Rebuilding a Do-All band saw

[A_Pmech]

After pressing in the new bronze bushing, I bolted the old bushing and the new bushing together with a 1/2" bolt. Then, I match-drilled the three mounting holes:





Now, I had to install this thing. That proved more difficult than I expected. See, it must mount from the inside, behind two bulkheads in an area already teeming with electrical conduit and the transmission shift linkage. Plus, I have T-rex arms, I can't reach that far!

I remembered that the machine frame has three tapped holes where the bearing plate mounts. So, I drove three 1/4" dome head screws though the frame and tightened them down. Then, I took a section of hot rolled 1/2" steel off the rack and poked it though the mounting hole, though the bulkheads and into the motor space where I could reach it. I pushed the rod through the bushing and fished the bushing plate back to it's mounting location:



Using an 18" 3/8" extension and some electrical tape, I installed the three nuts and lockwashers:



Finished! Yes, it's supposed to be that far off of center.

[A_Pmech]

Rebuilding the Variable Drive, Part 2 of ?

During yesterday's work session which lasted into the early hours of today, I rebuilt the variable speed change mechanism.

After painting the variable speed handwheel and setting it aside to dry, I took a close look at the various components that make up the adjustment mechanism. As I've showed previously, it has been repaired at least once and the main pivot pin had walked partially out of the bore as can be seen here:



I was worried about the condition of the main axle and the pivot pin bores in the main castings. After taking several measurements I determined that the threaded adjuster pin was scrap, as was the main adjustment arm pin. Both were galled and worn out of round in excess of .006". The bores in which they fit were in significantly better shape, having worn less than .001" out of round and still very much on-size. This is likely due to the pins being softer than the cast iron.

The main axle proved to be in perfect condition and required no attention. The pulley spindle and it's bronze bushings were in a similar condition. A slight amount of galling is present on the OD of the pulley spindle where a Bakelite pulley half fits, however I can deal with this on reassembly.

I decided to replace the worn pins with cold rolled mild steel rod. This will ensure that they are softer than the castings. Replacing the pin was a simple case of cutting off a section of cold-rolled, cleaning up the burrs and removing the oxide/oil film. Here's the new main pivot pin fitted:



Being sure that no machine work was required on the cast parts, I painted them and set them aside to dry. Meanwhile, I made a new threaded adjuster shaft to replace the one buggered up by a previous repair attempt:



Next, I liberated the old U-joint from the threaded shaft by grinding off the "shop head" of the rivet they used to replace the dowel pin. This hole is very egg-shaped and allowed the adjuster shaft to rotate in the U-joint.



Obviously, the egg-shaped holes in the U-joint can't remain. I considered drilling them out to 1/4", but that would make the new pinned joint weaker, as it the 1/4" hole would take out the majority of the cross section of the joint. Drilling a new series of holes was also out, as there isn't sufficient room for another two holes, in addition to the three already present.

Rather than make a new joint, I decided the easiest course of action would be to weld up this one. I began by drilling out the two egg-shaped holes to 1/4" and countersinking them to within .030" of the inside diameter.





The countersink makes filling the hole easier, by increasing the available surface area to play the flame on.

While the U-joint was cooling off, I installed the main casting:



Then, I took the freshly painted handwheel and shimmed it to the bearing plate with machine shims. Without the shims, the handwheel rim will rub on the side of the machine:

[A_Pmech]

With the main casting in place, I could now install the pivot arm. Before doing that, I slid the main pivot pin into place and drilled a divot in it though the set screw bore. This should help prevent the pin from sliding out in future, as the set screw will seat into this divot:



Here's the completed pivot arm assembly, including the new threaded adjuster rod and threaded adjuster nut. The long rod on the right is the handwheel shaft. It needs to be cut to length, which will be done next:



Normally, there is no thrust load on this joint. Instead, the threaded adjuster, U-joint, and handwheel shaft are in tension due to the overhung load of the pulley and the motor below.

Since the U-joint bottoms against the main casting and forms the equivalent of a thrust bearing, it's a simple job to measure the length of the shaft. I seated the handwheel against it's shims and measured the depth of the shaft from the machined boss equal to 1/8" less than the depth of the U-joint bore.





Installing the U-joint was simply a matter of sliding it onto the two shafts, tightening down the two set screws and drilling a new hole though the welded area. Drilling the other bore was a little more tricky as the U-joint was already drilled. I handled it the same way I handled Drilling the speed adjustment handwheel in Part 1.



