[Newbie] Half Nut

G

gunshot

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Jun 17, 2016
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Hello to everyone, and TKS for letting me join the forum. I have a logan mod. 6520H that I need new half nuts for, or is there a way to recut the threads, I have searched the web and cannot find this lathe listed anywhere, the closet I can find is a 6550 TKS in advance for any help.
 
Make a new set of half nuts! OF course you can only do this if you have a another lathe available and a mill. If there is enough cast iron left on the casting, you have two choices of what you can do. One, is to make a bronze nut to bolt into the half nut halves. I guess you could build up with bronze welding rod, machine new thread afterwards. Second is get some Moglice putty and form a new set of threads using the existing lead screw as a pattern.
Last thing you can do is get ahold of Logan Actuator Co, and visit with Scott Logan about a new set of half nuts. Don't be shocked at the price for new half nuts!
 
4gsr said:
Make a new set of half nuts! OF course you can only do this if you have a another lathe available and a mill. If there is enough cast iron left on the casting, you have two choices of what you can do. One, is to make a bronze nut to bolt into the half nut halves. I guess you could build up with bronze welding rod, machine new thread afterwards. Second is get some Moglice putty and form a new set of threads using the existing lead screw as a pattern.
Last thing you can do is get ahold of Logan Actuator Co, and visit with Scott Logan about a new set of half nuts. Don't be shocked at the price for new half nuts!
Click to expand...
Thanks for the replies, I found a set on ebay and ordered them, but I needed my lathe running asap so I made a cutter to chase the threads and recut them in my mill this worked great look like new.
 
" I made a cutter to chase the threads and recut them in my mill this worked great look like new."

Can you give more detail on how you did this procedure.
 
gwarner said:
" I made a cutter to chase the threads and recut them in my mill this worked great look like new."

Can you give more detail on how you did this procedure.
Click to expand...
first measure the shaft and the width and depth of a unworn tread, grind a 1/4 inch square tool steel bit to the length of the diameter of the shaft, on one end sharpen to the width and depth of the thread, I used a 8 inch boring bar with a 90 degree square whole, if you have a mill install in mill, now the fun how to hold the half nut one side at a time so you can see where the old thread bottom is at once you get the half nut in the mill you will have to rotate the nut so the threads are square with the mill table then bring the cutter down and align it with the old thread bottom, go very slow with it the into the nut cut one move down to the next I took the belt off my mill and turned it by hand. hope this helps but feel free to call me at 4072523857
 
Thanks for the explanation.
I think I understand what you did now. I was trying to envision how you cut threads on a mill with out a synchronized feed screw.
You basically deepened the existing groves that already existed. As you point out, holding and aligning the part would be critical.
Also spinning the cutter by hand would give the control you would want to have on this operation.
 
gwarner said:
Thanks for the explanation.
I think I understand what you did now. I was trying to envision how you cut threads on a mill with out a synchronized feed screw.
You basically deepened the existing groves that already existed. As you point out, holding and aligning the part would be critical.
Also spinning the cutter by hand would give the control you would want to have on this operation.
Click to expand...

The thread lead angle would be off however.
 
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