# Help. SB 16 Thread Dial Indicator jammed.



## Jimw (Jan 11, 2013)

The SB 16 I picked up Saturday came with the thread dial jammed. It will not budge a bit.
If I could get the Worm Wheel (gear) off the shaft I may be able to press the assembly out.

The set screw for the gear is hidden behind the casting of the indicator. There is just enough space between the gear and the housing to fit a ground down Hex key/Allen wrench in there.

I pick out a Hex key/Allen wrench ground it down and was able to move the set screw a bit. 
This key must have not been the right size because it stopped moving the set screw. I then ground down a larger one it was still the wrong size.

Can anyone tell me what size key fits the set screw on there Worm Wheel? The parts list shows this as a 122 x 506.


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## OldMachinist (Jan 11, 2013)

The South Bend list of commercially available hardware says thats a 1/4" x 3/8" long set screw. I went and checked my 16" SB and its a screw driver slot. There's nothing that can be ruined by soaking the whole thread dial in penetrating oil and/or using a little heat to free things up.


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## Jimw (Jan 11, 2013)

Thanks for the info.
I do not think it is rust. I have soaked it for 5 days and it did not look rusty to begin with. I think set screw at the indicator, on the top side backed out and jammed into the casting.

Another alternative may be drilling an access hole in the skirt of the casting to expose the set screw on the gear.


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## Jimw (Jan 11, 2013)

Ok, so I thought more about what you said.

The parts book shows the thread dial being pretty thick and the fit in the casting looks very tight, so there could be rust in there. The rest of the lathe is very rusty.

Then there is the fact that some kind gentleman is trying to help me with some advice, and may know more than a thing or two about these dials.

so I got out the mapp gas and cooked the dial portion a bit. Started to turn using a screw driver to pry on the gear. Then I removed the set screw from the gear. Heated the gear and drove the shaft out.

Yep rust down it there. Nothing was jammed up I suspected different.

By the way the upper set screw is slotted the lower is a hex on mine. 

So thanks very much. I will listen sooner next time.


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