift the arm, the motor and carriage, and if the gear ratio was in the right range. He did some research online and thought it would work, so I decided to make the purchase. I found the coupling at McMaster Carr, and felt lucky since the shaft on the motor is in millimeters and the shaft on the saw is SAE. 

The Housing

The question now was how to connect the motor to the saw? Obviously a housing had to be made. This sent me off on another journey - machinery for a home machine shop. While I won't go into excruciating detail, I purchased a South Bend Heavy 10 lathe (in another state - long road trip) and a Bridgeport milling machine, found locally. Also picked up an old Peerless Power Hacksaw on the cheap. My father was a machinist by training and trade but I never learned the skill because we didn't have any machines at home. So, I was into another learning curve. First thing to do was to come up with a plan for the housing. Below is the sketch I drew up, along with a puzzle I made to make sure the parts would fit together as planned and connect properly to the motor.

   

   

At this point I knew the motor would spin in both directions as I had it tested at a local electronics shop. So I set about making these parts. I had inherited some tooling from my dad so I began with it. As I went along, with help from folks at the Old Metalworking web site and Practical Machinist, along with YouTube, I was able to move forward and learn some basic skills.

   

   

   

(To be continued...... Maxed out on photos)

Doug

[Tapper]

   

   

   

   

   

This hole was to provide access to tighten the upper screw on the coupling around the shaft on the motor.

   
Trial fit - motor and housing sitting in place on top of the column before all the holes were drilled and tapped to secure the assembly.

"Mr. Sawdust" Table

Decided to build a "Mr. Sawdust" table as the one on the saw was pretty much toast. Two pieces of 3/4" MDF with the three metal stiffeners epoxied in, glued and clamped to my kitchen countertop.

   

   

To be continued.......

[Tapper]

   

   
Table finished with banding. Added 1/4" thick sacrificial sheet of MDF, attached with brass screws.

To be continued......

[stav]

Looking good. It doesn't look like it needed a repaint at all.

That motor for the column lift looks interesting. Can't wait to see how that works out. 

Hard to believe they call that thing the medium arm.  A bit of an understatement there.  The big arm must be used to saw cars in half or something.

[jteneyck]

Looking good. It doesn't look like it needed a repaint at all.

That motor for the column lift looks interesting. Can't wait to see how that works out. 

Hard to believe they call that thing the medium arm.  A bit of an understatement there.  The big arm must be used to saw cars in half or something.

I think the long arm goes out another 8", allowing 32" crosscuts.  I can tell you that the medium arm GA makes life in the shop a lot easier when it comes to cutting panels and wide miter cuts.  No more TS sled.  And the 3hp motor Doug and I both have on our saws goes through just about anything w/o blinking.  It's pretty amazing to see it go through 3" cherry w/o hesitation and no tendency to climb cut.  

Awesome job, Doug.  Mine is the person stepchild of yours.  

John

[Tapper]

I think the long arm goes out another 8", allowing 32" crosscuts.  I can tell you that the medium arm GA makes life in the shop a lot easier when it comes to cutting panels and wide miter cuts.  No more TS sled.  And the 3hp motor Doug and I both have on our saws goes through just about anything w/o blinking.  It's pretty amazing to see it go through 3" cherry w/o hesitation and no tendency to climb cut.  

Awesome job, Doug.  Mine is the person stepchild of yours.  

John

Thanks for the kind words, John! I've enjoyed our conversations about our mutual "children." 


Doug

[Tapper]

Back to the project......



The Back Table



I decided to make a full back table as I always thought this was a useful area that was wasted on these saws. It involved additional fasteners on top of the rear frame of the saw for support. Here's what I came up with to ensure alignment:

   

   

Made these "spears" from some threaded rod squirreled away. Drilled spaced holes on the flange on the rear of the frame and secured each one with two nuts locking them in place at the proper height.

   

Long story short, laid the back table material (3/4" MDF) on top of the spears and in alignment, tapped them with a light hammer to make indentations on the bottom, pre-drilled with 1/16" bit for location, and then countersunk and drilled out the holes on the top side. Added these recessed clamps to secure the back fence.



Electrical Box



Since this project required several electrical components, a metal box would be necessary to house them. A friend on another forum was known to "collect" these items and had a used one the size I was looking for. I didn't want a huge box that overwhelmed the saw so this was the right size envelope-wise, just not quite deep enough to take the VFD unit I ordered and close the door. So I decided to have it protrude through the front door.

   

First I made a template of the outline of the front of the VFD out of cardboard and transferred it to the door, aligned with the proper location in the box.

   

Then set about to cut it out on the Bridgeport. You can see some previously existing holes that were welded up later and finished with body putty.

   
Components in the Box:

Upper left - 24v power supply for the elevation motor.
Middle left - Power distribution box.
Lower left - Circuit breaker.
Lower right - Grounding strip.
Right - VFD

   

To be continued.....

[Tapper]

Control Panel

I wanted a control panel that was handy, ergonomically comfortable and simple. I decided to mount a 2x4 post to the LH rear of the frame, attach one of those articulating arms used to mount small TV's to the wall to it, and then mount an electrical box on that arm to hold the four switches needed to safely operate the saw. Here's what I came up with:

   
Found the arm and box on Amazon.

   
A little "serendipity" - the hole pattern on the arm bracket and the box matched up almost perfectly!

   
Made the front panel cover out of a of 1/8" thick sheet aluminum. Cut out the opening for the switches on the Bridgeport.

[Tapper]

Wiring going from the control panel to the elevation motor and electrical box.

   



Left - Momentary (rocker) switch to toggle blade up and down.

Middle - Main power switch; controls power to entire system.

Right - Start and Stop switches for saw motor.

   
VFD

Factorymation VFD - 3 HP, with braking feature; set to bring blade to complete stop in 10 seconds. 230v in, three phase out to motor. As an aside, the tech rep at Factorymation was very knowledgeable and very helpful. My first VFD installation and she could not have been more pleasant to deal with.

To be continued.....

[Tim in Indiana]

This is a cool project and you've done a great job on it. I'm glad to see a piece of vintage machinery put back to work.