According to Joseph Gwinn :

In article ,
(DoN. Nichols) wrote:

O.K. I've had to jump through hoops, as the newsreader timed
out and expired your article while I was down in the shop gathering
information for this followup.

According to Joseph Gwinn :
In article ,
(DoN. Nichols) wrote:

According to Joseph Gwinn :
In article ,
(DoN. Nichols) wrote:

[ ... ]

Yes -- but some styles of bearings are no longer made.
Certainly this is true for the bearings in the spindle of my Sanford
surface grinder.

[ ... ]

I took the spindle apart without difficulty. The bearings consist of
two ball bearings, one at each end, with a fingered flat disk spring at
one end taking up axial play. The bearing races are very thin, and are
pressed into place on the spindle (one end) and a spindle housing cap
(the other end). It does not look possible to remove the pressed-in
bearings without destroying the bearings (by forcing the balls into the
races), and the races are so thin I have to believe that they are
special-order.

Somewhat as I feared.

I think one replaces the assembly, not the bearing.

Are the bearings two-part, so you can remove the spindle from
the main casting?

The good news is that the bearings are OK, but were pretty dirty.

O.K. One of the nicest ways to clean small precision bearings
that I have found is a vapor degreaser. You boil a solvent (I used
Freon TF back when it was readily available -- or 1,1,1 Trichlor), and
put a double-walled liner at the top which gets cold water run through
it so it condenses the solvent and drips it back into the reservoir.

You could probably do a pretty good job with alcohol -- except
for the risk of igniting the vapors.

You lower the thing to be cleaned (usually in an open stainless steel
wire basket) into the vapor at the top, and the solvent condenses on it,
carries away old lube and particles, and drips into the reservoir. From
there, it is boiled again, and repeats the cycle, with only clean
solvent vapor reaching the object to be cleaned. You might need a pass
through an ultrasonic cleaner to dislodge particulate contamination, of
course.

The bearing pressed onto the spindle doesn't seem fully seated, and so
when the spindle body caps are fully screwed down, the axial takeup
spring is flattened. When the spindle is run at high speed and heats
up, the axial pressure on the bearings grows, increasing drag, causing
more heating, etc. This is what I observed when I first rat it at full
speed.

The current fix is to fully tighten the spindle cap that tends to
unscrew itself, and leave the other spindle cap loose by one turn.

Hmm ... use a feeler gauge to measure the gap, and cut a piece
of shim stock to serve as a spacer, so you can tighten it firmly without
crushing the bearings.

For the record, both spindle bearing caps are right-hand threaded. I
used the tips of a pair of needle-node pliers as a spanner wrench. The
caps turned easily. I did see some faint marks left by a pipe wrench on
the caps. Anyway, disassembly and reassembly were easy.

O.K. I've got some hinged pin spanners (which I use for the hub
on my surface grinder) which should work well on it, if I need to get
into it.

[ ... ]

Yes -- but they still might not be still in production. The
later ones appear to have a larger diameter spindle, with extensions
screwing in and locking with a taper.

OK. I have not had mine apart yet. Are you talking about the motor
bearings?

There, I am talking about the spindle bearings. On mine, there
is a projecting section of perhaps 1/2" (not measured), with a following
unthreaded section of 1/4", and finally a thread which appears to be
1/4-32 thread (though I kept getting not quite right measurements which
suggested that it was somewhere between 32 TPI and 30 TPI. Perhaps it
was a 1/4x8mm thread, which would work out to be 31.75 TPI. Well ... it
is now 32 TPI for sure, thanks to a die. :-)

Mine has an unthreaded nose with axial hole and grub screw.

Hmm ... "grub screw"? You're posting from the UK? I think that
is mostly a UK term. :-)

[ ... ]

Anyway -- the spindle adaptors shown in the eBay auction which
started this thread have a male thread with a taper, which apparently
threads into a somewhat larger hollow spindle. Whether the change in
design was forced by the original bearings becoming unavailable, or was
a voluntary change -- which *may* have taken the demand for the bearings
low enough so they are no longer made. Both are possible. Of course,
they are for a different model -- and probably a much later model than
ours.

From the current Dumore catalog, they had an assortment of spindles, and
the user was expected to change spindles as needed. So, there will be
many kinds of spindle floating around, but they should all fit the
grinder.