Finally, I lubricated everything lightly with ATF. The mechanism operates smooth as silk, with no squeaks or rattles. Here it is as I left it early this morning:



Regarding the U-joint:

You'll notice that I left the rather crappy "field repair" in place. The mushroomed rod section was actually a sound repair, even though it looks awful. By my normal standards I would have replaced this U-joint entirely by making a new one.

However, I recently watched a program on restoring an 1858 Steinway piano. Four craftsmen at Steinway, with a combined experience will in excess of 100 years, went out of their way to preserve some of the cosmetic damage to the instrument. One part of the restoration effort involved conserving damage caused to the ivory key veneer where mice had chewed the ivory off while the piano was hidden during the Civil War. While this machine is but 62 years old, I believe a few "clues" as to it's age and history should remain. The U-joint will be one of my concessions in this department.

[M. Moore]

Your machine is no Steinway but preserving some of it's history is helpful. I once heard a story about an antique ivory and brass handplane that had very carefully been repaired by it's current owner. Some people were mortified, others thought that there was no one better to do the repair than the master furniture maker who owned it.
"We" are keen to see the final (?) pages of this restoration. How are things coming along, or have you been too busy bandsawing to update us all?
Great thread.

Love the PM!
Michael Moore

[Pete F]

Thanks for taking the time to actually take photos of everything you're doing and then explain here your thoughts and processes. I'll almost certainly never restore the same make and model saw, but for somebody like myself at the bottom of the learning curve the information is invaluable and I try to absorb as much of this knowledge as possible.

Pete

[A_Pmech]

Guys,

You reminded me I need to update this thread. I'll work on posting the updates this evening.


Michael,

No, definitely not a Steinway. But, in it's own right a well-executed piece of machinery, the history and form of which is worth preserving. America as a country is not in touch with it's industrial heritage. Too much of our industrial past is being and has been destroyed in the name of dubious progress while we devour beat up "antique" coffee tables fetching exorbitant prices on "The Antiques Roadshow".

This is one my my little attempts at preserving some of that history. I would have restored the hand plane too.

Pete,

You never know! The 16", 20" and 36" Do-All's share a lot of basic parts and mechanism. Grey Rider's 16" rebuild website has helped me quite a bit.

[Pete F]

Originally Posted by A_Pmech

Pete,

You never know! The 16", 20" and 36" Do-All's share a lot of basic parts and mechanism. Grey Rider's 16" rebuild website has helped me quite a bit.

I was at the steel supplier yesterday and reckon I could have bought a Do-All saw pretty cheap at that time They have 2 modern Do-alls, one bandsaw and one ... I don't know what you call it, some sort of automatic cutoff saw. Apparently they packup almost weekly so guess they don't build them like they used to.

[A_Pmech]

Originally Posted by Pete F

I was at the steel supplier yesterday and reckon I could have bought a Do-All saw pretty cheap at that time They have 2 modern Do-alls, one bandsaw and one ... I don't know what you call it, some sort of automatic cutoff saw. Apparently they packup almost weekly so guess they don't build them like they used to.

LOL!

The current incarnation, the 3613-1 is about 500 lbs lighter than the V-36.

They've shaved a little iron out of them over the years.

[A_Pmech]

I'll be posting a number of updates this evening, please stand by.

[A_Pmech]

Things have slowed a little bit as I'm currently waiting on a few things:

A bearing for the tach drive
Felt for the variable drive pulleys
Parts to finish the saw guides
Belts

Installing the Air System

Now is a good time to install the air system since I'm waiting on parts and because once I install the motor it will be difficult to access the interior of the saw frame.

As I stated earlier, I don't intend to rebuild the air pump the saw was originally equipped with. Instead, I'll supply the machine with shop air for chip blowing duties and possibly the addition of an air-powered feed at a later date. To that end, I acquired a Norgren 60PSI regulator and a solenoid valve from the Surplus Center. These will serve regulate and control the incoming shop air supply. Air will be moved around the machine via 3/8" Nylon air brake tubing, which is readily available, relatively inexpensive, and good quality.

Before I can begin plumbing the machine, I need to find a way to get the air in and out of the machine. No readily available "bulkhead" fittings have the finished look and mechanical specifications I want. So, I made a few of my own.

