Lathe DRO Installation

I installed a DRO on the Clausing.  I got Aikron scales and console - the LCD console, a 1 micron slim magnetic scale for the cross slide, and 5 micron standard width scale for the carriage.  So far I'm very happy with it - the user interface is better than some US-made, much more expensive DRO's I've used, and being able to store a library of tool offsets is a real game changer - all the lathes I've used until now have been communal (and thoroughly abused...), so even though some of them had DRO's none of them had proper tool libraries.  Tool libraries make turning so much more efficient, and for tolerances over 50um or so I don't even need to measure anything. 

Mocking up the cross slide scale and read head placement - In order to not loose any travel, I had to get a scale that was slightly longer than the cross slide.  To get the the scale mounting fasteners to overlap, I had to make a longer cover on the back side of the cross slide.

The chuck-side scale mounting is a little unusual - this video from Robin Renzetti was the inspiration for that - as he points out,  if the scale is directly under the tip of the tool, machine inaccuracies like curvature in the travel of the cross slide don't cause diameter error between the scale measurement and where the tool actually is.  And these magnetic scales are small enough that chuck interference isn't an issue.

The original cover was a casting, but was almost the same profile as some off the shelf steel u-channel, so that's what I used for the new cover:

The extrusion was too big for my tiny mill so I used a Bridgeport at work:

I fastened the u-channel to the cross slide and indicated the faces of the cross slide in for final machining to ensure the faces (especially the scale mounting face) were flush and parallel to the cross slide:

Before un-bolting the cover from the cross slide, I match-drilled a couple dowel pin holes and fixed them into the cross slide casting with retaining compound.  If I have to disassemble the cross slide at some point, it'll go back together repeatably.

Checking that the scale aligns with the cross slide travel - I did the vertical alignment by loosely tightening the mounting fasteners at each end and just tapping the the scale into alignment:

Thanks to the match-machining I did on the cross slide cover, I didn't have to do any shimming to get the z-alignment of the scale right:

Scale and read head both mounted:

I made a scale cover by gluing a neoprene rubber sheet to the cross slide with some Loctite 380.  Eventually I want to make a proper guard for the scale and proper way covers, but this does the job for now:

Mocking up the position of the carriage scale and read head on the back side of the machine:

To get the scale parallel to the lathe bed vertically, I sandwiched some bearings between a ground surface on the underside of the bed and the top of the scale:

Double checking the alignment with an indicator after mounting, but no adjustment required on this axis.  It took a few shims between the bed casting and scale in the other direction:

The read head was mounted with the stock hardware that came with the DRO, with a few modifications:

A couple p-clips hold down the cables and route them in a manageable direction:

The console was mounted to the power switch enclosure with a scrap piece of aluminum u-channel:

And here it is all set up:

Clausing 4901 Moving and Restoration

 I've been keeping my eye out on craiglist and machinery auctions for a small (but not that small) lathe for a while now, but small lathes (other than import mini-lathes) are pretty uncommon.  Someone Austin knows just bought a house just a few miles away from me with this Clausing 4900-series lathe in the basement, so we visited to take a look:

The scale of this lathe really didn't come across in photographs - it's way smaller than I originally thought from the pictures.  MITERS has a Clausing lathe of the same era, a 6918, which looks almost exactly the same but scaled up around 50% in every direction - from the original pictures I saw, I was expecting something more like the MITERS-lathe. 

I took some measurements, determined it would be possible to fit in my apartment, checked out the joist situation supporting the floor where the lathe would sit, and decided to go for it.  

For for the move, I recruited Rob and Andrew, who have moved many tons of machine tools over the last several years (probably all of which are much heavier than the 800-ish pounds this lathe is), plus Austin, Aaron, and myself.

We started by splitting the lathe off its base, to make it less top-heavy.  The lathe and chip tray were un-screwed from the two legs and lifted up with an engine hoist.  We removed the legs and slid Rob's heavy-duty dolly underneath.  

