Lathe setup home visit

[JP SantosParticipant @jpsantos46123]

Hi there,

I've recently bought a south bend lathe, some of you have helped already with the idle/compound gears, thank you very much for that.

But now I think I have another issue.. well, actually I have 2 issues!

First issue is (and has always been like this) when I start the lathe, it trips out the main fuse in the house…. now, I know this is dangerous what I'm doing, but the way I got around it, is to spin the flywheel on the engine by hand and then hit the start button – never fails. not ideal, but seems like if the engine is spinning then it wont trip out.

Second thing – is there anyone who does home visits just to set the lathe up? I think mine is not aligned, what I mean is the tailstock is not bang in the centre.. now I've read loads about how to set it all up and check, but I dont have the tools for it or hability (will always be doubtful if I'm doing it right) so wondering if anyone does a home visit to set it up?

I'm using the lathe for simple things, like bushes and spacers, and different diameters pieces with threaded ends… but would like to know its all being done properly.
Specially as if I have to drill a hole on a piece of round bar, if the tailstock isnt centered that hole will never be right…

thanks in advance
JP

[JP SantosParticipant @jpsantos46123]

[John Stevenson 1Participant @johnstevenson1]

Would help if you put where you were as regards area, some clever guys and gals on this site but don't think we have mind readers ?

[JP SantosParticipant @jpsantos46123]

Ooppss!! sorry, Im in Andover, Hampshire

[Speedy Builder5Participant @speedybuilder5]

Tail stock is easy. Have a look on the right hand end of the tailstock just above the sideways and you should see two engraved vertical lines in the centre of the bed plate. When they are in alignment with each other, the tailstock should be in alignment with the spindle axis. To adjust, slacken the tailstock clamp and use the two horizontal adjusting screws either side on the base of the tailstock to align the two vertical lines. Adjust the screws so that they are both reasonably tight – Not gorilla tight !!
Its in the PDF Know your lathe on about Page 40

BobH

[mechman48Participant @mechman48]

Bob is correct in the initial set up but having the two marks lined up doesn't guarantee alignment; it is always best to machine a test piece to confirm any deviation & tweak ea. adjusting screw until your test piece reads the same on two machined collars with at least 6" between collars, or as near as can be +/- .0005". There are quite a number of threads in here re. test piece alignment set up.

Pity I am up in Teesside.. 250+mile from you otherwise I would gladly help.

George

[Brian Rice 1Participant @brianrice1]

First are you running a extention cable plugged in to the ring main in the house if so I would seriously look at getting a separate supply to you workshop with it own consumer unit,also have the motor check over. All you need are two centres one in the tale stock and one in the spindle and a six inch steel rule, place the rule vertical against the lathe centre and slowly bring up the tailstock until touches the rule if the rule twists you are out of alignment,I don't know wether your lathe as got any adjustment to the tailstock but I'am sure some one on here will explain.

[BazyleParticipant @bazyle]

Join ANdover Model Engineering Society and one of the club members may be able to help

[Steve PaveyParticipant @stevepavey65865]

Usually if you have to spin a motor to get it running it means the start capacitor on the motor needs replacing. However, you say it trips out the 'main fuse' – by which you could mean an MCB or an RCD. If it's an MCB, it just means you're trying to pull too much current (what rating is it?), and that seems to fit with your symptoms . If the RCD trips then you have a leakage to earth somewhere, and may indicate a bigger problem than just a blown capacitor.

More info needed on what motor you have (presumably single pahase, but how many kW and how many capacitors), how long a run for the cable between the consumer unit and the motor, and do you have a proper DOL starter fitted?

To fine check the tailstock alignment, do as Speedy suggests above, but by putting a centre in both the headstock and the tailstock, and bringing them up to touch with a small piece of flat strip (eg a 6" steel rule) between them you should be able to get a better idea if a fine adjustment is needed – if the rule tries to twist out of square it is out of line.

Edited By Steve Pavey on 26/02/2015 14:47:02

[KWILParticipant @kwil]

I am not surprised the trip goes if the starting capacitor is blown, you are just placing the running windings across the mains which will draw high current because there is not a back EMF (voltage) from a running armature to oppose the applied voltage. Fix the starting first..

[john fletcher 1Participant @johnfletcher1]

Before you go out and spend your money, remove the motor onto the bench. Scratch mark both end shield end, two across on the drive shaft end and one mark across on the no drive end. These marks are for easy reassembly, get them right and the motor will revolve freely, a flick on the shaft. Remove the through bolts and using a hide face mallet give the stator a sharp wrap. Carefully remove the rotor and store it carefully on the bench, don't let it roll off and bend the shaft. Have a good look at the centrifugal switch mechanism which is on of the motor shaft, the bob weights or what ever is used on your motor, should move freely and spring back after being moved by hand. Next check the switch contacts to see if they are clean and are not just blobs of weld, these are normally attached to the no drive end shield of a British made motor. The contacts can be cleaned up a bit by using a piece fine of wet and dry folded back to back. To test the windings you will need a multi meter on the OHMS range. There are two windings, start and run. The start will be thin wire compared to the start and will have a much higher resistance maybe 20 to 40 ohms. The run winding could be up to 10 ohms but more likely 4 or 5. Not all lathe motors have capacitors, especially if some one has changed a motor to one that was available at the time of need. Unfortunately there's not an easy way for the average person to check a capacitor other than to change it, like for like and it might not be the capacitor faulty after all. Electricians use their MEGGER to charge up a capacitor, then leave it for a few minute then discharge it by shorting out the terminals using a screw driver, if it give a loud crack they say it good, but how good. Do be carefully when re assembling the motor, its very easy to damage the windings, and look out for those marks on the stator. John

[JP SantosParticipant @jpsantos46123]

Hi all, thanks for the replies, I've read all of it.

