Category: Mechanics

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



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.


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


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…


China lathe goes Chinese on me.

Posted by on February 26, 2014

When steel turns into butter, again.

I’m starting to believe the best idea for a chinese lathe, as a first mod or project, would be to replace all threaded parts with proper ones. This is not the first stripped thread on the lathe… And rest assured, any time a thread strips, you lose at least half a lathe – functionality wise.

Actually scrap that, the best idea is, if you have the option, not to buy chinese. Buy old iron instead, problem is finding an old lathe that doesn’t have massive wear and isn’t missing most of the parts… So you might need some luck there.


Was it made out of rebar? or butter?


Dat oiler.

Discussing the problem

Since I don’t have any oiler inserts and I don’t plan on making any, the idea of making a new part from scratch seems sketchy as I wouldn’t have a way to seal the oil and prevent gunk from getting inside the port.

This part is the shaft for the double transmission gear on the banjo, it transmits power, through the two A and B gears, to the gearbox for power feeding, threading, etc. Without it, you only have half a lathe.

The oil port acts as a valve, allowing the oil to only escape through the hole on the shaft, which it does by centrifugal force, allowing a layer of oil to remain in between the bushing of the gears and the shaft itself, reducing friction and wear. Without the valve, very little oil would get onto the shaft and most would fall off the oiling port.

Thankfuly the T-nut didn’t strip, but the thread was slightly damaged and had to be dressed with a tap, it’s been since case-hardened and awaits installation.

Two Options

Either I turn down the stripped M6 portion, counterbore the shaft and press a new stud with an M6x1 thread or I make the whole part from scratch using mild steel (I would like to use brass, but I don’t currenly have any stock big enough). Of course we only have a square portion to chuck onto, that means moving onto the 4 jaw chuck and busting out the indicator. One problem though the square part wasn’t milled exactly 90°, it’s all over the place.

The second option, make the part from scratch out of mild steel and figure out a way to fashion an oiling port.

Contrary to what I thought, and as I’ve mentioned, the square portion was milled flat from round stock, this part did not start life as a square stock. Makes sense, since interrupted cuts are slower in production and you can trade in a bit more material loss over higher productivity time, which means more income in general… Of course, if you use crappy materials, it doesn’t matter how you make the part… it’s always going to be crappy.

Given the slot near the square portion is to engage another part, which acts as a washer and for lack of better words, a sort of thrust “bearing” or “clamp” which also helps lock the parts in place, the head of the part MUST be square, otherwise the other part would also have to be remade since it’s slotted to fit and slide through the square portion.


Critical Dimensions:

The shaft is 10mm and pennies, turned down for a perfect sliding fit on the gear train (Currently 10.05mm). The threaded portion is M6x1mm however originally it wasn’t long enough to engage all of the threads on the T nut (not shown on pictures). So while I will duplicate the original part, I might make a second part, with my own design. Of course if I could have it my way I would use at least M8 for this, M10 would be ideal.

Making due with what you’ve got.

For a temporary part, I’m thinking I could skip the oiling (maybe add oil “holes” on the shaft, not through holes, just small pockets throughout to contain oil) and use a slotted head on the end, to fasten the part. This would work perfectly on the short term while I come across better stock or a better design.

Thinking in advance…

Now I can’t help but wonder, should I make spares of every part that’s been damaged?, or should I trust my materials and skills?. For now, let’s make a working part, once I’ve got power feed and threading capabilities back, I might turn spares. This is not the first time a thread strips on this lathe.

Gettin’ busy!


Test fitting on the rough blank after careful turning it down to size, the gears turn freely with ever so slightly drag (excellent!)

Filed the flats, parted with the chop saw. Time to debur!

Filed the flats, parted with the chop saw. Time to deburr!


The almost finished part, compared to the original.

The almost finished part, next to the original. There’s no real need for all faces to be flat, two are the absolute minimum you need, two is what I did. I faced it on the lathe and deburred the remaining edges with a file.


The finished part, Bored the inside, drilled the oil port. Case hardened and black oxide finish. Ready to install!



All setup and working! Let’s hope it lasts. A new T nut is in order though.

Final notes

All in all a simple project, but shows how even the simplest parts can fail -one way or another- and cause you a lot of trouble.

Once I figure out a simple way to make oiler inserts I’ll most likely be adding one to the new shaft. Next time I will probably use a better material, cold rolled steel isn’t ideal, but it’s what I had. I will probably make spares anyway, including new T-nuts.

I have an idea for a different style oiler (gravity fed, bottle style) but out of cheap aluminum, I would ideally use glass with aluminum caps but at the moment I don’t have a source for small diameter glass tubing (8mm or so) and cutting it might end up being problematic.

Of course there isn’t a lot of space available and it has to be sturdy and reliable. Ideally the originals could be ordered (I really can’t do that anymore) or made to look alike, but they are rather complicated due to the fact they use a tapered spring and require flat milling on the bore of the part, the right sized steel ball bearings, etc..

Either way, rest assured something cheap and simple will be devised!

That’s all for now, cheers.

Improvising a die holder for the lathe

Posted by on January 11, 2014

This is another one of those “on a pinch” deals, I had to thread small diameters and a die was the ideal option however I currently don’t have a die holder (1″) … Here’s a way to improvise by using what I call a “paper clutch”.

The concept is very simple, open your jacobs chuck all the way so the jaws are inside the chuck body, place the die on the stock and push the jacobs against the die, now, in between the die and the jacobs, place two square pieces of sandpaper, I used 600 grit without trouble. This acts as a friction clutch and will slip past a certain torque value, but it will hold for threading brass and aluminum no problem.

Remember: the tailstock is locked, but the quill isn’t. You’ll need to keep up with the quill!

Lathe Improvised Die Holder

Die holder? Who needs one? — I know, the sandpaper is in contact with the die and the chuck and if it slips it will “polish” the surface of either or both objects, however that’s a small price to pay I say…


Once you’ve arranged this madness, to begin threading use your tailstock to apply force while you turn your headstock chuck forward using your key for maximum force, depending on the pitch of the thread you’ll have to keep up rather quickly with the tailstock but it doesn’t take a lot of practice to do this…

Alternatively you can try the same method but instead once you get the thread started, you can lock the die via the toolpost using an improvised tool so it indexes with the indent on the die, however without applying force with the tailstock the die will tend to skew off center during the first threads, so beware!

To back out the die you have many options, if you used it with the adjusting screw set to the minimum, you can try setting it to the maximum to ease the tension and hopefully you can back it out by hand, otherwise you can try a piece of cloth and visegrips.

Yes, it’s die threading on the lathe “ghetto style” but it works on a pinch.

Have fun turnin’ and threadin’!





PS: I promise to clean up the lathe soon…