# Fixing Knee Mill Ways Y-Axis



## ErichKeane (Nov 12, 2018)

So, I recently picked up a brand new mill vice from Kurt, and confirmed what I'd feared,my milling machine's ways are pretty bowled out.  I get ~3-4 thou angle to my vice if I don't shim it, so my face mill cuts leave an annoying step!  I supected the ways for my "Y" axis (the part attached to the 'knee' that the saddle rides on) are dished out.

I am prety sure that is the case now that I've got it apart!  I can see the original scraping/flaking marks on the front/back, but the middle is pretty heavily gouged.  I put a piece of extrued aluminum, and cannot get a 6 thou feeler gauge under it (smallest I have), but I can see the gouges.  Additionally, it gets REALLY tight on the ends, but loose in the middle.

My first thought was that I could possibly machine this surface with the mill itself, but I'd forgotten I've now removed all the parts that move   So thats right out.  I saw some videos on hand-scraping, but I don't see how to do so while maintaining the spindle/knee relationship properly!  If I can find a piece of metal large enough, I have a 6x18 surface grinder, so I suspect I can make a flat tool for marking dye, but I don't see how to ensure the correct 'flatness'.  Is there a good way to do this? 

Also, I suspect I'd be better off filling the low spots with something and sanding it flat, but again, have no idea how to do so.  

Anyone do this before and have a good guide on how to clean up this part?  Am I overthinking it, and just need to pick up a giant jar of JB-weld and a scraper? (plus a granite surface plate and some bluing paste  ?)


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## john.k (Nov 12, 2018)

This is the point where a Mr KIng tells you all about Rulon and Turcite......but definitely not about supergluing on a brass shim.


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## ErichKeane (Nov 12, 2018)

john.k said:


> This is the point where a Mr KIng tells you all about Rulon and Turcite......but definitely not about supergluing on a brass shim.



I've looked at the Turcite (and Rulon), though I'm having a tough time finding an appropriate amount!  I have 2 ways that are 2" by 21", yet I can only find 12" wide sheets of them!

Also, I'm missing a step with them I think.  It seems to me that they'd just move my 'bowl' shape up another 1/32", right?  Or is the idea that you glue that on, then shave it with some material to make it flat?  If it were thinner, I thought I could just glue it to the low spot (which I could do with brass shims maybe...) and get most of the benefit, right?  

This 1 pair of spots is a touch annoying, since the rest of the dovetails all still have the flaking marks in them, so its just some pretty dug-in centers (<.006, though I lack any way to measure better than that).


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## benmychree (Nov 12, 2018)

Typically, the unworn parts of the dovetail would be hand scraped to remove the hollow, and perhaps the gib would take up the lost material, or the gib can be shimmed or replaced; since you obviously know nothing about scraping or machine alignment, I would advise you to do nothing until you learn about the process.  There is a book titled "Machine Tool Reconditioning" that tells the whole process, and Rich King offers classes in hand and power scraping at various locations around the USA.
I was told many years ago, "If you don't know what you're doing, you shouldn't ought to f--- with it".  Good advice!


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## ErichKeane (Nov 12, 2018)

benmychree said:


> Typically, the unworn parts of the dovetail would be hand scraped to remove the hollow, and perhaps the gib would take up the lost material, or the gib can be shimmed or replaced; since you obviously know nothing about scraping or machine alignment, I would advise you to do nothing until you learn about the process.  There is a book titled "Machine Tool Reconditioning" that tells the whole process, and Rich King offers classes in hand and power scraping at various locations around the USA.
> I was told many years ago, "If you don't know what you're doing, you shouldn't ought to f--- with it".  Good advice!



Hmm... Not sure I can get away with it anyway.  I don't really have a good way to make sure it is square to the spindle either, which I suspect would make it more difficult.

I had an alternative idea... I wonder if I could just superglue some .001 shim-stock in layers to the ways in the low spots to make up a good amount of the slope that I get?  I figure as long as the edges of the shim-stock never get out from under the saddle that it should work, right?  

Or is this a stupid idea?