Note: Yes, the bar is shorter in a couple of the photos, as I didn't get all the photos I wanted on the first fitting. Thus, these photos encompass the making of several fittings, but are otherwise in procedural order.

I began by turning a section of 1.5" hot rolled stock down to 1.25":



I profiled the OD using a tool ground with a 3/32" radius. The "neck" is .75" OD:



I located the center with a center drill, which was conveniently at hand:



Then I drilled the bulkhead fitting for 1/4" NPT:



Then, I parted the blank fitting off the bar:



After parting off the fittings, I tapped them 1/4" NPT:



I made up some paper templates to mark the screw locations. I could have laid them out in the traditional fashion, but that would have required plugging the pipe thread with a section of dowel rod to give my dividers a place to center. This was faster.



Then, I center punched the intersections, pilot drilled with a 1/16" drill and finished with a #25 drill for 10-24 threads. Each hole is .35" deep:



I made a bottoming tap from the remains of a broken tap by grinding it off square:

[A_Pmech]

Finally, I tapped the blind holes to the bottom:



Here they are finished and de-burred, ready for paint. A 90-degree air brake fitting is threaded into one of the bulkhead fittings:



After painting, with a custom-made boring bar I'll be using for another saw part. I'll discuss it in the next installment:

[A_Pmech]

Installing the Air System, Part 2

A few weeks ago, I placed an order with the Surplus Center for a few parts of the air system. One of the items I purchased was a Norgren N72 0-60 PSI pressure regulator. Surplus Center currently had these on-sale and I thought it would be a good idea to make the shop air supplied chip blower pressure adjustable. There's nothing worse than having fine bandsaw chips blasting into your face at Mach 1!

When the regulator arrived I noticed it was missing the bulkhead nut for though-panel mounting. A call to Norgren confirmed that for most regulators the nut is extra and not included. They provided me with the part number of the nut and a local distributor. The distributor informed me that the nut is $8 and Norgren is out of stock until Nov 1, meaning I wouldn't receive the nut until the 5th of November at the earliest. Not acceptable!

Here it is:



Threading Calculations

I had a look at the regulator and determined that the threaded portion of the neck is 39.24mm (1.545") OD, but 16TPI. A 16TPI pitch would be 25.4mm / 16TPI = 1.588 metric pitch. The closest standard metric pitch is 1.5, but that is still too far removed from 1.588. 17 TPI is a very close approximation of the metric 1.5 pitch, being off only .006mm lead per revolution. This thread was definitely not 17 TPI. 1.535 is not a standard imperial thread diameter either. So, I was left with only one conclusion: This is a bastard thread, 39mm OD, 16TPI.

With those measurements in hand, I could begin to calculate the thread profile. First, I had to calculate the height of the sharp V-thread, which is:

.866 / pitch

or

.866 / 16 = .054" Height of the Sharp V-thread

Next, I calculated the depth of the sharp V-thread, which is equal to the major diameter of the internal thread. I found that the thread did conform to standard convention insofar as it's profile was concerned. Thus, the Major Diameter of the internal thread should be equal to:

OD of the thread + (height of the sharp thread)(external thread truncation as a percentage of sharp V height)(2)

1.545" + (.054")(.125)(2) = 1.558" Major Dia, Internal Thread

Finally, I could arrive at the critical diameter, the Minor Diameter of the internal thread:

Major Dia, Internal Thread - (Height of the sharp V)(2)(thread percentage)

75% internal threads, being common practice, were set, generating:

1.558" - (.054)(2)(.75) = 1.477" Minor Diameter

CHECKED:

OD - (Height of the sharp V)(2)(Distance from the truncated peak of the external thread to the truncated peak of the internal thread at 75% internal threads as a percentage of the sharp V height)

which becomes:

1.545 - (.054)(2)(.625) = 1.4775" Minor Diameter

CHECK OK.

So now I had my critical dimensions:

Height of the sharp thread form: .054"
Major diameter, internal thread: 1.559"
Minor diameter, internal thread: 1.477"

Making the Part

I selected a piece of 1/4" 2024 aluminum from the scrap pile. This thickness of nut will expose only a little bit of the first turn of neck threads when the regulator is installed in the machine. A thicker nut would look out of place.

