Installing a Logan QCGB. Logan 9B to 400 adaptation.

No picture but i was able to finish the ID plate from the above post. It came out really good as far as resolution and definition. I did not clean my sand paper enough nor did i wait long enough for the paint to be totally dry so i got some build up in the bottom left corner of residue. Actually, it looks like patina. I will probably use this one for the lathe.

I started playing with the gear box and the threading dial. Never have used one so why not. My belief is that you wait till the dial gets to the same number for each pass and engage the half nut there. Did some playing.

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Turned out OK but i have a hick-up in my threading. I noticed that every once in a while i would see the chips momentary stop while i was cleaning up the aluminum diameter. When i was threading you could really see the pause.

I think i traced it to my sloppy apron rack & pinion system. This will probably end up in the other thread but i did not re-bush either bores in the apron for the two rack & pinion shafts. I should have. Not sure the condition of the actual shafts either at this point. I also do not know how well the pinion gear should engage the rack.

Basically, each time the handle comes over the top if flops and again as it goes through the bottom. That is causing to half nut to momentarily jump on the nut. This also may be an indicator that my half nut is worn out.

What do you guys think?

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mjhenks said:
So i am convinced that any 9" or 10" will work. I am pretty sure the 11" as well but have less evidence to back that up. If i were looking at an 11" box i would want the seller to take the measurements from my last post.

The search for a proper box took about 5 weeks. Of course there were a number of them that sold prior to me looking but as usual when you want it you cannot find it. I resisted buying one with missing parts because the piece parts for these are crazy expensive.

I ended up with this one from a 9B-17.

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Overall it is in very good shape and included the input gears and drive shaft. The drive shaft was a huge bonus.

The drive shaft is set up for a power apron. (Has the key slot down the length) I have a feeling that all QCGB drive shafts will have this. The Logan 400 of course does not. The seller had the power apron as well but i do not see the need for a power apron on a 9" lathe that is not used daily and did not want to spend another $150. (Might as well just find a whole 9B.)

The parts arrived in good shape and my initial inspection showed that all was good. No broken gears, everything turned and could be adjusted. Great. The only down side is that the ID plate is in poor shape. It is readable but is a bit beat up. Will repair that later too.

Next steps. Tear it apart, clean, paint and start to figure out why it will not fit on the 400 as well as what i need to change or adapt to make it fit.

Matthew
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Sounds like you are off to a good start. Keep us updated on your progress.
 
No pictures but i tried to make another gear box label over the weekend. I am certain on how to apply the mask now in that you MUST apply the iron directly to the transfer material for at least 1 minute with moderate pressure.

I did 30 minutes again in the 1:1 acid mix but this time the etching came out really wide. Almost like it the part is out of focus. Will post pictures soon.
 
Ever get to a point in a project where you think it is just time to be done.... (Yes i stole this from my other thread.)

I am there.

All that was left for the QCGB was the ID Tag. Here is the whole lathe and the last steps for the ID tag.

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I mounted the ID plate last night even though it is not as nice as i would like it to be. Limited time means i will have to accept the tag as it is.

Took the home made ID plate for the Quick Change Gear Box, mated it to the old one and drilled the mount holes.

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The rivets i used. Lifetime supply

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Mounted and looking pretty.

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That should be all for the gear box.

I have used it and love it. Makes me think about the things i could do in minutes instead of hours with having to change the gears.

To be fair i am still missing the gear cover from a 9B to cover the left side where the change gears would be. I have not located one and am not sure i ever will. (Have one you want to sell????)

Overall a fun project.
I am fairly confidant that all the info you would ever need is documented here and likely it could be easily adapted to any Logan lathe that needed a QCGB.

Matthew

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Great job! Looks beautiful.
 
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mjhenks said:
To be fair i am still missing the gear cover from a 9B to cover the left side where the change gears would be. I have not located one and am not sure i ever will. (Have one you want to sell????)
Click to expand...

Matt, have you checked with Joe Bergamo at Plaza Machinery? I just bought a 9B spindle from him, and he's looking for other Logan parts for me.
 
So i was using the lathe last night to make some simple cuts. Reminded myself that i really need to adjust the rack & pinion on the apron. Anyways....engaged the half nut. About a second later the gear train audible started to stall as if winding up. Did not sound good. By the time i got the motor turned off i heard a big pop and snap. ummmm...... What just happened i asked myself.

I pulled the two levers on the gear box do disengage the gears. hand spun the spindle. All was OK. Turned the lathe back on. All was OK. Gear train on the back side of the head stock seemed ok. Problem in the QCGB. Went back to my work as i needed to get done and did not want to look at what happened in the gear box.

I am afraid i have some repair work to do that i really do not have time for......

Will post what i find when i get into it.

Matthew
 
Ok. Did some diagnostics tonight. Need some help.

Gear box installed and set to lowest feed rate. When i engage the half nut it runs fine but has a slight stressed sound to it. BTW, i loosened the half nut and re-aligned it to the screw. Just to be sure.

As i speed up the feed (by selecting different gears) the stressed sound get more intense and the lathe starts to bog down. I do not dare run it for more than a second.

The spindle and the saddle are smooth and run fine.

I pulled the gear box out.

With the selector handles disengaged i tested:

Spin the input side by itself it spins fine and smooth. All the gears turn nice and slow down as you move farther down the stack like it should.
Spin the output side by itself and it spins fine and smooth. All the gears turn together as they should.
Spin the shaft on the handles. They spin fine and smooth.
Spin the input side and engage the left side selector handle and it still spins fine and smooth.
Spin the output side and engage the right side selector handle and it still spins fine and smooth.

Engage both selector handles and it binds up. No matter what gear you select the system is not smooth at all. Feels bound up.

I confirmed i have no broken gears and everything seems to be smooth and fine.

Help....:whiteflag:

Matthew
 
I have never seen the inside of a Logan gear box. Can you post a picture? It sounds like there is a shaft dragging in a bushing or a bearing. Do the two cluster gear sets spin independently of each other, or are they trying to spin together?
 
With the QC and half nuts disengaged, can you turn the lead screw freely? The tailstock end bearing or bushing (whatever type it is) could be seized.

Robert D.
 
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