In general I agree with the previous posts but be warned, if you were to go for a larger, more industrial machine like the Colchester Student, they are very heavy and not that easy to move without a good team. For almost all motorbike sized jobs a 4 ½’’ is as big as you’ll need and a lot easier to shift and accommodate.
By and large avoid far eastern machines, build quality is, in my opinion, questionable, it is within my experience to find significant quantities of casting sand still adhering where it’d do no good at all. That speaks to the level of local quality control although the more reputable UK importers claim to do their own inspecting.
Do not under estimate the bed length you will need, you might not need it often but when you do you’ll be stuffed without it! Long bed versions of the popular makes are around and worth looking for.
Certainly I’d put a Q/C gearbox at the top of my list of desirable features. These gearboxes, sometimes referred to as “Norton” boxes, are if anything, even more useful for varying cutter feed rates than for screwcutting and you’ll be doing more machining than threading!
Buy an imperial machine if you have a choice, particularly if you are into old British bikes because you will be cutting mainly Imperial threads and inch diameters so it is nice to have the graduations in imperial too. It also happens that, by and large, it is easier to arrange the gearing to cut metric threads on an imperial machine than inch ones on a metric job. To that end a 100/127 tooth compound gear is a desirable addition. Make sure that the full set of change gears comes with the machine too; they do tend to “go walkies”. Check to see if the change-gear banjo has two slots or one, two is better, more versatile.
If you can only afford one good chuck then buy a 4-jaw first. You can do everything in a 4-jaw that you can do with a 3-jaw but not vice versâ. A good set of collets are a good thing to have, most collet adaptors will accommodate both imperial and metric collets but few machines up to 4½’’ centre height will accommodate anything over ½’’ diameter.
Some machines have induction hardened bedways and are worth looking for, less risk of wear but as bed regrinding is not humongosly expensive an otherwise good machine at the right price should not be dismissed out of hand.
The Myford is an excellent lathe much favoured by the model engineering fraternity, as a result there are lots of “goodies” available. They also have a “T” slotted cross-slide which makes small milling jobs possible. It is however a fairly light machine.
The Boxford or its earlier incarnation the Southbend, at 4 ½” centre height, is a slightly larger machine. It has a marginally longer bed than the Myford, (both Boxford & Myford can be had in long bed versions). The model ‘A’ version is the one to look for, they have Q/C gearboxes and power feed for sliding and surfacing cuts. Both makes are relatively light machines but are nevertheless capable of serious work.
As previously stated the Colchester Students are a solid lump and are a good general-purpose lathe, I particularly favour the older round head version, which to my mind seem a stiffer machine.
Avoid the Colchester Chipmaster, it is a good machine but badly let down by the Kopp Variator drive which hides under the headstock, it is thus “out of sight, out of mind”, but is prone to oil leaks and if not kept properly fed will soon develop problems and become very noisy. Service replacements, the only viable option, cost the proverbial arm & leg.
Finally is worth noting that machines such as the Myford, Boxford, Southbend brands are/were aimed at the amateur/experimenter, small workshop user and have more versatility built in than the more industrial types such as those by Colchester, Harrison, Holbrook etc. which are built for a single purpose. The penalty is that that the Myford etc. lathes are less robust but with the addition of readily available accessories they are far more versatile. Given that production rates are not likely to be an issue for the archetypical “man-in-a-shed” versatility is the more desirable feature.
I happen to own a pre-war Southbend, (flat belt drive ‘an all), that is still capable of ¼” cuts on alloy steel and of accurate work too so don’t dismiss a good old ‘un!
On the subject of phase converters: The faint hearted may care to bypass this bit – it’s more Jimmy’s Food Factory than Silicon Valley!
My Alexander milling machine happened to be fitted with a 440V two-speed motor, which by its construction precluded conversion to run on 240V, now that presented a problem with only a 240V single-phase supply available. I could have changed the motor for a one phase single speed one and an electronic speed controller but they don’t come cheap and I am singularly impoverished so I hunted around for an alternative.
Firstly I found a firm in Basildon, Essex who built an immaculate step-up transformer for me at a very fair price – voltage problem solved. (Unless you are in the same voltage dilemma this part you do not need.) The next item required is another 3PH motor of a slightly larger HP rating and a healthy pile of capacitors. Given my previously stated impecunious finances I went skip diving, look for places that are having the lighting re-fitted, what you want are the capacitors out of the old fluorescent fittings. The idea is to use the big motor as a “pilot” to create a psudo 3PH supply for the motor on the machine. The capacitors are selectively juggled to balance as far as possible the current delivered by each psudo-phase, you’ll need a clamp type ammeter for this. Once a reasonable balance has been achieved it only remains to box the thing up with due regard to electrical safety. If you are lucky the pilot motor will self start but if not you will need to resort to a starter cord on the pilot motor’s shaft. There are plenty of detailed instructions to be found on the web, I found https://www.waterfront-woods.com/Articles/phaseconverter.htm particularly useful.
