Repairing my first screw up, suggestions for 48 MW/Logan 10 inch

J

John TV

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OK, the back story. I am a complete nubie, but usually quite handy with other tools in other areas. On the Logan lathe I recently got home and am starting to set up, I noticed that the set screw holding the cross feed graduated collar was not going to come loose easily. This lathe has been sitting for more 30 years, unused, but in very good shape considering. I did the normal things, days of soaking in different loosening agents, heat and cool cycles making sure not to get it too hot, mild taping to try to break bond. Nothing was working. I also though that it must be a very short set screw since it was so deep in the collar. ( this part is a hint )

Fast forward to me getting impatient and starting to drill out the set screw with left hand drill bits, occasionally measuring depth so I would not go to far. Drilled and then tried to get collar to move, nothing. Drilled deeper, nothing. Now, I am below the level of the shaft but still cant get it to move. Went deeper still and then it finally started to move and I got the collar off. I completely drilled through the shaft and slightly into the other side of the collar.

Now for the mystery. In examining the shaft, I noticed that part of the "hole" I had drilled had threads in it. My father in law was a master machinist and was second generation in owing a full machine shop. To say that he was skilled is an understatement. This was a small hobby lathe that he had in his retirement. It is my assumption that he drilled out then tapped a deeper hole into the shaft and collar to "Lock" the collar in place. Can any of you tell me why he might have done this? If he did it, he did it for a reason,. I just am puzzled.

Now for your suggestions. I have a hole in a shaft that is not small, but the shaft is not needing too much strength. What are your suggestions, again knowing my very new skill levels? I could re-drill shaft hole and fill with plug or threads and then machine to original measurement, or should I use something like devcon or jb weld and fill the area and machine that down. Open to other thoughts too.

As mentioned in an early thread, I have quite a bit of backlash and at some point it will be likely that I have to replace this shaft anyway but following many of your suggestions, I was hoping to get a few chips under my belt first before spending the money to buy new parts.
Thanks for your thoughts.
 
If you drilled almost completely through then look at inserting a roll pin.

These are rolled steel and spring hardened and used for locking things together.

This is simple and cheap.

Next up on difficulty is selecting a taper pin that fits and this requires a taper reamer but it will lock the parts tight and come out via tapping.

Both of these are not adjustable meaning cooler will not move.

If you need to adjust the collar on the shaft fill the shaft with epoxy mixed with steel filings and reshape to fill the hole.

Drill other hole in collar and tap to next size setscrew.

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Where to start , you could weld the hole up , tap and plug with loctite on threads, jbweld should work or make a new one . If he was an old machinist , I bet he didn't use them. I don't use them or trust them , I set up indicators to keep things correct , stops, feeds , depths. I learned forty plus years ago they slip there not readable , some are direct some are double . With reading the indicators sizes are right , stops are right you get the picture. If you screw up a part by the backlash not adjusted for its all in your hands wrong start over . I learned that from from an old Scotsman who was a great machinist and friend. He'd say use the dials ,,,nooo wayy in his Scottish brough.
 
tq60 said:
If you drilled almost completely through then look at inserting a roll pin.

These are rolled steel and spring hardened and used for locking things together.

This is simple and cheap.

Next up on difficulty is selecting a taper pin that fits and this requires a taper reamer but it will lock the parts tight and come out via tapping.

Both of these are not adjustable meaning cooler will not move.

If you need to adjust the collar on the shaft fill the shaft with epoxy mixed with steel filings and reshape to fill the hole.

Drill other hole in collar and tap to next size setscrew.

Sent from my SAMSUNG-SGH-I337Z using Tapatalk
Click to expand...

Thanks for the ideas, most appreciated.


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Silverbullet said:
Where to start , you could weld the hole up , tap and plug with loctite on threads, jbweld should work or make a new one . If he was an old machinist , I bet he didn't use them. I don't use them or trust them , I set up indicators to keep things correct , stops, feeds , depths. I learned forty plus years ago they slip there not readable , some are direct some are double . With reading the indicators sizes are right , stops are right you get the picture. If you screw up a part by the backlash not adjusted for its all in your hands wrong start over . I learned that from from an old Scotsman who was a great machinist and friend. He'd say use the dials ,,,nooo wayy in his Scottish brough.
Click to expand...

Great thoughts and good advice. I bet you are right about my father in law not using the collar. I so wish I had been a brighter young man and gleaned from him a bit of his knowledge and wisdom...nope, thick headed young woodworker at the time. Now that I'm older, just want to reach back and thump my younger self for loosing that chance to learn from a master.

I am looking forward to learning more and your thoughts on not trusting the collars makes great sense to me.


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If you don't plan on using the collar, just put it back together: you don't need to do anything. When you get your refund at tax time, give Logan a call. :)
 
First, I disagree with not using the dials. But if you don't want to use them, that's your prerogative.

If the 1948 Wards branded machine is a Logan 800 Series, as it appears to be from looking in the respective catalogs, you really do not want to permanently lock the collar to the cross feed screw. If you do, you lose the ability to adjust the end float of the screw. And if you make it really permanent, the only way that you could remove the screw from the cross slide would be with a hack saw. What I would do is to tap the hole through the screw. Get a piece of steel threaded rod and stud lock it in place with a little bit sticking out of both sides. After the Stud Lock cures, turn the ends of the rod down flush with the cross feed screw. And pretend that it never happened. :)
 
wa5cab said:
First, I disagree with not using the dials. But if you don't want to use them, that's your prerogative.

If the 1948 Wards branded machine is a Logan 800 Series, as it appears to be from looking in the respective catalogs, you really do not want to permanently lock the collar to the cross feed screw. If you do, you lose the ability to adjust the end float of the screw. And if you make it really permanent, the only way that you could remove the screw from the cross slide would be with a hack saw. What I would do is to tap the hole through the screw. Get a piece of steel threaded rod and stud lock it in place with a little bit sticking out of both sides. After the Stud Lock cures, turn the ends of the rod down flush with the cross feed screw. And pretend that it never happened. :)
Click to expand...

I am sooo good at pretending. This does sound like a more permanent fix and I think I will take a better look at the threads and nit and if they seem like they might last awhile, I very well may follow your advice.

For today, just happy I was able to get the old leveling feet out of the base. Not much corrosion on the remainder of the lathe or base, but those 4 bolts were toast.

Thanks for the thought.


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John:

As many others have noted, thru tapping the shaft hole should fill it fine. A slightly long setscrew and going easy with a file should work OK, since the area is covered by the dial. If you're concerned about taking too much material out of the shaft for the next larger thread, you can also try filling the hole with the next closest metric thread size.

As to the dial - if yours is buggered up badly, I believe I have a spare that will work. It has a few dings, but the setscrew threads are OK. It can hold you over until you find a clean one.

TomKro
 
I just wanted to thank all of you for your great advice. I accidentally posted how this came out in another thread ( see: Finally got my Logan / MW 2136 home). I will learn the protocol soon, I hope


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