Resurrecting 1960 10EE with 460V Sabina drive

[Mr_CNC_guy]

The droop (they misspelled it) and the current limit adjust are used to set the running parameters of the control system. The droop sets how much the drive will be bogged down by an increasing load. If you set the droop to be two sensitive, the system will go into oscillation with the drive motor speeding up and slowing down on its own, sometimes quite violently.
The current limit adjust is probably what would be called damping. This acts like a shock absorber on the control system. It acts to prevent too rapid a response to load changes. A well-adjusted system is a balance between these two. It can take some fiddling to get the optimum setting for these adjustments.
You can start with the two settings in the middle. Move the lathe speed knob rapidly from slow to fast. Then decrease the speed rapidly. The spindle speed should come to the desired speed quickly without overshoot. You sense the overshoot by watching the RPM meter and listening. If this seems OK, then increase the droop knob and repeat the experiment. At some point, the lathe may go into oscillation. If so, hit the off button, it is possible a fuse will blow. Now you have gone too far, so back off the droop setting.
The purpose of the current limit adjustment (damping) is to reduce this oscillation. If you increase the damping, then you may be able to increase the droop setting some more without the oscillation. In this way, you can tune the control system so that the lathe will maintain the set speed from no load to a heavy load, as when taking a large cut.
However, you can over tune the system. Servo control loops are a very complicated subject, described by some very complicated math. This was researched in great detail in the early days of steam power.
If you over tune the system you can get into a situation where the lathe works perfectly when under no load but will oscillate violently when under load. The solution is to back off the droop and/or increase the damping. There is no "do this and it will work" answer here. You can come to a good setting if you understand what the two controls do. Just use the lathe and if you sense a problem with the drive make small adjustments to the droop and damping and in time you will get to an optimal setting.

 

[charlieman22]

Certain parallels with jetting a carburetor.

Superb overview.
Thank you.

 

[charlieman22]

Carriage backlash:

Lathe has been working ever since control board was repaired.
I've been collecting parts to assemble and install the missing taper attachment.
My plan is to pull the carriage off, clean the pump/filter/lines, and potentially modify the oiling system to be a bit more reliable/better fit to my sporadic use.

Before I tore down - I shot a bit of video to show existing backlash.
Both handle and internal gears.
I suspect some that watch this will know likely root cause after viewing?
Perhaps I can get started on sourcing of parts.

Here is a 15 second video both external and internal.

Welcome any comments on all above if anyone has insights/watch points, you think worthy of mention before I dig in.

Tks.
CM

 

[rke[pler]

That backlash is just the backlash between the pinion on the carriage drive and the rack on the bed. It really doesn't affect anything since the positioning of the carriage by the big-ass handle isn't precision anyway.

 

[charlieman22]

That backlash is just the backlash between the pinion on the carriage drive and the rack on the bed. It really doesn't affect anything since the positioning of the carriage by the big-ass handle isn't precision anyway.

Rke - Thanks.
Makes sense.
As part of my current efforts, I have an unused DRO that I plan to install on the carriage and cross.
That, some improvements to the oiling system, and the assembly of my taper attachment are the reason for the project.

Pulled apron and saddle off yesterday.
Found a bit of bodgery - as one might expect - but generally seemed pretty good.
Pump has been working - if imperfectly to all spots - feeding the ways though. Probably saved them from wearing out.
They seem in pretty good shape - no ridge from fingernail.

Machine’s been “rebuilt” at some point: there’s evidence of hand scraping.
Some pics below.


Prior owner gave it generally light use - but it involved long parts I suspect.
Looks to me like he machined away the component that houses the feed rod and lead screw shaft ends, to allow extra carriage movement.
The pins are also not original.
(if anyone has some components they are looking to sell...)
Worst of the bodgery here:


One surprise for me was the wipers.
I was expecting felt.
Found them all to be rubber.
Was this from factory?


Wadding for the oil reservoir on the apron was missing.
Surprisingly though - there was some form of it in the feed hole to the dials.
Don't think that was factory?
Perhaps someone utilized to slow flow there - and increase pressure for the higher X-feed holes.
Pulled this out:
Welcome general observations or insights.
Thanks,
-CM

 

[charlieman22]

Square dial apron tear down:

Tore down most of it today. Used an older post from gernoff https://www.practicalmachinist.com/forum/threads/10ee-apron-overhaul.269789/ with some nice pics of a square dial apron. Thanks!

