Replacing the Arbor Bearings in a Delta Homecraft 8² Table Saw

I have an old Delta Homecraft 8-inch Bench Model Tilting Arbor Saw that
my father bought used in the 1950s. This saw is a patchwork quilt of
components, the core being made by Delta, the wings having been
fabricated by somebody with a sheet metal shop and a welder, the motor
being a GE model 1E161, which is an industrial 115 Vac (60 Hz, single
phase) 3/4 HP capacitor-start 3450 rpm continuous-duty unit with
built-in overload protection (the original motor is 1/2 HP), all on a
shop-built wooden base that doubles as a sawdust collection bin.
The problem is that the arbor ball bearings are contaminated, and turn
roughly to the hand. It feels as if some sand has gotten into the
bearing grease. This is actually due to the bearing grease having
completely dried out. Time to replace the bearings.
First chore is to obtain a pair of replacement bearings. The bearings
are New Departure model ND-87503. While the New Departure company went
out of business long ago, many firms still make these bearings, which
were very widely used. On the web, there are many model 87503 bearings
on offer with wildly varying prices and quality claims, and many of the
offered bearings are reported in multiple user reviews to have very
short service lifetimes. The solution turned out to be a local
industrial bearing house (Action Bearing Company, 201 Brighton Avenue,
Boston, Mass 02134), which had ND87503 bearings made by KSK in Japan,
for US $10.27 each.
In the following description, Delta part and figure numbers are
9-19-49, 16 pages).
PM-1722 is available: .
It is assumed that the reader will have a copy of PM-1722 in hand
while
reading the following.
Now that I have the bearings in hand, time to install them. First issue
is how to get at the arbor. My initial approach was to unbolt the
cast-iron table top (TAB-101) and remove it from the sheet-metal housing
(TAB-110-S). This approach was abandoned because it was too much
trouble to get the two hand-wheel shafts disentangled from the sheet
metal housing because the tension pins (SP-2711) are difficult to remove
undamaged without a special tool to prevent the pin from splaying and
jamming as it is driven out.
The second approach was to unbolt the entire cast-iron table plus
sheet-metal housing assembly from the wooden base and place the table
plus housing assembly as a unit upside down on my workbench, after the
motor plus motor bracket assembly (and the saw blade) were removed and
set aside.
Removing the motor and motor bracket (TAB-109 and TAB-117 and Figure 5)
assembly as a unit is easily done, as shown in Figure 4. Disconnect the
power cord at the motor (after recording which wire goes where), loosen
the two square-headed set-screws (SP-301 in TAB-109), and slide the
complete motor bracket assembly off the two half-inch posts (Figure 3,
TAB-130 protruding from TAB-105).
With the saw table assembly upside down on the workbench, one can remove
screw (SP-301) in the front trunnion (TAB-104 in Figure 3), and tapping
the half-inch diameter steel hinge shaft (TAB-125) out with a short
drift punch and a small hammer. One rotates the hand wheels (TAB-165-S,
Figures 9 and 10) for blade height and blade tilt angle as needed to
maneuver and extract the arbor. A pair of wide black steel wave spring
washers (Figure 3, TAM-184) will also come out as the arbor is removed.
remove and replace without removing the table plus housing assembly from
the wooden base, but having the assembly on the workbench and easily
seen was essential the first time, as I was not able to fully visualize
how things were arranged in three dimensions from the figures in PM-1722
alone.
Once the arbor assembly (Figure 7) is liberated, one has the problem of
taking it apart. There are two nuts to remove, both at the pulley side
into the arbor while clearing the arbor shaft stub. The arbor shaft was
clamped by its hog ring (against which the saw blade is clamped using
nut BG-23 and dished washer LCS-8) in a big vise with copper jaws, but
the shaft tended to slip in the vise, and a little impact was required
to break the nut free.
radial slots spaced 180 degrees apart to accept a special spanner
wrench. Attempts to undo this nut by driving it with a drift punch in
the slots only served to mangle the slots, the nut being well recessed
inside the arbor casting (Figure 3, TAB-106-A), and so use of the punch
was abandoned.
Using a lathe and a vertical mill, fabricated the needed special spanner
wrench from a piece of 12L14 steel left over from another project. The
one end milled across the diameter such that there are two protruding
into the radial slots on the ring nut. The cylinder portion must be at
arbor casting and fully mate with the ring nut within. There must be a
central hole through which the arbor shaft (TAB-137-S) protrudes (a
parallel to the arbor shaft to accept the pins of an Armstrong model
34-154 3-Inch Adjustable Face Spanner Wrench that I already had. With
this newly-fabricated spanner wrench, the ring nut was easily removed.
While there are many ways to fabricate a ring spanner wrench, the point
is that such a wrench is essential.