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## benmychree (Nov 12, 2018)

ErichKeane said:


> Hmm... Not sure I can get away with it anyway.  I don't really have a good way to make sure it is square to the spindle either, which I suspect would make it more difficult.
> 
> I had an alternative idea... I wonder if I could just superglue some .001 shim-stock in layers to the ways in the low spots to make up a good amount of the slope that I get?  I figure as long as the edges of the shim-stock never get out from under the saddle that it should work, right?
> 
> Or is this a stupid idea?


In a word, yes, it is not a good idea ----


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## ErichKeane (Nov 12, 2018)

benmychree said:


> In a word, yes, it is not a good idea ----


Alright, thanks!  I guess I'll just have to learn scraping then.  I got a copy of the Connelly book and am reading it.  I see that for ~$350 I can get a pair of granite parallels 24"x2" wide (my ways are 2"x21") that I could use as straight edges.  I have a coax indicator I can use to ensure they are parallel to the spindle.

So, I just gotta read a bunch and get the parallels/bluing dye (presumably it isn't the same liquid dykem)/scraping tool and get on my way.  At least it'll give me something to do over the winter.


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## Technical Ted (Nov 12, 2018)

You sound new, so excuse me if I'm telling you something you already know. But, let's back up and check a few things. I'm not sure what type of mill you have. But, have you trammed the head? If the head isn't trammed in you will leave steps when you mill. I'm guessing this is what you are actually seeing. How are you checking things out to see that you have this dip? Don't do anything until tramming your head in. 

The Y axis on my Bridgeport is worn and I put a shim BEHIND the gib so I could adjust it for better adjustment. Things do get tight at both ends of the travel, but I seldom use that area and if I need to I just back off on the gib.

Ted


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## benmychree (Nov 12, 2018)

Dykem will not work, Rich King sells a water based marking medium that is better than Prussian Blue, it comes in blue and yellow, which he uses for a background color; they are easy to remove from the hands and tools.  What you will need is a dovetail straightedge to be able to get into the dovetails, a parallel won't do the job.


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## ErichKeane (Nov 12, 2018)

Technical Ted said:


> You sound new, so excuse me if I'm telling you something you already know. But, let's back up and check a few things. I'm not sure what type of mill you have. But, have you trammed the head? If the head isn't trammed in you will leave steps when you mill. I'm guessing this is what you are actually seeing. How are you checking things out to see that you have this dip? Don't do anything until tramming your head in.
> 
> The Y axis on my Bridgeport is worn and I put a shim BEHIND the gib so I could adjust it for better adjustment. Things do get tight at both ends of the travel, but I seldom use that area and if I need to I just back off on the gib.
> 
> Ted



I'm definitely a self-taught home-gamer, so I'm a bit of a newbie.

I have a Burke MVN, so I don't think my head rotates.  Even so, it doesn't adjust in the other direction (which is the one it has trouble with).  If I run my face-mill along the X-axis, then move it down the Y axis and cut again, I get steps.  That tells me that when moving fwd/backward, I'm getting the height movement.  Do mills typically adjust in that direction?  I also get REALLY tight at the ends, and can twist it by ~20 thou over ~6" in the middle.  Which makes tramming in the vice almost impossible.



benmychree said:


> Dykem will not work, Rich King sells a water based marking medium that is better than Prussian Blue, it comes in blue and yellow, which he uses for a background color; they are easy to remove from the hands and tools.  What you will need is a dovetail straightedge to be able to get into the dovetails, a parallel won't do the job.



I saw the dykem high-spot blue, which is what I'd figured on.  I actually don't have an 'inside' dovetail for this part, so I think the parallel would work though.


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## Technical Ted (Nov 12, 2018)

Why not post a picture of your machine so we're all on the same page. But, even though your mill doesn't nod doesn't mean that it is not out of tram. If the column is off or if the head tilts and there is debris or dinges in the joint it could throw your head out of tram. I suggest you tram it and see what you've got. I don't think that your ways being worn are going to make your table dip as much as you are seeing. That would take a LOT of wear.

