In article ,
(DoN. Nichols) wrote:

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

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

[ ... ]

I doubt that Dumore makes their own bearings. Actually, they may
still use the same bearings, or will know where they got them.

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. The manual I got from them (perhaps the last thing
that *anyone* got from them before they apparently closed shop) was
fairly old, and it was already talking about the spindle bearings not
being made in the US any more, and they had to get them from France, or
Japan at that time. Who knows whether those are still made at all? And
who knows whether something similar has befallen the older Dumore lines?

Right. Well, we shall soon enough see.

I hope that you luck out there. I suspect that the needle
roller bearings in the spindle run directly on a hardened and ground
surface of the spindle. (You need a toolpost grinder to make the
spindle to fix your toolpost 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. I think one replaces the assembly, not the bearing.

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

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.

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.


I'm hoping that they used standard bearings.

Perhaps -- but no bets there. Especially in the spindle.

If it's a ball/needle bearing, they probably buy them from one of the
usual suspects. Ball/needle bearing manufacture is very specialized.

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.


Anyway, I have made
centering hubs for various sizes of grinding wheels, but still need to
make the extension spindles to hold the mounted stones -- collet style,
probably with each size a separate extension spindle. These need to be
bored to the right diameter to slide on and screw onto the current
spindle thread. I may look for a closer nose -- or try my hand at
making one to fit.

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.


I expect the wrench to be something like the one for zeroing a
micrometer -- a quarter circle or so, with a spur to go into the slot
in
the hub which engages the flat on the spindle.

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.


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.


I just got through making the collet style clamp wrench.
picture a ring covering perhaps 300 degrees of the diameter, with
handles coming off where they join. Squeeze on the handles and the ring
tightens down on the pulley. I didn't bother making it pretty (yet) and
it is pretty stiff, but it worked, once I put the handles in a vise.
And at this point, I discovered that the pulley end of the spindle is
also right-hand threads.

A ring wrench, writ large. I thought of doing this, but in wood, which
has very high friction against steel. But the nuts yielded without the
need for added persuasion.

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.


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.


Out of
curiosity -- what color is the box for yours? Mine is a sort of light
blue -- almost hammertone, but I have seen other boxes which were black
crinkle finish, or Olive Drab.

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.


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.

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


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?


I've used this trick to disassemble an old B&S micrometer, using two
oaken clamps on the knurls.

If I had knurls to grip I would have gone with hardwood too. As
it was, I went with aluminum, with the lathe vibrating nicely with the
one jaw so far off center (and workpiece as well) at 550 RPM.
(Actually, slower was resonance -- perhaps around 300 RPM, and 550 RPM
was not bad. :-)

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.


My unit is set up the same way, with big pulley on motor and small
pulley on spindle. If the motor turns at 5000 RPM, the spindle will
turn (2.165/0.906)= 2.39 times faster, or 11,948 rpm.

*Way* too fast for the larger stones. But reasonable for the
mounted stones for inside grinding. (And I don't have the holders for
those -- yet. I've made the wheel shatter guard, and several hub
adaptors for different stones which I have, including a set still left
from the old Unimat SL-1000.

I think that's what Grandfather was using it for. I remember him
showing me a test piece consisting of a 0.5000" steel plunger fitted
into a socket with only 0.0001" clearance, such that it was almost
airtight, and the plunger would bounce up and down on the trapped air
acting as a spring.

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.


I don't recall why he made this, aside from it
being for some invention he was working on. His big thing was fuel
injection systems for automobiles, and there was a Corvette model that
offered his system as a factory option. I don't recall that the option
sold all that well.

Hmm ... do you remember what range of years this was offered on?
That might give a feel for when it was last used and oiled.

I looked through my file of stuff I got from Grandfather (Carl F. High),
and I find a 29-page report titled "Economic relationship of Engine-Fuel
Research" by one C.L. McCuen of the GM Research Labs, dated 3 May 1951,
that tracks characteristics of cars from 1930 through 1950. It's
basically a plea for greater fuel efficiency. I'll have to read the
report; one assumes that fuel injection was to have a role.

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


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

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.

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.


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.)


And I hope that your motor oil was not a detergent oil. If so,
you want to wash it out before running it again. Detergent oils should
only be used where there is recirculation through a filter.

Hmm. I'll get better oil. Too-heavy oil would cause heating, but I'm
still suspicious of the spindle bearings. It may be simply some rust
that will vanish into the oil with use, but I think I will still take
the spindle apart.

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.

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).

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.


(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.


Joe Gwinn