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Disengage 9A Threading Dial When Not In Use?

tobnpr

Hot Rolled
Joined
Sep 27, 2015
I found out- quite by accident when I went to thread a piece and the dial wasn't turning- that my 9A dial has enough "play" for it's lower gear to be pivoted off the leadscrew, even though both allen head screws are tight. Guess this doesn't surprise me given the screws are on a round shaft, but it hadn't worked it's way "loose" off the leadscrew in the more than a year since I bought and re-built it.

Now I wonder if it doesn't make sense to keep it pivoted out of the way when I'm not threading to avoid wear on both screws. Or, maybe that's what's supposed to be done by design and I never knew it?
 
Some lathes were built with threading dials that could not be disengaged. It seems to me it will not make much difference whether you disengage it or not.
 
If you're following the routines with the oil can as often as you should, it shouldn't be a big d3al to hit one more point.
If you hardly ever single point thread, I've seen alot of guys just take them off, but If you're threading regularly, its one more piece you would need to set up if it was disengaged.
 
Thread nearly every day. Rifle barrels...
Mine is on a big reinforced steel "pan" table so I'm not shy about using oil on everything that moves (trying to figure a way to retrofit for lube system as well by fitting with drains to a sump). Guess it makes more sense to just leave in place but just check periodically to to make sure it hasn't partially begun to disengage which would I assume cause issues from accuracy to premature wear.
 
The one on my 10L will rock enough to disengage. I don't do a lot of threading, so it stays that way most of the time.
 
I don't thread often,and when i do, it will be for a spell. I take the dial off and store it with the threading stop in a drawer. Both are clean when I go to use them. I also keep short brass screws in the tapped holes for the follower rest,keeps the crud out. On my 13 I also keep short screws in the tapped holes for the carriage stop adapter and the threading dial. Keeping a clea machine is part of doing accurate work.
 
A lot of merit in all the above comments. Looks like it comes down to personal preference and what one feels is the best way to take care of their particular machine. I remember a number of Navy machine shop instructors telling students to disengage when not in use. Probably across the industry the two approaches have been there since the beginning. Have always had my engaged, never much thinking about it. I don't do much thread cutting, but when I do I do multiple pieces. This thread brought me back to the Navy instructors and got me thinking because of my infrequent threading I might just start disengaging again. I am afraid if I remove when not in use I will be looking for it the next time I go to cut a thread. Don't have a messy shop as much as not having the best of storage areas for everything.
 
I always have the thread dial disengaged if not threading to keep wear down. On my LeBlond 13", it has a slip gear to disconnect the whole lead screw to keep wear off the bearing points if you aren't threading.
 
like you I do not do much threading, as a result I disengage my thread dial when not needed. I have a thumbscrew on my apron for that purpose. Just make sure it doesn't drag the bed way. And if you do a lot of threading, don't worry about it. It is your preference. For me, I don't like anything that is not necessary dragging on my lead screw.

stay safe and have fun.

Joe.
 
It's not just wear on the leadscrew (which may be hardened, but I'm not sure on that).

The gear on the thread dial can wear as well.

Now that just might end up being the equivalent of backlash - as long as you are working in only one direction (and in threading, you are), it might not matter.

I don't do much threading, so I leave it disengaged unless I need it.

Steve
 








 
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