Milling Rite

[Ischgl99]

The elevator screw does look like someone used an angle grinder to cut it to length, I would not expect Burke to do something like that. I'm wondering if there was a problem with the thread and someone took a grinder to it to clean them up.

I think you may be right about it being damaged and then sitting for a while. My guess is someone put something way to heavy on the table and caused the damage to the gears and elevator screw, possibly over a period of time, and then tried to get it working again. That would explain the heavy wear on the nut and the cracked gear teeth.

To clean up the thread for the gear, try using a triangular file first to get most of the damage cleaned up, then a die might be able to clean up the rest.

 

[Dave Bonzo]

The elevator screw does look like someone used an angle grinder to cut it to length, I would not expect Burke to do something like that. I'm wondering if there was a problem with the thread and someone took a grinder to it to clean them up.

I took a few minutes to look over things, and the more I look the more I think that something strange and unknown happened to this mill in the past. Certain parts - various fasteners, the elevator screw and shaft, the Unreamed-For Taper Pin of Uncertain Provenance, etc - just don't look the same as others: the parts that are undeniably Burke-made have a level of fit and finish that's palpable in its absence.

I think you may be right about it being damaged and then sitting for a while. My guess is someone put something way to heavy on the table and caused the damage to the gears and elevator screw, possibly over a period of time, and then tried to get it working again. That would explain the heavy wear on the nut and the cracked gear teeth.

I'm starting to have a similar idea...but - and I hate to say this - my version of that theory is that the mill fell over, or otherwise hit the ground at some point in the past. I'm starting to see indications of that, or of a similar trauma.

To clean up the thread for the gear, try using a triangular file first to get most of the damage cleaned up, then a die might be able to clean up the rest.

I hit it with a file and made enough progress to get a nut back on it, and I'll have a 1/2-13 rethreading die in-hand tomorrow. I'm otherwise stalled out until then.

 

[Dave Bonzo]

Finally...some progress.

Pictured: And a modicum of organization.




I found out what was causing part of the binding in that assembly, beforehand: in addition to everything else, the shaft collars were installed too tightly. When they're pushed tight against the mounting plates and tightened, there's just enough deflection/twist present to cause them to jam and/or lock up against the plate at one point in the rotation...and I'm strangely sure that this is what might have caused Chimpo to bash on things with hammers, at times. I ended up putting a .003" feeler gauge behind them all when I tightened them down, and that left them secure but free-spinning; a bit of assembly lube helped, as well.

Also, I took a bit of time and did some light restoration on the knurled locking screws for all of the bezels; Chimpo had used the exact wrong screwdriver to loosen and tighten them over the years, so the slots were a bit worn and curled-over at the top. I fixed that with a key file, a drill press and some sandpaper.

Pictured: Not my best work...but that'll do, pig.




And after that, things went back together. I used the existing hardware where possible and replaced the cobbled-together garbage where necessary.

Pictured: Sucks less.




I'd love to bead-blast that bezel and maybe do some paint inlays in the letters, but that's gonna be a project for Future Bonzo...and it won't be too bad: now that I know how this assembly goes together and what kind of tolerances it needs to work correctly, I can have it in and out pretty quickly. I also got the head freed up; it wasn't frozen in place, but some penetrating oil followed by a splash of 68 oil made it move a LOT better.

 

[Dave Bonzo]

So, uh... there's an issue. Big surprise, right? tl;dr is that I seem to be missing some pieces...but if you want the full version, take a look at the following diagram; it shows a shaft collar on the elevating screw. Part numbers 30/31, which also includes a second taper pin.

Pictured: Dafuq?




I don't have that collar. Or the taper pin. Or a bore for said pin. Or any space on the screw to install any of those pieces, because dropping the thrust bearing assembly onto the shoulder of the elevating screw indexes with just enough space to install the gear on top of the cast bore...at which point it just rides on top of the casting, it seems, because I don't have any kind of shim, bearing or anything else to go between it and the casting. I know it's basically seeing no real load and I know the thrust bearing mounts underneath the casting and takes effectively all of the load of the knee, but it seems like something should be shimming the gear so it's not just an iron-on-iron situation.

Also, it gets more interesting: my remedial self finally figured out what that extra hole in the knee is for.

Pictured: Oh.






That's the lubrication port for the elevating screw bore...which was clearly included for a reason, but had nothing but grease and swarf packed into it, and it was packed so tightly that I didn't even notice it existing until just now. So, I'm not sure what to do with this, because it seems like some kind of provision for controlled lubrication should be involved here - aside from just having a hole leading to the bore - but there's nothing shown on my diagram.

Also, I think that at last one portion of the screw shaft was machined to the wrong size...but I'll figure that out in a few. Lunch first, and then I'll see if my suspicions are correct and literally all of these parts are non-stock.

 

[RaisedByWolves]

I'm starting to have a similar idea...but - and I hate to say this - my version of that theory is that the mill fell over, or otherwise hit the ground at some point in the past. I'm starting to see indications of that, or of a similar trauma.



I hit it with a file and made enough progress to get a nut back on it, and I'll have a 1/2-13 rethreading die in-hand tomorrow. I'm otherwise stalled out until then.

I was going to say this earlier on, but I didn’t want to get you discouraged until you had the whole works torn apart.

The bent handle is a sure sign of a tip-over and that would also account for the broken dowel pins.

 

[Dave Bonzo]

I was going to say this earlier on, but I didn’t want to get you discouraged until you had the whole works torn apart.

