I just got (used of course) an old Dumore series 44 toolpost
grinder in a nearly complete kit. The one thing which is missing is the
#1 pulley (smallest).
Does anyone have one who can tell me the diameter over the
crown? The rest I can measure from the other pulleys so I can make my
own replacement for that missing one.
O.K. Is this one with only those two pulleys? That sounds like
a setup for maximum speed (38,500 RPM no load) for use with up to 1/2"
diameter wheels. (Likely mounted stones at that diameter.)
With a No. 2 and a No. 5, the no load speed is 27,700 RPM, for
stones measuring 5/8 through 3/4".
I'll have to measure the four pulleys which I do have for mine,
which are Nos 2 through 5 to see whether they are the same series.
Mine is marked "Model 44-011" on the nameplate, and I was able
to read the numbers on three of the four pulleys. The one which I could
not read has to be the No 4 based on a size comparison to the others,
and certainly not a 1. I think that I will want to stamp that one more
Hmm ... I don't find the #5 on their web page. The bore does
seem larger than mine -- which is closer to 3/8" as far as I can
remember. (It is downstairs in a cold shop, and I am up here typing
with warm hands at the moment. :-)
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[ ... ]
O.K. Yet another one -- but so far not a precise match in model
number. I think that my smaller one is a #11 -- a bit too small for a
12" lathe, hence the acquisition of opportunity of the Model 44-011.
O.K. I just checked the manual for the #11, and it only has two
pulleys. Yes, they are marked "No. 1" and "No. 2" according to the
manual. The bore is smaller than that on the Mode 44, so we are sort of
bracketing things at the moment.
FYI, Don when I got my grinder I looked for a manual which wasn't included.
I called Dumore and they hooked me up with a dealer. The name is familiar.
Wm Sopko & Sons in Cleveland. They were great. They faxed me a copy of the
complete operating instructions and parts list and I didn't spend a dime
with them. The contact info:
Wm Sopko & Sons Co. Inc.
26500 Lakeland Blvd.
Dumore is no longer in Racine, WI. They moved up north, Probably to get away
from the unions. They are in Mauston, WI now. Contact info:
1030 Veterans St
Mauston, WI 53948-9314
My series 5 machine is maybe a little big for my Clausing 5914, in fact the
book sez it's for 13"-18" lathes, but it works just fine. I think the 44
series is probably just right for your 5900. Have fun with it.
Sorry, DoN, but I don't have the answer you're looking for. I've bought two
used Dumore 44-011 grinders, and neither of them came with a full pulley set
(not even combined).
The chart at the bottom of page 8 of the download manual/parts list shows
that the fastest spindle speed would be 38500 RPM.
The pulleys for 38500 are shown as the #5 on the motor, and #1 on the
spindle. This seems a little odd since the motor is labeled to have a
no-load speed of 13000 RPM.
The #5 that I have measures 2.985" diameter, and the #2 measures 1.059
(although it's mostly flat without a full crown like the #5).
So the approximately 3" to approximately 1" would be about 3x the 13000
motor speed or about 39000 RPM (it seems to me, anyway).
The front page of the manual states model 8473 and dated 1/2008.
The "ser." numbers on the ones I have start with 8071 and 8171, which I
expect are series numbers, followed by a 4 (or more) digit serial number.
The 8071 appears to be older and had crowned steel pulleys with it.
The 8171 had flat, flanged aluminum pulleys with it.
#2 1.059" (but the crown is worn almost flat) steel
#3 1.562" flat aluminum with flanges
#4 2.125" flat aluminum with flanges
#5 2.985" crowned steel
Do these sizes correspond to the pulley sizes you have?
O.K. I've measured mine. Here are the results, with ??? for
the No. 1.
No. 1 ????
No. 2 1.1085"
No. 3 1.5480"
No. 4 2.1095"
No. 5 2.9815"
And playing with various calculations I come up with the
following possible sizes for the No. 1 pulley:
1.0067" (from no-load speed of motor and expected no-load
speed of No. 1 driven by No. 5)
0.7983" (Comparing no-load speed listed with No. 2 and
No. 1 pulleys driven by the same (No. 5) motor
0.7918" (Working from size ratios of adjacent pulley
The ID of the pulleys is 0.375", and the thickness (of No. 2, at
least) is 0.6890"
[ ... ]
Apparently not, since the 2.184" pulley is not quite right for
anything in my set.