To generate the blank, I used a hole saw with a solid pilot arbor. I drilled four holes in the kerf of the hole saw to aid in chip breaking and removal:



After cutting the blank, I used a center drill to carefully create a center where the hole saw arbor had run:



Over at the lathe, I faced off a section of 1.5" bar stock and drilled a clearance hole in the very center to clear the tailstock center point:



Then, I used the tailstock of the lathe to jam the blank into the faced off piece of bar stock and began turning the OD. Note that I'm using a dead center. This machine has it's own built-in live center, which is MASSIVE, nine bearings in all:



500TH PHOTO!!!

At diameter:



Then, I knurled the OD:



Filing off the displaced metal from the knurling op:



Facing off the front side and adding a chamfer:



The blank, ready for boring and threading:



I'll cover boring and threading in the next post.

[A_Pmech]

Installing the Air System, Part 3

Continuing from the last post, I now had a nut blank ready for threading. Going back a couple of days, I prepared for this operation by making a small custom boring bar to handle threading duties.

This boring bar was quickly made from a section of 1/2" cold rolled rod. I began by drilling a cross hole in the center of the rod, approximately 1/2" from the end. I centered the rod by using a 1/2" dowel pin in the drill chuck and a machinist's square on the drill press table. After spotting the location the cross hole was drilled with a #13 drill, which should produce a close approximation of a 3/16" hole per standard drilling oversize tables.

Here's the setup, after drilling the hole:



Over on the lathe, I installed the rod in a 4" 3-jaw chuck clamped in my machine's 12" chuck. Once centered, I set up my drilling and boring post on the compound. To locate the center of the rod, I used a 1/2" diameter center finder run up against the side of the rod:



I zeroed the DRO and made a move of .5", equal to the radius of the rod plus the radius of the center finder:



Then I located the center using a short and stubby center drill:



After that, I installed a #25 drill in the chuck, which is of course a tap drill for 10-24. Finally, I set the z axis of the DRO to zero when the drill had broken though to the cross hole:



Drilling the hole:



After facing the rod off to length, I tapped the center hole 10-24:



Cleaning up:



I posted the result several days ago, with the threading tool installed. It is simply a piece of 3/16" drill rod ground to the correct profile and installed in the cross hole. A 3/8" long 10-24 set screw threaded into the end holds the threading tool in place.

[A_Pmech]

God Hates a Coward

OK, so now I had a blank 2.5" in diameter than needs to be bored out to an inside diameter of 1.477" (the previously calculated minor diameter) and threaded to a major diameter of about 1.559" Due to the knurling and the desire to preserve concentricity, I didn't want to grip the part from the OD. That didn't leave me with a whole lot of options.

Thinking outside the box, or maybe outside the chuck is more appropriate, I closed the jaws of the 4-jaw chuck to a diameter of about 1.75". Then, I held the part in place on the front of the chuck jaws using the tailstock and placed one thickness of paper between each jaw and the part to prevent marring. I held the part to the front face of the jaws with two hold-down clamps and miscellaneous table furniture. To prevent marring the front side, I padded the hold-downs with a few scraps of leather:



I decided to set the speed at 157 RPM. I figured that's about as fast as I wanted to have the table furniture thrown at my face should anything go wrong.

Beginning the bore, with a small carbide boring tool:



Getting bigger. Not wanting to take any chances, I kept the DOC and feed conservative at .030 DOC and .006 / rev.



Final pass:



Another one of the things I like about this machine, the threading stop:



Threading the part:



Testing the thread:



Finished:





So there it is. $4 in material, 5 hours of labor, one really nice looking bulkhead nut.

[A_Pmech]

Mini Update

I've been fiddling a few minutes here and there installing the air fittings. First, a template is glued to the machine frame:



After spotting, drilling and deburring, the fitting can be installed:



Back side view:



Yesterday afternoon I picked up new belts, more air brake fittings, and my new water pump bearing. I should be getting into that shortly.

[A_Pmech]

Finishing the Tachometer Drive

Since bringing back the new water pump bearing a few days ago, I've repaired and reinstalled the tachometer drive.

Here's the new bearing and the old bearing. There are two differences with the new bearing. First, it is longer on one end. Second, the new bearing is 5/8" on both shaft ends instead of 5/8" on the short (adapter) end and 1/2" on the pulley end:



The bearing is, believe it or not, made in the USA:




I began by measuring the old tach cable adapter and cutting the shaft off to approximate length:



After sawing, I faced the bearing off to final length:



The bearing finished, I began turning up a new tachometer adapter:





Here's the adapter, after parting it from the bar stock:



Since the Bridgeport is outside under tarps and LPS-3 awaiting rebuild, I decided not to disturb it to slit the adapter. Instead, I installed a 1/16" slitting saw in a Weldon shank arbor and chucked that in my Edlund drill. Then, I mounted an X-Y table on the drill and went to town. It worked perfectly.

