# Bull gear missing one tooth



## Mike R (Aug 11, 2014)

Hello, I'm Mike and new to the site.   I just bought an Atlas 10" lathe the other day off of CL.   It was in a "garage" out back of the house. It was starting to get late and no lights in the "garage" and I hadn't taken a flashlight so I looked it over as best I could . Bought it for $125.00 with a homemade metal stand.  Loaded it up and started on my two hour drive back home.  When I got to looking at it the next day I was rotating the head gears and noticed on the bull gear that one tooth was broken out. My question is will the one missing tooth be a problem ?  I'm thinking that this lathe might just end up being a parts donor for my other lathe. It has an original Atlas motor that works nicely. End and gear covers are both there and in good shape.  Carriage and forward and reverse gears look to all be there and not broken.  Thanks ,   Mike


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## jererp (Aug 11, 2014)

My Logan 850 had 1 missing tooth on the bull gear when I bought it last year, and it has worked fine.  No problems.  I assume you will be OK as well.


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## Whyemier (Aug 11, 2014)

Mike R said:


> Hello, I'm Mike and new to the site.   I just bought an Atlas 10" lathe the other day off of CL.   It was in a "garage" out back of the house. It was starting to get late and no lights in the "garage" and I hadn't taken a flashlight so I looked it over as best I could . Bought it for $125.00 with a homemade metal stand.  Loaded it up and started on my two hour drive back home.  When I got to looking at it the next day I was rotating the head gears and noticed on the bull gear that one tooth was broken out. My question is will the one missing tooth be a problem ?  I'm thinking that this lathe might just end up being a parts donor for my other lathe. It has an original Atlas motor that works nicely. End and gear covers are both there and in good shape.  Carriage and forward and reverse gears look to all be there and not broken.  Thanks ,   Mike



Assuming your other lathe is in 'good' condition, $125.00 is not a bad price to pay for parts. I believe you could easily pay that for a motor, not to mention the other parts.

If the machine otherwise is good and you want to use it you could try to fix it if you have access to a torch for brazing in a metal block you could then shape on a mill. I seem to bremember me someone posted on some site a built up accumulation of braze they formed a tooth from. Don't know how that worked out.


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## pineyfolks (Aug 11, 2014)

You'll only be using it in back gear. Just see if it effects the finish when turning.  Most likely it was caused by someone locking it in back gear and using a large bar or hammer to remove the chuck.


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## Charles Spencer (Aug 11, 2014)

I have seen pictures where two small screws filed into shape are used in holes drilled and tapped where the missing gear was.


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## iron man (Aug 11, 2014)

For as cheap as you got it I would repair it those bull gears come up on ebay quit frequently.

http://www.ebay.com/itm/Original-At...308?pt=LH_DefaultDomain_0&hash=item2c88050c9c


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## Restorer (Aug 11, 2014)

Mike,

Do you have a another lathe and a milling machine or a shaper, Or access to use someone elses equipment.?  If yes the missing tooth can be replaced.


I have replaced several missing teeth over the years with good success in Cast Iron bull gears.  By replacing the tooth it eliminates the excessive load on the next tooth.
Of course replacing the bull gear is the best method but the most work, as it is press fit on to the spindle, and don't try to hammer it off!
A hydraulic press is required, and made up support blocks etc. to prevent damage to the spindle and bearings etc.

To repair the gear the spindle will need to be removed from the machine.  Wrap to cover any rolling element brearings and/or bearing surfaces.

In a mill or shaper cut a slot where the tooth is missing, slightly wider than the origional tooth with a depth approx. 1.25 times the width or more.

Machine a block to fit snug slip fit in the slot and slightly taller than adjacent teeth.  rough out (remove excess material) an approx. tooth but stay oversize.

I used Braze to attach the block into the slot in the bull gear as follows:
Silver solder may be a better choice if available.  Apply liquid brazing flux to the portion of the block to be brazed and only that area.

Holding the part with pliers or equivalent heat to bright cherry red with an oxy-acetylene tourch.  Apply some brazing rod sparingly to just coat the surface.

Mount the gear in a vise slot up, now do the same with the slot in the bull gear.  Keeping the gear hot, apply more flux to the replacement tooth, then try to push into the slot, It probably will not fit.
Dont worry!  Keep heating both until the braze melts and it should slip in no problem.
Add more filler rod to the joint as necessary and be certain to center the block on the tooth face.  Remove the heat, turn off the tourch.  
Using the pliers push the block down into the slot until the braze solidifies.  Allow to cool slowly, do not rush this part.

Once cool to room temperature wire brush to remove surplus flux and burnt paint.  Touch up paint to suit and allow to dry completely.

Now on to machining.  A) Put the spindle with brazed bull gear in another lathe (wrap threads or other precision surfaces to prevent chuck jaw damage with a single wrap of thin aluminum or brass sheetmetal) and turn the OD so the new tooth is the same OD as the rest of them, and flush on each side.  The only metal being cut should be the new block.  The clunk, clunk Lathe work is done.

Creating the proper tooth space - A) If you have an involute gear cutter of the correct Diametral Pitch and Pressure Angle by all means use it.   
For an Atlas lathe it will be 14.5 degree pressure angle and a Diametral Pitch, not the metric Module system.

B) I suspect an involute cutter is not available.  Thus take a Lathe tool bit blank and make a cutter.  Grind the top flat, no rake angle.  Then grind the sides of the bit untill it fits near perfectly between two of the good teeth.
Remember to have everything below the cutting edge clearance a 5 to 7 degree clearance angle is good. 

This cutter will function in a fly cutter or shaper tool bit.  Align the cutter to the work using a "good tooth space", Using an indexer or rotary table. Zero the dial for finished depth, and back away slightly in the Z axis,
 position the bull gear to cut one side of the block.  Keep in mind you want to cut the brazed block not the adjacent finished tooth.
Then repeat cutting the other side of the block.  Rember rotate the gear to get to the new position and be certain it is rigidly clamped.

Deburr, clean and reassemble.   It will function as good as new if you proceed with care.

by: Restorer


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## iron man (Aug 11, 2014)

I dont think repairing a tooth is a big deal you could file it by hand and come in close enough to work,, the problem I see is that it is not cast iron but made out of Zamack and all though I have welded this stuff I would not recommend it. It take time and alot of experiance, if it was any other material than that it would be a walk in the park.. Ray


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## Mike R (Aug 11, 2014)

Hey thanks everyone for the reply's.  That gives me something to think about in the time being as I try to find time to work on it.  I also have an Atlas MF Horizontal Mill that I've had for about 6-7 years and now I'm starting to tinker with it.  Then on Saturday I bought a Metal Shaper but I don't have a clue as to the maker. It has two tags with a few numbers on it but haven't tried to clean them enough to read them.  No name tags on it anywhere.  It is old and it runs, I oiled all the shafts, ways to get it moving ,it does a nice job. On the automatic feed gear there is a spot where some of the teeth have been striped because it advances the table for about 3/4 of a revolution of the gear then quit's until you turn the gear with the lever about an inch so it get hold of good teeth.   I've never used a shaper until Sat .  I got a chunk of aluminum and started playing.  I've got pictures of the machines and I'm going to try to upload them, that's new to me too . Again, thanks.  Mike


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