myford super 7 motor problem

[ZiggarParticipant @ziggar]

there should hardly be any heat at all from it

certainly not too hot to touch

[hugh mcwhinnie 1Participant @hughmcwhinnie1]

I have the myford book i had a look in that but it doesnt tell you much about the motor and i found this link to one being stripped and cleaned: **LINK**

[KWILParticipant @kwil]

It will not stay cold, but if there is not a problem with the motor it certainly should not be hot (whatever that is), Let us know when you have run it for 5 minutes, if not warm then, leave it longer. Ignore the link for the time being. If you have the Myford manual you should know not to use grease.

 

Edited By KWIL on 16/09/2013 14:41:28

[hugh mcwhinnie 1Participant @hughmcwhinnie1]

I'll go out and try it now without anything attached to the motor

[hugh mcwhinnie 1Participant @hughmcwhinnie1]

Right i let it running for 10 minutes without belts on, the casing on the motor does go hot but the pulley stays cold and the shaft goes hot but no where near how hot it was with the leed screw, you can actually feel hot air coming out the motor vents as it spins.

[KWILParticipant @kwil]

Duff motor, I suggest you find a local motor repairer and have them look at it at this stage. They should be able to advise you about it and then you can consider what next.

[hugh mcwhinnie 1Participant @hughmcwhinnie1]

Where near greenock will i be able to get it checked? any ideas?

[LambtonParticipant @lambton]

Hugh,

The motor should not get hot or even too warm when it is idling.

Just a point you say you greased the lead srew bearings but this is not the correct thing to do. You should be using the proper H32 hydraulic oil which is approx SAE 20 grade on all the oiling points on a myford lathe where things rotate and SAE 30 on the slde ways. If you like I can email you a lubrication chart. I use "3 in one oil " for the front headstock bearing. I dont recommend the use of slideway oil as is rather sticky an swarf etc sticks to it too readily.

Best regards

Eric

[Howard LewisParticipant @howardlewis46836]

Hi Hugh!

Some thoughts on possible causes of motor over heating.

Have you put light oil (say SAE 30 or so) into the bearings on the motor? If the lathe has not been used for 30 years the motor bearings will be dry. You should be able to see the oil caps.

A little while ago I was involved with a similar motor that stopped after ten minutes light use. The front bush was seizing to the shaft. There were no oil caps, just plugs screwed into the bearing housings. Fortunately the shaft was undamaged, so a new bush and topping up the oil to the felts feeding the front and rear bearings resulted in the motor running quietly without fuss.

30 year old oil will be just about solid (grease will solidify even earlier – do NOT use grease on plain bearings on your lathe!)

Oil every bearing and ensure that every bearing has fresh oil seeping out it.

Once you have a motor that runs without over heating (If its too hot to touch, then it is at least at 80C, and even hotter inside!), then as advised, connect the primary belt, but without the secondary belt from the countershaft, and run it to check for hot countershaft bearings. If this is OK after about 30 minutes, refit the secondary belt, and start to check for headstock bearings heating up. When you find that it starts to heat up again, the last item put into motion is the thing causing excessive load. That will be running hot as it disposes frictional load on the motor in the form of heat.

Page 29 of Ian Bradley's book, the Myford Series 7 Manual shows the Super 7 to have a tapered bearing in the Headstock, immediately behind the chuck. Ensure that the adjusting collar for Mandrel end float is not set so that there is zero endfloat, to preload this bush, If it is the bush/mandrel will bind. You want minimum endfloat, but not preloading!

Once all is well as far as the headstock, engage the tumbler gears, but with no change gears in mesh.

If all is well, fit one change gear and run. When that is all O.K. then mesh the change gear with another on the leadscrew and run (Does not matter what gears you use (unless one or more have the teeth excentric to the bore)

The right bearing for the leadscrew (tailstock end) might be tight. There is a collar than sets end float. If it is set too tight, that will cause the leadscrew to bind.

Once it is running reasonably well, I would suggest running for an hour so without trying to cut metal, keeping oil well supplied. (Set the drip oilers, if you have them, for the headstock bearings to one drop about every minute)

Above all, use plenty of oil in the early stages, it is not just to lubricate, (In pressure fed bearings the main duty of the oil is to cool. In Marine engines bearing temperatures are constantly monitored).

Hope that you soon get things up and running satisfactorily.

Howard

[hugh mcwhinnie 1Participant @hughmcwhinnie1]

I assumed grease nipples were for grease not oil thats why i used the grease gun with castral grease. i'll need to do some reading thats for sure!

