Atlas Horizontal Mill Bushing Help

[jster1963]

I really hate asking for help, but I've looked for an answer and just can't find it. I have researched and tried to figure this out and don't want to ruin this part on my mill.

I'm restoring my Atlas mill and it has a broken bushing. Someone brazed it to the gear/pulley in the headstock. I was able to get a new bushing (M1-255) from Clausing but it is slightly different. The ID fits correctly, but the OD is slightly too big to fit right in. I have the parts diagram, but don't know how tightly these parts are supposed to fit together.

The gear has 4 square protrusions that mesh with 4 protrusions on the pulley. To me it doesn't seem that they will ever come out of mesh while on the machine. I don't think there is room to pull apart while it's in the headstock.

Also, there are 3 holes in the smaller pulley. I think there is only supposed to be one for oil, but I'm not sure. I think they put the other holes into the pulley and bushing to lock the 2 together. However, there were no screws in the holes when I pulled it apart, except the one in the large pulley for oil.

So....
1. How tight is the bushing supposed to fit into the gear (M1-242A)? Sliding or pressed?
2. How tight is the gear and bushing supposed to fit into the pulley (M1-79C)? Sliding or pressed?
3. Are there supposed to be 3 holes in the small pulley and bushing?
4. Are there supposed to be slots in the bushings? The Clausing bushing did not have either holes or slots.

Here are a few pictures. Any help would be greatly appreciated. Ps. I'm doing the restoration on YouTube if you want to see it.

 

[4ssss]

I would say a slight press. It looks like it's pinned anyway.

 

[jster1963]

I would say a slight press. It looks like it's pinned anyway.

Thank you.....

 

[wa5cab]

It is not pinned and the holes visible in the photos above are not original. The only holes that should be in the pulley are the one through the center where the spindle fits and one tapped oil hole that is NOT tapped all of the way through. The set screw that fits it is being used as an oil plug and should not touch the spindle. This is a common problem found in the 10" and 12" lathes. It doesn't get noticed until the operator puts the machine into back gear. Then it becomes "Houston, we have a problem".

 

[jster1963]

It is not pinned and the holes visible in the photos above are not original. The only holes that should be in the pulley are the one through the center where the spindle fits and one tapped oil hole that is NOT tapped all of the way through. The set screw that fits it is being used as an oil plug and should not touch the spindle. This is a common problem found in the 10" and 12" lathes. It doesn't get noticed until the operator puts the machine into back gear. Then it becomes "Houston, we have a problem".

AWESOME info!!! Thank you very much. I think I will machine the brazed bushing out and press in the new one. The bushing says Oil Lite so my guess is that oil is impregnated.

My oil screw screws all the way through, so I will have to fix that somehow. I think I will leave the holes that are there and put oil in every now and then. And I see where the oil screw has rubbed into the spindle. So fix it time because I do hate "Houston, we have a problem" LOL!

Thank you so much for the info.....

 

[wa5cab]

Yes, "real" Oilite bushings, presumably including those supplied by Clausing, come from the factory already oil impregnated. However, one should always keep the oil cups (where fitted) topped up and one should pretty much follow the lubrication instructions in the manual. The one place that you could safely vary them would be on the pulley unless you routinely use back gear. The modification for for the pulley could read something like "remove set screw and inject a few squirts of SAE 20 either weekly or daily before every usage of Back Gear.

I would strongly recommend that you replace the spindle cone pulley and gear rather than trying to bore out the brazed bushing. The two step pulleys are not that hard to find, unlike the three-step or four-step. The two-step were in production for around 16 years versus the two or three years of the other two. In the event that the new bushings are not a press fit, you can safely knurl them but you will have to have an expanding arbor to do so.

If the oil plug has been forced through to the ID, the best solution is to buy a box of nylon patch set screws. Ideally you should use a new one every time that you oil the bushings but you may find that you can get away with using a screw 2 or 3 times.

