9A Power Feed Issues
First issue with my 9A………
No matter where the gear selector is placed on my apron with the half nut lever positioned “up” (engaged) the saddle will not move while the lead screw is turning.
Also the longitudinal or cross-feed apparatuses don’t move either. (no matter where the gear selector is positioned)
In other words nothing is engaging on my power feed apron.
The little star wheel just spins & spins when you turn it, and I can hear a clicking sound if I push or pull on the knob while I turn it.
All of the gearing is in place and the little star knob does move in conjunction with the large wheel crank with the gear selector in the up position, but that’s all I’m getting.
There aren’t any pieces missing as far as I can see and the lead screw threads are in very good condition with very little wear.
I tried to see if I could see how good the threads on the half nuts are but with everything still together it’s hard to see them.
I took a paper clip – straightened it out leaving a hook at the end, and dragged it along the inside of the half nuts and I could definitely “feel” threads.
I’m not sure if my problem is that the threads on the half nuts are worn to the point that they’re not engaging or if the clutch has something to do with it.
I attached a front picture of the apron so you can see what type it is and I tried to take some pics of the half nut while open to get a better idea of it.
Thoughts? and thank you…….
the clutch has nothing to do with the half nuts. and you should not be able to engage the half nuts in any position but nuetral on the apron selector(middle position)
something is seriously wrong if you can move the selector lever while the half-nuts are engaged - the interlock should prevent it.
you need to get in the apron and see what is going on. sounds like the interlock is missing or the scroll for the half nut is damaged or both.or something??
do the half nuts actually clamp down on the leascrew when you lift the lever?
if memory serves me the halfnuts should not be engaged on a powerfeed model.Put the selector in the proper position for power traverse or crossfeed and tighten the star wheel and it should feed without the halfnut lever engaged.You would only use the half nuts on non-power feed models.I have 3 of the power feed models but i use the pf very little and couldnt tell you the selector position for either.If noone chimes in i'll check on mine...matt
is it possible that the carriage saddle and apron) is not properly seated? When you screw it in (such as when dissassembling for cleaning), the gears have to mesh properly and connect with the ways longitudinal fix gear that runs the length of the bed underneath.
Also, when the selector is in the middle position, the clutch wheel should be loosened before operation, according to my notes. The clutch wheel is only tightened when the selector is in the top or bottom portion of auto feeds
Let me clarify:
I can’t freely mover the selector handle form hole to hole if the half-nut lever is pulled up.
The half nut lever has to be down in order for me to move the selector handle from hole to hole so the interlock is fine.
The picture I took of the apron hid the upper half nut. (It’s there) I attached a better picture with a different angle so you can see it.
The problem is” when the selector level is in the middle position – with the half nut lever pulled up (which should engage it) the carriage doesn’t automatically move with the lead screw turning the way it’s supposed to.
I also thought that maybe she was just off but she won’t move no matter where along the lead screw you try to engage the automatic feature that would allow you to cut threads.
I firmly believe the clutch is shot because as I stated in the original post – all it does is spin & spin without ever tightening, and I’m sure at some point it should tighten. Whether the clutch works in conjunction with the half nut feature or not, I believe it needs attention.
Guess I’m going to have to rip into it to see what’s missing (if anything) and what’s needed.
I concur with all the previous posts.
Have you ever had the carriage and apron off for cleaning and inspection? If not, then probably worth while to do that. I pulled mine on Tuesday afternoon. It took about three hours to disassemble, clean, flush, inspect and reassemble. Wasn't hard. Took my time. Runs like a champ now. (Note, my apron did not require full disassembly -- only clean and flush, and pulling the back of the clutch cover to get ALL THE GUNK OUT).
Its hard to assess the apron when it is on the machine -- all the working parts are on the back side. A light and inspection mirror don't do it justice.
Has the clutch been drained and flushed? My 9A clutch wasn't worth a damn when I got it until I flushed it with mineral spirits -- it took about 10 flushes and running it for a few minutes for each flush to get the accumulated crud out. Pull the drain plug and fill to see what you've got.
Has the cross feed screw been pulled and inspected?
Have you spun the gear-box input gear by hand and watched the drive mechanism to track down where the problem was?
Regarding the clutch -i had the same problem with it free spinning. If its like mine turning the star knob too much when loosening results in the clutch plate in the re#r of the apron disengaging from a slot (or slots) in the clutch housing. When you try to tighten the star knob the clutch plate hits the housing and never contacts the clutch plates and therefore the clutch doesn't engage.