[KWILParticipant @kwil]

Internet search "motor rewinds greenock" showed several firms.

[ZiggarParticipant @ziggar]

what they all said………………..

sounds like you have abearing/lubrication problem

if you have lubrication points on the motor, try squirting some wd40 down in them to try to loosen up anything that may have gone solid over the years
squirt it in and leave for 5 minutes then give a top up with oil and give a light running for 5 minutes. see whaat happens. may be all thats needed, to loosen up the solidified oil

[hugh mcwhinnie 1Participant @hughmcwhinnie1]

I used aeroshell flued 3 (its all i had lying arround) for the motor on the back end i didnt notice one at the front. All good advice and suggestions and comments thanks guys i'll keep you posted and up to date on progress!

[roy entwistleParticipant @royentwistle24699]

At one time the fan inside the crompton parkinson motor on my ml7 super came loose It appeared to be made of plastic I managed to get a metal one and it's been ok since Must be twenty five or thirty years ago

Roy

[Howard LewisParticipant @howardlewis46836]

Glad that someone said "Check that the centrifugal switch is operating, by listening for click as it runs down"

Several years ago, afternoon of New Years Eve, the motor on my Myford started with a flash, bang and cloud of smoke.

Fearing the worst, phoned a local electric motor repairer, and JOY, they were still open!

Removed motor and took it in. Just under two hours later, call to say it was working. Went over and they told me that swarf had got into the switch and arced. Not having a replacemnt, they cleaned up everything and got it going again. Since it had not been booked in as a job, it only cost a drink for the two chaps.

Went home and refitted motor with a guard to keep swarf away from the motor vents. No more trouble, right upto the day that I sold the lathe, and never had any come back from the colleague who bought it, so they did a good job.

Howard

[Ian S CParticipant @iansc]

Hugh, you say you don't want to change the motor for an orrigional type, is the motor perhaps under powered, what horse power is it rated? Ian S C

[Howard LewisParticipant @howardlewis46836]

Most Myfords used a 3/4 hp motor for single phase, 1/2 hp for three phase.

My suspicion, not being in Greeock, is much of the problem is that over the years, the oil has solidified and far from allowing things to turn more easily, is glueing things in place.

Anyway, Hugh will keep us posted on what he finds. We'd all like to know .

[hugh mcwhinnie 1Participant @hughmcwhinnie1]

Just nipped in for a second, motor is running now i put wd40 in the 2 motor ports the motor is 3/4r horse power. i need to go out and keep an eye on it, im giving it short 5 min runs and keeping an eye on the temprature!

[NJHParticipant @njh]

Hugh

Just in case you don't have access to the manual for the Super 7 you can see one HERE  as a downloadable PDF file. It contains all the information you need about lubrication ( and many more things too!)

Norman

Edited By NJH on 16/09/2013 16:52:51

[ZiggarParticipant @ziggar]

i would keep squirting wd40 in them oil ports every 5 miniutes or so. try to get everything loosened up nicely. keep checking the temp and see if you can tell when its starting to run cooler

then bung some oil in there as much as you can

and then oil it every time you use it for a couple of weeks till its all runnig nicely again

then oil as recommended in the manual

and hopefully that will be all thats wrong with it

Z

[hugh mcwhinnie 1Participant @hughmcwhinnie1]

I have run the lathe now on and off for a while without any load, i also put wd40 in the motor ports, when my hand is under the motor while running i can feel air coming from the holes on the casing at the front of the motor closest to the pulley but on the other end where the wires and things are there is no air blowing out those holes, the motor is still heating up, not so much the shaft but just the casing and its taking quite a while to cool down. Not sure if there is two fans or just one on these motors. I have attached a few pictures

[hugh mcwhinnie 1Participant @hughmcwhinnie1]

Thanks for the link Norman, i have the blue myford book that came with the lathe i'm sure its the same.

[hugh mcwhinnie 1Participant @hughmcwhinnie1]

Sorry to be a pain the rear guys, does anyone have the same motor on there myford lathe? If so would it be too much for me to ask if you could run the lathe 10 min to see how hot the casing goes on the motor?

[hugh mcwhinnie 1Participant @hughmcwhinnie1]

Or does anyone know the normal operating temp of the motor?

[KWILParticipant @kwil]

I do not have that motor so cannot help directly, Does anyone know whether that particular motor has ball or plain bearings?

Hugh I see you have a Griptru chuck, therein lies another story for later.

[Author]

Posts