Restoring a small capstan lathe – Part 1

Posted by on December 10, 2014

Small but sturdy…

This small capstan lathe was salvaged from certain doom, a lot of old machinery ends up sold as scrap metal — If you can avoid it and salvage at least one, do it. They’re well worth it.

Small Turret Lathe - Bare bones

First stages of restoration, initial coat of primer (still wet), ways cleaned up some and spindle / bearings removed, along with turret and slide leaving just the headstock mounted to the bed.

This is what the lathe looked like after the initial clean-up

This is what the lathe looked like after the initial clean-up

First order of business:

Remove all non standard parts, this includes the fume hood and other sheet metal parts that were fitted at the previous factory.

Upon removal of the sheet metal parts, I noticed a small 3 jaw chuck was fitted to the spindle — Unsurprisingly it was stuck, but we had to remove it and take it apart anyway as part of the restoration, so we’ll put that aside for now.

A few missing parts reveal themselves, mainly the X positioning for the slide was missing (no rack, no pinion, no handle). The slide was missing the handle and the push mechanism, no motor, only a single cast iron pulley, no collet chuck.

The turret was stuck, no surprise there. Water did get inside at one point in time.

 

Refurbishing the turret

What’s worse than a machine in bad condition, rusty, dirty, beat up?, a machine that is also missing one or more vital parts of it’s internal mechanism!

I was missing the lock trigger for the turret, this was a huge setback because I have never seen the part, I couldn’t find information anywhere, everyone I asked had no clue or they’ve worked on different capstan lathes, with similar but not-quite-the-same lock mechanism, so I was out of luck!

Decided to go full-on CSI on the lathe, I noticed a horizontal shaft where the trigger may have been pivoting on, I also noticed a wear mark on a stop block underneath, this gave me the depth of the missing part … Now I was “just” missing the geometry of the part.

Started with a rectangular piece of flat stock, steel (unknown alloy from the scrap bin, but with relatively high carbon content based on how it machined) — Marked the height for the pivoting hole — using an informed guess — Center punched, spotted and drilled it, then reamed it up to size.

I dyed the blank trigger, fit it inside the shaft and attempted to run a cycle on the capstan, it gets stuck (not a surprise there) — But this is good news, now we have transferred onto the dye where it hit. After several iterations or removing the part, grinding away some material, dying, fitting it, cycling, etc. I managed to get a full cycle going, success!

The final part looks like like this:

The fabricated trigger as seen from the side

Turret lathe trigger seen from the side

Turret lathe trigger being pushed back

The trigger installed, using a screwdriver to push it back for the picture.

 

Locking mechanism

However the locks were not working properly, a closer inspection showed a missing locating pin that would’ve locked both parts together, I machined one out of SAE1010 1/4″ round stock, should be plenty good for this application.

 

 

Turret lathe lock pin

Locating pin pressed onto one of the locks, it slides into the other.

Turret lathe locks

Both locks assembled together.

Turret lathe locks seen from the top

Top view of assembled locks

 

Now the turret cycles properly, it just needs to be fine-tuned so it doesn’t over-spin, failing to lock automatically on every cycle (requiring the usual “hand nudge” on old, tired lathes that aren’t setup properly).

The lathe is functional in the turret department at last, most of the remaining work on the turret will be to clean up threads chasing them with taps and other basic tasks such as priming and painting.

Focus is now on the spindle, carriage and chuck. Toolposts will be required.

 

So how did it look like when I got it?

It looked like it belonged to a landfill, take a look:

Turret lathe as-is condition

Eek!

 

To be fair the ways are in good shape, other than the peck-marks from who knows what (parts falling onto the ways or tools being thrown over the ways)

Here’s a close-up after cleaning them:

Oil scrape marks on the ways

Most of the oil scrape marks are still there!

More to come…

 

Restoring an old power hacksaw – Part 2

Posted by on November 28, 2014

Slight progress on the saw, mostly pictures today:

Retapping to clean up the threads.

I couldn’t get some parts properly adjusted, turns out the threads were very, very dirty and some were partially damaged, so I decided to clean them up with an appropriate tap.

Since I didn't want to machine all the parts, sleeve them, etc. I decided to add brass screws throughout the machine to reduce play. The holes could later on be covered up if need be.

Since I didn’t want to machine all the parts, sleeve them, etc. To solve the issue with the wear I decided to add brass screws throughout the machine to reduce play. The holes could later on be covered up if need be. Here’s how I chucked them to face them as the last operation.

