8ob
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- Nescient in the vale
Yes you can.
2 tins of things.
I agree, one for big things and one for small things
Bob
Yes you can.
2 tins of things.
Do not manually wind the saddle(!)
Power the lathe backwards and as the TDI starts turning backwards, re-engage the half nut at the mark. Note because you stopped the lathe very quickly after disengaging the half nut, the TDI has only moved a small amount past its mark. The half nut is of course in the exact same phase as if you hadn't disengaged it SO LONG AS YOU DON"T MOVE THE SADDLE MANUALLY WHILE IT IS DISENGAGED.
If the saddle moves at all while not connected via the half nut, the relationship of its position wrt the thread is lost.
My driving the saddle back is done by hand by turning the over head pulley backwards as I don't have complex reverse gearing on it so it's dead easy to get it back the the precise point you started off at every time by meeting the edge of the saddle with a bed stop clamp device .
What is good though is that you initially said it was impossible , now you've had a chance to read the manuals ( RTFM ) you can see that it is easily done , so it's a win all round .
What's with the abrasive response?No. Not at all. I have no idea what you are trying to say here. The process as you describe it is in fact impossible for all he reasons I have stated. You cannot move the saddle manually with the half nut disengaged and still remain in phase with your thread.
I should just leave it there really because I have said everything A THOUSAND TIMES now and you keep coming back telling me I’m wrong. You are completely wrong, what you suggest is impossible.
There is one method where the half nut is briefly disengaged WITHOUT MOVING THE SADDLE, which actually, I picked up from Abom79. I don’t use that technique, I just hit the stop and reverse the machine.
As I have said a thousand times you cannot move the saddle by hand, by kicking it, yanking on a pulley or whatever other excuse you want to think up. Running the saddle back to a stop is pointless, it will not work for the reasons stated earlier. If you want to keep pretending you’re somehow right, knock yourself out, I am experiencing sense of humour failure and have no more interest in trying to explain it. If you can’t understand it now, I give up.
You can indeed move the saddle all that matters is that you re-engage on the same mark of the same turn. If you're feeling brave, you can wind the saddle back all the way to the end of the bed counting the thread dial turns then reverse the lathe until the leadscrew has un-wound those turns and then pick up the same mark, and you'll still be on index. It's a risky venture with a high risk of messing up your turn count, and the only thing to gain is reduced war on the screw and nut, but it works perfectly well.
For short threads it's far less risky. If you divide the number of teeth on the threading dial gear by the leadscrew's TPI the result is the number of inches you can move the saddle without the threading dial even making a full turn, so suppose you have a 8tpi screw and a 24t gear you can move up to 3" and still be on the same turn of the dial. It's easier than it sounds TBH.
This is my understanding of it tooSame turn of the thread dial. Read through my post again properly and try to understand what I'm saying instead of going all rage-faced.
If you stop the lathe and wind the saddle back the thread dial will turn.How far you wind it is completely unimportant. All you have to do is reverse the lathe until you undo those turns and re-engage the half nuts on the same line then you are properly indexed.
All makes sense to me as well.Same turn of the thread dial. Read through my post again properly and try to understand what I'm saying instead of going all rage-faced.
If you stop the lathe and wind the saddle back the thread dial will turn.How far you wind it is completely unimportant. All you have to do is reverse the lathe until you undo those turns and re-engage the half nuts on the same line then you are properly indexed.
Pete, I fully understand what you are trying to get across and it’s something I do on occasion. The big DSG lathe worked on that principle. It had trip levers that automatically disengaged the half nuts. You then wound the saddle back manually. It even told you with which pitches you could re engage on odd numbers and which were even numbers.Same turn of the thread dial. Read through my post again properly and try to understand what I'm saying instead of going all rage-faced.
If you stop the lathe and wind the saddle back the thread dial will turn.How far you wind it is completely unimportant. All you have to do is reverse the lathe until you undo those turns and re-engage the half nuts on the same line then you are properly indexed.
Wait till you get it calibrated.but apart from that it's great!
you re-engage on the same mark of the same turn.
If you're feeling brave, you can wind the saddle back all the way to the end of the bed counting the thread dial turns then reverse the lathe until the leadscrew has un-wound those turns and then pick up the same mark, and you'll still be on index. It's a risky venture with a high risk of messing up your turn count, and the only thing to gain is reduced war on the screw and nut, but it works perfectly well.
Same turn of the thread dial. Read through my post again properly and try to understand what I'm saying instead of going all rage-faced.
If you stop the lathe and wind the saddle back the thread dial will turn.How far you wind it is completely unimportant. All you have to do is reverse the lathe until you undo those turns and re-engage the half nuts on the same line then you are properly indexed.
Pete, I fully understand what you are trying to get across and it’s something I do on occasion. The big DSG lathe worked on that principle. It had trip levers that automatically disengaged the half nuts. You then wound the saddle back manually. It even told you with which pitches you could re engage on odd numbers and which were even numbers.
Unfortunately there are certain members on here with little to no real world experience when it comes to machining,but that doesn’t stop them adding their two roubles worth.
I’ve found the best way to deal with silly little people on here that like to sprout nonsense and use uppercase letters…the ignore function works wonderfully…
Spec savers?Someone needs to invent a digital counting dial thread indicator.