- Joined
- Dec 5, 2017
- Messages
- 464
I acquired an ancient Seneca Falls Star 30 Lathe. There's a separate thread on that story.
One of the first problems that came up was that the compound angle adjust wouldn't lock. After asking around and fussing with it some, I discovered that the original locking set screw had broken in the hole. I extracted the remnants, chased the threads with a bottoming tap, dropped a new screw in and got it to lock.
I thought.
I came into some windfall money and used it to buy a new Shars AXA QCTP. After machining the nut to fit the slot on my compound, I installed it and as I was tightening the nut on the QCTP, the compound moved. Tightened the set screw until I was worried about ripping the threads out of the casting and it STILL moved. What the...???
Got to looking at it a little more closely and figured out that what I thought was the post it rotates on was actually MORE of the original set screw! Fiddled around trying to fish it out of there with a pick and did get it to turn a little but couldn't fish it out.
So, I reasoned that the rotating part HAD to come off so I started a little tapping and gentle persuasion and got it to move a little and thus encouraged, used some wedges to pop it off the post. Oh, look! The set screw doesn't bear on the post, it bears on a wedge and the post is actually a dovetail...Neat! Ground down a nail for a punch, punched the retaining pin out of the wedge, removed the wedge and was able to remove the remnants of the original set screw and chase the full depths of the threads.
And here is where the tactical error comes in. While reassembling, I used a Q-tip and applied some way oil to ALL the surfaces including the face of the wedge and the dovetail on the post.
Reassembled, turns smoothly seems to lock good.
Yeah...except that when using a boring bar on an interrupted cut (keyway...) there's enough vibration that the compound won't hold zero no matter how much I tighten the set screw. In retrospect, I'm guessing it's the lube on the dovetail. So, next shop day, it's take it all apart again and clean the lube off the wedge and dovetail.
Sigh...
One of the first problems that came up was that the compound angle adjust wouldn't lock. After asking around and fussing with it some, I discovered that the original locking set screw had broken in the hole. I extracted the remnants, chased the threads with a bottoming tap, dropped a new screw in and got it to lock.
I thought.
I came into some windfall money and used it to buy a new Shars AXA QCTP. After machining the nut to fit the slot on my compound, I installed it and as I was tightening the nut on the QCTP, the compound moved. Tightened the set screw until I was worried about ripping the threads out of the casting and it STILL moved. What the...???
Got to looking at it a little more closely and figured out that what I thought was the post it rotates on was actually MORE of the original set screw! Fiddled around trying to fish it out of there with a pick and did get it to turn a little but couldn't fish it out.
So, I reasoned that the rotating part HAD to come off so I started a little tapping and gentle persuasion and got it to move a little and thus encouraged, used some wedges to pop it off the post. Oh, look! The set screw doesn't bear on the post, it bears on a wedge and the post is actually a dovetail...Neat! Ground down a nail for a punch, punched the retaining pin out of the wedge, removed the wedge and was able to remove the remnants of the original set screw and chase the full depths of the threads.
And here is where the tactical error comes in. While reassembling, I used a Q-tip and applied some way oil to ALL the surfaces including the face of the wedge and the dovetail on the post.
Reassembled, turns smoothly seems to lock good.
Yeah...except that when using a boring bar on an interrupted cut (keyway...) there's enough vibration that the compound won't hold zero no matter how much I tighten the set screw. In retrospect, I'm guessing it's the lube on the dovetail. So, next shop day, it's take it all apart again and clean the lube off the wedge and dovetail.
Sigh...