Introduction - New Atlas Lathe Owner

Three comments:

The correct and factory recommended oil for everything except the gear teeth and the ways is SAE 20 ND. If you find the equivalent but with an ISO rating, either ISO 68 or ISO 46 cross to SAE 20. With ISO 68 probably being preferred. For the ways, use Way Oil, which differs mainly in clinging to the vertical surfaces better.

The proper lubricant for the gear teeth is grease, specifically one with a high temperature rating. Most grease found in tubes at consumer grade Autoparts stores will be unsatisfactory because it will quickly liquefy and sling off. The claim that you shouldn't use grease on the gears because it attracts and holds chips or shavings is, while partially true, apparently due to the results of operating the lathe without the gear covers provided but often lost or discarded. So it is a case of one bad decision leading to another one. SAE90W would be fine for the gears if the Atlas lathes were provided with an oil filled sump and possibly an oil pump. However, they are not.

Not wishing to re-start the argument over link-belts versus V-belts, I will only point out that the lathe in question here has babbit bearings which require little effort to remove. And that in any case, the owner needs to do that anyway for condition inspection of the bearings and journals and possible adjustment.
 
wa5cab said:
Three comments:

The correct and factory recommended oil for everything except the gear teeth and the ways is SAE 20 ND. If you find the equivalent but with an ISO rating, either ISO 68 or ISO 46 cross to SAE 20. With ISO 68 probably being preferred. For the ways, use Way Oil, which differs mainly in clinging to the vertical surfaces better.

The proper lubricant for the gear teeth is grease, specifically one with a high temperature rating. Most grease found in tubes at consumer grade Autoparts stores will be unsatisfactory because it will quickly liquefy and sling off. The claim that you shouldn't use grease on the gears because it attracts and holds chips or shavings is, while partially true, apparently due to the results of operating the lathe without the gear covers provided but often lost or discarded. So it is a case of one bad decision leading to another one. SAE90W would be fine for the gears if the Atlas lathes were provided with an oil filled sump and possibly an oil pump. However, they are not.

Not wishing to re-start the argument over link-belts versus V-belts, I will only point out that the lathe in question here has babbit bearings which require little effort to remove. And that in any case, the owner needs to do that anyway for condition inspection of the bearings and journals and possible adjustment.
Click to expand...

Thank you very much for the information, sir. Are these bearings easily replaceable and maybe carried by online suppliers (McMaster/Amazon/etc)? I'm just asking since if I'm going to be taking it apart... It may make sense to have some new bearings on hand.

Who knows... maybe I'll be lucky and they're just find based on Page 9 of MOLO_1973_V1 saying "This type of bearing is being used universally in automobile main bearings and maintains its original accuracy and alignment under heavy loads.... No adjustment of the bearings should be necessary for hundreds of hours."

Are there any items yall recommend having on hand when dissembling the spindle? How will I know a bearing is "bad"?


Side question: Would direct mounting the motor to the bench add rigidity in the system?

@Nogoingback - Thanks for the link to the belt convo!
 
James,

If your machine had Timken tapered roller bearings, they would be replaceable. But it has babbit bearings that were poured in place. There is a brief description of them in the MOLO including how after pouring they were line bored in place. Although two or three people over the years have claimed to be going to re-pour theirs, I have yet to see a machine that was claimed to have had that done. As the discussion in the early MOLO's says, they all came from the factory with a 0.010" 5-part laminated shim under each of the bearing cap screws. General procedure is to set up a dial indicator over each bearing cap in turn. A 3 foot long piece of 3.4" diameter round bar is stuck through the spindle and after pressing down on the bar and zeroing the indicator, pulling up on the bar and noting the reading. Then one or more laminations is peeled off of the rear and/or front shim packs until with all four of the cap screws tightened, the dial indicator movements is reduced to 0.001" or a little less without locking the spindle when the screws are tightened. If your initial test indicates that shim layerss should be removed, remove the bearing cap and shim packs and mic the pack thickness. Do not mix up where each shim pack came from. If both of each pair are the same thickness, remove a layer from the rear one first. If the rear pack is thinner than the front one, then the first removal should be from the front one. Read the text in the MOLO on the subject first.
 

And, if you're interested, an excellent video on how bearings are poured, just in case you feel like giving it a try... :)
 
A couple of things:

1.) The question I had about direct mounting the motor to the table doesn't make sense after looking at the arm on my machine... so disregard.
2.) Anyone Use cogged v-belts for the drive portion (since the motor pulleys are kinda small)? How about narrow profile belts?
3.) What are the idea belts for this machine 1/2 x 3/8'? Lengths?