Thanks to John Fletcher, I shall read yours in more detail later when I get a bit more time.

Just thought of putting some photos up, on something I thought, correct me if I'm wrong please.
So what I've done was set my facing off tool in the tool post, slightly below what I think is the centre, surely by doing this it would not face perfectly and leave a little pointy bit on the round bar…this little bit would be where the exact centre is?
then I brought he tail stock with a dead centre on it and tried to match it to the pointy bit on the bar…. would this work?
I did read about mounting a dead centre on the chuck but I dont have one that is not tappered, so I'm guessing it wouldnt stay completly dead centre, right?

you can just see here, the little tip out of the round bar

and from above

I also took some photos of the motor

Sorry, not much info, just in a rush at the moment, will come back later.

thanks to all who have helped so far, really really appreciate the help.

thanks
JP

[Neil WyattModerator @neilwyatt]

If you are happy to work by eye (OK for non-critical stuff) turn a 60-degree point on the bit of stock in the chuck and match that up to the tailstock centre, much easier to judge by eye. Better still try and nip a steel rule between the two, when it sits straight they are lined up (don't sit the points in the graduations).

Neil

[mechman48Participant @mechman48]

Neil's method is the easiest way to check alignment but also check for horizontal alignment with the same set up turn the rule horizontal & eyeball the rule from above & it should look straight across the bed, parallel with the chuck, thus confirming vertical & horizontal alignment. Going back to your tool centre height; one easy way to set centre height is to face off some material & look to see if there is a 'pip' left in the middle of the faced off surface, if so then adjust your facing tool up or down to get rid of this 'pip'… tool height centred .

George.

[JP SantosParticipant @jpsantos46123]

Thanks everyone for the tips on the alignment! think I got that one right now, i'm happy with the results achieved.

Now in regards to the motor.. maybe a good start just to change the capacitor? they dont seem very expensive, although I cant find one exactly like the one I have on the motor

[Bob Brown 1Participant @bobbrown1]

For the capacitor try here **LINK**# a phone call should get you sorted

Bob

[Paul LousickParticipant @paullousick59116]

Hi JP,

A video of aligning the tailstock on a Southbend is on Youtube. Search for South Bend Lathe Tailstock Alignment.

There is also a Southbend user group on Yahoo.

Paul.

[Les Jones 1Participant @lesjones1]

Hi JP,
I found this one on eBay that would probably do. (You need to select the 60 uF type.) If you spend some time searching you might find cheaper ones. I did find some cheaper but they had pus on connections. I think one with a length of cable will suit your application best.

Les

Edited By Les Jones 1 on 27/02/2015 12:29:31

[JP SantosParticipant @jpsantos46123]

oh thanks for that!!!

its only a tenner, and there's even the 55uf on that list! 😀 thanks! will probably give that one a try before going with John Fletcher suggestion, as that all sounds very complicated and time consuming, so I'll start with the easy ones first

[Les Jones 1Participant @lesjones1]

Hi JP,
I think it is worth following John Fletcher's advice as I think it is more likely to be the centrifugal switch causing the problem. Even if the fault is the centrifugal switch it may be worth replacing the capacitor as the one in the picture looks very old.

Les.

[JP SantosParticipant @jpsantos46123]

got the capacitor on order now

thing is, the lathe was working fine at the sellers house, but then again his fuseboard might have been better than mine or something might have got damaged when in transit to mine.

I'll try the capacitor and then go with Johns advice

thanks!

[Rex HanmanParticipant @rexhanman57403]

Come and see us at the Andover club….someone will help you I'm sure.

[Steve PaveyParticipant @stevepavey65865]

Charging a capacitor with a megger and discharging it with a screwdriver is not good advice. Apart from the fact that it doesn't really tell you all that much, there is the risk of an unpleasant shock, or of damage to the capacitor (because the discharge current will be so high).

A capacitor is relatively cheap and very simple to fit, so without test equipment the best advice is to simply replace it. I would only dismantle the motor if a new capacitor didn't fix the problem. If it is the centrifugal switch at fault it may well be very difficult to find spares for an older motor.

In fact, even before dismantling it, I would attempt a cheap and easy way to find out if the switch was at least working in the mechanical sense – wrap a piece of cord around the motor shaft and use it like a pull start on a lawnmower to spin the shaft. If the switch is working mechanically, and you are able to get the shaft up to a decent speed you will hear the click of the switch.

Further, by disconnecting the leads in the motor terminal box and with a simple multimeter set to the lowest resistance scale you should be able to test the electrical operation of the switch when you spin the shaft with the 'pull start' cord. You can also use the meter to check the continuity of both the start and the run windings, both of which should give you a lowish resistance reading, say 5 – 15 ohms.

As with anything of this nature, take a few photos and make some notes/drawings on the existing connections so you can replace everything as it was.

[JP SantosParticipant @jpsantos46123]

Hi all,

just thought of coming here and update this seeing as its only fair as so many of you helped.

Got lathe all lined up and she's a beauty working and the best of all is she's working on the button again, without tripping the house main fuse!!

went with the cheaper option first by ordering the new start capacitor and that sorted the problem, happy days!

thanks to all for your input and the links!

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