Ted


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## ErichKeane (Nov 12, 2018)

Technical Ted said:


> Why not post a picture of your machine so we're all on the same page. But, even though your mill doesn't nod doesn't mean that it is not out of tram. If the column is off or if the head tilts and there is debris or dinges in the joint it could throw your head out of tram. I suggest you tram it and see what you've got. I don't think that your ways being worn are going to make your table dip as much as you are seeing. That would take a LOT of wear.
> 
> Ted


I don't have a picture handy, but I have the machine he's tramming here: 




I guess perhaps I could shim the bottom of the head in order to make this up once it is all back together...   Though removing the head doesn't seem like fun!


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## Technical Ted (Nov 12, 2018)

Even though your head doesn't rotate in the other plane (nod) doesn't mean it's not off. I think this is what your problem actually is. If there is any misalignment in the column where it rotates, or in the joint where it rotates side to side, it is going to throw the tram off.

Put an indicator in your spindle and check the table from the back side near the column to the front side where the operator stands. This needs to read very close to 0. If it doesn't read 0 or very close to it, you will most likely see steps when you mill on the X axis like you are seeing.

Ted


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## Technical Ted (Nov 12, 2018)

I have a Jet mill that the head doesn't nod. When I first got it the tram was off front to back. I pulled the head off and stoned the mating surfaces. Now, it's within a few tenths. Problem solved.

Ted


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## ErichKeane (Nov 12, 2018)

Technical Ted said:


> I have a Jet mill that the head doesn't nod. When I first got it the tram was off front to back. I pulled the head off and stoned the mating surfaces. Now, it's within a few tenths. Problem solved.
> 
> Ted


Alright, perhaps I'll give that a go!  I pulled the entire saddle/table off for cleaning (previous owner, a HS, used grease in the fittings instead of oil, so I'm going to clean that out), so when I get it assembled perhaps I'll give that a try.  It would be really nice to be able to cut actual 90 degree angles...


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## Technical Ted (Nov 12, 2018)

Clean and lightly stone all mating surfaces. Only stone enough to find and remove burrs, dinges, etc.. Don't go crazy, just lightly. After cleaning and stoning put a light coat of oil on the surfaces and reassemble being careful how you tighten things down. You want balanced, even tightening on the bolts. I would start with what's easiest, which is probably just the head where it tilts sideways. You also have to worry some about the joint where it rotates on the column and the dovetail slide where the whole things moves in and out. But, start with the easiest and check things. You might not have to go through everything to resolve your tram issue.

Ted


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## ErichKeane (Nov 12, 2018)

Technical Ted said:


> Clean and lightly stone all mating surfaces. Only stone enough to find and remove burrs, dinges, etc.. Don't go crazy, just lightly. After cleaning and stoning put a light coat of oil on the surfaces and reassemble being careful how you tighten things down. You want balanced, even tightening on the bolts. I would start with what's easiest, which is probably just the head where it tilts sideways. You also have to worry some about the joint where it rotates on the column and the dovetail slide where the whole things moves in and out. But, start with the easiest and check things. You might not have to go through everything to resolve your tram issue.
> 
> Ted



Well, the dovetail slide for my head is actually siezed up pretty tight.  I tried to loosen it up with penetrating oil and a dead blow at one point, but couldn't get it free.   There is ALSO a spacer in the column which could presumably cause the problem, but I doubt I can get the head itself off, let alone the whole thing!


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## Technical Ted (Nov 12, 2018)

ErichKeane said:


> Well, the dovetail slide for my head is actually siezed up pretty tight.  I tried to loosen it up with penetrating oil and a dead blow at one point, but couldn't get it free.   There is ALSO a spacer in the column which could presumably cause the problem, but I doubt I can get the head itself off, let alone the whole thing!



I'm not a betting man, but I think it's a pretty safe bet that the column spacer is the culprit. The dovetail problem is adding as well. I think you know what you have to do. Get things apart and in proper order. If that column spacer is home made and hasn't been properly scrapped in you might as well remove it until you learn how to scrape. Just machining it will not be accurate enough to maintain your tram (unless your head can nod so you can compensate for it's being off). 