We now have both nuts removed. Now to remove the arbor shaft from the
arbor casting. This was accomplished by tapping on the pulley end of
the shaft with a lead hammer. The components that emerged are as
follows, on the saw-blade end: hog ring (an integral part of the arbor
shaft TAB-137-S), ball bearing (ND-87503), two narrow bearing-loading
wave springs (LTA-516), and a machined steel spacer (TAB-124). The
specifies that one wave spring should be used, in fact a stack of two
spring washers was installed. One assumes that this is a later change,
to increase the bearing preload. At the pulley end, one ND-87503
bearing remained, stuck in the arbor casting. This bearing was removed
using an impromptu puller consisting of some half-inch all-thread, two
nuts and a big washer. The bearing was not pressed in place, but had
been glued in place by old dried oil. Everything was cleaned with
acetone and/or brake cleaner to remove all the dried oil.
One bearing is still on the arbor shaft, very close to the hog ring, and
puller will make short work of this, except that the puller jaws are too
store, and a roughly square piece was removed to yield a C-shaped
washer. This was slipped between hog ring and bearing, allowing the
gear puller jaws to apply force to the old bearing, which promptly slid
free under the urgings of the puller.
The arbor shaft was then cleaned up with crocus cloth and solvent, ready
for installation of the first new bearing using the puller and a big
steel washer. This is a very light press fit. The lubricant used is
traditional for press fits, Castor Oil (which can be bought in small
quantities from drug stores, where it is sold as a mild laxative).
Mobil-1 synthetic grease (available at auto parts stores) would also
work.
The arbor was then reassembled with the new bearings in place. ND87503
bearings are asymmetrical, where the inner race protrudes beyond the
PM-1722, the bearings are installed back-to-back with noses protruding
outward, with the machined spacer between the backs.
It all took 12-14 unhurried hours, including the fabrication of the
ring-nut spanner wrench and the C-washer, the unsuccessful attempt to
take the cast-iron table off the sheet-metal housing, and some machining
of the left wing for a better fit to the table.
The above text and the photos listed below are in the Metalworking
Dropbox. Google for "Delta_Homecraft_Bearing_Replacement" without the
quotes.
Photo 1: Front view of the saw, for context.
Photo 2: Perspective view of the saw tabletop and blade.
Photo 3: Various components mentioned in the text. At the top is the
Armstrong Adjustable Face Spanner Wrench. The middle row is a thick
washer used for pushing a bearing up against the hog ring, a thick
washer with a piece removed for pulling a bearing away from the hog
ring, the shop-made spanner wrench for the ring nut, and a six-inch rule
for scale.
Photo 4: Closeup of the shop-made spanner wrench for the ring nut.
Photo 5: The back of the saw, showing the motor and motor bracket
attached to the rear trunnion. There is a trouble light in the saw
housing. The orange belt is a link-belt; this was a great improvement
over a standard V-belt.
Photo 6: Closeup of the saw blade (this is a 7-inch blade, although the
saw will accept an 8 inch blade). The rind shaft at the top of the
photo is the arbor hinge pin.
Joe Gwinn
Reply to
Joe Gwinn
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Nice writeup.
I haven't had a problem removing or installing dowel, taper and roll pins with standard flat-ended drift punches, or custom length / diameter punches turned from steel or brass welding rod. If access is poor you could drill the end of rod stock to make a starter punch that holds the pin in line. -jsw
Reply to
Jim Wilkins
Great write up. If you could locate the other Delta Homecraft 8-inch Bench Model Tilting Arbor Saw owner, he would probably appreciate a copy.
Bob
Reply to
Bob Engelhardt
Ditto.
Also, consider installing springy roll pins vs the tapers. Sometimes it works, sometimes not.
Using a slightly smaller punch with tape around the end (to center it) can work, too. The pin never touches the sides.
Reply to
Larry Jaques
The taper pins are on my South Bend lathe, which I'm trying to keep original, or at least not damage it when installing homebrew replacements for missing parts. .
There are gunsmithing roll pin punches with a centering dimple that keeps the punch from scratching the finish. I couldn't care less on most of the stuff I have that uses roll pins. -jsw
Reply to
Jim Wilkins
Oh, there is a whole community. They made millions of these saws, and they were made very well. I'll probably post in that world, if I figure out where best to do this. Dried-out bearings is a common problem.
Joe Gwinn
Reply to
Joe Gwinn
The pins I didn't drive out are roll pins, not taper pins. The pin sticks out about 1/4 inch on either The problem is that as one tried to drive the pin out, the end being driven splayed, making it harder to get the pin through the tight-fitting cross hole in the 5/16 inch diameter shaft.
The driving tool must prevent splaying, or everything will jam tight.
Joe Gwinn
Reply to
Joe Gwinn
Are these the multi-turn coiled "Spring" pins of thin sheetmetal?
