Burke Millrite Spindle Bearings Access Plug

I could use the assistance of anybody familiar with milling machine
spindle bearings, in particular anybody familiar with the lower "Timken"
bearings on an older Burke Millrite spindle.
I've never serviced the lower spindle bearings and today, after running
the mill for about 15 minutes at the highest possible spindle speed,
(which I've never done before), I noticed that the bottom of the quill had
become too hot to touch.
After letting it cool down I reset the drive belt to run at a lower speed
but noticed the quill was still warming up although not as bad. Maybe
it's been doing this for a while and I just hadn't noticed.
At this point it seemed a good idea to check the lower bearings for
sufficient lube and proper axial preload as, in the service manual, these
are the listed causes of this end of the spindle running hot (other than
shot bearings altogether).
Per the manual, if you drop the quill all the way down it exposes a
threaded plug in the side of the quill that can be removed with a 5/16"
hex key to lubricate or adjust preload on the lower spindle bearings.
However the quill plug on my mill has a curious arrangment occupying the
5/16" hex socket in the plug which precludes being able to engage the plug
with a hex key. It appears to be something in the way of a "half
Alemite" fitting that somebody made up and inserted to facilitate oiling
the lower bearings without removing the plug. At least this is what the
guy at DC Morrison (they handle Burke Millrite machines) postulated when I
described it over the phone. Even if this is what it is, efforts to pass
oil through the fitting in the plug did not appear to be very effective,
most/all of the oil coming out of the spout just dripped down the outside
of the quill .
Before I attack this setup with a drill and an easy out, so that I can
remove the plug and properly lube/adjust the bearings, I thought I'd post
a couple of pictures to the drop box for scrutiny by those more
knowlegeable than I, to confirm that this arrangement is not stock/proper
and that I'm not going to mess any thing up by removing this " modified
oil port" in the hex socket of the plug.
The jpgs of the quill plug are at:
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If you know anything about it, I really appreciate anybody who takes the
time to look at the jpgs and let me know whether this plug ought to stay
this way or if I ought to remove the "oil port" by what ever means and
restore the plug to original in order to service the bearings.
In particular if there's anybody who has a Burke Millrite that could maybe
check the quill plug on their mill and compare it to the posted jpgs to
establish whether it's the same or different than my quill plug, that
would be great.
Thanks,
Dennis van Dam
Reply to
Dennis van Dam
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My Millrite has the same fitting. There is maybe 0.1" depth of hex available to grip with a wrench on mine; depending how tight the screw is, it might be removable. But you've probably tried that already. I'm afraid I can't help on your other questions, don't know anything about this fitting. Steve Smith
Dennis van Dam wrote:
Reply to
Steve Smith
Steve,
Thanks for the reply.
That you have the same arrangement tends to indicate that this is not a one off but something the factory introduced and then didn't cover with an update to the service manual.
On mine the depth of the hex key socket is much less than 0.1", maybe only 0.030" to 0.040" . I tried pressing the hex key into this shallow recess and carefully turning but the key just smears the recess and climbs out. Not only is it unclear how to get the plug out as configured, how the hell did they get it in?
Thanks again for the reply.
Dennis van Dam
PS
You ever notice the bottom of the quill warming up?
Maybe I'm worried for nothing and this was just a one time thing because I ran the spindle at 3400 rpm when usually I'm only running it at 250 to 725.
(Still, I ought to be able to run the machine at 3400 rpm without overheating the spindle bearings.)
Reply to
Dennis van Dam
Look at McMaster-Carr p/n 10595K14. Does that look like what you've got? If so, and the fitting is still OK, you'll need something like p/n 1090K54.
Do you have any way of measuring how hot does the spindle actually gets? Even 200F isn't likely to harm anything unless the bearing preload changes drastically due to thermal expansion. If it's getting tighter I'd expect the temp to run away (hotter->tighter->hotter still-> even tighter->....), if too loose, accuracy and/or finish may suffer.
Ned Simmons
Reply to
Ned Simmons
That looks exactly like what I've got, Ned. Thanks!
Steve
Ned Simm>>
Reply to
Steve Smith
Ned,
That's basically what it is only instead of being Style 3 your part number indicates it would be more like style 1 or style 2 which are round at the OD instead of hex shaped.
