Ryan,

I see... Sounds good. I'll give it a try!

I thought about polishing them. But, they're rough castings with sprue and porosity. It's more work than I really have time for to clean them up enough to even begin polishing. But the thought crossed my mind! I sprayed them in primer this afternoon and I'll paint them with the frame this week, weather permitting.

Painting the Band Wheels

Yesterday, I had a few minutes of spare time, so I masked off the band wheels and sprayed a quick coat of self-etching primer.



Then, this morning I had a chance to spray the paint. The wheels will be a slightly darker gray than the machine frame.



Installing the Tires

Today, I received a package from Sulphur Grove Tool, as promised. Inside was a set of the correct, .125" thick, urethane tires.



I set to work this evening installing them on the wheels. They actually went on much more easily than I had originally expected. The key, as described by others as well as Bill at Sulphur Grove, is to heat the tires in warm water. The instructions accompanying the tires stated 140F was the necessary temperature.



The tires did not require any form of lever or tire iron for installation, as you'll see in the video. Just set the wheel on your workbench and wrap the tire around the wheel. Then, hold it in place with your belly while working it onto the rim with both hands from one direction. When this becomes too difficult, rotate the wheel. Using one hand on each side of the tire, push the remainder of the tire over the band wheel lip. Then, simply slide the tire into position on the wheel.

Here's a mounted tire:



Installing the Bearings

With the tires mounted, the only thing left to do to the wheels is install new bearings. The original bearings were shielded on one side and open on the other. The new bearings, 6204-2RS-NR-C3-SR12 are sealed both sides, which should improve bearing life.

The bearings have a clip that runs around the outer circumference of the bearing. This clip locates the outer bore depth in the wheel. It is important when pressing these bearings to be sure not to apply too much pressure or press too far, which might distort or destroy the clip.



Here's the finished product:



Three wheels, ready to go:



Here's the accompanying video, Part #5 of the series:

Installing the Tires and Bearings

It's been a month since my last update, so it's time to post up. I've been busy with other work, so I haven't had a lot of time to work on the saw. Anyway, here's the next installment:

Transmission Disassembly

I decided to make disassembling the transmission it's own post. Partly because doing so is rather involved, and partly because I haven't made the necessary repairs to put it back together yet. I hope to have that done by the weekend.

Here's a photo of the transmission as removed from the saw, from the bandwheel side:



Another photo, from the input shaft side:



As you can see, it's a mess. However, spinning the input and output shafts gave a nice smooth feel in both speed ranges, so I was hopeful that I had a good transmission. The transmission gearing is supposedly available, according to Do-All. At what price is anyone's guess. I was anxious to get it opened up to see the extent of repairs required inside.

To begin the project, I attempted to drain the oil and found it really didn't have any oil in it! I drained about approximately a cup of 80W gear oil. Better than no oil, I suppose, but not enough to keep the large reduction gear set lubricated.

Before opening up the transmission, I had a look at the illustration in the Do-All parts manual, to guide my work.



As you can see, the transmission has three gear sets. From the right hand side of the illustration:

Input reduction set
High speed set
Low speed set

The transmission is shifted between high and low range with a sliding shift dog on the upper shaft.

With the illustration fresh in my mind, I began by taking the the bearing covers off, followed by removing the case cover. While removing the case fasteners, I realized that somebody had been here before me. The case fasteners are 1/4-20 recessed head screws and all showed signs of having put up a battle for the last guy. They came out easy as pie for me.



Initially, I was disappointed at the sight. Everything is caked in sludge! Not that I wouldn't expect that from a transmission this old, I just wanted to see more oil!

After inspecting the gearing, I was pleasantly surprised. The only gear that looked worn is the low-speed pinion, as shown below. Thankfully, the gear tooth faces are not spalled, just worn. I don't think the wear is particularly bad either, considering it ran without oil for who knows how long. I've seen far worse come out of aircraft engine accessory drives!



The next step involved removing the shift dog and bandwheel bull gear. It simply lifts off the pilot stub of the input shaft.



After tapping out the input shaft and it's two bearings, I was left with the brain teaser:



Referring back to the parts catalog illustration, you'll note that the large gear, part of the input reduction gear set, is keyed and pressed onto the secondary shaft. The same is true of the spacer and high speed reduction gear. Complicating things is the wall of cast iron preventing the whole assembly from being withdrawn from the case, which must happen to replace the secondary shaft bearing behind it.