The No. 4 became partially visible when I cleaned all of the
pulleys with ScotchBrite. That number turned out to have been stamped
where a couple of balancing holes were drilled, so only part of the
number was visible.
Thanks. As it turns out, DuMore now has the manuals on line, at
least for some machines, including the Series 44. The first thing that I
did was go on the web and find and download the manual. They don't
still have the Series 11 manual (for the smaller TP grinder which I also
have), but thy still list the Series 44.
Hmm ... The voice phone does not look right, though the FAX
matches what is printed on the front of the downloaded manual. For
others who may hit these articles later, the voice phone printed on the
front cover of the manual (which bears a 1/2008 date) is
Phone: 1(608) 847-6420
Thanks! The manual says that it is for 8 to 14" swing lathes.
Various calculations suggest diameters between 0.7918" and
1.0067". If I don't get the measurement soon, I'll probably try making
a 1.000" one and use my GR StroboTac to measure the resulting speed. If
it is too slow, I'll turn it down a bit more as indicated.
Ouch! Maybe I can help you fill out the set -- at least as far
as the crowned pulleys go.
Yes -- it also has one column mis-labeled. It labels the two
Pulley on Pulley on
And as far as I can tell, both "Spindle" and "Wheel" refer to the same
shaft -- just opposite ends. And judging from the contents of the
table, the one which is labeled "Wheel" should really be "Motor". :-)
Thus one calculation for the likely pulley size is:
38500 / 13000 = 2.9615
2.9815" / 2.9615 = 1.0067"
(Assuming that the No. 5 pulley is relatively unworn.
That is badly worn. I'll put a table of the sizes which I have
No. 1 ??? (1.0067" ?)
No. 2 1.1085"
No. 3 1.5470"
No. 4 2.1095"
No. 5 2.9815"
(all measured with a Mitutoyo dial caliper, not a real micrometer, but I
think that this is close enough.)
The smidge smaller diameter than 3" (2.9815") actually bumps the
No. 1 pulley just a little over 1" diameter for the 38,500 RPM.
(Assuming that the motor no-load RPM is not reduced significantly by
the belt, pulleys and spindle bearings.) After I make a 1.000" No. 1
candidate, I'll check the speed (with no stone in place) with a GR
StroboTac (no contact speed measurement).
The same one which I downloaded. Once I report the table
nomenclature problem, there may be a 3/2009 release. :-)
O.K. Mine starts with 8473, followed by what looks like a
five-digit number. It is downstairs, and I am not again, so I can't
verify that part.
O.K. Mine has the crowned steel pulleys. I wonder whether
someone made his own pulleys for one of the two you have. The manual
shows crowned (and presumably steel) wheels.
1.1085" (mine +4.67%)
1.5470" (mine -0.96%)
2.1095" (mine -0.720%)
2.9815" (mine -0.117%)
So your No. 2 is really badly worn compared to everything else.
You now have my figures -- and the percentage difference in size.
I'm beginning to think that the No. 1 crowned was originally a
precise 1.000" and the others were scaled to that as a starting point.
Thanks, DoN. I'm surprised that there weren't numerous replies with the #1
I wondered if the aluminum pulleys that came with one of the model 44s might
have been shop made. I don't know if I'll actually use either grinder on a
lathe, or end up using them for some other grinding setup.
Your approach to try a 1" diameter for pulley #1 is logical (not
surprising), as I anticipated that if you didn't get an accurate reply,
you'd just go by the speed chart, (despite the mis-labeled wheel/motor
error) and come up with a properly-sized pulley.
Dumore and users can't actually be sure that all grinders will run at the
same exact speeds anyway, since there are differences in AC voltage levels
at various locations.