Only thing that still confused me is in the catalogue on the style 1 and style 2 type flush grease fittings, there are "dimples" on the fitting perimeter so that it can be engaged with a flat screw driver to install it into a threaded hole . These dimples are not in evidence on my fitting.
Without some way to thread the fitting into a tapped hole in the bottom of the hex socket in the plug I couldn't figure how the fitting was installed into the plug and further with the fitting entirely occupying the the hex socket in the plug I couldn't figure how the plug was installed into the quill.
I could just leave the whole arrangement as is and, as you suggest, get a special narrow coupler to get lube through the fitting to the spindle bearings but that won't address removing the plug in the event that I need to adjust the preload on the spindle bearings.
Accordingly I finally decided to drill the fitting out so that I could get a hex key in and remove the plug.
This took place without any complication and only took a few moments.
Once I had it out I examined the back side of the plug and the remains of the flush grease fitting and discovered the fitting wasn't threaded into a tapped hole it was pressed into a plain hole. That explains the lack of screw driver dimples on the fitting..............and possibly all that might have been required was with the plug still in the quill, give the face of the fitting a light rap with a hammer and punch thus (if there was space behind it) setting it further into the hex socket in the plug allowing a hex key to fit into the socket.
Either that or a predrilled plug was threaded into the quill and then the flush grease fitting was set all the way in to the predrilled hole in the plug but since the plug is already installed it doesn't matter that you can no longer get a hex key in (thus a one way trip unless you drill the fitting out).
Oh well live and learn, this is why I hesitated and posted to the group as I frequently miss salient details like this one until after the fact. (-8
Actually I do. After I sorted out the business with the plug and got some oil to the bearings (the manual describes obscure type of grease but my guy at DC Morrison says "straight 30 weight oil") I attached a nice little magnetic surface temp thermometer to the quill and turned it on at full spindle speed (3400 rpm).
Within 30 seconds I could feel the quill starting to warm. Within 2 minutes it was acutely warm and at between 4 or 5 minutes the thermometer was indicating and stable at 130 degrees. The way this thermometer works it measures temp just above the surface it's attached to. That means the quill is actually hotter and the bearings hotter still.
If 200 degrees is within allowable operating parameters maybe this is perfectly normal (normal enough) and I just have to get used to it when ever running at full spindle rpm.
Other wise the next thing to fiddle with is bearing preload or possibly consider replacing the bearings.
Ned, thanks for the reply it helped to explain what was going on right at the quill plug.
Dennis van Dam
Even 200F isn't likely to harm anything
Reply to
Dennis van Dam
Keep it oiled and I think it'll be fine. The limiting factor will be lubrication, and just about any grease or oil will operate at 200-250F. If there's old grease in the spindle that may be part of the reason it gets as hot as it does. If that's the case, I wouldn't be surprised to see it improve as you continue to run oil thru it. Even SAE30 is pretty heavy at 3400 RPM - the oil for a Bridgeport spindle is approx SAE10, for example.
Ned Simmons
Reply to
Ned Simmons
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Hmm ... one thing which I just thought of -- too late, I know -- was to take an appropriate sized hex key, cut off the bent end, and put it in the lathe to bore out everything up to a diameter corresponding to the dimension across the flats. This would give you something which could slide in the little corners between the cylindrical body and the hex screw socket. Not good for much torque, but probably enough to unscrew the device, as the cylindrical part would give some support to the fingers from collapsing.
[ ... ]
Unless the modified hex key would work.
Good Luck, DoN.
Reply to
DoN. Nichols
Indeed. Scounge up a gallon of DTE Light, and run it in as much as it will take for the next 4-5 times you use it. It will help flush out the mange and is a good high speed spindle oil in its own right.
Gunner
"This device is provided without warranty of any kind as to reliability, accuracy, existence or otherwise or fitness for any particular purpose and Bioalchemic Products specifically does not warrant, guarantee, imply or make any representations as to its merchantability for any particular purpose and furthermore shall have no liability for or responsibility to you or any other person, entity or deity with respect to any loss or damage whatsoever caused by this device or object or by any attempts to destroy it by hammering it against a wall or dropping it into a deep well or any other means whatsoever and moreover asserts that you indicate your acceptance of this agreement or any other agreement that may he substituted at any time by coming within five miles of the product or observing it through large telescopes or by any other means because you are such an easily cowed moron who will happily accept arrogant and unilateral conditions on a piece of highly priced garbage that you would not dream of accepting on a bag of dog biscuits and is used solely at your own risk.'
