DIY Traverse Gearbox 10F-11

bhusted

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Like every 10-12" Atlas/Craftsman lathe, the gearbox on mine was broken in 4 different pieces when I got it. To get it up an going I tried "brazing" it back together using MuggyWeld. This worked for a while, but several of the places broke again and I knew it was time for something different. I had seen on eBay and other places that people sold replacements from aluminum for $$$. I wanted to see if I could make one for myself, but decided to use steel. Probably overkill, but in the words of Tom Lipton "nothing overbuilt ever broke."

Here's where I'm starting. You can see where I repaired and re-repaired the original part.


I came across a thread on another forum where someone had posted a drawing of the part, which would make my life much easier. I also liked that this design incorporated the use of bronze bushings for the gear shaft. For material, I got a 1.5" thick section of 1144 steel 3.75" in diameter. It was very inexpensive and a wonderful material to work with. Yes it would have been easier to start with a rectangular block, but this was much cheaper.


After facing it off and doing some layout, I got to work. It's fun using the machine to fix itself.






Fortunately before I started the large radius on the side, I realized that I had laid out the mirror image. It was a quick fix to swap that around and come up with this sketchy setup. No drama, but I didn't run it above 80RPM so it took a while. No pictures of the machining because I was too focused on not screwing up.

 

bhusted

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From here, I used a hacksaw to cut as close to my layout lines as I dared. The faces were then machined with the milling attachment on the lathe. This was about as big of a part as I could fit, but it worked.





Making the cross hole for the leadscrew was probably the most difficult part. The jaws on my chuck were not tall enough to grip it flipped 180 degrees, so I had to improvise. I drilled it to 1/2" with the milling attachment and then bored to 7/8" in the chuck.



The radii on the corners were rounded over on the belt grinder and finished with a file. While the original mounting holes are slots with square nuts, I chose to simply drill and tap the holes. To get things lined up just right I clamped it to apron on the lathe and transferred the hole centers.





I did spring for replacement gears and shaft from eBay. I do want to try milling gears at some point, but not ready for that yet. There was a mismatch between the print that I referenced and the length of the gear shaft (the shaft was longer), so I made a washer to take up the difference between the bushing and the gearbox on the top. I also had some trouble with the locations of the mounting holes from the print. I have not gone back to inspect my part vs the print, but I'm glad I chose to align the part on the machine itself. If you choose to make one of these, be warned that you may have a similar issue. In the end, I couldn't be happier with the result. The carriage moves smoothly and the play in the traverse wheel is almost gone.

The next project is to repair the power cross feed...
 

bill70j

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Probably overkill, but in the words of Tom Lipton "nothing overbuilt ever broke."
bhusted:
Nice.

I think you will be extra happy with the overkill, especially if you do any broaching on your Atlas.

I now have drawings of the gear case in Fusion 360. PM me if you would like a copy for reference.

Good luck!
Regards, Bill
 

bhusted

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I now have drawings of the gear case in Fusion 360. PM me if you would like a copy for reference.
I'd like to see your drawings if you don't mind. I made a model of the part in Fusion as well to help me wrap my head around the order of operations.
 

bill70j

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I'd like to see your drawings if you don't mind. I made a model of the part in Fusion as well to help me wrap my head around the order of operations.
Happy to post the drawings.

First, I need to make one addition to the drawings. That is to add the slot to the back of the case that provides clearance for one of the saddle bearing plate (10F-54) retention screws.

I see that you have included that slot in your build. If you could provide the location and dimensions for that slot, I can finish the drawings without disassembling my saddle and taking measurements.

Thanks
 

coffmajt

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Good looking work = I know it will be reliable for you now --
 

bhusted

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Happy to post the drawings.

First, I need to make one addition to the drawings. That is to add the slot to the back of the case that provides clearance for one of the saddle bearing plate (10F-54) retention screws.

I see that you have included that slot in your build. If you could provide the location and dimensions for that slot, I can finish the drawings without disassembling my saddle and taking measurements.

Thanks
Are you referring to the step at the top? If so, it is 1/8" deep and 1/2" from the mounting face of the apron.
 

Aukai

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I like how you operate :encourage:
 

Dranreb

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That's a very nice job you've done there, you can be proud of that!

I made mine in ally a few years ago all on the lathe, slow work but well worth the effort.
 

bhusted

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That's a very nice job you've done there, you can be proud of that!

I made mine in ally a few years ago all on the lathe, slow work but well worth the effort.
Thanks! I'm really happy with the result and I always like the idea that I can use a machine to repair itself. Granted not everyone has a milling attachment for their lathe, but without a mill I was still able to make a new gearbox that will probably outlast the rest of the machine.
 
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