Running a Colchester lathe with 2HP motor

[graduate_owner]

Hi everyone,
I'm new to metal turning and have the opportunity to get a Colchester Master Mk 2 lathe locally at a sensible price. It has a 3 HP 3-phase motor, and I am thinking of replacing the motor with a 2 HP one as I have a 2 HP 3-phase inverter. Does anyone know if a 2 HP motor would be feasible on this lathe, or would it be way too underpowered? I'm hoping to avoid buying a larger inverter. What's concerning me is that the newer Masters have 5HP and then later on, 7.5HP motors, so perhaps even a 3HP was considered under powered.

I'm not expecting to do any super-sized work on it, but it would be handy if it actually rotates when switched on.

K

 

[dickm]

Difficult to answer without knowing the size of the lathe (OK, could look on lathesUK, but...), what you are likely to be machining and whether or not you are in a hurry. Think of all the patient old chaps in brown dust coats who did amazing model engineering on ML7s, Drummonds and even treadle lathes, using about half a horse at best. Obviously if you need to turn stainless steel of 10" diameter, for production processes, you want more horses, but you can almost certainly get away with 2hp for amateur use.

 

[wizard]

A lathe of that age may be 440v only so you may have to get a more expensive 440v inverter. But its a great lathe and worth it.

 

[graduate_owner]

Thanks guys.

The Master will turn about 13" diameter, but I'm not anticipating anything like that. The lathe is a 1969 model, and indeed the motor may be 440v, but I have a 2HP dual voltage one ready to swap it for, hence the original question.
I hope I can sort out a solution to make the purchase feasible.

K

 

[nathandavies]

how sensible was the price?

nathan

 

[graduate_owner]

Hi Nathan,
it's not straightforward. The lathe I can get for £300 because the seller is my friend. However there is a broken cog which needs to be replaced at an approximate cost of £140, and we don't yet know if there was any other damage done when the cog was damaged, but we think not. We can't check until the first cog is replaced as it's a main driving cog on the input shaft of the gearbox. Finally there is damage to the half nut, although I can live without thread cutting for the moment. If all else goes well we plan to machine a half nut out of bronze.

However if the 2HP motor idea is going to be an issue, then I have to look at getting a 3HP inverter (estimate £200) and possibly take the motor to a local firm who can dig into the wiring and pick out the connexions to enable me to set it up as a 220v motor (perhaps £50). That could take the total to about £700, possibly more, which is not too dear for a decent lathe, but I have to consider whether I want to spent that much on a machine which I won't use all that much (I'm more interested in wood, and I could do a lot with £700+ ).

Still, I do fancy it. I'm thinking in terms of turning up a pulley to drive my Kity spindle moulder, and then to make a sliding table for tenoning on it. Essentially it will be used for fabricating bits for woodworking, in conjunction with my milling machine. I will then be quite well equipped with metalworking machinery, considering I prefer woodworking.

K

 

[nathandavies]

As you say spending £700+ on a metal working lathe when you prefer wood, doesn't seem to make sense, a wood lathe and a metal lathe is on my shopping list. Preferably a Wadkin RU or RS for wood. But at the moment my budget is about 19p. Metal working does sound good though, as you say especially if you can create woodworking tools as well.

Nathan

 

[bellringer]

keep what on there they put them on for a reason also when you take big cuts 5 MM in mild steel that will put strain on it so just leave it

 

[graduate_owner]

Hi Nathan,
yes, kit doesn't come cheap. I've been building up my workshop for a few years now. I've always wanted some decent kit, and now I have a Myford ML8 for spindle turning and a Union Graduate for bowl turning, also a Scheppach 10" table saw and an Axminster planer thicknesser. What I really need now is time to build up my skills and get the most out of them.

K

 

[woodfarmer]

I run my Holbrook lathe on an old brook 2 hp single phase motor without any problems. The Colchester is similar. My max revs though is 400 rpm, being a very old lathe, your modern one will run much faster and I suspect you might need more power cutting heavy cuts at high speed. especially if you use carbide tipped tools which are more blunt than tool steel ones.

 

[graduate_owner]

Thanks woodfarmer. I've noticed that some Boxfords on sale have motors as small as 1 HP, so I'm hoping 2HP will be man enough for the job. I'm looking forward to getting the part I need machined and, if there are no other issues, getting it installed in my workshop. I have been making a list of things I want to make (to justify the expense) once I've built up my metal turning skills. Then it's back to the Union Graduate for some more fun.
I love being retired !!!

K