Reply to
Gunner
First Ned and then Gunner advised;
Now that you fellows mention it, while I was running my quill temperature test after having given the bearings a healthy dose of oil (SouthBend Light Medium Saybolt Universal Viscosity 150-240 seconds is what I actually had on hand) large clods of old grease, more the consistancy of sludge, started seeping out the bottom of the quill. It stopped after several minutes running at high rpm after the quill temp stabilized at 130 degrees, so I assume I cleared most of the old lube. Per Gunner I'll continue to flush to see what further comes out.
I don't anticipate running at 3400 rpm very often, in fact after getting the spindle oiled I completed the (non-critical) job I started at 3400rpm at 725rpm and the mill bit cut-finished the material just fine.
McMaster-Carr shows a gallon of Mobil machine/turbine DTE light for $11.98 which sounds reasonable to me. The next item down is Mobil spindle bearing oil. I assume either in a comparable viscosity will serve? If I can't find one or the other here in town I'll phone in an order.
Thanks to you both for the help,
Dennis van Dam
Reply to
Dennis van Dam
Don,
While the hex key configuration you describe did not occur to me, I did realize there where tiny voids between the flush grease fitting OD and the "points" of the hex socket. I briefly considered that there might be some scant purchase to be obtained here but dismissed it fairly quickly as being too tight a space to practically engage.
After I read your post I produced the geometry you describe in a quick CAD sketch on the computer, just a .3125" circle arranged concentric to a hexagon .3125" across the flats.
On a vector from any hex point oriented to the center of the hex-circle it measures .026" from the hex point to the fitting OD........If I end drilled the hex key sement very carefully and kept the depth of drilling fairly short, say 1/16 to 1/8...........that *might* have worked. Even if the drilling operation wasn't perfectly concentric to the hex key segment and I only came away with 4 or 5 instead of all 6 "hex point fingers", that might have been enough of a toe hold on the plug to get it out.
On the other hand if who ever had just taken the time to configure the plug-grease fitting arrangement such that there would be sufficient hex socket depth left in the plug above the fitting, I wouldn't yet again be reminded that Necessity is a real Mother. (-8
Thanks for the reply,
Dennis van Dam
Reply to
Dennis van Dam
Since SAE30 was recommended the spindle oil (ISO 22) may be on the light side. SAE30 is approximately ISO 68 or 100, which seems rather heavy to me. The DTE Light (ISO 32) sounds like a good compromise. A comparable viscosity quality hydraulic oil would also be OK and perhaps easier to find locally in gallons.
Here's a good viscosity conversion chart.
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Ned Simmons
Reply to
Ned Simmons
Indeed. I just happen to like DTE Light for its various properties and the fact its very commonly used in high speed collet closers, very high speed air spindles and whatnot. Shrug..Im sure there are others that are very good.
Gunner
That rifle hanging on the wall of the working-class flat or labourer's cottage is the symbol of democracy. It is our job to see that it stays there. - George Orwell
Reply to
Gunner
My access plug is just a plain allen screw.
A guy at d.c. morrison told me the same thing - they just throw in some straight 30 weight before using it. I use light spindle oil.
What I want to know is: what grease corresponds to the description given in the manual? I forget the exact wording, but it involves 'sponge' and 'soap base', and goes on to say it's not all that important. But it *does* emphasize not to use too little or too much. Well, yeah, that's always good advice. And useless, too.
The drawback to the spindle oil is that it ends up running out onto the work. Since I frequently mill wood, that can be an issue. Hence my interest in quantifying 'not too little, and not too much, but just the right amount'.
I'm a great believer in empiricism, but not in this instance.
Reply to
rohamm
Nearly all such spindles are direct loss lubrication..ie the bearings are not sealed to retain oil and leak out down the quill etc. Or sealed poorly due to age etc. This really is indeed an issue when milling woods and paper based materials. Ive seen some home made slingers that clamp around the quill that folks have put together for this, but the only really good solution is finding another type of mill, use a router head, or run it for a bit before putting any wood down and hope that one forlorn droplet doesnt finally wend its way down and around and jump off on that piece of work.
Ive been seeing some high speed 30 taper spindles on Ebay recently, that perhaps you could make up a sub spindle that will clamp to your ram or head for wood work.
