Thread: AL250G problem

Brian, theory says that you should lock the carriage when facing and lock the cross slide when cutting longitudinally. The reason is to prevent precisely what has happened. Of course we all do it all the time, scrupulously and never take short cuts...

What happened is "normal". A bit of vibration and moving parts will move.

Michael

When using the cross feed wheel, particularly if the carriage is not as tight as it should be, the carriage will move right or left depending on which way you are turning the cross/compound wheel. If the gibs are loose-ish, the carriage will naturally follow the path of least resistance - away from the work. When I'm facing, I always use the carriage lock, that's what it's there for.

On most Chinese lathes there are two recessed allen head bolts on the top front of the carriage, each side of the cross slide. The one on the right will have an L shape block dangling underneath, tighten the allen bolt on top and the L shape block will clamp on the underside of the bed. There are various locks on lathes, they are meant to be used when the particular function they serve isn't being used..

I always lock off everything when not in use: carriage, compound, cross, tailstock. At the very least it stops you accidentally knocking them and ruining what work you have already done.

Thanks Michael and casjon,
I think the lathe has been stiff enough in the past to not move and now with being used more actively things are smoothing up so I will need to definitely lock things now.
I appreciate both of your inputs and I feel a bit of a klutz but I can now go looking for the locks and be more caerful in future
thanks again
Brian

When you find the carriage lock bolt or set screw it would pay to replace it with a home made T-bar, it makes locking the carriage for facing and parting off much quicker and easier.

Gavin, thanks for the idea.

Amen to that, trying to find an allen key when you're in the middle of things is a PITA.
My current lathe has an allen bolt in the usual place but the cross slide gibs interfere with it so a T bolt wouldn't fit. Instead I had to manufacture a bar that sits on the end of the carriage with a through bolt in the middles bringing up a clamp. Works better than the usual because it actually clamps up under both front and rear ways. Every lathe seems to have it's share of design faults!

Thanks Gavin,
A picture is worth a thousand words!!
I can't believe I've got away with out locking the carriage all this time, but it might be because most of the work I have done in the past is very light cuts.
I'm off out this morning to take a closer look at the carriage and see if I can find the existing lock.
Thanks again everyone
brian

I found it!!
Now I really feel like a goose!!
Thanks again
Brian