The basement the lathe was in had a door directly outside (so we didn't have to go up any stairs), but the door was pretty far from where we could get a pickup truck.  A dumpster blocked most of the driveway, so we had to haul the lathe up a small hill and around the dumpster.  The dolly rolled surprisingly well over the dirt and grass, even with ~600 lbs on it:

Lifted up again, dolly and all, ready for the truck to be backed under it:

Loaded up and strapped down in the Sliski-mobile.  The 8' truck bed makes the lathe look even smaller:

Getting the lathe into my place was a little tricky since there wasn't a lot of space to maneuver, but it went smoothly.

Here we are going through the front door.  We hand-lifted the lathe up the two steps.  A couple feet inside the front door there was an area of floor we had to avoid, where there's a trapdoor to our water heater.  There aren't joists spanning that section of floor, so we skirted around it.

The dolly just barely fit through the internal doorways, once the doors were removed from the hinges:

To re-assemble the lathe, we again lifted it with the engine hoist and re-attached the legs while the hoist was supporting the weight.  I put a couple 2x6's under the lathe's leveling feet, with big felt pads underneath, to spread the load and protect the floor.

The lathe back on it's stand, in all it's grungy glory:

Initially the headstock was full of paper and cloth scraps - some mice had made a home there.  Fortunately the mice were long gone, and thankfully hadn't left behind any mummified remains.  After vacuuming out all the detritus, here's what the inside of the headstock looked like:

The gears looked pretty rusty, the lever for engaging the back gear was stuck, and the spindle wouldn't turn once the power feed was engaged.  I worked things free by liberally spraying all the gears and shafts down with WD40 and gradually working the spindle back and forth by hand with the power feed gears engaged.  Eventually all the sticky spots in the gearing smoothed out, and the power feed and back gear shifted smoothly:

At first I thought I'd have to take the headstock apart to clean the rust off the gearing, but I was able to do it in-place with a small wire brush.  The state of the gears in the headstock also made me worried about the spindle bearings.  I oiled the spindle bearings and ran the spindle, and the oil that leaked out from the spindle was clean - so I'm assuming the spindle bearings aren't full of rust.

Scrubbed feed gears:

Scrubbed headstock gears:

Gears cleaned, power feed gears greased with some molybdenum disulphide grease, and a fresh timing belt installed - the original was damaged trying to remove it during the move.

I cleaned the decades of gunk off the painted surfaces by spraying them down with WD40, scrubbing with a plastic-bristled brush, and wiping away the sludge.

Here's the chip pan mid-scrubbing:

Hard to believe this was hiding underneath all the dirt and oil:

I took the cross slide off, and the sliding surfaces look like they're in great condition.  The original grinding marks are still visible across the whole underside of the cross slide, and the lead screw nut has very little backlash.  Also encouraging, the cross slide doesn't tighten up at the extremes of its travel, which would have been a symptom of worn ways.

Here it is all scrubbed with the covers back on.  Looking pretty good, I think:

The lathe came with some great accessories, including the change gears for metric threading.  Most of the accessories had surface rust, but cleaned up really well with some Evaporust.

Before:

After:

8" 4-jaw chuck post-cleaning:

The lathe also came with the original paper manual, factory inspection report, and accessory manuals:

The manual is full of beautiful hand-drawn exploded view like these:

There were some other good bits of history in the manual.  The metric threading gears apparently cost $150 in ~1970 (~$1000 in today's dollars).  Unfortunately the micro carriage stop listed isn't around any more.

Eventually I'll get the manual properly scanned and post it online.  I was able to find the operator manual online already, but not the exploded views, parts lists, and accessory manuals, so someone else might find those useful.

Here it is running and taking it's first cuts out of some scrap aluminum:

The lathe is fully operational now, but I am planning on a few immediate upgrades like adding a digital readout.  All the lathes I've used have been communal (and most of them haven't even had a DRO).  I'm excited for the opportunity to set up a proper tool library with tool offsets stored on the DRO, and no one but me to mess them up.  That should make work way more efficient.  Along with the DRO I'll likely make a solid tool post mount to replace the compound slide, a-la-Renzetti.

The 3/4 HP single-phase AC motor and v-belt system might get swapped for something a little more powerful eventually (should be able to get around 3X the power out of a typical outlet), and electronic speed control would be a big improvement over shifting v-belts around.