Just my two cents,
Ted


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## benmychree (Nov 12, 2018)

ErichKeane said:


> I'm definitely a self-taught home-gamer, so I'm a bit of a newbie.
> 
> I have a Burke MVN, so I don't think my head rotates.  Even so, it doesn't adjust in the other direction (which is the one it has trouble with).  If I run my face-mill along the X-axis, then move it down the Y axis and cut again, I get steps.  That tells me that when moving fwd/backward, I'm getting the height movement.  Do mills typically adjust in that direction?  I also get REALLY tight at the ends, and can twist it by ~20 thou over ~6" in the middle.  Which makes tramming in the vice almost impossible.
> 
> ...


Dykem high spot blue is grease mixed, and hard to wash off everything, including you.


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## ErichKeane (Nov 12, 2018)

Technical Ted said:


> I'm not a betting man, but I think it's a pretty safe bet that the column spacer is the culprit. The dovetail problem is adding as well. I think you know what you have to do. Get things apart and in proper order. If that column spacer is home made and hasn't been properly scrapped in you might as well remove it until you learn how to scrape. Just machining it will not be accurate enough to maintain your tram (unless your head can nod so you can compensate for it's being off).
> 
> Just my two cents,
> Ted



Alright, well, I decided to use some additional force and tear everything down upon getting home from work today.  I was surprised how much of the machine has factory scraping/half-moon flaking on it, every contact surface I could find!  The riser block is factory looking (scraped, and has the details including the 'center' part.  

Once I got the motor/spindle off the machine, a little back/forth tapping with a dead blow moved the sliding dovetail, so th at came off reasonably easily.  After that, the bolts came apart with no problem.  Here's some after-the-fact photos:


Machine as it sits now.  Missing the head and tables 




Here's a photo of the ways.  You can see the gouges out of the near one.



The top of the machine, scraped though it doesn't show up very well.



And the rest of the machine, torn down and waiting for cleaning.:


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## Technical Ted (Nov 12, 2018)

That riser does look factory so it's most likely good. Just clean and lightly stone everything like I discussed before and hopefully everything will be better after reassembly.

Did you check your tram prior to tearing things down to see how far it was off? I hope so, so you can determine the improvement. Measure, then make adjustments, then measure again. That's the way to systematically work towards a viable solution to problems like this. 

Ted


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## Technical Ted (Nov 12, 2018)

Another thing came to mind. When tramming your head, make sure the knee gib is adjusted properly and lock your knee lock. If the knee is sagging on the ways it will throw your tram off as well. 

Ted


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## ErichKeane (Nov 12, 2018)

I hadn't checked tram before hand, but the tables were already off.  My thoughts while tearing it down was to find a way to measure it "live", but i'll probably just clean and reassemble.

I don't really have an accessible knee gib, so I'm going to tear the knee off next, another person on the burke email list mentioned that it is likely sagging so I should do that. It'll give me a chance to clean grease out of there as well.  If I can figure out how to adjust that with the machine together, it'll likely be better for adjusting it anyway.

This is turning into a pretty intense project


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## Technical Ted (Nov 12, 2018)

ErichKeane said:


> This is turning into a pretty intense project



That is one thing that I find very enjoyable about this hobby... buying a piece of equipment, tearing it down, cleaning it, repairing and refurbishing where required. I enjoy getting a machine to run the best that it can for the amount of wear that it has.

Welcome to our hobby!

Ted


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## Bob Korves (Nov 12, 2018)

Erich, I also have a Burke Millrite MVN, my second one.  The first one had the nodding head, and that machine was quite well worn.  My second one does not have a nodding head.  It came to me new, never used, from 1967, NOS.  It only needed to be cleaned up of nearly 50 years of grime on the outer surfaces.  No rust.  I even made a great deal on it.   It is MUCH more rigid than the first one was.

The original specs on the MVN call for the the head to be square to the table, with the front of the table from zero (level) to .0005" higher than the back of the table.  With a substantial part on the table, it will sag more than half a thou.  The ways of the mill will also wear with time, and the table will appear to sag.  Most of that will be in the knee to column ways, perhaps more in the top of the knee and the bottom of the saddle.  Make sure that every axis and every slide is locked down tight before you measure anything.  Test it with the table all the way in, in the middle, and all the way out.  The problems will almost for sure be with the saddle and knee ways, not in the ram slide or the turret swivel or in the ram face where the head swivels left and right.