I thought about this situation for a couple of minutes, when I had an idea. I decided to support the input reduction gear with two pieces of angle iron faced square. Then, by inverting the entire transmission in the press and pushing on the secondary shaft though it's bearing, I'd press it out of the input reduction gear.

Here's the angle iron setup:



As you'll see in the video, it worked perfectly.

With everything basically apart, I headed over to the solvent tank to begin the de-gunking process. Ever lose tools or parts in the lagoon? This had been in there at least three years! I wondered where it went....



Here are the parts, after the gunk tank:

Overall, I'm happy with the condition of the gears in the transmission. While they show obvious signs of wear, they should be serviceable for at least another 15 years. At that point, I'll make new gears.

VIDEO: Transmission disassembly

In the next post, I'll cover machining and installing a new main shaft pilot bearing, painting, and reassembly. :beer:

Machining a new output shaft support bearing

I posted about this last week, asking for thoughts on the finished bore size of the bearing.

After disassembling the transmission, I noticed that the output shaft support bearing was bell-mouthed about .011". New spec on a bronze bushing this size should be about .001" to .0025" greater than the shaft diameter, depending on the shaft speed differential according to Machinery's Handbook. Obviously, I needed to do something about this.

I decided to err to the large size, as I felt a fit of .001 would bind. I settled on a fit of .0025 to .003", which is the outside of the fit range shown in the handbook. I suspect the machine had been operating for years with the incredibly loose bushing. I didn't want to have to take the transmission apart again just to shave a hair off the new bushing due to tolerance buildup in the output shaft bore.

Extracting the old bushing proved to be another brain teaser. It was bottomed in the bore, so a standard bushing puller wouldn't work. In addition, it was seized in the bore, so threading it and using a slide hammer would have presented a work holding problem. I used a trick I learned as an apprentice. I threaded the bushing 1/2" NPT and install a 1/2" pipe plug, drilled to accept a grease zerk. Then, I blocked off the oil holes with sections of softwood and C-clamps and pumped away. The bushing broke free with only a little effort. Once it reached the oil hole, it was loose enough I could finish extracting it with a hammer and a short section of pipe as shown in the video.



While I was over at the bearing supply picking up the new ball bearings for the transmission, I also bought an oil-impregnated bronze bushing blank:



I turned the blank to be a press fit in the shaft and roughed out the inside diameter:



Then, I beat the new bronze into the shaft and cut off the excess:



Over on the Pacemaker, I faced and bored the new bronze to final size:



To finish, I drilled a new oil hole though the wall of the new bushing:



Here are the two halves brought back together again:



This was the only repair work I had to do inside the transmission, beyond replacing all the ball bearings. I'll be covering reassembly in the next post.

Here's the accompanying video:

Rebuilding a Do All Saw, Video #7

Reassembling the Transmission

Once I finished machining the new bronze bushing, I could begin reassembling the transmission. Here's the remainder of the box of stuff I got from the bearing supply:



My supplier could not obtain the original Norma Hoffman bearing installed in my transmission. He suggested a Hoover substitute, which was also standard equipment on other serial number Do-All V-36 transmissions as shown in the parts catalog. Each type of bearing uses a different cover plate, as the width and depth of the bearing flanges are different with each design. Later, you'll see how I dealt with this.

My bearing supplier had the 6204 bearings in stock, but only in the 2RS (both sides sealed) configuration. I decided to "convert" two of them to 1RS bearings and the third to an "open" bearing, to allow transmission oil to lubricate them. A little screwdriver is all you need to pry out the seal.



Here's the first bearing installed, one of the counter shaft support bearings:



With the counter shaft bearing in place, I pressed the counter shaft into the transmission.



I didn't quite get the counter shaft seated on it's spacer the first time, as this view though an inspection mirror shows:



Next, I installed the input shaft outer bearing:



Then, the input shaft can be pressed into the outer bearing. The spacer goes between the bearing and the input gear. I suggest using a small screwdriver to test the shaft for seating. Try to move the spacer around the shaft. If you can't, then the shaft and gear are seated firmly on the bearing.





