Saving a Logan 825

[bhusted]

Not much time in the garage today, but I did make some progress. I made a new locking piece for the back gear plunger. This was a major pain to get the shape right and I really resent the person that removed or broke the original. I still need to source a spring small enough for it before I put the pin back.

I also managed to wire up and test the "new" motor that will power this thing when the time comes. It's not OSHA approved yet, but everything works. I need to wire up a reverse and power switch. The motor is a 3/4 HP 1750 RPM DC motor I picked up on ebay. The brushes look good and the bearings are quiet. Control is a KBM-125. No more changing belts for speed!

 

[mattthemuppet2]

I don't know of an electrolyte better than and as safe as baking soda. If there is still quite a bit of firmly adhered original paint, perhaps you could first brush on some cheap paint remover with the bed sitting on blocks in the empty container and then after a few days pour in the water and soda which should take care of the paint remover.

I read somewhere that washing soda is better than baking soda for electrolysis, though I honestly can't remember where I read that or why it is so. It was a long time ago. Either way, I've had alot of success with washing soda and usually find that the electrolysis will "blow" the paint off the surface, as well as removing rust. It was quite some time ago, but would be worth a shot.

Beautiful looking paint work there bhusted, this will look wonderful when you've finished.

 

[wa5cab]

I think that you are correct. I didn't get up and go out in the shop and look at the box that I have but I just did. And it is washing soda. So it's the baking soda that doesn't work very well.

 

[mattthemuppet2]

I can't remember the chemistry behind it, but I think you need more baking soda in solution to get the same effect as washing soda.

 

[bhusted]

I can't remember the chemistry behind it, but I think you need more baking soda in solution to get the same effect as washing soda.

Apparently "washing soda" is another name for sodium carbonate, which can be quite caustic. Right now the bed is in the same condition it has been. I'm putting off dealing with it for now while I keep busy with other parts of this project.

After a long day of working at the computer today I had a little time to get down to the garage and make some progress. I decided that I'd make the spacer for the drive gear on the QCGB. These went well enough until I realized the "simple" spacer needed a keyway. I've never tried cutting a key on a lathe before today, but I think it went pretty well.

I went from this abomination involving some washers and a pipe fitting?

To this. I don't really know the dimensions of the original so I just made it work.

 

[wa5cab]

The diameter isn't particularly critical so long as it is small enough. But the length should be the same as the nominal hub length of all of your change gears. I don't recall whether your lathe is a Change Gear or a QCGB version so the issue may never arise but if you needed to for example put the 48T gear in the Front instead of the Back position, the spacer would need to correctly position the gear so that it lined up with the previous gear in the gear train. The OD is typically something a little smaller than a 20T gear. If you had had a change gear with a broken tooth, you could have made the spacer from it by turning the OD down until only the hub was left..

 

[bhusted]

Good. I made the length the same as the thickness of the gear because that seemed to put the nut in the right spot. My model is a QCGB version. Fortunately no broken change gears, just one of the backgears with a missing tooth.

 

[wa5cab]

OK. Sorry to hear about the back gear.

 

[bhusted]

I plan to try and braze a tooth on the backgear and see how it goes. Moving to the DC motor with variable speed, I don't know that I'll be needing the backgears, but want to try and fix it anyway. I figure it can't get worse by attempting the repair. Keith Rucker has done a couple like this and it seems to work.

I did some more cleaning and painting tonight, but didn't have a lot of time to work. One of the parts I did work on is the clutch for the power feed on the carriage. This is MUCH more complex than the setup on my Atlas and I'm excited about the possibility of having a real power feed rather than just utilizing the half nuts. It's a good thing that I knew there were some springs in it because one of these almost got mistaken for swarf. Does anyone have a source for such small springs? Logan lists them for $10 each. The dimensions are 0.112" OD x 0.305 long with 0.020 wire. I didn't see anything on McMaster-Carr that fit the bill.

 

[bhusted]

In between online meetings I've gotten some more parts cleaned up. I want to get the spindle reassembled soon and that meant working on the spindle pulley. Most of this was just surface rust, but it does bring up a question. There are 2 1/4-20 set screws on the pulley. One of them is clearly marked for oil for when the backgears are engaged. The second is the mystery. Is this how the small gear is retained on the pulley? It doesn't seem like a good port for more oil as it's in the bearing surface. If this is how the small gear is held on, should the other set screw be loctited in place?