Brass screws were added as a temporary fix to deal with the play on the shaft.

Brass screws were added as a temporary fix to deal with the play on the shaft. I drilled and tapped three holes on the main shaft bearing.

These are the temporary modifications on the saw, the other side of the con-rod has another brass screw. These are temporary until I have the time to sleeve all the parts.

These are the temporary modifications on the saw, the other side of the con-rod has another brass screw. These are temporary until I have the time to sleeve all the parts.

Some parts were cleaned up, slightly polished and blackened as part of the restoration.

Some parts were cleaned up, slightly polished and blackened as part of the restoration.

DSCN5888f

This is how it cuts after the mods.

 

Hey not bad for such an old machine!, but we can still improve it.
More on this next week…

Restoring an old power hacksaw – Part 1

Posted by on November 25, 2014

A power hacksaw you say?

I always wanted one of these machines, this particular unit was based on a patent from circa 1890, amazingly these machines still have a spot in our hearts, and shops.

After many weeks of looking for one I managed to find a power hacksaw that was both in good shape (read: no missing parts, more on this later), it was listed for an “OK” price and it was also located somewhere near me, so I could have it delivered for a reasonable fee.

Despite what some people in general told me (“avoid this, buy an import bandsaw instead”) I went ahead and pulled the trigger on it. I’ve seen the import bandsaws and they require the same amount of work, or more and it is still a weak little thing that will fail sooner than later. Don’t get me wrong, most of them are meant for hobby use and will probably work fine for you after an adjustment or two, I just don’t like them.

And it arrived on my birthday!

This is what I got fresh out of the truck after a quick wipe-down…

Some assembly required...

Some assembly may be required…

 

The dovetails looked fine, there is some visible wear on the gib, but this was expected.

The dovetails looked fine, there is some visible wear on the gib (not shown) but this was expected.

 

Now THIS is what a 3/4" HP single phase motor should look like, at least size wise. Unlike the China crap we see these days with extruded aluminum body and two end caps made out of recycled pea cans this thing is all cast iron and steel, yey.

Now THIS is what a 3/4″ HP single phase motor should look like, at least size wise. Unlike the import crap we see these days with extruded aluminum body and two end caps made out of recycled pea cans this thing is all cast iron and steel, except for the pulley.

 

partially assembled, checking the wear on parts -- This needs to be addressed.

Partially assembled, checking for wear on parts — This needs to be addressed.

 

A bit of history

According to the guy who sold it to me, this machine used to be “blue” — However I was able to count at least 4 different colors after sanding one part down, who knows how many people owned this thing, for how long, where it’s been… how many parts did it cut?, we’ll never know!

I do know this belonged to his dad, he was what I would call a general fabricator / welder and I know he bought it used already.

I’m thinking this might be from the 50s but could be slightly earlier, sadly it doesn’t have a hydraulic feed, just gravity.

What’s wrong with it?

All the parts were  there, except for the depth stop. Oh well, that’s the least of my concerns right now given the wear on some of these parts, I’ll have to figure out a way to fix them at least temporarily…

 

  • The upper belt does not fit properly and thus slips under load, the lower belt is brand new and fits perfectly, so that’s good.
  • While the dovetails can be adjusted for wear/play, everything else can’t — The machine uses simple bearings (steel on iron, with grease ports) wear does occur and given the nature of this design, some parts end up being oval, which makes it even harder to fix without major machining.
  • The motor needs new bearings, it sounds terrible but the start winding works fine and the centrifugal switch also works properly, so not all is bad.
  • Conrod has play, the holes are not round anymore!
  • Wiring, terrible job and no PG / Ground, what the heck. Needs an upgrade, although I’ll keep the Bakelite switch, since that is part of the automatic shut-off and also, original to the machine.
  • Motor pulley is not running true at all. This was NOT the original motor. The machine most likely came with a 1HP 3 Phase motor as it was quite common back in the day.
  • Color, this would not be my first choice. Plus they did a terrible job painting over the old paint and rust.
  • I’m sure there’s something else terribly wrong with this machine but I haven’t found out yet.

 

First cut

Despite the machine sounding like an engine with a set of loose valves, broken rings and a bent con-rod I managed to get a relatively good first cut after assembling it. Clearly we’ll need a coolant system for this puppy…

So it cuts... but slow. OH WAIT A MINUTE!! -- They mounted the blade the wrong way around!

So it cuts… but slow and it vibrates a lot. 2″ round aluminum rod, 20xx series

Slow?

