Buying a lathe - how to check powerfeed without being able to run it?

[Friendly non murdering Sword]

Hello everyone,

I've been on the lookout for a lathe for over a year now. Finally there might be an interesting opportunity next wednesday. I'll be checking out a Knuth 150 Basic Super for roughly ~1200€ with lots of tooling. Knuth is a german reseller for chinese import lathes.



But there is one catch... there seems to be a gearbox for the powerfeed, but the owner told me there is still one place in the spindle housing for change gears to choose between two input speeds on the powerfeed gearbox and the change gear is missing. So I will not be able to check the powerfeed gearbox under power at all.

My question is: Is there any way to check the different powerfeed speeds, the halfnuts and the thread-cutting by hand? Will I be able to turn the powerfeed input-shaft by hand or is the torque needed too high?

The missing gear is no problem for me because I have a mill with a dividing head so I can make one myself if these aren't readily available and I'll be able to negotiate the price down. But still if there is no chance of checking the lathe's powerfeed settings at all that is a somewhat risky deal... But then again if I can buy the lathe for maybe 900-1000€ I would be happy to fix it myself.

Any thoughts on this?

 

[Lo-Fi]

You won't struggle to turn it over by hand assuming it's not gummed up with congealed oil or something.

 

[extropic]

Welcome to H-M.

I would be suspicious of the coincidence that an integral part just happens to be missing.

Two ideas occur to me. First I would visually inspect the gear train to see if the missing gear is necessary to drive the QCGB. It might be that the missing gear is to switch between metric and Imperial threads/feeds (which should not prevent you from using the other gear.

Alternatively, maybe you can use a cordless power tool to drive the QCGB. It would be very easy if there is a hex head fastener on one of the input shafts. Driving the QCGB with an alternative power source would let you run thru all the QCGB and apron power functions.

Good luck.

 

[Janderso]

I don’t see a tail stock.
After looking for a year the frustration may be building?
Make sure it’s a good lathe, missing parts could be very challenging

 

[francist]

I think I see a tailstock on the floor in the background behind the machine. Not sure though.

-frank

 

[C-Bag]

I’d be very wary of this machine and look for evidence of a crash. I’d also check to see if the lathe is still being made and there are parts available. You cannot believe what a pain it is to find parts for a discontinued machine. And to me a QCGB is the absolute heart of a lathe outside of the spindle. I know it’s hard to keep looking but it’s even worse IMHO to have a machine you can’t use and now don’t have the $$ to buy another. Been there did that once and nevermore.

 

[markba633csi]

I wouldn't worry too much about the gears since you can make them. I would however be looking closely for damage and at the spindle bearings and condition of the ways. See if you can find a manual for it online. Look for cracks in the castings too. Then make your best deal (be ruthless) and drag it home!
-Mark

 

[Friendly non murdering Sword]

Thanks to everyone for the help! So I will be trying to turn the powerfeed either by hand or with some sort of powertool to check it out.

The tailstock and chip pan are indeed laying behind the machine. With the information given I will definitely be cautious and inspect the machine as good as I can and consider if this problem is easily fixable or not. I would rather wait one more year than having a 1000lb worthless boat anchor sitting in my back yard.

I'll keep you informed on how this story turned out.

 

[pacifica]

Thanks to everyone for the help! So I will be trying to turn the powerfeed either by hand or with some sort of powertool to check it out.

The tailstock and chip pan are indeed laying behind the machine. With the information given I will definitely be cautious and inspect the machine as good as I can and consider if this problem is easily fixable or not. I would rather wait one more year than having a 1000lb worthless boat anchor sitting in my back yard.

I'll keep you informed on how this story turned out.

You're relying on the honesty of the seller and how much you trust them only you can say.
Check run out on spindle nose, flatness of the ways , check gears and oil quality in gear head, a stethoscope to listen to bearings.
Looks like a rusted , scrape mark on the back gear cover-about halfway up. Remove the back gear cover to check gears and bring some belt dressing to spray on the belt drive-that way if the belt is noisy it will quiet down so you can hear the other gears.

 

[Friendly non murdering Sword]

So I said I will keep you informed how that whole story turned out.

Short story: I'm now owner of a lathe.

Long story: The previous owner postponed the original appointment due to illness and I had to postpone further appointments because I was very busy on other things so I already wrote that deal off. But never the less I was able to inspect the lathe lately and was actually pleasantly surprised. The missing gear from the power feed turned out to be one of the change gears for thread cutting but since there were others I was able to try out all lathe functions under power. So I tried out all speeds and feeds, did a visual inspection and a test cut and measured the spindle cone and nose runout, which was lower than what I was able to really measure with my 0,01mm (0,0005") dial test indicator.

So this is what I got for one grand:



Thank you everyone for the help on this one.