# Apron Worm gear axial play On South Bend 16



## Jimw (Jan 21, 2013)

While disassembling the apron on my 16" lathe I noticed quite a bit of axial play in worm gear.
The slot in the bushing on one side, I think is for the felt wick, is completely worn away.

i measured .145 play side to side play. I am looking for repair suggestions, and minimum axial play for the worm gear in the bushings.

I do not have a mill. I have a drill press with a good cross slide vise, and a 126 year old Barnes number #5 lathe.

I am thinking filling a new slot for the wick, taking up the play with the collars and drilling new holes for the retaining pins in the collars.


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## woodtickgreg (Jan 22, 2013)

You could also contact Joe at Plaza machinery, he might have a used set of collars.


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## Pacer (Jan 22, 2013)

I had that problem on my Heavy 10 --

I removed the 'lip' that had formed from wear using a belt sander to re-flatten them. I reassembled the pieces, taking a new measurement. Found a piece of brass in the scrap box and sliced off 2 'washers' to take up the space - IIRC, about .100 or so. Had to make 2-3 tries on the spacers to get a good fit, but turned out nicely. While bras would probably be best, think most any metal you got in the scrap box would do for the spacers.


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## OldMachinist (Jan 22, 2013)

I found the exact same thing when I took my 16" apart last year. Your plan is what I did. I faced the collars flat and recut the slots. I then put a spacer behind the collar with a clearance hole for the locating pin.


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## Jimw (Jan 22, 2013)

All Great ideas. Any Advice on the minimum clearance for axial play? 4-5 thousands ?


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## OldMachinist (Jan 22, 2013)

.005" is a good starting point and then make sure every spins freely after assembly. I ended up taking a little off one of the spacers after I tried it with .005" because it had little tight spot.


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## Jimw (Jan 27, 2013)

Here is what I did so far. This is my very first machining job on a lathe, other than turning a bolt down just to make some chips. I ground a right hand facing tool bit. Chucked the parts in the old barnes lathe. I had to shim the parts to compensate for the Barnes not running true. Then I faced the collars and bushings to clean them up. I cut new slots for the wicking in one bushing and made the other deeper with a file.

I plan on drilling new holes for the collar pins. I measured the collar retaining pins at .124" I believe these are interference fit. What size should I drill the holes for the pins?


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## OldMachinist (Jan 27, 2013)

The pins are there just to keep the collars from rotating and destroying the felt.


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## Jimw (Jan 27, 2013)

Yes the pins hold the bushings from turning, which would destroy the felt. The collars, or nuts without flats if you will, are retained by pins to the worm gear that are a press fit. My question is that for .124" pins what size hole will give a good press/interference fit without working their way out.

Picture of the collar retaining hole.


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## OldMachinist (Jan 28, 2013)

.1235" would be the size for a press fit. Any smaller and you'll bend the pin installing it.


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## Jimw (Jan 28, 2013)

Thanks Don. Your a wealth of information and a pleasure to have on the board.


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## woodtickgreg (Jan 28, 2013)

Jimw said:


> Here is what I did so far. This is my very first machining job on a lathe, other than turning a bolt down just to make some chips. I ground a right hand facing tool bit. Chucked the parts in the old barnes lathe. I had to shim the parts to compensate for the Barnes not running true. Then I faced the collars and bushings to clean them up. I cut new slots for the wicking in one bushing and made the other deeper with a file.
> 
> I plan on drilling new holes for the collar pins. I measured the collar retaining pins at .124" I believe these are interference fit. What size should I drill the holes for the pins?



Nice work! )


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## Jimw (Feb 6, 2013)

woodtickgreg said:


> Nice work! )



Thanks.


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