Project Lathe

[Tom Fenton 1,526]

So I've acquired a lathe, it arrived in my garage with help from Allanallen on Saturday afternoon.

 

Apart from the paint on the bed here it is as it arrived. It is 3 phase so I have some work to sort it out to single before it will do anything useful.

 

 

I'm lucky as it has come complete with all the changewheels for screwcutting, a 4 jaw and two 3 jaw chucks, and a big faceplate.

 

 

 

At the moment I am giving it a good clean, lubricate and check over, a lick of paint, and then most importantly sorting out a motor for it.

[pip470 61]

Hi Tom, Have you thought about getting one of those magic boxes that allows you to run 3 phase from a single phase socket. I think they range from around £250 400 so quite expensive but at least it will be plug and play.

[woo83 0]

You could make one with a separate 3 Ph induction motor, I'm not 100% how its done but I'm sure you could find a guide on the net some where. Might be a bit cheaper.

 

Nice lathe by the way

[oz. 2]

I have a 240 - 3-phase inverter here that I have failed to sell for months.

 

I'd be happy to sell it if thats the way you're going.

[Tom Fenton 1,526]

Gents

 

It is a 2HP motor so not out of the way to convert to single phase- a new single phase motor is about £100, and my compressor is 1.5HP and runs fine as single phase.

 

I have looked into an inverter and haven't ruled anything out yet, just after the most cost effective way of doing really. I won't be doing anything that serious with it so although the single phase motor will be slightly down on overall torque compared to a 3ph, it should be OK for what I want.

 

The old rotary convertors are a bit old hat now inverters have come down in price, so that isn't really the route I want to go down, plus the fact they are quite thirsty on electric.

 

Oz, talk to me good buddy

[M@tt 77]

nice Mr F!! thats next on my list or maybe a bridgeport mill

 

where'd you get it from?

Edited May 10, 2010 by M@tt

[Gentrix 2 1 Cars]

I have a big barn-fan in my garage and got the same problem with it being 3-phase.

 

I got round it using the Steinmetz-circuit - you'll need a suitable capacitor and then ...

 

 

I tried to google it in english and the best I could come up with is this..

 

 

 

And a hugh suitable text.

 

....SINGLE PHASE SUPPLY TO RUN 3PH MOTOR

 

Operation of three-phase Motors in single-phase supply Induction motors with a three-phase stator winding can either be driven from a three-phase supply or from a single-phase supply when suitably connected with a capacitor (Steinmetz circuit). A three-phase induction motor with its stator connected in star for a 380V three-phase supply has 220V as phase voltage. The motor can therefore also run on a 220V threephase supply when delta connected. If the motor is designed for 125/220V then its phase voltage is only 125V and the motor must be connected in star for a three-phase supply of 220V. The Steinmetz circuit gives similar characteristics to three phase operation but with a single-phase supply.The motor runs as a three-phase machine, if the capacitor voltage causes a symmetrical voltage star at the rotor windings as with a three-phase supply. A symmetrical voltage distribution can however only be obtained with a certain capacitor at a certain load. For all other loads an asymmetrical voltage star is formed at the rotor, so that the

motor can no longer operate under optimum conditions. The starting torque is reduced and the heat

generation in the motor can become higher at no load than at full load.

Experience has shown that with a voltage supply of 220V, a capacitance of 70 mF/kW of motor power is necessary in order to give a starting torque of 30% of rated torque and in operation about 80% of the rated three-phase power.

In order to obtain a higher starting torque, a starting capacitor with about double the capacitance must be connected in parallel. This must be switched off during run up to avoid overloading the motor. The direction of rotation can be reversed by connecting the capacitor to the other supply connection. The voltage across the capacitor terminals in the “Steinmetz” circuits is, at the rated power of the motor, about the value of the supply voltage, and under no load about 15% higher. If the “open star circuit” should be used for a special application please state this when ordering in order that the correct capacitor can be supplied. This circuit can be used when 125/220V three-phase motors are to operated from a 220V single-phase supply.

 

 

Just to say - I am happy, that I got it running once and I can not help with any further explanation.

 

Good luck and be careful

 

 

andi

[oz. 2]

Although I do want to sell this inverter of mine I think that you may be better off changing the motor. £100 is around where I've been looking to sell it for but unless you're going to be buying any more 3-phase machinery then it's a bit pointless really.

[Tom Fenton 1,526]

Small update, single phase 2HP motor ordered, arrived, and mounted on some adaptor brackets.

 

 

 

Also a bit more painting

 

Tomorrow morning I'm off to get the pulley modified to the shaft size of the new motor. Then it will need wiring up and some gearbox oil before its first run in my possession!

[swordfish210 20]

Nice, if i had a lathe i don't think i would ever leave my workshop, i'd just be turning pointless things all the time.

[Henry Yorke 269 3 Cars]

What are you going to make first Tom?

[oz. 2]

First thing I would make if I had a lathe would be a can holder!

[davenport 51]

looks a tidy ol beast!!

 

did you get much tooling with it?? live centres?? does it have a coolant pump? or are you resorting to what i do and having several washing up liquid bottles of mixed fluid mixed up and ready to fire!!!

 

they are a bigger outlay initially than HSS tooling but the replaceable tip`d tools are very very good.. having said that i like to keep a few chunks of square HSS so i can grind ceratin radius cutters...

 

a decent parting off tool is a must too imo..

[Tom Fenton 1,526]

I'm certainly pleased with it for the cost, I got a box of tooling most of which was HSS, a few brazed carbide tipped tools, and then a couple of replaceable tipped tools. Nothing amazingly fancy but certainly good enough to be going on with, I also have a live centre for the tailstock and a decent sized chuck for the tailstock. On the list to buy is a small boring bar, a decent parting off tool, and a screwcutting tool as well. It has a coolant pump but its 3-phase, however I have a small single phase motor lined up, so now it is up and running I am hoping to turn up an adaptor to mate this to the old pump.

 

Anyway a small update. A mate of mine was good enough to spend a couple of hours with me on Saturday morning and bore, sleeve, and keyway the old pulley to suit the new motor.

 

With this done I fitted the motor to the lathe, adjusted the belt tension, topped up the gearbox oil, and voila!

 

As for what did I make first- that is easy to answer- SWARF!

[sonofsam 5]

Nuice machine.

I fookin hate swarf though

[oz. 2]

ooooh, swarf in the palm of the hand

[allanallen 528 2 Cars]

Looking good tom, that floor paint looks good on the bed

 

I'll have a look for some 'tipped' tooling for you this week

[Baz 421]

Nice acquisition! There'll soon be nothing you can't do in your garage Tom!

 

 

You have to beat my cousin's swarf mess;

 

 

Edited May 21, 2010 by Baz