The input shaft inner bearing can then be pressed over the shaft and into it's bore. I used a washer to distribute the load between the inner and outer race. A cheap deep socket that fit over the input shaft transferred the press load.

Once the inner bearing is in place, tap on it to be sure it's seated. Then, install the low-speed gear thrust washer on top. Shim the outer input shaft bearing to it's bearing cover until the thrust washer is clear of the case .020 or so.



This photo shows the outer input shaft bearing before installing the bearing shims and the cover temporarily to hold everything in place:

Then, the shifting clutch, shift fork, low speed gear, and output shaft can be installed. (See the video for more detail).

The transmission originally used thin paper gaskets, no thicker than regular printer paper. This is because the varying effects of a crushed gasket will disrupt the shimming of the outer bearings. Rather than make up some paper gaskets, which I knew would leak, I used Aviation Form-A-Gasket. It is specifically designed for this application, sealing surfaces which must mate very closely together due to internal machined features. A common application for Form-A-Gasket is sealing the case halves of an air-cooled horizontally opposed piston engine.



Here it is, ready for the cover:



Next, the cover fasteners are installed loosely, and the main thrust bearing and the other counter shaft support bearing are placed. I used a small hammer and a soft steel pin punch for this application. Normally, I would be afraid of brinelling the bearing. However, the case bores are a very light press fit while the shaft fit is reasonably tight. Very little load is transferred from the inner race though the balls to the outer race. These steps are shown in the video as well.

As I explained earlier, the Hoover bearing is slightly wider than the Norma Hoffman bearing removed. Do-All made a special deeper cover to fit the Hoover bearing, which stands 3/32" too proud of the case for the Hoffman bearing cover. Rather than attempt to order one, I decided on a different approach.

First, I cut a 1/8" thick rubberized cork gasket. Then, I used a .065" bearing shim on the counter shaft outer bearing. I torqued the cover bolts until I felt the cover seat on the back side of the both bearings, compressing the gasket approximately 1/32".

Here's the gap left by the taller Hoover bearing:



The finished gasket with the shim in place:



The finished transmission, with the cover installed:



Now I need to decide what I'm going to do next. Maybe I'll paint, or maybe I'll start in on the trunnions? I suppose it will just depend on my mood when I start the next work session.

Finally got the latest video to upload:

Do All Rebuild Video #8, Transmission Reassembly

Pmech, great thread. Keep up the good work.

I liked your tip on getting the bushing out with a grease gun. My question is, what would be the drawback in just boring out the old bushing on the lathe?
Thanks in advance for your insight..

Michael

Michael,

Thanks for the compliments.

I could have bored the bushing out. In fact, I considered that option. However, it would have required a second setup in the lathe as I would have had to remove it to pound in the bushing. At least .005" of the bushing would still have to be picked out by hand from the deep bore, unless I spent a few minutes to center things up very carefully like I did when I bored the new bushing.

Tapping and pushing out the bushing just felt easier at the time. I probably didn't save any time after drilling the pipe plug, but it went into the "special tool drawer" for future use.

The grease gun trick really shines when a bushing is pressed into a blind bore to full depth, in an object too awkward to fit in the available machinery. Any thread you can get the bushing to take will work. It's best used with a "high pressure" grease gun that has a long handle. It's also a great "field" trick, for use out in the sticks away from the shop. Standard internal bearing pullers use little fingers to grip behind the bearing or bushing. If the bushing is driven to the depth of the bore, you might as well throw your bearing puller into the weeds.

Well, I woke up Saturday morning with the full intention of painting the machine and all the smaller parts I have primed and ready. However, overnight some weather moved in. It started raining about 5am. By 2pm, I went down to the shop and just started looking over all the pieces, trying to decide what to do next. I was bummed, as my plan to paint was shot all to hell. So was sandblasting the trunnions, which needs to be done outside as well.

While looking at the pile of removed parts, I spied this little thing, the blade tachometer:



What the heck? Let's rebuild that!

Luckily, I spent a lot of time talking to and watching aircraft instrument repairmen at a repair station, as the work interested me. Lots of the tricks I learned I used for the first time today.

Band Speed Tachometer Disassembly

As you can see, the tach is in rather nasty shape. The indicator is hung up, as one of the instrument face screws has vibrated loose, causing the face to seize the needle shaft. Not for long!

