How flat/parallel for horizontal mill ways

I'll be doing a full refurbish of several old Burke No 4 horizontal mills. I was wondering what factory fresh tolerance (e.g. how flat, how parallel, etc) would be for the ways for these mills? And also what should one expect for backlash on x/y/z?

Any decent mill was scraped in to the maintained spotting MASTERS the company made for itself

"NUMBERS" do not come into play here. The scraping masters were "good enough" to suit them and were kept that way

At assembly the gibs were adjusted to just what they thought was the right drag and the machine went out the door

Back lash is a non issue. Any acme thread and its nut will be loose enough to actually be "turnable" and will naturally get "worse" with use

Take a look in the book Foundations Of Mechanical Accuracy by Moore for more on the subject

drcoelho said:

I'll be doing a full refurbish of several old Burke No 4 horizontal mills. I was wondering what factory fresh tolerance (e.g. how flat, how parallel, etc) would be for the ways for these mills? And also what should one expect for backlash on x/y/z?

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Burke #4? "Not MUCH righteousness in any respect!" RTFM.

Literally an "FM". Army Field Manual. They are honest little worker-bees, even as far as stronger than first appears, yet just NOT in the same class as a comparable work-to-be-done Hardinge TU or TM nor as flexible as a Nichols.

My one is not worth a lot more care than a decent carpenter's sliding mitre-box saw.

Nothing you do to it will make it into anything more than a very basic "get 'er done if it's SMALL enough to get your cutter into" mill. At their best in roles such as "same-cut, different-year" volume-production horses

For general purpose or "toolroom" tasking? The ways are not wide enough, the positioning screws are not stout enough, travel is SHORT, and a narrow one-slot table needs a fixture plate, mostly.

JF Deal With That until you have need, funds, and space for something stouter and of higher precision.

My case, that was a USMT "Quartet" combo-mill I mought rather was a Rambaudi or an Oerlikon Italia, but "she'll do".

And nooooo.. you don't REALLY want one of those weird "Quartet" orphans EITHER. DAMHIKT!

The #4 is at least honest, not an attempt to brand Rube Goldberg austerely simplistic.

Here are the specs on the Burke Millrite. They apply to the table, but the ways would have to be at least this good. I would assume the #4 would be as good as the Millrite. I didn't see anything on the screw backlash



Irby

IrbyJones said:

Here are the specs on the Burke Millrite. They apply to the table, but the ways would have to be at least this good. I would assume the #4 would be as good as the Millrite.

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It can be "made to be", I am sure. But only "barely".

Note that the ranges in the extracted publication run from one-thou per foot, 8 inches, 6 inches, even 4 inches.

If/as/when a #4 can be held to even TWO thou, I'd be inclined to call it good enough and put any spare coin or hours into some other needy project with a better prospect for more useful gains.

There's a LOT more TO a Millright than the tiny #4, BTW:

https://www.sterlingmachinery.com/m...powermatic-burke-milling-machine-brochure.pdf

... and more-yet to USMT/Burke/Houdaille's later, larger, and right-decent horizontals, such as the "333":

Miller, Horizontal: Horizontal milling machine Burke 333, D C Morrison

IrbyJones said:

Here are the specs on the Burke Millrite. They apply to the table, but the ways would have to be at least this good. I would assume the #4 would be as good as the Millrite.

Irby

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This was just what I was looking for, Thanks!