Except that those had the entire spindle cartridge removable
from the frame, I believe. If you can't get the bearings off the
spindle, and can't get the spindle out of the cylindrical part of the
housing, then you can't change spindles, I believe.

FWIW -- my complete model number is 11-011.

[ ... ]

I just looked at the unit. I think it would be hard to keep a
quarter-circle spanner on that. I would guess that a piece of thick
sheet metal with two teeth coming in 180 degrees apart would work
better.

Perhaps -- except that I'm not sure that it could be fitted into
the slots while the pulley is in place. Perhaps so.

On mine it can, so long as the sheet metal isn't too thick. The gap is
0.200" or more, and the tool needn't be more than 0.100" thick. It
could be made from a piece of oil-hardening steel.

O.K. That is exactly what I was expecting to make it from.
Though with the ring spanner, I probably won't need to make one right
away. :-)

I looked closely at the smaller pulley when I had it off. The corners
of the slot where the wrench would go are buggered up, and look like
someone tried to use and ordinary wrench on them.

O.K. I can believe that. :-)

Yes -- there was some interesting gummed oil under the pulley on
the spindle when I finally got it off.

My grandfather must have bought the unit in the late 1940s.

O.K. I have no real idea when mine was made.

I'm guessing that my Grandfather got this unit used and incomplete, in
the 1950s.

O.K. Mine, I got used and incomplete at Cabin Fever (or was it
Iron Fever) a bit over a year ago.

[ ... ]

While I don't have good woods for the task -- just whatever is
used to make cheap 2x4s these days -- a bit too soft, I think.

The local Home Despot carries Oak, which is what I used. Oak flooring
cutoffs are often available. Likewise, Maple.

O.K. Maple I would save for use repairing concertinas, not for
one-off tools.

I did
have to go to a vise because the small pulley was slipping inside with
just a hand grip -- though I have not reduced the size of the OD of the
ring enough yet.

But -- with the vise, it worked.

Big vice, big hammer -- tools to live by.

Well ... not too big a vise in this case. It is a drill-press
vice from Craftsman from about 1970 or so. One with the ability to
mount it at an angle to the surface. Mostly, it had a big enough jaw
opening (barely), it was heavy enough for my task, and it was easy to
get to at the moment. :-)

[ ... ]

Mine is olive drab, all steel, 12.5" wide by 7.5" deep by 7" high, with
drop front.

O.K. No drop front on mine. I have to loosen the bolt through
the compound mount, swing the motor forward against the spring, and
slide the T-slot adaptor out backwards to get it out. I suspect that I
would prefer the drop front case -- but I have what I have.

Does the box say Dumore? Mine does not have any indication of a maker.

It certainly does. The OD ones were government issue to the
Army, and would probably not have maker's names on them. I wonder
whether that drop-front design was part of an Army spec to make it
easier to get to under certain storage conditions? I've only seen it
(so far) on the OD cases.

A random collection of stones et al are included, but no pulleys aside
from those on the grinder.

I think for that series, only those two pulleys are supposed to
be used. The metal label on the motor show only two speeds -- with
large pulley on the motor, and with small pulley on the motor -- no
other choices. (Still better than a toolpost grinder which someone
found on one of the small lathe sites which has only a single speed, and
mounts only for wheel stones with holes, not for ones with shanks.)

I wondered about the pulleys, because current grinders from Dumore show
more than two sizes.

Right - they do.

What speeds are quoted on your grinder? Mine says nothing.

Motor first:

15,500 RPM no load
8,000 RPM full load.

Pulleys
Wheel size RPM Spindle Motor
=====================================
1/8" to 3/4" 30,000 #1 #2
2" 6,900 #2 #1

For a quick-and-dirty web page showing details of the label,
plus other features of the grinder and what I am making for it, see:

http://www2.d-and-d.com/PROJECTS/TP_GRINDER/index.html

I also need to make a holder for a truing diamond to hold in the
lathe chuck -- or in collets. But the machine is almost ready to use.
Then the question is how long can I resist using it, since I don't like
to expose the lathe to the grinding grit if I don't have to.

Set it up like surgery, with a sheet of plastic covering everything
except what absolutely must poke through?

Reasonable. I've read suggestions for covering everything with
several layers of wet newspaper, so the abrasive will stick to the
newspaper.

[ ... ]

What is the swing on this lathe?

