How to Properly Disassemble and Clean a Unisaw

Modified on 2015/03/01 20:16 by Bill Nance — Categorized as: Restoration Topics, Tablesaws

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How to Properly Disassemble and Clean a Unisaw
   Preparation
   Remove the Top
   Yank Out the Guts
   Disassmble the Subassemblies
   Cleaning and Replacing Worn Parts
   Painting
   Reassembly
   Lubrication
   Calibration

How to Properly Disassemble and Clean a Unisaw¶

Written by Keith Bohn December 27 2007 {Reference:http://owwm.org/viewtopic.php?t=32049|http://owwm.org/viewtopic.php?t=32049}. Quote "In reality you could dismantle and clean a Unisaw and have it all back together over a good weekend."

The pictures in this wiki are of a 1953 Unisaw disassembly, and were provided courtesy of Joe Wells{Reference:http://www.joewells.org/owwm/Unisaw|http://www.joewells.org/owwm/Unisaw}. They were not taken specifically for this wiki, but fit (mostly) pretty well. Larger photos are available on Joe's website.)

If you are a first time restorer of woodworking machines you might want to read the Restoration Guide and the Electrolysis Guide

Preparation¶

On the scale of Easy to Hard the Unisaw really falls way down on the list towards Easy as a machine that normal humans can dismantle and put back together *if* you have a little bit of mechanical knowingness and the proper tools. This article will take you through the process and in the end you can, if you choose, take every bit and piece apart, bring it back to factory fresh and put it all back together to where it works like the day the saw was born. It should be noted that even the saddest of bastards with no broken parts really only need a good cleaning to get them back to working properly. Most people, if they are going through the entire process, will elect to repaint. As the saying goes, “in for a penny, in for a pound”.

I should note that this write up is based on an early vintage Unisaw. Since 1939 there have been many “value engineering” changes to the Unisaw and while I’ll try and catch each one I won’t guarantee that I’ll cover them all. I will say that the make up of the saw hasn’t changed drastically and any smart human can and will figure out how to get a newer saw apart. This article does not and will not account for left tilt saws so if you can’t work it out in your own head as to what I mean when I say “tilt to the left/right” then you really should sell the saw and buy some knitting needles or be discussing trademark, patent and copyright law with others of your same ilk.

The Tools You Will Need

Hammer
Set of Pin Punches
Screwdrivers (note plural)
Socket Set
Combination Wrenches
Straight Razor and Holder (Handle)
Scotch Bright Pads (Coarse to Medium)
WD-40
Marvel Oil or Preferred Equivalent
Parts Tubs (you can use cheap plastic shoe boxes or any container for this)
Baggies (small sandwich size to large)
Air Compressor
Shop Vac
Awl(s)
Wire Brush
Bench Brush (optional)
Dead Blow or Rubber Mallet

It is important to use the correct tools when the correct tools are called for. For instance, under no circumstance is a Stanley nail set the same as a pin punch just as a chisel is never a screwdriver.

Remove the Top¶

Depending on the fence style remove the screws holding the rails in place.

For the table extensions I find it best to loosen all the screws but remove the two screws at each end first while supporting the table with my gut. The reason for the support is once you have two of the three screws removed the whole weight is on the last screw which isn’t quite rated to hold the entire extension. I like it loosened because I can gage when there’s pressure exerted and in fact I hold it up (don’t let it sag to where all the weight is on the one screw). With those gone, and still supporting the table, remove the last screw. The table will want to swing down one end or the other and you can just let it do so while holding the table with one arm and removing the last screw with your free hand. It does not hurt to note which extension is right and which is left.

Before moving on to removing the top it is a good idea to make note of where one or the other miter slot is in relation to the blade. Chances are you’ll never get it exactly right back where it was (exact being within a “thou” or two) but you need to get it as close as possible. This will ensure that any sleds you have or zero clearance inserts will not have to be overly re-calibrated. More on re-aligning the top can be found at the end of this articlette.