There's a youtube video about them but I can't check it on dialup.
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-jsw
Reply to
Jim Wilkins
I've never had a problem getting the extended pin to seat so I could use a punch. Small hammers are your friend, and they don't splay the exposed roll pin. My 4oz warrington gets a lot of use, as does my little Japanese style hammer and a brass hammer.
Finding the exact diameter punch to move the pin out is critical. If it has too much clearance, you'll damage both the roll pin and the shaft. Got a set of transfer punches? It gives you a much better selection, so you can find that nice, close fit.
Reply to
Larry Jaques
Good video/idea. He uses a u-shaped backing plate with a hole in it for the roll pin to pass through as it is pushed out. Two long bolts attach said plate to an old fly-wheel puller. Starting out the fly-wheel puller is just used to take up slack. The two long bolts holding the u-plate to the fly-wheel puller are tightened back and forth to apply pressure. Once the roll pin is moving well you can then use the fly-wheel puller screw to finish pushing it out.
Brownell's has a video showing how their roll pin punches are used too:
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Reply to
Leon Fisk
I've seen someone grab a roll pin with the wire cutters on electricians pliers and lever it out. This destroys the pin and damages the pliers but puts less stress on the shaft than hammering.
-jsw
Reply to
Jim Wilkins
No, they are one-turn slotted spring pins, also known as roll pins, of 1/8" nominal diameter by about 3/4" long.
Interesting. I was thinking of making just such a tool, only a bit smaller, to fit a 5/16" shaft and a much smaller roll pin.
I would machine the pushing screw tip to have a concave end, so it tends to compress the free end of the roll pin, versus causing splaying.
I was thinking of a solid piece of steel that one slips over the 5/16 shaft, with carefully positioned slots to accept the protruding ends of the roll pin, and a threaded hole for the pusher screw to travel in.
Turns out one can buy such tools for small money:
..
..
But no dimensions are given, so it's unclear if these particular ones will work.
Joe Gwinn
Reply to
Joe Gwinn
Also interesting. One problem with the hammer method is that with the say, things are far floppier than with a gun body, so I would guess that the screw pusher method will be easier to use.
I bet that Delta used a standard automotive roll pin remover, rather than invent their own special tool.
Joe Gwinn
Reply to
Joe Gwinn
I have done this on other things, but it's hard to avoid damaging the shaft as well. Nor is there enough space.
Joe Gwinn
Reply to
Joe Gwinn
I do have transfer punches and small brass hammers. But in the saw, everything bounces, and the free end of the roll pin (which protrudes by at two diameters) tended to splay, causing jamming. I was afraid to be too aggressive. A roll pin removal tool is safer and easier on the nerves.
Joe Gwinn
Reply to
Joe Gwinn
I hate it when things bounce around when I'm trying to hammer on 'em. It's fairly easy, though, to find a backer which will stop that movement, like a brick wrapped in a hand towel. (Yes, we Oregonians often use such high-tech solutions.) Getting the right mass of hammer to work with the particular situation is also key. Faster swings with less mass usually work better than slower swings with a bigarse Ford hammah, but too small a hammer is also bad. You already have the experience for that, right? I'm just reminding you. ;)
That said, pullers definitely have their uses. It just takes 3-6 hands and a grinder every freakin' time you use one. I have at least half a dozen pullers in my toolbox. I even bought one to remove the plastic idler screw limit caps off California carburetors back in the '80s, when I had my smog license. And I've made a small puller from a piece of plumber's tape, 2 square nuts, and a screw. Whatever it takes to get into the small space in which you need to work.
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Reply to
Larry Jaques
I've an old pair, maybe 7 to 8 inch SK Diagonal Cutters with a slight offset in their jaw alignment that I use for such stuff. Mostly for pulling out nails where I am trying to minimize damage to the underlying wood. Once you give up on having perfect jaws that will cut fine stranded wire they work amazingly well for such abusive stuff :)
Reply to
Leon Fisk
Kind of had something like those pictured in my mind for that. Think you could use a C-clamp with a few mods to it for same. Or a "Kant-Twist" if you want to splurge. You can apply a lot of force with one of the latter:
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Maybe drill a hole through the two blocks for the sizes you need. Should still work fine as a regular clamp then too.
Reply to
Leon Fisk
A beam clamp and a cup point setscrew?
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-jsw
Reply to
Jim Wilkins
Oh, yes. It's hard to explain to SWMBO why I need all those hammers.
Anyway, it's hard to swing a hammer there without hitting something unrelated.
You are thinking 3-jaw puller, for which one needs four hands.
These roll pin removers push the pin out, and so only require two hands. And no hammer.
Joe Gwinn
Reply to
Joe Gwinn

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