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

[mjhenks]

Rex (or anyone with access to a 9B with gear box.)

Can you measure this for me? Outside edge of the stud gear to the mount face on the reversing lever assembly.



The Logan 400 is 1.13"



For documentation and future reference I found this thread about installing a QCGB on a Logan 200. He talks about the 11/32" mod
http://madmodder.net/index.php?topic=7917.0

Thanks

 

[AR1911]

??? = 1.660"
that spacer is .750"

 

[mjhenks]

Thank you Rex. I have already started to make a new shaft.

I also received a replacement shaft for the gear box selector handles as well and start making that too.

 

[mjhenks]

Final Gear Box Alignment

Now that i know the length of the Stud Gear shaft i can locate the gear box along the bed. I expect it to overhang the left edge of the bed and the left most mount hole to be near the end of the bed.



Setting the gear that the Stud gear interfaces with to 1.66" sets the gear box ~ .410" overhung from the end of the bed. Right where i thought it would be. These holes are now marked for drilling later. I will not drill them until i get the lead screw aligned properly.

Lead Screw Alignment to gear box.

In previous posts i have shown that the lead screw does not align to the box. The power apron from the 9B (as reported on the larger Logans) changes that location. I will have to mill the box down but by how much?

I decided to try a new approach. The half nut engages the lead screw but allows some radial play. What if i grabbed the lead screw on the area that is not threaded. That would center the shaft really well on the closing center of the half nut. Assuming the OD of the lead screw is concentric with the thread center (which i think is fair) i could grab that part of the shaft to show where the gear box needs to be. The other bonus is that i will be grabbing the shaft near the end which minimizes the overhang of the shaft. Also i have the tail end of the shaft in its mount which i have already shown to be OK. Does this all sound fair to you guys?



The center of the Lead screw from the bottom of the bed is 2.77"
The center of the lead screw to the face of the bed is .35"
Note that both measurements are to the mount surfaces for the box.

Now where is the input shaft location on the box?



The center of the Lead screw input bore from the top of the gear box is 1.85"
The center of the Lead screw input bore from the mount face of the gear box is .30"

That means i should have to remove from the mount surface of the gear box:
2.77" - 1.85" = .92" from the top.
.35 - .30 = .05 from the face.

I will baby step into this one. Fortunately you can always shim back out.

The change gear cover does not fit??

Rex or any other 9B owner. Can you take a few pictures of your cover as it closes down on the gear box? Mine does not close so i am betting the red below is removed from the 9B.





I have these from an unknown owner and it looks like it is cut back. I also see the hole in there. Is that the grease the shaft just below the stud gear? I have the change gear chart there. Hm....

What is next?

- Making a new stud gear shaft.
- Making a new gear selector shaft.
- Modify (shorten) the Rack.
- Make riser blocks.
- Drill & tap bed for box mounts.
- Mill box to align shaft.
- Rebuild gear box
- Mount it all
- Re-make the ID plate.

I see things to do for at least another month.

 

[mjhenks]

Some progress this AM.


Gear Box selector shaft. Will put the key slot and pin hole in next week. No plug welding. Loc tite.


Stud gear extended shaft. Have to put the key in next week.

 

[Mister Ed]

Final Gear Box Alignment
Does this all sound fair to you guys?

I got lost on the threaded/non threaded bit (I have a heck of a head cold and am not thinking clearly) ... but yes. Mounting the right side of the screw in its bearing and clamping the half nuts on the left side of the screw, should bring you in right close. I think I would put the half nuts right on the last bit of threads. Really at that point, only wear in the nuts could make a little difference. At least the way I am thinking.

 

[mjhenks]

As usual I could have been clearer....

What I meant was that I am betting that the OD of the non-threaded portion of the lead screw has the same centerline as the rest of the lead screw. Grab and center on the non-threaded portion of the lead screw, use that to align things and it would be as good as trying to grab the thread with the half nut.

Matthew

 

[mjhenks]

Gear Box selector shaft is done.





Made the new 3/4" spacer for the stud gear and learned how to use a new tool. Never have used a broach before. I did not have the right size. (5/32) I made it 3/16 as it does not transmit load, only serves as a spacer.





Re-bushed the gear box housing. Replaced the selector shaft and gear cluster shaft bushings. Pressed them in, indicated the location of each and reamed to size.



Rebuilt both selector assemblies. I opted to mill flats on the shaft and bushing that are set screwed in place. Never understood why people set screw directly on a shaft. Never comes apart easy and you are prone to spinning the shaft if it is transmitting torque.
I also re-painted the handles and knobs. Turned out nice. The only part i had trouble with is what way the gear goes. The gear has a boss on one side. That goes toward the side of the handle that has the wider width for the shaft to pass thru.









I also have finished the artwork for the new data plate and have the transfer film and new drive pins ready to go. Have yet to get the sheet aluminum or acid.

Up next is to put the 5/32 key slot in the new stud gear shaft and make a corresponding key as well as get material for the risers i have to make.

I am also working to get a fixture rigged up to cut the gear box mount surface. That is the next big step.

It is kind of nice that i have gone from research to actually doing things.

Still looking for information on the gear cover clearance for the gear box. Any measurements out there?

Thanks

 

[Mister Ed]

Really nice. What kind of mill do you have?

 

[mjhenks]

Grizzly G3102

Had a mini mill. Sold it to get the grizzly

The picture above was done at another shop. That one is a Bridgeport. Can't fit one of those in the garage...