With the extensions off you only need to remove the four hex head cap screws at the four corners of the cabinet and the top is off. At this point the table can be handled by one person but it doesn’t hurt to have a helper.

Yank Out the Guts¶

Now you are gazing into the cabinet and in awe of the genius of Herbert Tautz. Despite your first thoughts that only a fool would press forward believe me, it tain’t nothing what you are about to do next.

View Inside Cabinet With Top Off

Start the process with a good cleaning. Remove all the saw dust. Using your awl, a stiff bench brush and brass wire brush get into every nook and cranny and remove the built up grime. You’d not believe how easily you’ll over look set screws hiding beneath a couple/few decades of inattention. Get it all.

Your next step is to take pictures. Take lots of pictures and while you are at it go to the Old WoodWorking Machines Web page and download a parts drawing for your vintage. I like to take parts drawings and enlarge them at the copy machine at work (of course) and make several copies of each page. I use these in conjunction with a high lighter and make pages specifically for each of the major assemblies. That way I can clearly see what it is I’m working on and not be distracted by all the other parts. I also use parts drawings from different eras and actually sometimes prefer the newer drawings as they might show how parts are arraigned better than the older drawings.

Splitter Bracket

Splitter Bracket Removed

The view from the front of the saw to the back is as follows. Standing at the front of the saw, the part across the front attached at each end to the saw cabinet is the Front Trunnion Bracket. Its job is to sit there and allow the saw blade to tilt. This part is machined with a half moon Trunnion and fitted into that, the next part in line, is the Front Trunnion Assembly. The Front Trunnion Assembly is the part that moves when you tilt the blade and in turn has attached to it the Yoke. The Yoke’s job is to join the Front Trunnion Assembly to the Rear Trunnion Assembly and to hold the Motor Bracket. Attached to the back end of the Yoke is the Rear Trunnion Assembly. Its job is the same as the Front Trunnion Assembly and attaches via the same half moon Trunnion to the Rear Trunnion Bracket which is secured to the saw cabinet just like the Front Trunnion Bracket. It’ll become clear as you move through the clean up.

View From the Front of the Saw to the Back (yes, Same as Above Picture)

Back to the Yoke for a minute, you’ll notice a large pin going through it and to that pin is the aforementioned Motor Bracket. To the left of that is the Arbor Bracket which by the name tells us that it holds the saw arbor.

Hopefully you aren’t so silly to have not removed the saw blade prior to now so I won’t ask you to remove it at this time. Open up the switch box and disconnect the wires. It’s never a bad idea to make a sketch (schematic) of how the switch is wired.

Remove the blade tilting Hand Wheel (side of cabinet) and tape the straight key to the Hand Wheel and set these aside in one of your parts tubs. You can leave the blade raising Hand Wheel (front of cabinet) on for the time being.

Blade Tilting Hand Wheel

Lay a cinder block or a stack of tubafors on the ground and tilt the saw over to the left (as viewed from the front) so the top rim of the cabinet rests on the blocking and so the motor opening is in the up position. This will prevent you from buggering the end of blade raising shaft that exits the side of the cabinet. The motor is held in place by a large hex head cap screw and a pivot pin. Loosen the screw but don’t remove it. The pin should be held in place with a wire spring clip. Remove the wire spring and then the pin. Depending on age and grime you may need to drive the pin through with a large (I used a 3/8”) pin punch. Next you can remove the hex head cap screw. Please note that this can be done by one person but a helper would be most helpful as the motor (90 to 100 lbs on a vintage saw) will want to fall into the cabinet when the screw is removed.

Tilt the saw cabinet back up and marvel as to how much lighter it is.

Motor Off

On the side of the cabinet where the blade tilting shaft exits you’ll find a Shield Plate held with two fillister head cap screws (cheese head screws). Remove those and place all the parts (including the fiber washer) into a baggie.

Remove the blade raising Hand Wheel (front of cabinet) and set it aside with the straight key. Don’t tape the key to the Hand Wheel at this time as you will need both of these pieces at different times throughout the disassembly.