Turns out the previous owner mounted the blade the wrong way around… But this was a new blade, odd. He handed me three blades in total, one worn (trash) one fine, one coarse (installed). I can’t help but wonder if they used this machine like that all the time, or if he just wasn’t paying attention when he swapped the blade prior to the delivery.

At any rate, the machine now cuts as fast as a power hacksaw should cut, with a coarse blade. At least the vise seems well trammed, I noticed some shim stock underneath, interesting. We’ll measure how well it cuts later on.

For now I’ll focus on minimizing the play on the main parts of the machine, replacing bearings, etc.

Paint can wait!

 

To be continued…

 

Reviving an old Jacobs chuck – Electrolytic Rust Removal

Posted by on November 24, 2014

I’ve been using electrolytic rust removal for quite a while now, but this method never ceases to amaze me!

Here’s how I found the chuck, it came with a milling machine I acquired a few months ago, the previous owner had left some tooling in a rotten shed and this is the end result.

Jacobs chuck fossil

I was willing to bet this chuck was trash, and I was ready to throw it away. However it turned out to be an older type Jacobs, it was also a size I didn’t have… So I gave it a try, what can we lose right?

It was frozen shut. In theory the electrolysis should not affect the inside portion of the chuck, because it isn’t in the line of sight with the anode — but I had my hopes this could just work by freeing up the rust near the jaws and the collar.

Surprisingly after a few hours the chuck was in working order!

Sadly it's been abused (more than we thought) and it won't center within spec anymore, however it was quite an interesting experiment nonetheless!

Sadly it’s been abused (more than we thought) and it won’t center within spec anymore, however it was quite an interesting experiment nonetheless!

I did remove the arbor later on, not sure how they were using it like that, the inside of that arbor is hollow and threaded, but it has no surface to register with, aside from the flat face on the hexagonal portion — odd, maybe it was meant to be screwed onto a turret tool blank for a capstan lathe?

So there you have it, you CAN turn your archaeological finds into usable tooling, assuming no apes were previously involved.

Cheers,
Gus

Improving lathe saddle feel and turned surface finish

Posted by on June 3, 2014

I kept getting stiction and rough surface finish on my lathe, in a way that I couldn’t pinpoint exactly, until I decided to begin lapping and hand scraping parts on the lathe, to improve it. Prior to a thrust bearing upgrade, among other things. Turns out the saddle clamp (which is held by 3 capscrews on my lathe and it’s simply a machined bar of cast iron with a slight angle to it) had a terrible surface finish, a quick blueing showed it was only making contact on both corners, but no contact anywhere else.

I quickly decided to degrease it, strip the paint and begin the lapping process starting with 80 grit all the way up to 600, with good cleanup in between grits (very important). In the end I had a relatively reflective part with at least 80% of contact area against the flat surface I was working with.

This is great, since we previously established almost no contact by comparison, and a very rough shaper machined surface with deep imperfections.

Once cleaned, dried and oiled, I proceeded to reinstall the part on the lathe, making sure I only adjusted the screws enough so I wouldn’t see any deflection on the dial indicator as I pushed the saddle up with quite a lot of force. Any more torque on the screws would only be detrimental, as it would increase drag with no real added benefit.

In the future I plan to replace this part with a custom machined bronze one, which I believe will perform even better.

Sadly I didn’t take any pictures of the process, but rest assured you will notice a huge difference, specially on the feel of the saddle and the surface finish.

My theory behind the improved surface finish is simply that the previous imperfections were making the saddle tilt ever so slightly, this tilt was amplified by the distance from the toolpost to the pivot, decreasing the quality of the surface finish and of course, in turn, less rigidity was observed previously due to the low contact area.

I stopped lapping at about 80% contact, there is in fact a point where “too much” is “bad” in terms of stiction, also, slight imperfections allow for oil to be retained and carried, without the need of machining oil grooves.

Even better would be to lap the rear bearing surface of the bed, to this now flat part. But, that would take a lot of time and right now I’m happy with the results, so hopefully you’ll try this out and let me know how it went, remember only a small amount of metal is being removed in the process, we’re talking less than a thou typically, unless your part is pretzel shaped…

Given the lower friction and flat surface on the clamp, the saddle now feeds and feels a lot better.

The next “mod” will be to lap and hand scrape the cross-slide, including the gib strip, which is very rough from the factory. I’m doing these improvements slowly, because you can always continue what you were doing later, after you tried it out for a while. Which I feel is the correct way to go, to avoid potentially expensive mistakes.

Good luck and get lappin’!