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Lead screw question.
- Thread starter Exuptoy
- Start date
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- Dec 25, 2011
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If you are referring to the change gears on the left end of the headstock (that you assemble in various configuration to change the traverse power feed to the lead screw for various feeds or thread pitches), short answer is that they as well as the back gears in the headstock should be lubricated frequently. For the details see the lubrication charts in various vintage editions of the MOLO.
You use grease on the gear teeth and SAE 20 ND on the bushings that they turn on. That being said, the grease usually recommended is a lithium base grease rated for use on open gears. To keep from being quickly slung off, it should have a fairly high melting temperature and be tacky. The common greases found in the auto-parts stores usually lack both properties. Unfortunately, the company that made the grease that Atlas recommended (whose name escapes me at the moment) was bought out by the French company Total who very quickly ceased the production of that grease.
You use grease on the gear teeth and SAE 20 ND on the bushings that they turn on. That being said, the grease usually recommended is a lithium base grease rated for use on open gears. To keep from being quickly slung off, it should have a fairly high melting temperature and be tacky. The common greases found in the auto-parts stores usually lack both properties. Unfortunately, the company that made the grease that Atlas recommended (whose name escapes me at the moment) was bought out by the French company Total who very quickly ceased the production of that grease.
- Joined
- Dec 25, 2011
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Back Gears: If you study the Headstock page of any 10F illustrated parts list dated from 1946 up to the final one in 1966, they are all the same as there were no changes to that part of the headstock. The back gears are engaged and disengaged through the actions of two eccentrics, 10-251 and 10-252. For the back gears to remain disengaged or engaged when subjected to vibration and when engaged to torque reaction while driving the spindle, the two 10-167 Wave Washers must be present and slightly compressed and the eccentrics must be on one side of their peak when engaged and the other side when disengaged. If the eccentrics don't cross over their peaks while being engaged, torque forces and vibration will combine to make the lever slowly move back to the disengage position.
With the motor off, watch the motion of the back gears as you move the lever to engage them. They should move toward the spindle and then back away from the spindle slightly, indicating that the eccentrics are rotating past their peak when going from disengaged to engaged. If this is the case, all that I can suggest it to loosen the set screws in either or both collars and move them slightly on the shaft in the direction to squeeze the wave washers a little more. If the gears move toward the spindle but bottom out and stop before breaking over center, you need to increase the thickness of the 10-261shim pack. If the 10-254 Handle hits the headstock before the eccentrics cross over their peaks, the only solution that I see is to make sure that the handle is tight, mark the headstock side of it, remove and and bend the handle away from the headstock.
As an aside, given that the lathe has obviously been repainted, it would not surprise me any to find that there are no 10-261 shims present.
With the motor off, watch the motion of the back gears as you move the lever to engage them. They should move toward the spindle and then back away from the spindle slightly, indicating that the eccentrics are rotating past their peak when going from disengaged to engaged. If this is the case, all that I can suggest it to loosen the set screws in either or both collars and move them slightly on the shaft in the direction to squeeze the wave washers a little more. If the gears move toward the spindle but bottom out and stop before breaking over center, you need to increase the thickness of the 10-261shim pack. If the 10-254 Handle hits the headstock before the eccentrics cross over their peaks, the only solution that I see is to make sure that the handle is tight, mark the headstock side of it, remove and and bend the handle away from the headstock.
As an aside, given that the lathe has obviously been repainted, it would not surprise me any to find that there are no 10-261 shims present.
I removed the motor earlier today to check bearings as it was noisy.
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The motor I found had no roller bearings but instead had soft bearings with helix cut for grease retention!
So I greased the shaft on both sides and reassembled then refixed the motor after aligning it correctly and shimming the motor as it was twisted in relation to the head pulley. I filled both main bearing cups with 10W40 as it was all I had handy and it sounds far better. Little improvements all the time. I should have a nice lathe once I’m finished.
[media]
[media]
The motor I found had no roller bearings but instead had soft bearings with helix cut for grease retention!
So I greased the shaft on both sides and reassembled then refixed the motor after aligning it correctly and shimming the motor as it was twisted in relation to the head pulley. I filled both main bearing cups with 10W40 as it was all I had handy and it sounds far better. Little improvements all the time. I should have a nice lathe once I’m finished.
[media]
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One thing I just realised is when I removed the head it had 2 piece split white metal bearings which were set in the body of the casting & caps (which I assume are Babbit bearings?) and were maybe 20mm thick! I wish I'd taken a pic now! The model plate deffo states TV36 but I never noticed Timken roller bearings in there.
Could it have been modified if the PO couldn't source the correct timken bearings or just incorrectly badged?
Maybe the previous owner sourced a different bed for this lathe (which is where the name plate and serial number came from) as there are so many different parts with it like the spare lead screw, spare reversing box making up the home made QCGB, the extra gears etc. I'd assume the Babbit bearings would be normal for an earlier lathe although this one does have the power cross feed? Confusing. Maybe not all is as it seems?
Could it have been modified if the PO couldn't source the correct timken bearings or just incorrectly badged?
Maybe the previous owner sourced a different bed for this lathe (which is where the name plate and serial number came from) as there are so many different parts with it like the spare lead screw, spare reversing box making up the home made QCGB, the extra gears etc. I'd assume the Babbit bearings would be normal for an earlier lathe although this one does have the power cross feed? Confusing. Maybe not all is as it seems?
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- Dec 25, 2011
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Glad that you noticed that. I would guess more likely that the PO swapped the bed but didn't bother to swap the nameplate. When I look at some of your photos, it is obviously a babbit bearing headstock. Which would make the actual model number V36 assuming that the bed length is correct.
However, both Timken and babbit bearings were available on the 10" as far back as about 1935. Which was well before the 10F appeared. And as late as 1945. The headstock castings, although physically interchangeable and containing some of the same parts, are not themselves interchangable. Different spindle and the babbit one is a little bit longer because of the ball thrust bearing. My guess is that he changed the bed and happened to get one off of a TV36. But in any case, it is a 10F because it has power crossfeed and a 2-piece carriage. The actual model number would be V36.
However, both Timken and babbit bearings were available on the 10" as far back as about 1935. Which was well before the 10F appeared. And as late as 1945. The headstock castings, although physically interchangeable and containing some of the same parts, are not themselves interchangable. Different spindle and the babbit one is a little bit longer because of the ball thrust bearing. My guess is that he changed the bed and happened to get one off of a TV36. But in any case, it is a 10F because it has power crossfeed and a 2-piece carriage. The actual model number would be V36.