Blade Raising Hand Wheel on Front of Saw

On the front of the saw and sitting in the “smile” cut out that allows the blade raising shaft to swing you’ll find a Pointer Bracket over the blade raising shaft. It is held in place with two Special Fillister Head Cap Screws. Believe them when they say “special”. Remove these screws and place the Pointer Bracket, screws and fiber washer into a baggie and that baggie into a parts tub.

"Smile"

Remove the saw dust deflector (U-shaped piece of bent steel attached to the Blade Tilting Trunnion).

Dust Deflector

Now we’re getting serious and about to go beyond the point of no return. There are two different approaches to removing the internal guts of a unisaw. One approach is to remove the tilt shaft while everything is still inside the cabinet, which frees up the tight fitting connections between all the major components and enables you to lift them straight out. The other approach removes the major components intact for further disassembly on your bench. Yes, believe it or not you can remove the entire guts of the saw with minor disassembly. I know because I did it. The shafts on my saw were so buggered up and grimy that I just couldn’t remove them to facilitate an easier disassembly. For the record, the doing of this (removal with little disassembly) was as close to child birth as I will ever get, and despite the fact that the official hat of the club of those of us that have done it is the dunce cap, we are a proud bunch.

Some people find that it's easier to use the first approach where you remove the shafts by popping out the pins, with the castings still installed inside the cabinet. Others find the second approach easier and faster by pulling the castings and taking them to the bench to drive out the pins. In some cases, folks may not even remove the pins to take apart the assemblies, choosing instead to just tape them off before painting. Over time, we've come to see that pulling the guts intact is not as daunting as it seems at first, and many folks use this approach as the first option rather than as a fallback. A primary consideration of which approach to use is how much fight the taper pins give you when you first go to drive them out. Some have been known to come out with a few good solid raps with a well placed punch and deadblow hammer. Others have been known to fight back with a ferocity that makes a sledge hammer shudder. If you are trying the first approach and your taper pins are putting up a good fight, it's probably a good idea to change approaches rather than to grab a bigger hammer and whack on it even harder.

Approach 1: Removing the guts by pulling the blade raising and blade tilting shafts first.

Now the real fun begins. Inspect the two shafts used for blade raising and blade tilting. These need to be removed but it’s very important that you follow the procedure. Don’t Ask Me How I Know This. If the shafts are the least bit grimy, clean them. Lube the shafts using WD-40 and start scrubbing with a coarse Scotch Bright pad. Get them clean. Shiny is not required. Next inspect the shafts for any buggering (raised metal) and file away the high spots with a fine metal file.

Height Adjustment Shaft

Tilt Shaft (With Gears Removed)

Height Adjustment Shaft Removed

While cleaning you will see that there are collars and worm gears attached to the shafts. On vintage saws these are held in place with tapered pins and set screws. On later saws the pins were replaced with roll pins and in some cases Allen head set screws. Your next task is to start loosening these collars and worm gears. If you have the tapered pins it is important that you drive these pins out in the right direction. The tapers are very slow and you will find yourself scratching you head wondering which side to drive from. Be careful and find the narrow side. Using a small pin punch begin to drive them using a moderate blow. If nothing happens increase the blow but do not wail on them. You may need to apply some Marvel oil and let thing sit a bit before proceeding. Another procedure is to use a small C-clamp and a washer. Place the washer on the wide side to where the wide side of the taper pin will exit into the hole of the washer. Use the C-clamp to apply pressure. This method is a lot smoother than banging on the machine and possibly breaking parts. Again, the important thing is to determine which end of the taper pin is small and which is large.

The worm gear attached to the blade tilting shaft has to be rotated to where it allows the pin to be driven from the inside of the cabinet towards the front of the cabinet. The Front Trunnion Bracket actually has a hole cast into it to allow for this and the shaft has to be oriented to where the pin is parallel to the ground.

Once all the collars and worm gears are free you may still need to go at the shafts and clean the areas under where the collars and worm gears sat to allow the shafts to slide free from the saw cabinet. Slide the now cleaned shafts out while catching the collars and worm gears as they become free.