BTW, the Millrite mills do not have any factory scraping on them, only flaking after the ways were finish ground.  Flaking is several thou deep when new, so it looks pretty good even when the ways are quite worn.  Using it as a visual gage is only useful to get a rough idea of how much wear the machine has.  If it is through the flaking anywhere, you are looking at medium to heavy wear.


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## 8mpg (Nov 13, 2018)

If you have slop in the table, definitely measure it. HW Machine has a great video on shimming the gibs to get a tighter fit with less slop.


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## ErichKeane (Nov 13, 2018)

Bob Korves said:


> Erich, I also have a Burke Millrite MVN, my second one.  The first one had the nodding head, and that machine was quite well worn.  My second one does not have a nodding head.  It came to me new, never used, from 1967, NOS.  It only needed to be cleaned up of nearly 50 years of grime on the outer surfaces.  No rust.  I even made a great deal on it.   It is MUCH more rigid than the first one was.
> 
> The original specs on the MVN call for the the head to be square to the table, with the front of the table from zero (level) to .0005" higher than the back of the table.  With a substantial part on the table, it will sag more than half a thou.  The ways of the mill will also wear with time, and the table will appear to sag.  Most of that will be in the knee to column ways, perhaps more in the top of the knee and the bottom of the saddle.  Make sure that every axis and every slide is locked down tight before you measure anything.  Test it with the table all the way in, in the middle, and all the way out.  The problems will almost for sure be with the saddle and knee ways, not in the ram slide or the turret swivel or in the ram face where the head swivels left and right.
> 
> BTW, the Millrite mills do not have any factory scraping on them, only flaking after the ways were finish ground.  Flaking is several thou deep when new, so it looks pretty good even when the ways are quite worn.  Using it as a visual gage is only useful to get a rough idea of how much wear the machine has.  If it is through the flaking anywhere, you are looking at medium to heavy wear.




Ah, Hi   You'd responded to my Burke email thread as well!  I ran out to the garage on the way to the office today and checked the knee against the column ways with a short square and I believe I could see a little light, which would confirm it is a problem with sagging.  I'm going to see if I can get the knee off the mill (it needs cleaning up as well!), but I didn't see an obvious way to do so.  Do you have a tip on how it comes off?  

The only screws visible from my perspective are the little bump-stops at the top of each dovetail, and the steel bar that acts as the other part of the bump-stop.  I presume removing the screw from the knee won't help (since the nut will still be in place), so the only thing I can think of is to remove the top of the bump-stop and run it off the top?

Or is there some disassembly step I'm missing?


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## Bob Korves (Nov 13, 2018)

ErichKeane said:


> Ah, Hi   You'd responded to my Burke email thread as well!  I ran out to the garage on the way to the office today and checked the knee against the column ways with a short square and I believe I could see a little light, which would confirm it is a problem with sagging.  I'm going to see if I can get the knee off the mill (it needs cleaning up as well!), but I didn't see an obvious way to do so.  Do you have a tip on how it comes off?
> 
> The only screws visible from my perspective are the little bump-stops at the top of each dovetail, and the steel bar that acts as the other part of the bump-stop.  I presume removing the screw from the knee won't help (since the nut will still be in place), so the only thing I can think of is to remove the top of the bump-stop and run it off the top?
> 
> Or is there some disassembly step I'm missing?


http://www.mikeamick.com/millrite_project/knee.htm


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## ErichKeane (Nov 13, 2018)

Bob Korves said:


> http://www.mikeamick.com/millrite_project/knee.htm


Huh... THATS what the manual was referring to for gib screws!  I actually don't believe I have any of those...

I thought it was just a bad image and was referring to something internal.   Mine is a Powermatic green one (but still with the manual spindle speed), so perhaps they changed that design?

That said, that site is going to be gold for learning how this works.


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