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Logan 820 direct drive?

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tmenyc

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I'm teaching myself how to use the 820, my first lathe and foray into machining, all to significantly up my skills in fountain pen restoration. So I'm learning as I go, and it's a wonderful puzzle, I must say.
In the absence of Logan 820 For Dummies, I've done pretty well with the South Bend book and the 820 operators manual, and almost continuous reading of this forum, much DM help from Mikey, and watching tubalcain and other recommended YouTube videos.

At this point, I have this question I can't answer: I think I've been running on back gear rather than direct drive. I think I've been using the back gear knob as a spindle release. But I can't seem to find how to engage direct drive. I'm looking for the "lock pin located in the side of the bull gear." (Logan manual) Is the lock pin what is shown in the closeup shot? And from mid-distance. It swivels but does not pull out. Is it possible that the flat belt falls off the 4 position of the countershaft because I'm in back gear? It works fine in 1 and 3.

Many thanks in advance. I promise other questions are brewing.

Tim
20190115_175835.jpg20190115_175839.jpg20190115_180118.jpg
 
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Nogoingback

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To engage, or disengage back gear there are two steps that need to be accomplished.

1. To operate in direct drive, the pin on the bull gear is "in", or engaged with the the pulleys. In this position the pulleys, bull gear and
chuck all turn as a unit, together. To the left of the "Logan" ID plate there is a knob. In direct drive that knob must be in, as shown below.

IMG_0304.jpg

2. To operate in back gear, the pin on the bull gear must be out, which disengages the bull gear from the pulleys. The knob on the
headstock also must be out and latched as shown below. The latch is a small metal piece in a slot in the bottom of the rod, which
cannot be seen from above. If you have difficulty pulling the rod out to the engage position it's usually because the gears aren't
meshing. Just rotate the pulley a bit and try again until they do. If the rod pulls out all the way but doesn't latch, it's probably
because the latch is broken or missing. Parts are available from Logan. While in back gear, power flows from the headstock
pulley through the gear to it's left to a gear on the countershaft, which rotates another gear that engages the bull gear and rotates
the chuck.

IMG_0302.jpg

I'm not familiar with the lever style pin on your bull gear. This is what mine looks like. It doesn't matter,
as long as it engages or disengages the bull gear from the pulleys properly.


IMG_0303.jpg

The important thing to remember is that when changing in or out of back gear, BOTH steps must be accomplished.

As for your belt slipping, you might need to adjust the countershaft alignment a bit. It looks as though you have the adjustable
countershaft supports:

IMG_0305.jpg

Notice that they have a screw and locknut arrangement. By adjusting these a bit so that the shaft is angled in or out some, you should
be able to keep the belt on the pulleys properly. It's a trial and error sort of process.

EDIT: One more thing I didn't mention above. As I said, when returning the lathe to direct drive from back gear, the rod on the headstock must
be pushed back in. To release the rod, the latch on the bottom of the rod must be pressed upwards with your finger. It then can
be pushed in easily. Just pushing the rod in won't do it.
 
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tmenyc

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Thanks, appreciated. The knob and latch work fine. The issue is the bull gear pin. I didn't know what to do with it; wonder if it's stuck in. I'll work at it tonight. Also the countershaft supports. Will let you know!

Tim
 

Briney Eye

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Your locking pin looks homemade. If the bull gear turns with the cone pulley you're in direct drive, and that pin needs to be pulled out to shift into back gear. If the pin has the gear and pulley locked together then putting it in back gear will lock everything up solid. Someone will probably flame me for saying this, but I find it useful for loosening the chuck (as long as the chuck isn't stuck and you don't crank on it hard enough to break a tooth off the bull gear, which people have done). Of course you subsequently have to remember to take it out of back gear, or the belt will squeal/the motor will stall (ask me how I know ;).

