DIYbanter - View Single Post - FA: Dumore Tool Post Grinder Inserts, K.O. Lee Index Disc and other metalworking items on Ebay

In article ,
(DoN. Nichols) wrote:

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

[ ... ]

Yep! As long as I can find the proper replacement. These are
wider than I would have expected for the diameter. I'll have to dig out
the number from one and see what I can find to match.

I doubt that Dumore makes their own bearings. Actually, theyt 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'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?

Do you have the wrench for holding the pulleys still while you
undo the nuts securing them? I'm going to have to make one. I just
made a wheel guard for mine for the larger wheels (if I can ever get
the nut off the smaller pulley on the spindle to swap them for slower
speeds for the larger wheels).

I don't think so; I'll have to look again. The belts are flat and the
pulleys are smooth and crowned, and a steel-jawed wrench would chew the
pulleys up I would think. Unless there are holes in the pulley disks
to admit the pins of a spanner.

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.

I bet people just grabbed the bigger pulleys by hand, or used a strap
wrench on the crown.

The larger pulley came off nicely with just that -- a hand grip.

The smaller one (on the spindle) is too tight.

I was able to get both pulleys off without difficulty, although the
smaller didn't want to slide on the shaft after the nut was removed.
What worked was a set of Jacobs JT1 wedges applied by hand. This
started the pulley sliding, breaking the gummed oil bond loose. Solvent
would also help.

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.

I think that I'll have to make a collet style clamp for the OD
to hold it unless I can make a working hook wrench as above.

Or, bore a hole the same size as the pulley in a piece of hardwood, saw
into two halves, and use the pieces in a vice to firmly grip the pulley,
and have at the nut with a socket wrench.

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.

I'll pretty it up later, and keep it in the box with the
toolpost grinder, along with the other accessories I have made. 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.

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

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.

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?

Are the pulley nuts right-hand, or left-hand?

The one on the motor is for sure right-handed. The spindle
*looks* right-handed from what I can see of the threads, but until I get
it off, I can't be sure. If you can get the nut off your spindle end
pulley, you could tell *me* which hand it is. (Which side has your
smaller pulley -- the spindle or the motor?)

It turns out that they are both right hand.

As I discovered.

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. 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.

The next task is to make some holders for the mounted stones --
1/8" shank -- and perhaps smaller as well. There were some of each type
in the kit.

I also need to make the adaptors for mounted stones for inside
grinding. I *think* that the thread on the business end of the
spindle
is 1/4-32, and have just ordered some taps and a die for making
things
to fit -- and for cleaning up the threads on my spindle.

There appear to be three lube points for the spindle -- one with
the flip-top lid near the center, and two with felt plugs under
hollow
screws near the ends -- probably for small needle roller bearing
cages.

I found three as well, and filled them all with oil.

Good -- a light spindle oil, I hope.

Well, ordinary motor oil. 10W-30? What grade is light spindle oil?

10W-30 doesn't sound right. Too thick for the kind of speed
which the large pulley on motor gives. I got a light spindle oil from
MSC for the surface grinder spindle, and that will work on the Dumore
toolpost grinder as well. Though I have been known to use the Starrett
"Tool and Instrument Oil", which is similarly light.

I think that the spindle oil was labeled as an ISO-27, but I may
be misremembering. Dive into your MSC catalog, and find the lightest
which you can find.

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.

The bearings in the motor are sealed, and I think that I'll need
to replace one -- the one at the pulley end.

On mine, the bearings are not equally toasted, but I'll replace both if
I can.

The one on the free end of the motor is in very good condition,
absolutely free motion. But, I'll probably [buy] at least buy two
bearings so
I have the option of replacing it at need.

Good idea.

I originally freed up the motor bearing somewhat by hitting it
with a heat gun. Then I was able to run it several times, and it felt
better each time. It now feels pretty good. But I still want new
pulleys.

What's wrong with the pulleys? Flat belts are pretty tolerant of
smoothed-out dings.

Joe Gwinn