4.) After all the conversation we've had here and playing around this machine... I'm fairly confident that I'm going to do a "full refurbish".... or at least take it all apart, clean it all, re-lube it, wire brush & re-paint the castings, and repair my motor mount... it deserves that.

5.) After reading page 14 of the MOLO... I came upon this question. Should the "tension arm" be in this (see red arrow in attached pic) position even when the machine is running (that is with the stop on the post)?... I've been running it with the weight of the motor fully supported by the belt... I think that was the way this machine has been run in the past and that the belt is too long (32''). By turning the handle (screwing it in or out) I think I'd be able to adjust belt tension with the stop seated in the post?

Thanks,
James

Edit: on Point #5.....yep... been doing it wrong. This poor machine. I would imagine that could add to the little bit of vibration I was seeing too. Looks like I need a much shorter belt. This video answers that question visually.
 

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As far as lubrication. I'm looking at ordering the following unless yall have better recommendations or prices!... These quantities seems larger than I need for sure.

Mobil ISO68 SAE20 Hydraulic Oil for general lathe oiling - https://www.amazon.com/gp/product/B00PM9KTC8/ref=crt_ewc_img_dp_2?ie=UTF8&psc=1&smid=ATVPDKIKX0DER

Timken High Temp Grease for gears - https://www.amazon.com/gp/product/B00036BUGO/ref=crt_ewc_img_dp_3?ie=UTF8&psc=1&smid=ATVPDKIKX0DER

Vactra #2 for ways - https://www.amazon.com/gp/product/B00A3UXP54/ref=ox_sc_act_title_1?smid=A2OXMHTADGRD5V&psc=1

Edit: Do yall often replace the wicks in the oilers?

Edit #2: Would some 30 weight or way oil suffice for the gears instead of the grease if you oiled them more frequently?
 
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Re: Post # 26
1. OK

2. I don't think that a cogged belt would hurt anything. However, my 3996 is 40 years old and is on its second motor belt. So the smaller pulley groove probably isn't too small.

3. The correct belts seem to be 4L350 for the motor belt and 4L310 for the spindle belt. I say "seem to be" because the parts list gives the Atlas part number only so the two numbers were arrived at by asking numerous people what was found on their machine. More than 90% either reported those numbers or said they had something else but it was either too short or too long. Fortunate,y, unlike the 10" Horizontal and the 6" Type 2 and Type 3 countershafts , the 12" ones are always in the same position since they are attached to the bed instead of the bench.

4. OK. This would then be the best time to add the back gears, or at least the two mounting brackets.

5. Never depend upon the motor weight to tension either belt. The motor should be rigidly mounted by tightening the 9-42 Lock Nut onto the L6-267 Motor Lock Bolt. And the spindle belt should be tight when the two collars on the tension rod straddle the L3-108 Lock. To demonstrate why the motor should be locked into place, try some interrupted cut like turning a piece of hex stock to round.

Re: Post #27

The oils and grease listed should be OK.

Unless you live in a very dry and dusty climate, the felt plugs in the oil cups over the spindle bearings should be good for 20 or 30 years. Their purpose is two-fold. to delay the speed at which oil drips through, and to prevent dust and swarf from getting to the bearings.

#2. No. Although way oil would be better than SAE 30, both will sling off pretty quickly, leaving the gear teeth dry. And as I indicated yesterday, the common excuse for not using grease is BS.
 
Incidentally, up until sometime in the 1950's, the factory was recommending SAE 10 oil. Then they changed the recommendation to SAE 20, retroactive. So anything printed around the time that your lathe was made will still say SAE 10. Disregard this.
 
@wa5cab Thank you greatly sir!

#4 the back gears are installed on this machine, but I haven't used them yet.

#5 I will fix this issue! I'm happy I noticed that in the MOLO before attempting to use this guy heavily. That belt must have been changed out a long time ago... and they must have used an oversize belt they had on hand. I'm surprised to see the 31'' belt ( 4L310) listed since the measurement I took while the handle was in the saddle is ~29''... I guess there is some wiggle room here. I took my measurement by running a piece of 1/4'' cord over the pulleys then taking it out and measuring it.

I was able to find some ISO68 SAE 20 oil from Home Depot in a reasonable quantity... https://www.homedepot.com/p/Husky-S...ergent-Oil-Air-Compressor-018-0079H/205183905


Thanks a million for the information, sir.
 
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