Columbia Grafonola Tabletop Barn Find and info on its restoration

[Herderz]

Next the governor, I disassembled the rotor from the shaft to clean and polish the slide area as the shaft speeds up. I could not disassemble the lower end because the screw heads were in bad shape. The lower end did not need polishing so I was ok with it. I did polish the inter rotor bore and the riding shaft area along with the shaft end.

Now the drive shaft to the main shaft. This setup unlike what I has seen in my short exposers to these motors ride on cone bushings to convex pivot points in the shaft. Different type of setup. I polished both cones and the inter pivot points. The cones using my leather lap stick and the convex pivots with a wooden dowel shaped to the angle of the pivot. Wood is also a very effective way to polish material.

[Herderz]

Thanks Curt, I am getting it there.

[Herderz]

Now to start the reassembly. First the main shaft. Before I disassembled the main shaft I used a filler gage to measure the lower drive gear to the body and the upper anchoring sleeve. they were .028" drive gear to body and .007" sleeve to upper plate. Why is this important? This is the datum point to start proper setup for all the gear train. I oiled the lower pivot and the upper shaft and bushing.

Next governor shaft to main spindle gear mesh. The blue arrow shows movement for depth of the worm gear to the drive gear. This setting is crucial to achieve the best mesh and back lash for the worm gear. I am no expert on phono motors but have experience on drive trains. My years of experience tells me that you want mesh to make contact of the drive gear to touch the worn at about 25% from the start of the face of the drive tooth with contact to push 75% of the remaining tooth space. This affects the noise that the train will make plus the wear on the gears. To tight of a mesh will stop the drive at some point and to loose will cause noise in the train and premature wear on the drive gear.

Once I have the mesh right I grease the gears and oiled both pivot points and the rotor bore and shaft and moved on.

[Herderz]

Next the drive gear to the main spindle. This is the cone bushing setup and probably the most difficult to do and also to understand. I will try my best to explain. When starting this setup the first adjustment is the drive gear to the main shaft (red arrow). this is the datum point for the proper setup. start by setting this cone where the gear is not bottoming out on the main shaft gear, just a little loose. Then set the input end of the shaft cone just enough to hold the shaft in place. Check the endplay of the drive gear to main gear buy moving the drive shaft back and forth. There should be just ever so slight back and forth movement, (blue arrow). Now shaft side to side movement must be ever so slight (purple arrow). This took me a few times to get right and you will need to start over if there is to much movement with the side to side. Too loose or to tight start at the beginning and adjust step by step until you have no movement but not tight back and forth (blue arrow) and minimal up and down (purple arrow). I did not say it would be easy.

Now for the final setup check of the drive gear. Set the plate up sideways. Check the gear mesh endplay (red arrow) back and forth, pushing the main shaft sideways to mimic the downward position the shaft would be in once the motor plate is mounted. It should have just a little movement back and forth without moving the main shaft gear. Clear as mud, right?

[Herderz]

Grease the drive shaft and the pivot cones and inter race as I go.

The next gear on the train. The last drive gear from the spring drive. This gear after cleaning has 4 holes to the mounting shaft on the frame which tells me that it is oil lubricated. I oiled it up with clock oil and fastened it to the shaft with the c clip to hold it on the shaft.

Like wise for the next gear in the train, same oil holes.

Grease up the gears as I go.

[Herderz]

Now for the spring drum. This is a long post so I will not go into the spring drum cleaning and rebuild, you can see that from my other restorations. First grease up the shafts for the wind ratchet mount.

The spring drum is greased and ready to mount. I greased the drum shaft by running it back and forth through the drum to make sure that it had grease through out.

I mounted the drum and made sure that the clamping bushings were in the proper position, the gap at the 10 position so it would clap tight.

Next the winding shaft mount in position.

Lastly tighten the mounts screws.

[Curt A]

Great instructions...

[Herderz]

Next the speed control and the turn table brake. Mounted and connect the tension spring.

I like the engineering here. One setup to control both the speed and brake. Blue arrow for speed through one cam for the felt pad. Red arrow for brake on the other felt pad using a cam. I put a drop of oil on each felt pad.

[Herderz]

Okay got the motor mounted to the case base. Tested for function, running like I had hoped. I set it into the case and installed the speed levers and the brake lever.

Next to set the speed at 78 rpm to the middle of the scale using a cardboard strobe. wind it up and let her spin. tighten the set screw on the speed lever to middle.

While I was doing all the motor rebuild I used some carpet cleaner on the turntable felt and was able to get the stains out of the felt. I had to do some contact cementing on the edges but was able to preserver the original felt. I also polished the nickel edges with polish.

Now for the acid test!
After getting the machine all back together I wind it up and let her go to see how the motor sounds. I am so pleased, It is turning so smoothly and there is no motor sound at all, not a rattle or gear drive sound. Man this is the best that I could ask for.

I played the first disc. Oh so sweet, clear and crisp, I can't believe the frequency range. I played the same disc on it and compared it to my victor VV-VI and I can see that I must revisit tuning the exposition reproducer. It is no where near the sound of the Columbia.

[Herderz]

The summary, take a machine that probably no one would think of touching, don't look at the state it is in but what you can make it, because it deserves not to be junked or thrown in the trash. The preservation of history out ways the labor, very few people see things in this way but not me.

It is only a matter of time and finding the next thing to restore.