It is very important that while you are removing the collars and worm gears that you mate them back up with their respective pins and set screws. On my saw and other saws I have disassembled the holes for the pins were drilled with the parts in place making each hole unique to the part and where it places on the shaft. It is a very good idea to reassemble the collars and worm gears to the shaft once all is removed from the saw cabinet. Place these assemblies into a parts tub. Never allow yourself to being lulled into thinking you’ll remember where everything needs to go. Don’t Ask Me How I Know This.

Also, depending on the vintage of your saw there will be Wedge Key (butterflies) or brass bullets at the Hand Wheel ends of the shafts. These are what press into the inside of the Shield Plate and Pointer Bracket to lock the blade raising and blade tilting. Place these back where they need to be on the shaft prior to setting aside. It never hurts to wind some masking tape around the shaft so they don’t fall out later.

Congratulations! The sphincter puckering hard parts are done.

You can now remove the Arbor Bracket at this time. Actually this could be removed prior to the shafts but I’ll take you through the process and you can decide which order to use. The Arbor Bracket is held to the shaft coming off the Motor Bracket by a hex head cap screw. Loosen but do not remove the cap screw. It may take some Marvel oil to loosen the seat on the shaft. To remove the part take a large screwdriver or pry bar and pry the part away. It seems like a bad idea but really it’s all you can do. Once you’ve maxed out the pry of your bar take a 1X piece of wood and back up your pry bar and pry some more. Eventually you’ll be greeted by the satisfaction of a part slipping away for the first time from where it sat for years or decades.

If prying is unsuccessful at removing the Arbor Bracket, instead you can use a gear puller with two claws on it. The end of the motor bracket shaft doesn't have a center dimple, so to keep the point on the puller from digging an ugly off-center dimple in the shaft, I put a 1/4" nut between the end of the shaft and the puller.

Pulling arbor instead of prying

Arbor Assembly Removed

The next step is to remove the hex head cap screws holding the Front Trunnion Bracket and Rear Trunnion Bracket to the top of the saw cabinet. Your first thought will be that all the castings will come crashing down into the cabinet but things are tighter than that and you will be able to remove the screws while everything remains suspended. It doesn’t hurt to have an extra pair of hands but you can remove the combined assembly of these parts all by your lonesome. The procedure is to swing the assembly made up of the Front Trunnion Assembly, Yoke and Rear Trunnion Assembly and let it slide along the half moons (Trunnions) of the now loose Front and Rear Trunnion Brackets. It’s that simple and as easy as eating pie.

Trunnion Assembly Removed

Take the now removed assembly and place it on the bench or in a parts bin if you have one large enough. Return to the saw and pluck the Front and Rear Trunnion Brackets off the saw cabinet rim before you bump the cabinet and cause them to come crashing to the ground.

Front and Rear Trunnion Brackets Removed

All Apart!

Approach 2: Removing the guts leaving the major components assembled.

If you find that it is particularly difficult to pull the main shafts for some reason, an alternative approach for removing the guts is to pull the main component assemblies out of the cabinet intact and do the further disassembly on your bench. Here is how you do it, noting that it is not as straightforward in real life as it appears here in print.

These photos are taken from the front of the saw, with the manual labor occuring in back.

Step 1. Preparation. Remove all exterior parts and bracket mounting bolts as described in various instructions above. Remove the arbor bracket as described above and tilt the arbor a fair bit. Push all of the components as tightly to the front of the cabinet as possible. Don't forget to remove the guide block on the bottom of the gears.

Starting point

Remove the guide block

Step 2. Remove the rear trunnion bracket. Gently wiggle the rear of the yoke and the rear trunnion bracket apart, to the point where the half-moons of the two pieces disengage. You may need to lift the yoke assembly a few inches to provide clearance above the edge of the cabinet for the rear bracket to disengage completely and slide out. Note that the yoke should not fall off the front trunnion if you happen to let go of it for a moment after removing the rear bracket, but that is neither recommended nor encouraged.

