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10L Carriage lift / poor finish

StrayAlien

Cast Iron
Joined
Aug 18, 2014
Location
Melbourne, Australia
Hi all,

I am having troubles getting a good finish on my 10L. For one - I definitely have the 24tpi bands on the finish discussed over here:

http://www.practicalmachinist.com/vb/south-bend-lathes/10l-poor-finish-power-feed-330098/

That is a very interesting thread. I'll try to solve that one by looking at the apron worm etc. But my main concern is a 'lumpy' finish.

The surface is just not smooth - I don't mean torn, on 12L14 most of the surface is good except for lots of not so little ridges. Not at 24tpi. It is like the cutting tool is not being held at the same position along the cutting axis.

I get same when I lock the cross slide using the taper lock handle, and I also have the compound set along the axis of the cut .. so any pull etc should hopefully not pull itself into the work.

I am not sure whether the carriage/apron should be able to be lifted at the front but I can lift mine a fair bit. I also noticed that I can press on each corner and register movement if I have a dial on it.

On the weekend I used my taper attachment for the first time and it is pretty stiff (the machine is quite worn so I guess it is not quite aligned correctly anymore more). What I did notice is that when I turned the hand wheel the front of the carriage lifted and brought the workpiece closer by about two thou.

Any help an assistance is much appreciated.

Greg.

PS. The machine has been rebuilt at some stage and the gearbox, rack, etc are shimmed down.
 
No hold down arrangements on the front of a Heavy 10 saddle so its easy to lift.

Taper turning attachment is often cause of problem. Idiot design and a complete pain to get running smooth and shake free. I eventually pulled mine off and set it up from scratch on the bench which cured it so I could make good tapers. Shouldn't affect things if it free running with the drag link clamp left completely unclamped tho'. SouthBend set these things up at the factory then poured babbit into the drag link bracket to ensure alignment. Fine when all is new but any wear and problems start because there is no way to correct the alignment.

Have you pulled the gib at the back of the saddle, given it a proper clean and done a good clean up under the bed where the gib rides. Grunge builds up over the years giving uneven drag so the saddle twists as it moves. With no hold down on the front it lifts and wanders all over the shop given half a chance. Before I sorted my taper turning unit out the front of the saddle would lift and drop visibly when attempting to taper turn. However previous owner had adjusted things. The stupid boy way! Some of the errors I didn't believe even after I'd found them!

Compound slide is too weak to set parallel to the bed. Gets seriously in the way too. My normal position was at about 25° off parallel to the cross slide. Ready for threading either 55° or 60° threads using the Zero-to-Zero method and keeps the handles out of each others way. Slide locks are essential on an ageing Heavy 10 if you want to do good work. I have a PDF covering the versions I used which worked well. My Heavy 10 was near mint but it still needed the locks to be reliable on tenths work. Heavy by name but not by nature.

Clive
 
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Thanks Clive,

I thought as much re the range of lift at the front of the carriage - that either something was waaaay wrong or it is just like that.

The drag link on mine does not even approximate being aligned - the air gap is pretty substantial. So, I shimmed it underneath the clamp inverted V to try to keep it aligned.

The rear gib should be clean. The machine is not too long back together are a nut-and-bolter. But, it could be lose - I'll check that.

Thanks also for the tip on the compound being too weak to be parallel - thought admittedly, I have it like that to try to solve stuff so it likely is not the culprit.

Can you share the PDF of you slide locks? You made them yourself? Got a pic or three?

Apols for being a pain but any chance you could explain a little further about what you did to set up your cross slide?

Many thanks,

Greg.
 








 
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