12" (x24" between centers). A Clausing 5418 from 1957, if you
care.

Nothing to be ashamed of here, Clausing. Someday.

I'm quite pleased with it. It came with a bed turret (with
matching serial number) and no normal tailstock. I had to chase down a
replacement tailstock to bring it into full service -- though I get
quite a bit of use out of the turret.

[ ... ]

Nice work. One trick to get that kind of precision is to set
the compound at 5.7106 degrees (as close as you can get, at least), and
for every 0.001" you crank the compound feed, you move 0.0001" closer to
the axis. (If you care, that decimal degrees comes out to be:

5 degrees, 42 minutes, 38 seconds

Good luck on the typical compound angle scale. :-)

It's a nice trick, even if one cannot set this on the angle scale. I
would just set it to something, measure the effect of advancing by a set
amount, and then use a hand calculator to figure out what to do to
achieve a specified effect.

Actually -- setting it to 5-3/4 degrees by eye should get you
close enough. You are only going to be making very small reductions in
diameter, so frequent checking with a good micrometer should suffice in
addition to this. This simply lets you make adjustments in finer steps,
and it would be useless for turning, as there is often more spring than
that in even a good rigid lathe.

[ ... ]

My recollection is that it was the 1957 model year Corvette, but I have
not found any documents.

O.K. That was pretty close to the start of the Corvette line,
wasn't it? And the same for the Ford Thunderbird line, for that matter.


It turns out that the bread and butter was fuel injection systems for
general aviation engines.

O.K. So this was not just your grandfather, but the company for
which he worked?

I have an ad from the Ex-Cell-O Corporation in Detroit (where
Grandfather lived) for their "Gasoline Injection Systems for Personal
Planes". The ad is not dated, but looks to be from the 1950s.

O.K. "Personal Planes" sounds as strange now as "Personal
Computer" must have sounded then -- though there are still personal
planes, they are getting harder and harder to afford.

I also have a "Fuel Injection Service Manual" dated 1 March 1941 from
the Fuel Injection Corp, Muskegon, MI. This system was used on aircraft
piston engines.

O.K.

And a whole bunch of patents. The most interesting is "Fuel Injector
Apparatus for Internal Combustion Engine", 2,839,040, issued 17 June
1954. This goes into the control laws needed to properly utilize the
engine. (Go to http://www.pat2pdf.org to get the patent.)

Too much more to do tonight. Well ... I just took a look at it,
and was reminded how difficult I've found it to follow patent
descriptions of almost anything -- including electronic circuits for
which *I* hold the patent. :-)

[ ... ]

Agreed. But be careful -- a clean workspace over a tray, in
case a bunch of needle rollers fall out, or a spring launches parts or
itself.

As described above, I took the spindle apart without surprise of
difficulty, or necessity of medical attention.

Good.

I don't think that this spindle needs real "spindle oil". The oiling
system was interesting. There are two wool felt oilers, one per end,
resting on tapered parts of the spindle axle. Both had a waistband of
heavy thread right where contact is made with the taper. I can't tell
if this was an original, or added by Grandfather. It looks like carpet
thread, and is attached to the wick by being sewn through the wick
(which is cylindrical).

Hmm ... I really think that you still want spindle oils for
this, not motor oils.

I think that oil is wicked to the taper, and propelled towards
increasing diameters by centrifugal force, leading the oil to circulate
through the bearings enough to keep them lubricated. This will work far
above the speed at which splash lubrication fails.

Did you figure out what the central oil port does? Perhaps it
provides a reservoir to replenish the oil from the wicks, and you are
only expected to remove the caps at the ends to replace the wicks?


(I remember the MGA shop manual when discussing disassembling
the transmission saying:

"Withdraw the three sliding rods and forks. Note the three
balls and springs released in consequence."

"released" actually means launched hard enough to bruise, if you don't
have several layers of cloth to catch them. And if you are not
sufficiently forewarned, they vanish into the weeds surrounding where I
worked on the car. No -- I didn't lose them, but I did get a bit of a
surprise. These were the detent balls which engaged notches in the rods
which slid the gears inside to engage the synchromesh rings.

Been there, done that. Cameras are like that too, although physical
bruises are uncommon.

Yes -- the springs are not nearly as strong. :-) I've worked on
them, too.

Enjoy,
DoN.
--
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