Separate the rear trunnion bracket from the yoke

Lift the connection slightly

Lift the rear trunnion bracket out

Step 3. Remove the yoke. This is the (in)famous drop/twist/rotate/lift all-at-one-time move. That's literally what you do. It helps to have a second pair of hands. First pull the yoke towards the rear of the cabinet to disengage the half-moons from the front trunnion. Then, bearing the full weight of the yoke, drop the front end down, twist the yoke so that the gear teeth come up towards the side, rotate the entire assembly as much as possible diagonally across the cabinet. Curse at it a couple times, look to see how much further you need to go for the shaft to clear the cabinet, and wrestle it on out. Nicely done.

Separate the yoke from the front trunnion bracket

Drop the front end of the yoke

Twist, rotate, and lift the yoke out

Step 4. Remove the front trunnion bracket. Now that the heavy lifting is done, the front bracket comes out easily. Gently ease it to the side and rear so that the shaft clears the cabinet, and lift it out.

Note that this photo is taken from the right rear of the cabinet, not the front.

Remove the front trunnion bracket

Pull the front trunnion bracket out

Step 5. Relax and smile. Enjoy the fact that you just got those things out of there and realize that in a few days/weeks/months you'll need to reverse the process to put them back in just so. Here is what they will look like sitting in your shop at this point.

Unisaw guts removed intact

Take a break, make yourself a cup of coffee, have a smoke, even if you don’t smoke, because you deserve it.

Disassmble the Subassemblies¶

From here it’s a matter of studying the parts against the parts drawings and becoming familiar to what Herbert Tautz had in mind when Delta was designing the Unisaw. It’s all pretty simple but I’ll go over a thing or two.

The Front Trunnion Assembly, Yoke and Rear Trunnion Assembly will all need to be taken apart. The Front and Rear Trunnion Assemblies are held to the Yoke by hex head cap screws and are located with dowel pins. You’ll remove the cap screws but the parts probably won’t come away from each other. Use a dead blow or rubber mallet to separate these parts. A little Marvel oil will go a long way and you should not wail on these parts.

Trunnion Disassembled

Base Removed

At this point in time you’ll be looking at parts bins full of parts, assemblies and baggies with the itty-bitty parts and pieces. What I like to do is start cleaning by assembly. This way you only need to keep track of those parts and pieces and won’t find yourself later trying to remember what went where and why. Don’t Ask Me How I Know This.

You might be tempted to try and remove the brass bushings from the Front and Rear Trunnion Assemblies but I’ve never seen a need for this. Partly because I’ve never found them that critical to clean, they don’t wear that badly and I was plain afraid of cracking the castings trying to remove them. Speaking of cracked casting, never force parts beyond what you feel comfortable with. Most parts are a press fit and a little Marvel oil is usually all you need to help with freeing up a piece. A cracked casting, especially if it becomes cracked by your stupidity will pretty much ruin the best of days.

Cleaning and Replacing Worn Parts¶

At this moment you should strongly consider replacing the arbor bearings. This can be done by you with the aid of an arbor press. I would not try and jimmy in bearings with a hammer. If in doubt contact The Saw Center and consider their package of bearing replacement and truing up the arbor flange. It’s actually inexpensive (less than a hundred) and they provide new bearings and true up the arbor flange in place making it just about as good as it gets.

It is a very good idea that as you work your way through the cleaning (and painting) that you reassemble as you go and to bench assemble all the parts to be sure you have everything back to its functioning position prior to loading it all back into the saw. Don’t Ask Me How I Know This.

You will be tempted to replace the fiber washers to take out back lash in the hand wheels but if you use washers too thick you’ll find you can’t crank the hand wheel at all. A small amount of back lash is needed to make the hand wheels function correctly.