You need a long straightedge to check the the side-to-side alignment and squareness of the countershaft pulley. As has already been pointed out, that model countershaft bracket has pairs of finicky adjusting bolts on each side. I set mine so that the bearings were generally centered in the yoke and tweaked until the belt was square to the pulleys. Don't torque down on them too hard or you can distort the bearing and cause the shaft to bind. There is a set screw in the small end of the countershaft pulley that you loosen for the side-to-side adjustment if the shaft isn't buggered up too badly. I had to disassemble mine and file the divots out of the shaft.

The countershaft bracket should pivot freely front to back when the lid is open. Mine was pretty stiff when I got it because the drive box holes for the one-piece bracket shaft weren't aligned, so I made two short pivot pins retained with E-clips. Logan later went to two pivot pins when they got rid of the fiddly adjusting bolts on the countershaft bearings.

Best of luck.
 

tmenyc

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Briney, thanks, this is really specific and helpful. If I didn't have this day job on the other end of Manhattan from my shop I'd go check this out right now. Tonight!
Tim
 

Nogoingback

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So, does your bull gear pin do anything? Can you pull it out and push it back in? Does it rotate? Or does it just not move?
 

tmenyc

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Since I didn't know which direction it was meant to go, I didn't push or pull hard, but it has not yet come out. The little pin is hinged, now I know to provide a grip, but I wasn't sure if there was more action to it than that. So I haven't given the pin a good tug yet. I suspect the same thing is happening with the clutch on the apron, but one thing at a time...
Tim
 

tmenyc

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Ok, back gear and direct gear work fine. The pin is actually a switch that is turned. Took me a bit to get it looser. Forward is "in", per the Logan Manual; back is "out. I can't actually tell the RPM difference until I receive the old-fashioned revolutions gauge next week.
Now, on to the belt adjustment! Sadly, there are plans afoot for tonight, so it may have to wait for tomorrow.

Thanks for the help!
Tim
 

CluelessNewB

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Your locking pin looks homemade.
Logan used two different style pins over the years. The earlier design (like Tim shows in the first picture) is part number LA-676 and was used on serial numbers 37063 and below. It is called "handle" in the parts manual. The mechanism is a bit more complicated. The newer simple style that Nogoingback shows was used on later models. It is part number LA-345 and is called "bull gear plunger".
 

tmenyc

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Rich,
That's reassuring. Did I get the explanation of how it works correctly?

Tim
 

CluelessNewB

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Rich,
That's reassuring. Did I get the explanation of how it works correctly?

Tim
Truthfully I don't remember which way the "switch" works but it should be easy to tell if the bull gear is engaged to the pulley which is what you want for direct drive. So my guess is yes you got it right. If I get a chance later today I will go out to my freezing shop and see which way mine works.
 

tmenyc

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You could always work in my overheated apartment!
 

CluelessNewB

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So on mine with the bull gear rotated so the "switch" is at the top, rotating the switch so the lever points toward the front of the lathe engages the bull gear for direct drive. Rotating the lever so it points toward the back of the lathe disengages the bull gear for use when in back gear.
 

Nogoingback

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Logan used two different style pins over the years. The earlier design (like Tim shows in the first picture) is part number LA-676 and was used on serial numbers 37063 and below. It is called "handle" in the parts manual. The mechanism is a bit more complicated. The newer simple style that Nogoingback shows was used on later models. It is part number LA-345 and is called "bull gear plunger".

Clueless, are you sure about than serial number? My lathe is s/n 22910 and it has LA-345. Both of the Headstock diagrams I have also
show that part as well. It seems like that change was pretty early.

Tim, what serial number is your lathe?
 

CluelessNewB

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Clueless, are you sure about than serial number?
I can only tell you what I see in the manuals.

This is what I see in the 800 series manual:

It shows the following:
  • "LA-27-1" Headstock with the "LA-676" style with note "To S/N 32777"
  • "LA-28" Bull Gear Assembly also withe the "LA-676" style with note "To S/N 37063"
  • "LA-27-2" Headstock with the "LA-676" style with note "From S/N 32777 To 37063"
  • "LA-27-3" Headstock with the "LA-345" style with note "From S/N 3703 To 62129"
  • "LA-27-4 Headstock with the "LA-345" style with note "From 62129"
The manual for the 200 series shows two headstocks, "LA-108-1" "To SER# 48577" and "LA-108-2" "From SER# 48577" both show the "LA-345" style.

