Burke Millrite Spindle Bearings Access Plug

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

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

(Still, I ought to be able to run the machine at 3400 rpm without overheating the spindle bearings.)

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

That looks exactly like what I've got, Ned. Thanks!

Steve

Ned Simm>>

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

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

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.

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

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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

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

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.

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

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.

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

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

"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

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> > >

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

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.