Fortunately, the spot on the spindle that gets damaged is between the two bushings. So although it will probably damage one of the bushings when you disassemble the spindle, so long as you file it down and don't repeat the damage, there will be no problem with using the original or a replacement spindle.

 

[jster1963]

Yes, "real" Oilite bushings, presumably including those supplied by Clausing, come from the factory already oil impregnated. However, one should always keep the oil cups (where fitted) topped up and one should pretty much follow the lubrication instructions in the manual. The one place that you could safely vary them would be on the pulley unless you routinely use back gear. The modification for for the pulley could read something like "remove set screw and inject a few squirts of SAE 20 either weekly or daily before every usage of Back Gear.

I would strongly recommend that you replace the spindle cone pulley and gear rather than trying to bore out the brazed bushing. The two step pulleys are not that hard to find, unlike the three-step or four-step. The two-step were in production for around 16 years versus the two or three years of the other two. In the event that the new bushings are not a press fit, you can safely knurl them but you will have to have an expanding arbor to do so.

If the oil plug has been forced through to the ID, the best solution is to buy a box of nylon patch set screws. Ideally you should use a new one every time that you oil the bushings but you may find that you can get away with using a screw 2 or 3 times.

Fortunately, the spot on the spindle that gets damaged is between the two bushings. So although it will probably damage one of the bushings when you disassemble the spindle, so long as you file it down and don't repeat the damage, there will be no problem with using the original or a replacement spindle.

I tried to replace the pulley/gear with Clausing and it is no longer available. Hey, I'll try Sears. Sometimes they still have replacement parts. If not, I'll have to try to machine the bushing. I'm taking heed to your warning though! I'm trying my best not to do the "Ready, Fire, Aim" way I usually do with my projects. Also, I'll try to find those nylon patch set screws. If not, I will try to use a nylon piece in the set screw hole or try to fix it so the set screw doesn't touch the spindle.

Thank you very much for the information and I will Keep everyone informed on my progress......

 

[wa5cab]

Most of the mill parts, unfortunately, are only available on the used market. That includes all three of the spindle pulley types.

You might also try a nylon set screw. They are usually made slightly oversize so that they are self locking. Would be ideal for this application. Try McMaster for either type.

Also, if you do try to bore out the existing pulley, I would recommend holding it with an expanding mandrel. There is a relatively inexpensive 4 or 5-piece Chinese made set available that is cheap enough to machine the next larger one to fit either the bushing bore or the pulley bore. I am pretty sure that one of them is large enough for the 618 and Mill spindle pulleys.

 

[jster1963]

Most of the mill parts, unfortunately, are only available on the used market. That includes all three of the spindle pulley types.

You might also try a nylon set screw. They are usually made slightly oversize so that they are self locking. Would be ideal for this application. Try McMaster for either type.

Also, if you do try to bore out the existing pulley, I would recommend holding it with an expanding mandrel. There is a relatively inexpensive 4 or 5-piece Chinese made set available that is cheap enough to machine the next larger one to fit either the bushing bore or the pulley bore. I am pretty sure that one of them is large enough for the 618 and Mill spindle pulleys.

I don't plan to bore out the pulley or the gear. I plan to machine the bushing. I will need a mandrel for that and only need to take off about .003" from the OD so I think that is more do-able. I will check McMaster as well. Thank you again for the reply......

 

[jster1963]

Update...2 steps forward, 1 step back. I machined off the brazing and pulled the broken bushing from the gear. After measuring again, it see that the OD was just .002" over the ID of the gear and the pulley. So I froze the bushing and heated the gear and pressed them together. Once that was together, I froze the gear/bushing and then heated the pulley. Then it was all pressed together.

Here's the problem. Before I pressed in the new bushing, it would slide right onto the spindle. Now that it is pressed into the gear/pulley, it is WAY too tight on the spindle. I think I will try to machine it slide on the spindle. My guess is 1 or 2 thousands. Now I have to figure out how to hold this in the lathe and not damage it. YOWZA!