Painting¶

Give some thought to painting. For the interior pieces Rustoleum Machinery Gray is just fine but will not be correct to the vintage of the saw. For a correct color find a painted part that has sat against another part (where the Trunnion Yoke sits against the Front and Rear Trunnion Assemblies is good). This surface will not have oxidized like exposed surfaces. A good paint store can computer analyze this surface and make up a perfect color match. You’ll need at least a pint of paint to spray a saw. (Note: Paint info may be available here.

If you decide to paint you’ll notice that time will appear to stand still. There’s nothing worse than waiting on paint to dry.

Reassembly¶

Reassembly is basically a repeat in reverse of what you’ve done. As I said it’s not a bad idea to bench assemble the parts and be sure to have everything and everything in its proper place and orientation. Remove the shafts from the bench assembly, set the worm gears and collars in order of how they go back in and have the pins close at hand. While re-installing the shafts back into the cabinet don’t quite drive home the pins. Instead wait until you are sure you’ve not botched the re-assembly. The pin holding the Blade Tilting Worm Gear may rub against the Front Trunnion Assembly so be aware of this. It’s not a problem and the rubbing will go away once you have driven the pin home.

Lubrication¶

Somewhere throughout all of this you will want to lubricate the guts of the saw. You need not do it as you go nor do you need to wait until it’s all back in place (prior to putting the lid back on). An advantage to doing it as you go is it gets done specific to the spots where lubrication is needed. The down side is you have to be careful when handling the assemblies (you get lubricant on yourself). Personally I recommend that it be the last thing you doing prior to installing the blade guard and putting the top on. The recommended lubricants are shown on the Web pages below.

Dry Moly

Penetrating Lubricant

I am not recommending the brand and you can use an equal found locally to you.

With the saw at 90 degrees and the arbor fully down spray the worm gears and segment racks on the Motor Bracket and Tilting Trunnions. Tilt the arbor to 45 and raise the arbor fully and re-spray the same parts. Run the hand wheels lock to lock a couple of times to distribute the lubricants. You are done. In the future you can re-lubricate these items with the top in place but you will have to remove the Dust Deflector (bent steel shield in front of blade) to do so.

The Blade Raising Shaft and Blade Tilting Shafts should be lubricated where they pass through the brass bushings. These also can be gotten to later but doing this before the top is on is easier.

Mount the Dust Deflector and replace the Top and you’re done with assembly. The top will more than likely need alignment. Going back to the dimension you took before removing the top re-align the top as close as possible to that dimension. Aligning the top on a cabinet saw is relatively easy. Since the top sits atop the cabinet you can minutely shift it left to right, front to back or corner to corner. Start by finger tightening all four hex head caps screws found at each of the four corners. Wrench tighten these screws slightly (until enough pressure bears on them that you cannot move the top by pushing).

Calibration¶

Ways of calibrating the slots to the blade are many (OK, that’s a lie, there are only a small handful). Some say they can do it with some chewing gum, dental floss and a pointy stick. Others swear by a brass screw in the end of a stick and a sloppy miter gage. The definitive method, In My Humble Opinion, is to use a dial gage. I’ll not go into it any further as the site below does a much better job of it.

http://www.ts-aligner.com/newindex.htm

Now, do you need a $150 gizmo to re-align a top? No, though you do need to understand all that’s involved. Read what’s said at the above site and decide for yourself. I will say this. With a saw that’s properly tuned (a true arbor and flange aligned to the miter slots and with a fence aligned to the miter slots) you can get glue line rips with a good blade. Don’t feel like going through all of this? It’s your time and your money.

There is also an argument that goes like this. The wood will change overnight. It will swell, shrink, twist, cup and bow making all these finite calibrations we make on our machines foolish because, well, the wood changes. Whilst I agree the wood does what the wood wants to do I also feel that taking the inadequacies of the machine out of the equation leaves us with only having to worry about what the wood is doing. In other words, the machine establishes a zero datum that we can always rely on allowing us to worry about the rest of the stuff. Life, it is good.

Last but not least take pictures of your brand new saw. post them on the Mothership, and send them to your friends, family and co-workers. Sure they won’t have a clue but what do you care, you’ve got a brand new saw!