Now you know what I know! :)

FYI my S/N is 32071 made 8/20/45
 
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tmenyc

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Clueless, are you sure about than serial number? My lathe is s/n 22910

Tim, what serial number is your lathe?
Must have been a month or two before yours, 22473.

Tim

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Nogoingback

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I can only tell you what I see in the manuals.

This is what I see in the 800 series manual:

It shows the following:
  • "LA-27-1" Headstock with the "LA-676" style with note "To S/N 32777"
  • "LA-28" Bull Gear Assembly also withe the "LA-676" style with note "To S/N 37063"
  • "LA-27-2" Headstock with the "LA-676" style with note "From S/N 32777 To 37063"
  • "LA-27-3" Headstock with the "LA-345" style with note "From S/N 3703 To 62129"
  • "LA-27-4 Headstock with the "LA-345" style with note "From 62129"
The manual for the 200 series shows two headstocks, "LA-108-1" "To SER# 48577" and "LA-108-2" "From SER# 48577" both show the "LA-345" style.

Now you know what I know! :)

FYI my S/N is 32071 made 8/20/45

OK, I get it now. I guess I assumed that they would use the same parts for the 820 and the 200 since they were built at the
same time. Mine's a 200, so I was going off the diagrams for them.
 

wa5cab

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So it would appear that the early Logan Series 800 Lathes had a radial pin that locked the cone pulley to the bull gear, and the later ones had an axial pin. I will add one thing that no one seems to have mentioned yet. Disengaging the direct drive pin (both types) required only rotating the spindle so that the lever that rotated the eccentric in the early types or the direct drive pin itself in the late type was accessible. But with either type, in order to re-engage either pin, you not only had to rotate the spindle so that the lever or pin was near 12:00 o'clock but you also had to rotate the cone pulley so that the hole in the pulley that the pin was to fit into was aligned with the pin. The early type was probably easier as you could see the hole in the pulley. One of the first things that I did on my Atlas (which has the axial pin) when I bought it in 1981 was to take a center-punch and mark the pulley over the hidden hole (actually on it, holes, as it has two).

Also, I noticed in the only Logan 800 Series manual that I've seen that in the Operator's section, it only mentions the axial pin. Which would be confusing to anyone who owned an earlier version.
 

tmenyc

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Really interesting. I'll check mine for that this weekend.
 

Nogoingback

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So it would appear that the early Logan Series 800 Lathes had a radial pin that locked the cone pulley to the bull gear, and the later ones had an axial pin. I will add one thing that no one seems to have mentioned yet. Disengaging the direct drive pin (both types) required only rotating the spindle so that the lever that rotated the eccentric in the early types or the direct drive pin itself in the late type was accessible. But with either type, in order to re-engage either pin, you not only had to rotate the spindle so that the lever or pin was near 12:00 o'clock but you also had to rotate the cone pulley so that the hole in the pulley that the pin was to fit into was aligned with the pin. The early type was probably easier as you could see the hole in the pulley. One of the first things that I did on my Atlas (which has the axial pin) when I bought it in 1981 was to take a center-punch and mark the pulley over the hidden hole (actually on it, holes, as it has two).

Also, I noticed in the only Logan 800 Series manual that I've seen that in the Operator's section, it only mentions the axial pin. Which would be confusing to anyone who owned an earlier version.

On mine, the hole in the bull gear is lined with the oil hole in the center pulley, so easy to see. No center punch required. But, it's a good
idea.
 
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tmenyc

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Yes, that is exactly correct. When forward, the pin is locked in place and in direct gear. Swivel it up, turn the center pulley, it disengages, you can feel the hole in the bull gear. Swivel it back to stay in back gear. I marked the spot on the center pulley with a sharpie.

Tim
 
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