Turned out nice

[simond]

Rob,

A quick look on mine (a Unimat 3) suggests about 0.4mm of free play between the leadscrew and its bearing. This should be able to be taken up by adjusting the handwheel on the screw, though I haven’t bothered.

I haven’t looked at the nut, but I don’t seem to have any appreciable play there at all.

Are your gibs snug?

Atb
Simon

 

[JimG]

It's no big deal as I have plenty of the rods left to have another go but I thought I would ask if anyone knew how I might reduce the play?

Rob,

On the lathes I have owned there's normally some sort of locknut arrangement on the feedscrew arrangement to allow adjustment for end play. On the Myford, the graduated dial was threaded and also had spanner flats and the ball ended handle was also threaded. To cut down play, the graduated dial was screwecd in until the end play was negligible and the ball handle was screwed up to lock the pair together with a spanner on the dial.

I've just checked my Cowells and that has a different arrangement with the handle and dial assembly being mounted on a plain end of the feedscrew and locked with a grubscrew. There is a screw in a tapped hole on the end of the shaft. To adjust the end play, the grubscrew is loosened on the handle/dial assembly and the screw on the end is turned until the end play is adjusted to what you want, then the grub screw is tightened.

I'm sure your lathe has something similar to one or the other.

Jim.

 

[Rob Pulham]

Thanks Gents,

I will have a look to see what can be done - I must confess that although we were taught how to turn at school there was never any instruction in setting the machines up in the first place so it's all very new but fascinating nonetheless.

I did manage to get a fair way through making a brake standard with a taper last night. But then the motor got quite warm (it's only 95 watts) and kept tripping the earth trip. And so I left the part still chucked and plan to carry on with it this morning.

 

[simond]

“The earth trip”...?

If it is tripping an earth trip (ELCB or RCD) then please be careful, it should not do that, and it’s hazardous.

If it is overheating, it would be worth finding out why; many small machine tools typically have a reduced duty cycle, they are designed to only operate for eg 10 minutes in any 30, and they will overheat if this duty is exceeded. They probably/normally include a thermal protection switch to prevent damage.

It may be that attacking the motor with a powerful vacuum cleaner will pay dividends, assuming it has ventilation slots.

Someone else had the same issue, on a 3; Emco Unimat 3 – glue-it.com

He also links to some ideas of replacement alternative motors

Best
Simon

 

[Rob Pulham]

Hi Simon,

It seems that a few of these older motors are a bit prone to it. There is a a thread on RMWeb where someone had the same issue. Mine has an old tilt switch and some tape over a section of the wire so I will replace these and see if that improves matters.

Someone on the thread had said that they had the same issue where the machine had a small amount of earth leakage and the workshop circuit must have had some too and when combined they tripped the Earth trip. However when plugged into a different circuit it didn't trip.

So it is with mine - It doesn't trip when plugged into a circuit in the house. Which means at least that the motor isn't jiggered.

When I mentioned it was warm, it was warm but I had been using it for quite some time without realising it - doesn't time fly when you are having fun....

 

[Paul Cambridge]

ELCD (earth leakage current detectors) and RCD (Residual current detectors) work in in different ways. ELCDs are obsolete and have been replaced by RCDs, You can have a fault that does not go to to earth via the earth wire and the ELCD will not detect it. The RCD will. A photo of your consumer unit posted on here would identity what you have got.
As Simon says, it’s hazardous. I’d go as far as saying it’s potentially fatal if you don’t know what’s causing it and what type of protection is installed in your consumer unit. Electrics in the home and driving cars are some of the most dangerous things the we use.

 

[Rob Pulham]

ELCD (earth leakage current detectors) and RCD (Residual current detectors) work in in different ways. ELCDs are obsolete and have been replaced by RCDs, You can have a fault that does not go to to earth via the earth wire and the ELCD will not detect it. The RCD will. A photo of your consumer unit posted on here would identity what you have got.
As Simon says, it’s hazardous. I’d go as far as saying it’s potentially fatal if you don’t know what’s causing it and what type of protection is installed in your consumer unit. Electrics in the home and driving cars are some of the most dangerous things the we use.

HI Paul,

I am pretty sure that mine is the ELCD type (the house is just over 19 years old) it has a blue breaker switch with a blue push button at the side of it.

 

[Ian@StEnochs]

Rob,

I had a Unimat 3 in my 4mil day’s complete with milling attachment. Both lathe and mill worked well and could produce accurate work within its capabilities. However the short working time before the motor cut out really got me down. I did look into upgrading the motor but, as I was doing a serious amount of commission work then, I decided to bite the bullet and got myself a Myford. It has been a worthwhile investment and is still in almost daily use.

Ian.

 

[Big Train James]

It's nothing special, but I apparently now know how to use a milling machine. At least in a rudimentary way. Stock squared and sized to length, slots of varying depths located and milled, holes located, center drilled, then drilled and power tapped.


I got it mostly right, having some issues with the depths of the slots and the depth mic. I'm guessing that I had some burrs that I failed to remove fully, so that the mic wasn't sitting properly. Which makes sense, as the slots measured over in expected depth after the roughing cut. So I never took the finish cut, and not surprisingly ended up about .010" under in the end . I should have trusted my process with the Z axis adjustments from touching off on the top of the stock. Got the widths and locations correct within tolerances, and didn't break any cutters or taps, so not a bad go for essentially my first solo effort. And I only bled a couple of times, from banging my knuckles when loosening the table locks and smacking a sharp corner when they pop free . The Y axis lock gets me about every other time. Really need to stop doing that .

Starting on the lathe on Wednesday.

 

[Jon Nazareth]

If it's any use saying it now, I always touch off from the top or measure down from the final top cut, that way it's right first time every time.

Jon

 

[Big Train James]

That's pretty much what I was doing, having touched off from the top. My mistake was double checking, but incorrectly, after the roughing cut, which introduced an opportunity for error. It's still a bit early for things to be automatic for me, so I sometimes over-think it instead of trusting my starting measurements.