Here's the bad news - at least on my lathe - to get at that clutch adjustment you need to pull the apron which required that the headstock be pulled to access the phantom gearbox screw, the gear box and power feed need to be removed from the apron and finally the apron can be removed by taking out the cross slide screws. Once the apron is off you need to drain the oil and remove the oil gasket/guard plate. Finally you are at the clutch. I never could find an easier way.
I actually need to do all of that BuzzyB.
I just hooked up the belt & motor and actually ran it for the first time just now (yes I was hand turning the chuck when I discovered the power feed not working properly).
She runs like a beast and everything is super tight, overall I’m very happy with this lathe - but sure enough the power feed issues are still there even under power.
I did notice that with the selector handle in the middle (neutral) position, the little star wheel “vaguely turns” while she’s running confirming my suspicions that the clutch is either very worn or like you say very clogged.
I’m going to do everything you suggest and see what happens after that.
Honestly the power feed feature is great for turning threads and such but I’m just getting back into this after a long hiatus so for now I’ll be happy just re-familiarizing myself with the lathe.
I’ll concentrate on fixing anything that needs to be fixed as I go.
Thanks a lot for the great suggestions…………..
What type of lathe do you have Rick???
Speedy - i-ve got a SB heavy 9 1939 vintage. It is very similar to a heavy 10. The apron looks identical to what you have.
To repeat what was hinted at in post #2, the power feed feature (and the star shaped clutch knob) has nothing whatever to do with cutting threads.
Honestly the power feed feature is great for turning threads and such
Rick: I hope I don't have to go through as much disassembling my apron, but thanks for the heads up.
Johnoder: I understand, acknowledge and agree with you - but there's something definitely funky going on with the clutch so when I rip it all apart (and it looks like I'm going to have to) I might as well inspect it while it's apart to see why it won't tighten.
At this point, you have mentioned the long feed and the threading not working. Those two things are nearly independent inside the apron, other than the interlock. Can you engage the half nuts with the lathe off, while slowly moving the carriage left/right with the handwheel? It is possible you are not closing the halfnuts all the way, and riding on the top of the threads. Once engaged, the carriage should be nearly immobile, except for the play in the halfnuts and the leadscrew mountings.
Allen - just for my education (which is severely in need of help :-) ) are you saying the clutch mechanism is different fromSpeedy64's? Just curious how they may be different
Star Clutch wheel
I didn't read all the posts word for word, but the screw on the star clutch hand knob is LEFT HAND Threads.... I just repaired the problem on a lathe i purchased and someone broke off the screw, tried drilling, broke a drill and ezout in the clutch shaft. WOW what a screw up!
I got all the broke stuff out, but ended up and had to make the threads larger... 1/4 x 28 LH and I had to make a special screw...
The apron isn't very complicated when it's all said and done.... Buy the little book on how to repair a SB 9.... Lots of photos...
Let me know if you need a part or two..
That’s exactly how I came to the conclusion that I did my friend, very astute of you.
I was hand turning the chuck watching the lead screw turn (slowly) noticing that with all the proper levers and gear selectors set for the saddle to move via the lead screw……….. (she wasn’t moving)
Then I tried every other possible combination to see if anything would move while hand turning the chuck………….nothing.
I spun the little star handles clutch until my wrist hurt………never got tight……..nothing.
After I hooked the power up and actually ran the lathe under power……..still nothing, except for that the little star handle wheel now was moving slowy while the lead screw was spinning at like Mach IV.
I attached a video of her in action, I hope it works and you can see it.
As you can all see, the apron isn't moving after engaging the half nuts with the lever selector in the middle position.
Ajclay: thanks for the advice and I'll definitely contact you if any of the internals are broken, thanks.....
ah, the video helps. When the lever is pushed down, the carriage should definitely have stopped but it seems to have kept moving. Is that correct diagnosis of problem?
Actually she's not moving at all.........
I know it's hard to tell in the video, but the exact problem is that she doesn't move no matter what position the selector lever is in or where the half nut lever is positioned.
Take a closer look at the video and pay attention to the bed ways in relation to the apron while she's spinning and you'll see she's not moving at all.
The handwheel would be spinning if the threading was working. Apron's gotta come off, but you knew that