Managed to get everything to come apart so far without too much struggle.
Taper pins can be tough.
To get them out without stressing the casting, I spun the collar upside down, and slid it off far enough to reach between the collar with a punch. To orient the pin for access - I spun the handle and housing on the front side 180° and put two bolts back in - so the small side of the taper was pointed up. Wood then provided support on the back while I used a punch (pic).

Came across one thing that seamed strange
There’s a grub screw on the C shaped part that moves the gear.
Here is a pic - its towards the top.

And a better close up. Was this how it was done oringally? Doesn't seam to have a means to loosen or tighten...


As for carriage backlash, the pinion gear that interacts with the carriage track appears to have some wear.


I believe that's part EE1693, however, there is a gap in mine that doesn't appear to be in the parts diagram from Monarch. Can anyone educate me on that?



Thanks,
-CM

 

[Cal Haines]

...
One surprise for me was the wipers.
I was expecting felt.
Found them all to be rubber.
Was this from factory?
View attachment 407477
...

If you look closely, I think you'll find that it's lamination of three layers of rubber (or similar) and two layers of felt. Monarch installed these for a while, but I don't believe that the material is available anymore, so they've moved to something else. I've toyed with the idea of using contact cement make my own laminated wipers from thin rubber and felt sheets.

 

[charlieman22]

If you look closely, I think you'll find that it's lamination of three layers of rubber

Thanks Cal! I'll have a look.
I like the rubber - it serves somewhat like a squeegee - which is great if you are feeding oil underneath and between the two squeegees...

Managed to tear down the rest of the apron and carriage today.
Have access to an auto parts cleaner - and utilized it to strip things down.
Given the likelihood of lead in the paint - nice to do it this way.
Also cleans the castings very nicely.

The usual mess when I started - looked like this.

The cleaning machine:

Paint just scuffed off - no dust...


A few after pictures:



I plan to bow out all the lines - and test the pump to see if all the fittings are still feeding.
I've got some in stock - though I need to make sure they match flow restriction rates.

One issue I will need to address.
Appears the arm (3534) is particularly worn on the side facing the tailstock. Considering braising some additional material on it to help ensure it is tall enough to properly activate the pump. Welcome other's experience with this issue.


(Is there a good rebuild thread on the bijur pump anyone is familiar with? Seen a few - but nothing definitive.)

(

 

[charlieman22]

Another day of clean up.
Have run into a challenge - could use some insight.
Part number 1377 I believe.
Its the aluminum ring that dresses the end of the tailstock casting.
There appears to be a locking pin of some kind underneath it - but it has no head to turn or unscrew with - and no exit to punch it out.

 

[rke[pler]

The pinon looks stock, here's one I pulled from my '56:



I once found a supplier of the way material but neglected to note it, I'll try to find them again.

The saddle mating points to the apron looks normal, factory likely did that. The way scraping does not look factory.

I'd just get replacements for the Bijur meter units on the saddle, they're usually bad. I've see folks spend $35 in time trying to clean the $15 part and it seldom works.

On the Bijur pump, normally all that's needed is the replacement of the check and the filter felts. For the rocker I'd just braze the flat up and clean up on a belt grinder or with a file. It'd likely work OK as it is.

That collar on the tailstock should be steel and have a hole for a pin spanner, clocked to be on the bottom when tightened. If it's plugged you might be able to pop it off with a strap wrench with rubber on the strap.

 

[charlieman22]

Thank you Rke - 5 sentences worth about 5 hours of frustration saved for me. Much appreciated.

I'd just get replacements for the Bijur meter units on the saddle, they're usually bad. I've see folks spend $35 in time trying to clean the $15 part and it seldom works.

Chuckled. Indeed.
I will replace the units at the manifold...

On the Bijur pump, normally all that's needed is the replacement of the check and the filter felts.

Looks like there is some discussion on what the right pressure relief /check valve is (5lb, 10lb, 15lb, 20lb-25lb...). Not sure if there is consensus. Anyone have some specific experience?
https://www.practicalmachinist.com/forum/threads/10ee-apron-bijur-unit.377462/ which I believe is focused on the check that comes out

replacement of the check and the filter felts

If you were referring to the inlet check valve - I'm still looking for that part number if anyone has/can share. Same for felts.
Tks.

That collar on the tailstock should be steel and have a hole for a pin spanner, clocked to be on the bottom when tightened. If it's plugged you might be able to pop it off with a strap wrench with rubber on the strap.

Terrific.

Thanks for weighing in - helpful all around.