Having a drill press that has a knee makes these kinds of operations easy. I simply locked the quill and used a dial indicator along with the table elevation adjustment to locate the center of the adapter:



Centered:



Under way:

[A_Pmech]

The slot complete:



Back in the lathe, mounted in a small 3-jaw, I bored the back side for a shrink fit to the bearing and faced the adapter off to length:



Finished:



Shrink fit to the new bearing:



After pressing the new bearing and new adapter into the old housing, I bored the old pulley to fit the 5/8" shaft. Chucking the pulley in a small 4-jaw chuck makes it easier to center:



I didn't take any photos of cleaning up the tachometer cable. Basically, I swabbed the cable sheath out by dragging swabs though it with a wire. Then, I cleaned the drive wire up and lubricated it with white lithium grease and re-installed it.

Here's the interior of the saw as it stands now, with the tachometer drive installed and the belt tensioned:



As soon as the parts arrive, I'll be putting the variable drive together. In the meantime, I'll continue with the pneumatic system.

[A_Pmech]

Finishing the Pneumatic Installation

Yesterday I finished up the chip blower system on the saw, with the exception of wiring the solenoid valve. I'll do that when I wire up the motor, as everything runs though the same conduit.

I began by disassembling the solenoid valve which will control the chip blower circuit:



Then, I took the mounting bracket and installed it on an unused stiffener plate above the motor location:



Here it is plumbed up:



Next, I installed the regulator, which will adjust the airflow to the chip blower circuit. To do this, I had to use a 1.5" hole saw on the 1/8" frame. I located the regulator where it would be easy to service from the back side and not interfere with the many stiffeners inside the saw.

To make the hole, I used a standard 1.5" hole saw, but used a solid pilot. This prevents the pilot drill from augering out the pilot hole, with the usual oversize hole resulting:



Deburring the blind hole proved to be a pain. A die grinder with a round stone proved to be the solution to reaching the burr on the back side.

I prepared the regulator for installation by blocking off the gauge port and the spare input port. Then, I installed two 90 degree air brake fittings to cover the input and output.

While plumbing this regulator I discovered something interesting. The ports are identified by both a stamped marking on the plastic portion of the regulator and stickers placed at each port. These stickers contradicted the stamped port designations! Maybe this is why the Surplus Center got them so cheap, because they're factory seconds?



Regulator installed:



I also installed a Milton Type M connector on the pass-though port below the table. This fitting receives line pressure air continuously, regardless of whether the saw is on or off. I'll mount a blow gun and hose here:



After finishing the plumbing below, I installed the final bulkhead fitting on the topside of the saw. This is the port controlled by the regulator and solenoid valve. It will soon have a length of flexible Loc-Line installed:



Plumbing the back side of this fitting was difficult, to say the least. There's not a lot of room behind the guidepost!

[A_Pmech]

Installing the Guidepost

With the pneumatic installation complete behind the guidepost block, I could now install the guidepost and it's controlling hardware.

First, I made a new friction plate from Brass. The original was Copper and in sorry shape:



With the guidepost and alignment pins installed:



Installing the guidepost was fairly easy. I placed the whole assembly in position and moderatly tapped the alignment pins most of the way home, using a pin punch. I finished seating the guide block using the mounting hardware and clamp handwheel to suck everything together.

Here it is, back on the saw. You can also see the tight spot I had to fit the chip blower plumbing into:



To finish for the evening, I installed the upper guide block assembly to the guide post:



Next, I'll install the upper wheel.

[A_Pmech]

Installing the Upper Idler Wheel

This evening I installed the upper idler wheel. Much like the third wheel, I began by installing the trunnion and trunnion pivot. Then, I coated the spindle with Loctite and installed it with it's setscrew. Should this assembly ever have to come apart again, I'll bake it before pressing it apart:





Then, the wheel goes on the spindle. I temporarily snugged the spindle nut and installed the tracking knob as the shims located between the wheel and spindle may change when I adjust the tracking.

Here it is, everything here is done, short of tracking it in:



Next up:

The drive motor.