The first step was to remove the front trim bezel and the crystal. To do this, I had to pry the trim bezel open in four locations, as shown below:



The first thing I noticed was a date, written on the inside of an acetate window for lighting the tachometer. The tach was built sometime this month, 63 years ago.



Then, I extracted the instrument from it's bucket:



Followed by removing the needle and instrument face. When removing an instrument needle, there are two approaches:

1) Lubricate the shaft. Then, gently turn the instrument to the zero stop and keep twisting, while gently pulling up. The needle should pull of it's tapered shaft easily.

2) Use a hand remover with internal punch such as the tool shown below:



I used technique #1. NEVER attempt to remove an instrument needle by simply pulling, or prying it off the shaft. You will bend the shaft and destroy the instrument's bearings or jewels.



Then, I taped up the cup and indicator shaft so I wouldn't lose the spring preload and removed the forward bearing. This is another trick. By wrapping electrical tape around the shaft, the cup is kept up against the zero stop, preventing loss of spring preload.

Aircraft instrument manufacturers provide specifications for spring preload at the zero stop in the form of torque around the shaft, or turns from slack spring. Unfortunately, I don't have those specifications for this instrument. If I lose the spring, I'll have to re-calibrate the instrument by trial-and-error once the machine is operational. So, it's imperative that the assembly be handled with care!



Finally, I removed the eddy cup to access the magnet and lower instrument bearing.



With the instrument apart, I noticed that the magnet bearings were rather gummy. Initially, I considered taking the assembly apart completely. However, this proved impossible due to the design. The shaft is actually hollow, to accept the teleflex cable. At the cable end of the shaft, it is swaged over a tapered bronze thrust washer. I didn't feel comfortable removing this, as I didn't want to have to make a new shaft.

Instead, I found a small brass plug pressed into the side of the journal:



Behind the plug was a small piece of oiled felt. After removing the felt, I realized the instrument used a journal bearing. So, rather than take it all apart, I simply flushed out the journal with carburetor cleaner though the felt hole.

That completed disassembling the instrument. For more information on how an eddy current tachometer works, check out this link:

http://auto.howstuffworks.com/speedometer2.htm

Here's the latest video:

Do All Saw Rebuild Video #9, Band Tachometer Disassembly

Band Tachometer Overhaul and Reassembly

This morning, I set to work rebuilding the tachometer. I finished just a few minutes ago, after a solid 14 hours of work.

One interesting tidbit I discovered is that the tachometer was made by the AC Spark Plug Company of Flint, Michigan. It is a converted automotive speedometer, as it has obvious provisions for a recording odometer and trip meter. In fact, several patent numbers I found on the frame cover things such as a "quick resetting trip meter" with a patent date of 1938!

I began this morning by cleaning up the gauge face. I did this in two steps. First, I used 3M Perfect It compound to gently rub off all the gunk and dirt built up on the laquer finish. Then, I sealed the face with 3M Hand Glaze.

Here's before:



and after:



With the gage face cleaned up, I set to work on the crystal bezel and the crystal:



Once I had the bezel, shadow ring, and trim ring apart, I set to stripping them, along with the needle:





After a thorough cleaning, here's what they looked like:



Then, I painted the shadow ring Satin Black, as I didn't have any Instrument Black (very Matte Black) on hand. I also painted the needle, using Satin White:



At this point, I was presented with a problem. The same guys who painted my saw an ugly, nasty hammertone blue also went wild with a wire wheel. Not only did they get a couple placards, they also got the brass trim ring that surrounds the tachometer when mounted in the saw:



I looked at it for a few minutes, totally dissatisfied with the idea of going to all this trouble only to install that ugly thing as the crowning trim. I considered machining one from solid, but then I had an idea: Why not build up the damaged areas with solder, just like body leading? I've done it in the past, why should this be any different? Under no circumstances was I going to use body filler, it would only crack out at a later date, probably during installation of the flexible ring.

So, I wrapped the trim ring with some .020" safety wire to keep the silver solder joint together and got to it:



The torch in use is the commonly available Smith "Micro" torch. The smallest tip has a ruby orifice .006" in diameter, roughly the same diameter as a human hair. Here's a scale comparison:

After cleaning away all the dirt as best as I could with Scotch Brite, I used regular old plumber's flux and electrical solder to build up the worn areas.



