I picked up a table saw at a count auction about a year ago. I figured, for $17.50 it would be a good project and if it turned out as hoped, it would be a great saw.
The saw, is a Rockwell Unisaw. Today that would be Delta (following an acquisition and rebranding). From some casting marks, I conclude the saw is from 1979. The saw has seen a number of significant changes in the past 4-5 years but prior to that, it saw almost no mechanical changes since it debuted in 1944! This saw spent it’s first life in a vocational school and it was a tough life.
The saw was equipped with a three-phase motor. I could care less if it was any good since my shop does not have 3-phase power. From the start, I knew the saw was going to need and get a new motor. I eventually settled on a Leeson 3HP motor. The biggest advantage to this unit, in addition to its power, was that it already was configured with the necessary pivot bracket used by the Unisaw. With the motor on order, I set to working on the saw.
The plan was to refinish the top, check the bearings (and pray they were all right), replace the belts, figure out the electrical system, create some option for dust collection, and build a motor cover.
The frame #1 in filmstrip shows the saw with the fence removed and my first attempts at cleaning the top. Eventually, I went for a substantial tear-down. You can see the yoke and other castings in frame #3. After more effort than I care to acknowledge – and more than a few recitations of "wax on / wax off" – I finished stripping the coating on the top. The mess I was dealing with was painted on urethane. This was most likely applied because a vocation school could not be bothered with enforcing proper tool maintenance by the students. Sadly, it was applied after some amount of abuse had already been inflicted. I used a combination of solvent and variously grades of sandpaper and scotch pads to get down to metal. Then a wipe down with Naval Jelly (now just call "rust remover jelly") to get at the rust in some of the scratches and tiny pits that I could not remove. After washing and neutralizing the (phosphoric acid) jelly, I did a little more sanding with 320 wet/dry. The remaining scratches and machine marks were too significant to remove without rendering the top unusable. I finished with three coats of good old fashion paste wax (frame #7).
I had to remove the fence and top along the way so I decided I’d clean up the fence rails even though I plan to eventually replace the fence with a Biesemeyer. I also cleaned the various screws and bolts (a habit I picked up on the clock restoration).
I had to do a bunch of digging but thanks to the Old Wood Working Machines wiki – yes, there is a web page for everything – I found I could use most of the existing electrical system. The control box houses the "Magnetic Motor Starter". I had to switch the step down transformer (which feeds the remote starter buttons and back to the relay) from 200v (part of the 3-phase wiring) to 230v and replace the main power leads and plug. I then used just the first two legs of the system for the new power and motor. Frame #4 shows the electric box with the motor, power, and remote switch wires left-to-right at the bottom; the 24v relay switch for 3-phase power in the upper left and the step-down transformer in the upper right; the block that looks like it has springs is actually the thermal breaker and those are heavy gauge heater coils that will trip the breaker if they got too hot from too much load.
The new motor arrived via UPS and was install that same night. Frame #5 shows the new motor already installed and the old motor and 3-phase power on the floor. The local industrial /farm supply only had 2 of the belts I needed. The motor drives the blade using three redundant belts. The last had to wait a couple of days.
For dust collection to work, I needed to create a filler panel that is behind the front louvered access door (frame #8) and build a motor cover (frame #6). The cover has a frame contoured and attached to the side of the base cabinet and then, using a piano hinge and latches, the box cover enclosed the motor. Remember, the motor pivots and tilts with the blade so it move quite a bit inside the cabinet – hence the motor cover needs to be spacious.
The finished assemble is seen in frame #8 and you can see the clean and slippery smooth top in frame #7. The blade insert is in bad shape but at $40 each, I’ll make a set out of hardwood. I need to make my zero-clearance and dado inserts anyway so another couple won’t take any extra time. The last step is to align the top to the blade before tightening it all down. Frame #9 shows the dial indicator gauge in position. The first test measures the distance from the track to the blade at both the leading and trailing edges. The second test measures any wobble in the blade. Wobble could be from a bad blade or from misalignment in the mounting arbor disks. Final calibration is not finished yet and I have 0.008 front to back and 0.006 of wobble.
It’s been a fun project. I am really looking forward to setting the Unisaw in place. It will go at one end of the long outfeed table and my JET Contractor Saw will say at the other. The nice part is that the JET Dust Collector has two inlets so I won’t need to switch when I go back and forth between saws (though a remote might be handy <grin>).