Ive got a shop I service, that has a number of old Bridgeports that have a simple die grinder type unit mounted on the end of the quill with a simple pinch clamp made from aluminum plate. They use them for fine work in phenolics and such. Easy to install, easy to remove, and allows them to use the table and down feed as normal. A dremel tool could be so adapted as well. This allows them to get 10,000-30,000 rpm oil free, and still allows them to use the regular motor/spindle when they need to. They make the clamp from 1" aluminum plate, so they only loose 1" of spindle down travel as the clamp goes on the first 1" of the quill.
Just a heads up.
Gunner
"At the core of liberalism is the spoiled child - miserable, as all spoiled children are, unsatisfied, demanding, ill-disciplined, despotic and useless. Liberalism is a philosphy of sniveling brats." -- P.J. O'Rourke
Reply to
Gunner
Ned,
Thanks for the link, that really helped to equate the different viscosity designators in McMaster-Carr from one lube to the next. I see what you mean regarding the spindle oil being on the thin side even in its most viscous form (ISO 22) compared to the range of viscosities the DTE oil comes in.
Thanks again for the help.
Dennis van Dam
Reply to
Dennis van Dam
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Gunner
"At the core of liberalism is the spoiled child - miserable, as all spoiled children are, unsatisfied, demanding, ill-disciplined, despotic and useless. Liberalism is a philosphy of sniveling brats." -- P.J. O'Rourke
Reply to
Gunner
That's how DC Morrison Man says a Millrite ships out. Either the arrangement Steve Smith and I have on our quills is a common after market mod or there was a period when the factory *did* make quill plugs that way but then stopped (possibly because somebody realized what a pain it was to get back into the quill with this type of plug).
What is curious is that while the manual doesn't refer to a flush grease fitting in the quill plug in any text, the cross section diagram of the quill on page 14 appears to show a cross section of the fitting inside the plug. Additionally it shows it set into the plug deep enough to leave room for an allen key.
Moot point now. I replaced my fittinged plug with a plain plug like yours. 27 cents at my local industrial supply.
Per the manual;
"Sohio Sactram No. 2 or equivalent" otherwise described as "a shot fibre, medium sponge grease with sodium soap base".
I happened across a brief technical blurb "About Grease" in the McMaster-Carr catalogue at the begining of the listings for grease products. It sheds a bit of light on what is meant by this but I had the same reaction as you, what-n-a-hell is "a shot fibre, medium sponge grease with sodium soap base" and where do I find it.
But it *does*
Again I came away with the same impression as you. The manual states twice in two paragraphs, the second instance in caps, how important it is not to overfill the quill and then pointedly does not indicate what the correct amount is or at least what a subjective indicator would be in advance of the spindle bearings over heating. If it's that critical, they ought to put a dipstick on the quill. (-8
I could be wrong but I'm inclined to think that over filling with oil wouldn't be as likely to over heat the bearings as over filling with grease. But then tending to over fill to be sure there's enough doesn't help with dripping on the woodwork.
I recently discovered how useful the MIllrite is for precision routing wood. On sections of wood smaller than the mill table travel distances, it beats hell out of hand holding a router against a clamped straight edge that needs to be reset for every cut. The only aggravation is keeping the wood chips/saw dust off of the ways and out of the works. I've been told the resins in wood chips/dust don't do the machined bearing surfaces of the mill any good. Near term project for the Millrite is way covers and/or way wipers.
Dennis van Dam
,
Simm> > >
Reply to
Dennis van Dam
Food for thought. I just finished milling several smaller plywood boxes with each plywood panel end mortised into the ajoining plywood panel. It's amazing how tight you can fit up wood joinery when you gauge lengths off to the nearest thou. Using the mill for routing operations on smaller wood working projects is something I'll be doing more of in the future and you've got me looking at how best to mount my die grinder up to the quill/head of the Millrite.
Dennis van Dam
Reply to
Dennis van Dam
snipped-for-privacy@mindspring.com (Dennis van Dam) wrote in message
Isn't it though?
Using the mill for routing operations on smaller
We have a two century-old home in New England, and I save all the old material when we make any changes to it. The sub-flooring is called hard red pine, and now it's petrified, but man, it's beautiful. Now this is the stuff that was too hard - lots of knots - to plane smooth back then, but it's no match for a fly cutter on a vertical mill.
You really think that wood chips are bad for the ways? I clean them off from time to time, but they seem pretty harmless compared to steel.
Reply to
rohamm

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