Once I faired in the lead with a file and 400-grit sandpaper, I was left with this:



Which looked like this after primer. Look Ma! No missing chunks!



At this point, I was left with a pile of cleaned an painted parts that looked something like this:



Before I could actually begin reassembling things, I needed to make a few parts. The first part I made was the oiling hole plug. Here it is, turned from a piece of scrap brass. The dime in the photo provides scale:



The next thing I needed to make are two silicone gaskets to mount the crystal.



Reassembling

At long last, I could finally had everything in order and could begin reassembling the thing. To begin, I lubricated the magnet journal bearing with Automatic Transmission Fluid, which approximates instrument oil closely enough for this application. Then, I installed a new felt, saturated it with ATF, and tapped home the brass plug.



Then, using another instrument repairman trick, I lubricated each of the instrument bearings with ATF using a piece of .020" safety wire. By dipping the wire into oil, a small amount adheres and flows down the wire. The depth to which you dip the wire regulates precisely how much oil forms as a droplet at the end of the wire.

I reinstalled the eddy cup and very gently seated the instrument's main bearing.



Once the eddy cup was in place, I set the upper instrument bearing and thrust washer. The frame for the upper instrument bearing also holds the gauge face, so that was the next thing to go on.

Another thing I learned from the instrument repairmen is NEVER touch the gauge face with your fingers after cleaning it. Otherwise, every pilot who looks at your overhauled instrument will also notice your fingerprints. Not only is it annoying, it's a sign of poor workmanship. Like greasy fingerprints on a white cowling.



I could then install the entire instrument into the gauge bucket:

Then, I cleaned the crystal with rubbing alcohol to remove any traces of finger oil, set the gaskets I made and assembled the bezel to the gauge bucket. I made new crimps using a 3/8" duckbill pliers.



Finally, I trimmed the excess gasket from the front side of the crystal:



Here it is, all ready to go:





The before view again, just for the sake of comparison:



The pile of overhauled parts is growing:



That wraps it up for today! I'll try to get the video up tomorrow evening, so stay tuned.

Here's the video to go along with my last post:

Do All Rebuild Video #10, Band Tachometer Overhaul

Control Switch Cleanup

I had a little over an hour to kill today, so I picked out another small project, the control switch box.

Here's what it looked like before I started:



Interesting Observations On the Age of the Switchgear

Back in my first post on disassembling the saw I remarked about how well preserved this switch was. Today, I learned that the buttons aren't quite original, but it is still rather old.

The original machine had a 3-pole unprotected Cutler Hammer control, as evidenced by this stamp I found inside the switch box:



Yet, the control buttons and the switchgear is Allen Bradley. So, somewhere along the line, they replaced the switchgear and added a magnetic motor starter. Looking inside the Cutler Hammer motor starter enclosure, I found several stamps and placards, with date codes of January 1984, October 1986, and October 1987. So, it would be my guess that the new motor controls were retrofitted sometime in the late 80's.

That's probably about the same time they savaged the machine's placards and tachometer bezel with a wire brush.

Disassembly

There really wasn't much to disassemble here, so I'll forgo the usual step-by-step and leave you with a photo of the parts. There's a trick to getting the buttons apart, as you'll see in the video.



With everything apart, I set to stripping all the old and nasty paint:



While waiting for the stripper to do it's thing, I cleaned the buttons with straight Super Clean degreaser:



Putting it Back Together

Then I went back to the other parts and scraped off all the old paint. After priming and painting the stripped components, here's a pile of cleaned parts ready to go back together:



Here it is, reassembled and ready to go again:



Another addition to the "finished" pile:

Nice job! Keep us updated with the project. I wish I had time to rebuild/refurbish some items in the shop.

Ironically they just finished tearing down the building that speedo was most likely made in....

Great job on the saw going to be a show piece when you are done

A_Pmech, Thanks for an informative and very well documented post. I've got an old DoAll with the same transmission that has a bit of slop, and thanks to you I've probably been saved a couple of days of futzing around with it. I know just where to go and what's causing it. Much more ready to whack it back into shape now.

Excellent job,

Rob