Threading dial alignment.

[Richard-B]

I have recently purchased a Chin Hung lathe. It seems to be in pretty good condition but today whilst I was cleaning her up, I noticed the threading dial was loose to rotate. From the parts breakdown I am missing a washer but it appears there is no key way or spline or even a small pin to locate the correct alignment of the threading dial to the lead screw. The dial is reversible with numbers on both sides.

Looking in the manual i have just acquired, it doesn't mention setting up the dial indicator or mention this sort of issue in the troubleshooting. How would i go about setting the dial to be in the correct position with regards to the lead screw ?

 

[Lo-Fi]

Just make sure that one of the lines is aligned to the marker when the nut is engaged. No more alignment or calibration than that is needed as you choose which marker to follow when threading.

 

[Tozguy]

If you are referring to how the thread dial gear meshes with the lead screw then I would venture to say that it is designed that way ie. to rotate in and out of mesh with the lead screw. When not doing a threading operation the dial can be swung away from the lead screw and not be used.
When swinging the dial assembly into mesh with the lead screw it just requires that you hold the dial assembly in position by hand while you tighten the bolt or screw to hold it there. This might require a bit of practise so you set the gear mesh without it putting pressure on the lead screw.

 

[Richard-B]

Lo-FI - I did wonder if this was the case but I wanted to be certain, thanks.

Tozguy - What you are explaining is how I discovered the problem. I was reading the manual and it suggested that the dial be rotated away from the leadscrew when not in use to prevent excessive wear. It was carrying out this advice when I discovered the actual dial was free to rotate independently of the leadscrew when engaged.

Thanks for both replies guys.

 

[Jim F]

Lo-FI - I did wonder if this was the case but I wanted to be certain, thanks.

Tozguy - What you are explaining is how I discovered the problem. I was reading the manual and it suggested that the dial be rotated away from the leadscrew when not in use to prevent excessive wear. It was carrying out this advice when I discovered the actual dial was free to rotate independently of the leadscrew when engaged.

Thanks for both replies guys.

The dial and gear should be free to rotate separately, they both should be secure to the shaft.

 

[Janderso]

I've had to adjust mine before. I can't remember how I did it but it was off. It clicked in just after the line/number so I just rotated it back a bit. Or was it forward?
I didn't know there was an actual procedure.

 

[Richard-B]

The dial and gear should be free to rotate separately, they both should be secure to the shaft.

The problem I have is the small knob on the top of the dial is missing a washer under it. This means that when the knob is tight, it is not pushing down on the actual dial itself. This means the dial is free to rotate, or not rotate when the shaft of the dial indicator rotates when engaged with a moving leadscrew.

 

[Jim F]

The problem I have is the small knob on the top of the dial is missing a washer under it. This means that when the knob is tight, it is not pushing down on the actual dial itself. This means the dial is free to rotate, or not rotate when the shaft of the dial indicator rotates when engaged with a moving leadscrew.

Ok, so won't stay engaged.

 

[RJSakowski]

You will need to align the dial with the half nuts. Engage the half nuts and loosen the screw which holds the thread dial. Rotate the dial so one of the marks on the dial lines up with the index mark and tighten the screw.

 

[Jim F]

I think I know the issue now after watching a YT video.
Can you just put a washer under the knob ?
Also , is the dial marked for the Imp.side and Metric side ?