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Turret tail stock in a model 820 Logan 10 inch lathe
- Thread starter Richard White (richardsrelics)
- Start date
- Joined
- Dec 3, 2015
- Messages
- 243
The picture in the tread where I started the restoration shows the sad state this lathe was in when I found it. I did not even try to start it as I wanted to be sure everything was up to snuff. On the turret, I have noticed when I approach the stock with a 3/4 inch, or any other drill for that matter, the drill contacts the work and then "shifts towards me, the operator. This seems to me to imply that the bore on the turret is not in line with the bore of the lathe spindle. The turret functions wonderfully, except for my perceived issue.
Setting up the turret stuff is an art. But as I understand it, you set up the turret as best you expect it to behave, then run a part and see how it turns out. Check against specs, and adjust the turret tooling to get within specs.
It's pretty hard to expect a turret to deliver really good precision, at least not without some adjusting. I don't know the tricks of making the adjustments. But in a production setting, the old timers have talked about a set up guy coming in and setting up the turret tools overnight so when the production guys came in the next day all they had to do was load the work and pull levers for that run. What tricks the set up guys used, I don't know. I suspect many are not in the manual.
It's pretty hard to expect a turret to deliver really good precision, at least not without some adjusting. I don't know the tricks of making the adjustments. But in a production setting, the old timers have talked about a set up guy coming in and setting up the turret tools overnight so when the production guys came in the next day all they had to do was load the work and pull levers for that run. What tricks the set up guys used, I don't know. I suspect many are not in the manual.
- Joined
- Dec 3, 2015
- Messages
- 243
dlane,
I sharpen my drills to center-cut on a multi-thousand dollar Black-Diamond drill sharpener. Having said that, what is happening is, the drill doe not contact the center of the stock. I face the round stock, which as you know leaves the center visible, and when I bring the drill in, it does not make contact with the center of the part. It is off by about .06 or so...
Not a lot, but enough to just bug me. As I finish boring the parts out anyway, if it is actually off it does not matter, but for just bugging me.
Now looking at the parts drawing I have a set screw and lock nut on mine that doe not show up on that drawing, I will post photos later to show all this, but it is still morning coffee time..
And eeler1, not looking for precision, but it should be a bit closer in my opinion.....
Regards
Richard
I sharpen my drills to center-cut on a multi-thousand dollar Black-Diamond drill sharpener. Having said that, what is happening is, the drill doe not contact the center of the stock. I face the round stock, which as you know leaves the center visible, and when I bring the drill in, it does not make contact with the center of the part. It is off by about .06 or so...
Not a lot, but enough to just bug me. As I finish boring the parts out anyway, if it is actually off it does not matter, but for just bugging me.
Now looking at the parts drawing I have a set screw and lock nut on mine that doe not show up on that drawing, I will post photos later to show all this, but it is still morning coffee time..
And eeler1, not looking for precision, but it should be a bit closer in my opinion.....
Regards
Richard
- Joined
- May 4, 2015
- Messages
- 3,583
Which way is it out . Up down or side to side? If up you may need to take metal off the turrets bottom or down shim it up . Side ways the ratchet stop can be welded up if it's past center or remove some if before center. I would think there should be a fine adjustments set screw to the stop I'd see if there's away to install one.
- Joined
- Dec 3, 2015
- Messages
- 243
Side to side... I am going to tear it apart soon and see what is in there......
- Joined
- Dec 25, 2011
- Messages
- 10,511
Actually, that is what's called a bed turret. A tailstock turret looks like a tailstock with one of those turrets on an MT arbor permanently installed, only beefier.
Back when Atlas used to sell tailstock and bed turrets, by default they came in with the tool holder holes all drilled undersize, usually for 3/4" tooling. And with instructions of how to mount a boring bar in the spindle to finish cut them both to size and in proper alignment with the spindle. If the turret assembly originally came with the lathe, that would have been done at the factory. As yours is apparently off front to back, the turret is probably not original to that machine. However, whether the front to back offset is adjustable or not, I do not know. On the tailstock turrets, it generally is by the same method as it is on a normal tailstock. But I don't know about bed turrets as I've never had one.
However, once you get done with anything else that you plan to do to the lathe, your first step with the turret should be to confirm that the indexer and the fore and aft movement lever or handwheel works properly and is properly lubricated. Next step is to check the alignment. If you have a centering type indicator, that works best. Otherwise you will need a mirror to read the indicator through part of the rotation.
Lock the turret to the bed. Set the feeler for the hole, run it in 1/8" to 1/4" and check how far and in which direction the center of the hole is off. Then run the indicator feeler in to near the bottom of the hole and repeat. Note where the high spot is in each position.
If the error is the same front and back, the indexer is probably working OK but the turret is not matched to your lathe. If the front to back position is adjustable, adjust it.
If the error is different front to back, the indexer is off. If it is adjustable, adjust it. Then repeat the test to determine the direction of any front to back error.
Back when Atlas used to sell tailstock and bed turrets, by default they came in with the tool holder holes all drilled undersize, usually for 3/4" tooling. And with instructions of how to mount a boring bar in the spindle to finish cut them both to size and in proper alignment with the spindle. If the turret assembly originally came with the lathe, that would have been done at the factory. As yours is apparently off front to back, the turret is probably not original to that machine. However, whether the front to back offset is adjustable or not, I do not know. On the tailstock turrets, it generally is by the same method as it is on a normal tailstock. But I don't know about bed turrets as I've never had one.
However, once you get done with anything else that you plan to do to the lathe, your first step with the turret should be to confirm that the indexer and the fore and aft movement lever or handwheel works properly and is properly lubricated. Next step is to check the alignment. If you have a centering type indicator, that works best. Otherwise you will need a mirror to read the indicator through part of the rotation.
Lock the turret to the bed. Set the feeler for the hole, run it in 1/8" to 1/4" and check how far and in which direction the center of the hole is off. Then run the indicator feeler in to near the bottom of the hole and repeat. Note where the high spot is in each position.
If the error is the same front and back, the indexer is probably working OK but the turret is not matched to your lathe. If the front to back position is adjustable, adjust it.
If the error is different front to back, the indexer is off. If it is adjustable, adjust it. Then repeat the test to determine the direction of any front to back error.