Parting Problems - Backlash ?

As John says use the low speed range - I don't use anything else for all my turning.

Have you also locked the top slide?

Is the lathe stalling or are you actually getting a dig in that stops the work dead? It would be worth putting a turning tool into the toolpost and seing if you can take a facing cut the same width as the parting tool, if this also stops the lathe then its more of a VFD setup issue than tool dig in.

Andrew, when I mentioned parting at teh tailstock end I wa sthinking of a long way from the chuck eg 10x the work dia, your example is not much more than 1x which I would expect to be more rigid.

Michael, yes I too was thinking of parting on the right of the steady until I saw Ega's post. Thinking about it this afternoon the fixed steady method would really only be useful on bright bar as the surface of cast iron or bronze bar would need turning first to give a suitable surface for the fingers to run against.

J

Edited By JasonB on 20/01/2016 16:48:24

The steady is good for parting off drain pipe. I had to angle the peatol so that the rest of it could go out the back door. I got lovely smooth square ends on lengths up to 10ft.

John

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The 290V has a 1.5kW (2hp) motor, so should not be stalling. Is the belt slipping? If you have selected low range and are operating it anywhere near base speed for the motor (1500rpm?), you shouldn't be able to stall it.

Otherwise it's got a Delta inverter (VFD) IIRC, so worth checking it's set up correctly. Doesn't sound like it.

Edited By Muzzer on 20/01/2016 16:30:46

Many thanks for all the help - especially the suggestions since my last post - finally some success:

You were all correct, stall not dig in (mostly, I am sure my clumsiness caused some actual digs)

I had originally been in high range (the low range is a bit annoying on the 290v as is 30-450, so bit low for general use) and it was definitely stalling then. I had then moved to low range first thing this morning, and thought it was stalling, but was actually the belt slipping (thanks Muzzer). The belt from the motor to the idler for low range (M26) was quite loose and slipping under load.

Cleaning some of the muck off the pulley helped and I got my first successful cut under power feed for the day. It started slipping again quickly, but at least I know what the main problem is.

I've had the lathe about 4 months - is it likely to have stretched in this time or am I going to find a replacement is also slack ? (There is no adjustment for this belt)

Thanks again,

Dan

Can you post a photo of the motor mounting? on the 280 you can slide the motor to set the belt tension.

That is quite a slow low range, I get 50 to about 1000 in the low range which is a more useful spread.

Jason's spread is just about ideal for the majority of work really. I'd guess they have gone that low to ease screw cutting to a lower speed than many may need unless they want to cut an extremely coarse thread.

They have done this on a Wabeco 2000 too. I wouldn't be surprised if at some point I changed it. I'd probably go for a top speed of about 800 rpm if I did that.

John

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According to the 290V brochure, the low range is 50-850rpm and high 110-1800rpm. That sounds pretty useful.

Muzzer, Warco are not that good at keeping up their website data, I think you will find that te PDF with the two speed ranges relates to the older non inverter version, if you look at the page your link takes you to first it gives 30-2500 and the two extreams

My little 8 x14 lathe is not very rigid so parting off can be difficult at times. I've tried standard HSS and insert tooling but the best to date have been the T shape HSS blades with the groove in the top. Very reasonable price at Chronos for both the blade and holder.

Jason,

Photo of motor mounting below - the cold may have finished me off but I don't see much useful adjustment.

Muzzer - I wish. Actual ranges are 30-450 and 150-2500. I don;t use 2500 much

Vic - I tried one of the blades jury rigged in my dickson parting holder, but am planning to buy a real holder. It seemed to work pretty well before my latest round of woe.

John - Yes, at some point I reckon a new pully will be on my long to do list.

Looking at that picture you could make up a jockey wheel to tension the belt. Plenty of room to tap some holes in the end of the bed. I wish my lathe would go down to 50 RPM I find 80 to quick for some screw cutting.

Power Feed?

Sure if you are doing a batch and can test: for one offs I prefer to hand feed, this enables me to pull back if the sound changes to the growl that often accompanies a dig in.

Regards
John

Must admit I never power feed when I am parting off or facing - I'm usually using a boxford with a gearbox so setting the rate is easy and quick.

It's a bit strange that they haven't allowed for belt tensioning. Maybe there is some scope in the motor mounting. They shouldn't need to be that tight with sensible pulley sizes as they tend to pull in and grip on the side that is transmitting the power.

John

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I agree. Very strange if that proves to be the case.

However. This product **LINK** will probably get you out of a tricky spot as you can make it within reason virtually any length you wish. It's OK if it's a tad tight to start with as it beds into the pulley grove with a little use. - Make sure you get the right width though.

Lots of people on this site use belts such as this. Myself included.

Nick

Quite a different mounting method to that used on the 280 which has a flange mounted motor

John McNamara:

Those who choose to hand feed are likely to find an extended cross slide handle helpful - see the DHC photo I posted earlier in this thread.

If you do go for a linked belt I would avoid buying the cheap black one. (RDG I think) In use it's a bit like trying to use toffee.

The T and nut types that use metal link joiners are fine but not the easiest thing to join up. Fenner make one that doesn't use metal joiners but have chosen to only sell it in rather long expensive lengths. Maybe that one is ok.

Not sure what section your belt is but if you look here for instance at A section the steps in size get smaller as the belt length goes up. This is the way I would probably go, Cheaper and efficient - even if you have to buy 2.

**LINK**

John

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Edited By Ajohnw on 21/01/2016 09:39:05

I had a Fenner Power Twist belt on the primary drive of my lathe for nearly twenty years, I replaced it a couple of months ago with a similar, but non Fenner belt, it's taking it's time in settling in, does not have the feel of the old belt, but is getting better.

Ian S C

it is a bit of slack fit, and I doubt it helps that the motor pulley for low range is small - about 4 or 5cm diameter without measuring. As suggested above, a tensioner would be easy enough - in fact it could fit on the stud to hold the cover on without any further drilling required.

I think I will try a slightly shorter belt for now, but then the Chronos link belt in Nick's post will come in handy as on reflection I will be trying to change the pulleys sooner rather than later - I don't much want to have to change belts between turning and parting operations ...

Thanks to all for bearing with me - would still have been flailing about feeling grumpy otherwise.

Regards,

Dan

An idea that I used on my vertical mill. Because the small pulley on the motor, some where about 40 / 50 mm, this is far too small for a B section belt, I went to the local Garage and got a suitable size fan belt that has notches in the inside of the belt allowing it to fit on a smaller pulley, it's done alright for the 25 years, looks as though it will last 25 more.

Ian S C