Yes, discouragement at the point of no return is definitely preferable to all other information-conveying choices.

In all seriousness: I've long been thinking that some kind of forbidden liaison between Millicent and Gravity took place in the past... I've just not been sure what, and when, and to what extent.

The bent handle is a sure sign of a tip-over and that would also account for the broken dowel pins.

I think you're 116% correct... it's just a question of exactly what tipped over. Without seeing much else that's damaged in the same way, I almost think that the saddle was just dropped... possibly by itself, or possibly with the table attached. I agree that the lock handle is a sure sign of that kind of incident: it's deformed in a cohesive way that indicates a singular impact, and the secondary strike marks probably happened later, since there was no real prohibition against damaging the handle any further. Same goes for the damaged handwheel in the same area; I think that took part of the same impact. Dowel pins would have certainly come apart from that kind of force...but I'm not sure that this is what caused the damage to the gears inside: I think that was a separate incident. On that note: things have happened...

Pictured: Assembly-shaped things, at that.




Those are the mangled stock gears, obviously...and now that they're set up with a modicum of care, they actually work really well; I'll still have to go back inside and change them, but the assembly is now functional if not entirely intact. I think the discrepancies I've noted between my elevator screen assembly and the diagram in the manual is due to the diagram being representative of an earlier screw design. At some point, Burke changed to a larger-diameter screw - something like 1.3" or so - and this is the screw that I have; the previous one was smaller, and it may have needed the collar and taper pin that was noted in the diagram. Once I got the knee back off the ground and to where I could work on it, I made a few test-assemblies and discovered that the deformed retaining nut that held in the gear was just that: a deformed-thread nut...and Burke used one of these to set pressure on the gear. If you use a conventional nut and even barely snug it down, the entire gear train jams and locks; part of me wonders if this is how Chimpo broke this portion of things, and whatever he did to the elevator screw shaft was a different episode. Regardless, I experimented a bit, and I was able to find a setting that allowed very little unwanted movement yet still allowed free rotation of the gears. I'm also not sure if the screw itself is stock or rebuilt, but now that things are installed and basically snugged-down, it's all working mostly as intended; I think there are a few slightly-too-loose and a few slightly-too-tight dimensions, but nothing that's exceptionally concerning to me at this point. After getting the screw and gears and shafts in place, it was just a matter of pulling everything upwards and dropping it back onto the base.

Pictured: I really like this little shop crane.




I'm definitely keeping this hoist... especially after swapping in that extra air-over cylinder that I had: it's literally push-button lifting and controlled descent, and my back LOVES not being involved with any of it. I'd like a better release valve on the cylinder, but I can fix that at some point in the future: either way, that part of the day was dead simple. Also, for reference, here's the reason I had to do the up-and-over movement in the first place:

Pictured: So close, but...




Pictured: ...missed it by *that* much.




So close...but yeah, not a big deal: drop it over, get the screw and nut into place, snug up the set screw in the base, set the gib into place, and then just snug up the gib screws.

Pictured: At least, snug up the ones that I have.




I'll figure out the misses and mismatches in the near future...right after I figure out how to set up gibs: all I get from the manual is "sufficient tightness" and "desired amount" and other phrases that sound like they were written by the allergic-to-specificity trolls at Land Rover. So, for now, I'm just kind of installing things per those directions and hoping that I'm not smurfing it up.

Pictured: Smurfing it up.




It's kind of a counterintuitive process, installing that thing; you have to pull the gib and shift things around and shim stuff kind of sideways and even then, the nut will BARELY fit. The dowel pins definitely change things up; there's one very narrow alignment window with them in place...but I didn't break them, so yay for me. I added some oil to the ways, slid the table around for a bit, got the screw installed, lubricated it, ran out of oil zerks, and called it for the night... but holy f***, does this thing slide and move smoothly, now. Like, I thought it was fine, before: it wasn't. It wasn't fine at all.

 

[Dave Bonzo]

Well, I got to this point...

Pictured: Foreshadowing.




... before I realized that the table gib on the saddle is adjusted incorrectly, and the table can't slide onto the saddle as it should. Furthermore, said gib can't be adjusted while the saddle is installed; the knee itself is in the way. So, now I'll have to remove the saddle and pre-fit it to the table, then slide those pieces apart, then reinstall the saddle and eventually get myself back to this point. Because reasons.

 

[Ischgl99]

Yup, they made it difficult to adjust the gibs. I need to do that on mine, but have been pushing it off because of how involved it is to do that.

 

[Dave Bonzo]

Yup, they made it difficult to adjust the gibs. I need to do that on mine, but have been pushing it off because of how involved it is to do that.

What I'm not sure about is how to determine the correct tension without putting the entire screw assembly in place and/or doing lots of test-fitting. I guess I can try to put an indicator on the saddle and get it down to minimal movement relative to the table, but I'm not sure how to take it all back apart and then shove it all back together again without doing exactly that, multiple times...and then having to leave it pre-assembled anyway, and heave it all into place as one unit.

 

[Ischgl99]

I haven’t done it yet, so can’t offer any advice. I think I recall reading somewhere it is trial and error to find the right amount. It might be easier to put the table somewhere upside down and then mount the saddle so you can adjust it that way, then reinstall as an assembly. Since you have the hoist, you can put a couple eye bolts in the table t slots and lift it that way to make reinstalling the assembly. That’s how I took my table off when I cleaned it up a number of years ago.