The manual for download is probably for the current version of the 44/8473
version, which utilizes the bent rod for mounting the belt guard. The older
models that I have don't have this feature (no hole in the base/spindle
casting), so I assume that the guard mounted by clamping around the machined
end of the spindle housing, similar to the way the wheel guard does. It
shouldn't be too difficult to fabricate a guard and an improvised
I've been in touch with DuMore, and these are still made. At
just under $16.00, it is less trouble to order than to make when you
consider trying to get something balanced for 38,500 RPM. :-) Yes, even
the "No. 2" has a small hole drilled for balancing.
And -- in the process, he mentioned the diameter that the No. 1
pulley *should* be -- 7/8" (0.875").
Assuming that the others are also made to some number of eighths
or sixteenths of an inch, that would probably be 35/16" or 2-3/16".
Yours appears to be a bit less worn than mine, though I've been told
(not by DuMore) that they vary somewhat with date of manufacture.
I also pointed out to DuMore the error in the headers of the
pulley table on page 8. The two pulley columns are marked "Pulley on
Spindle" and "pulley on Wheel" -- which to me sound like the same
pulley. The rightmost column should really be "Pulley on Motor". The
fellow at DuMore agreed with me, so I presume that pretty soon a new
version will be available for download. :-)
It will be interesting to see whether I receive a crowned steel
pulley or a flanged aluminum pulley. :-)
Perhaps that was the first pulley to be lost from everybody's
I tried calling someone who had a Series 44 on eBay with eight
pulleys (at least two appeared to be No. 1 pulleys, and it is not clear
what the ones shown on the motor and spindle were) but it was too late.
It was already packaged for shipping.
So -- I called DuMore -- just to see what the pulley cost. It
turns out to be just under $16.00. Cheap enough to be worth it for not
having to try to balance a pulley at those speeds. :-)
While talking to him, he mentioned that the size of the No. 1
pulley is supposed to be 7/8" -- so about halfway between my smaller
calculations and the 1" one. From that, I decided that probably all of
the others were also some integer number of 8ths (or in one case, 16ths
seems a bit more likely), and everything has worn a bit over the years.
I've been wondering the same thing. Well ... when the pulley
from DuMore arrives (near the end of the week is his prediction) I'll
find out. If you are interested, I'll report that here when it arrives.
There is always a bit of worry when it comes to mounting a
grinder on a lathe. But I've got to try it at least once, so I wil know
how much difference it makes.
Or at least one which errs on the side of caution. :-)
Agreed. And of course most stones are some degree smaller than
when brand new -- since you are expected to true it with a diamond each
time you set it up. :-)
As it turns out -- what I got came with the bent rod and the
guard. The two wing nuts which hold the guard in place turn out to be
bronze, not steel. :-)
Well DoN, it seems that you're in good shape for getting started on all of
those tooling projects that you wanted to have a ground finish.. centers,
tapers, collets, adapters, etc (valve jobs for all the IC engines).
I'd be very interested to hear if the new pulley is flat or crowned, but
also interested in seeing pictures of your shiny projects.
I think the pulley sizes have changed. The pulleys I have are made of
hard steel, and do not appear at all worn. Nor is the caliper going to
be off by 0.906-0.875= 0.031" without being noticed.
I inherited my DuMore from my grandfather, he probably got it in the
1940s, and who knows when it was made, although it appears to have been
made for the US military. The kit is not complete, contains lots of
non-DuMore stuff, and appears to have been obtained for a single
purpose. Probably bought used.
I bet it's steel. Aluminum would wear out pretty fast with a little
grinder dust on the belt.
O.K. Someone in this thread (or another thread elsewhere)
mentioned at least one which was worn so badly that it only had the
edges of the crown remaining, and the rest seemed to be almost flat. :-)
Olive drab wrinkle varnish on a drop-front cabinet? My Series
44 is in a smooth black cabinet without the drop front, and the Series
11 is in a blue hammertone cabinet without the drop front. The Series
44 has a pair of uprights with a half-moon cutout to support the spindle
housing, and the Series 11 has a spot-welded housing to cover the T-nut
to hold it down in the box.
O.K. Hmm ... did he do automotive engine work? Perhaps he was
using it to re-grind valve faces.
[ ... ]
That is what I am expecting, at least.
Depends on how much the belt slips, I think.