Spindle adjustment

[Gard]

14 1/2 inch south bend from mid 1940s. I checked the bearings by pushing down and pulling up with moderate force on a bar inserted in the spindle. A 0.0001" indicator is on the spindle adjacent to the threaded nose got 0.0005" movement which is a little too tight. A little reading indicated it is supposed to be 75 lb. I went back and gave it everything I had. The indicator slowly increased to 0.003" which surprised me. I set up a small block and tackle with a force gauge on the bar. Up to about 30 lb there is very little movement of the spindle. At about 40 lb it increases to 0.003". Between 50 and 75 lb it stays at 0.0035". Is it normal to take such a high force?

This Lathe does not have a drain for the spindle oil so I made a small puller to take out the oil cup plug. Was happy to see the oil that came out looked like new with little gunk in there. The felt cannot be seen because there is a vertical brass tube. Next up I will remove the spindle per instructions on the lathe and in the SB literature I found on wswells.com. I am inclined to clean the felts and adjust the bearings but I could disassemble the spindle if there is some need to.

I started this investigation because of a very loud rumbling noise that the lathe sometimes makes when I first turn it on. I always immediately turn it off then back on again and it runs perfectly. This has happened about one in every 20 or 30 times the lathe starts for over a year. Yesterday it happened when the belt was loose so I assumed it must be the motor or countershaft. I will post this question over on the Transformers and motors section on PM.

 

[Tony Quiring]

Fix the motor first.

Leave spindle alone for now.

If you want to do more, invest is the rebuild book.

There was not a kit for 14.5 when we did ours so we got an assortment of felt from grainger.

The book has great detail on how to do the work and is by section so you can start anywhere you wish.

Sent from my SM-G781V using Tapatalk

 

[Gard]

Fix the motor first.

Leave spindle alone for now.

If you want to do more, invest is the rebuild book.

There was not a kit for 14.5 when we did ours so we got an assortment of felt from grainger.

The book has great detail on how to do the work and is by section so you can start anywhere you wish.

Sent from my SM-G781V using Tapatalk

I do have that book as well as some of the south bend literature. I have already removed the spindle before reading your reply, the spindle wicks look in good shape, I think I can clean and reuse. Spindle and bearings look good so I do not think I will disassemble it. The shims were 1 or 2 homemade ones so I will need to make up some new thinner ones, I do have a quantity of shim stock. The brass tube that the wick rides in on one side was pushed down flush with the cast iron bore and stuck so it will not hold the bushing in place but I think once it is assembled the expander will do the job.

The spindle is quite heavy so I think that is the reason I could not get a measure of bearing clearance without putting close to the 75 lb upward force that the book says.

 

[Gard]

I do have that book as well as some of the south bend literature. I have already removed the spindle before reading your reply, the spindle wicks look in good shape, I think I can clean and reuse. Spindle and bearings look good so I do not think I will disassemble it. The shims were 1 or 2 homemade ones so I will need to make up some new thinner ones, .

Does anyone know if there was a minimum recommended shim thickness? Or can you keep removing them to adjust gap until you get to zero and then replace the bushings?

 

[Technical Ted]

Thought I'd pass this on in case you haven't seen this one. It's got a section on spindle bearing adjustment.

http://vintagemachinery.org/pubs/1617/3533.pdf

Ted

 

[jwearing]

Does anyone know if there was a minimum recommended shim thickness? Or can you keep removing them to adjust gap until you get to zero and then replace the bushings?

As you remove shims, you lose backlash in the reverse tumbler gears. I had a machine that was so badly worn I had to remove all the shims, and the reverse tumbler wouldn’t engage the detent.

 

[Tony Quiring]

You cut a shim from a soda can and place it under the bushing...if it comes out.

Sent from my SM-G781V using Tapatalk

 

[Gard]

Thought I'd pass this on in case you haven't seen this one. It's got a section on spindle bearing adjustment.

http://vintagemachinery.org/pubs/1617/3533.pdf

Ted

Ted, thanks, I have that one and read thru it a couple of times. The following one is also good, a little more specific to the 10-16" models and also a slightly smaller spec for clearance. I will be making a new stack of shims today.

http://www.wswells.com/data/howto/1965-form-2002.pdf

That is an interesting idea to shim outside the bushing if needed to get the reverse tumbler to engage. The alternate is o replace the existing bushings. The instructions say the bull gear needs to be pressed off to disassemble the spindle, I would avoid that if possible. Would need to make a press then there is always the possibility to damage something.

 

[Technical Ted]

Maybe I'm not understanding what was said in some previous posts, but if you shim "under" the bearing it would effect spindle alignment with the ways of the lathe, right? Maybe that would work if you shimmed under both back and front bearings the same amount???

I guess in cases of bad wear you would shim the bearings so to make the spindle in plane with the ways.

Ted

 

[Gard]

Maybe I'm not understanding what was said in some previous posts, but if you shim "under" the bearing it would effect spindle alignment with the ways of the lathe, right? Maybe that would work if you shimmed under both back and front bearings the same amount???

I guess in cases of bad wear you would shim the bearings so to make the spindle in plane with the ways.

Ted[/QUOTE

Good point Ted.

As the brass bearings get worn you remove thin shims from under the bearing caps to maintain the correct bearing gap. The 1946 SB "H-4 Keep your lathe in trim" booklet says the gap should be 0.001 to 0.002". However the newer SB "Headstock spindle sleeve bearings 10" to 16" from 1965 says the gap should be between 0.001" and 0.0007". I am not sure which is correct or better but I am inclined to go with the older document that is closer in age to my war board machine.

My lathe currently has a crude homemade shim of around 0.021". I will be making some new shims that will add up to 0.020 and see how that works. The next question I was curious about is how thin is too thin for the shims? I had not really thought about the gear engagement or lathe alignment but I guess both would be affected by excessive bearing wear. I suspect that at some point the best thing to do would be make new bushings from brass tube but kind of hard to do while the lathe is apart. I guess adding a thin shim to the outside of both the front and rear bearings would be another option to get the 80 year old machine up and running. I think I am nowhere near needing to do that.

I think while I have it apart I will make some measurements to try to determine what the original bearing and shim thickness were.

 

[Technical Ted]

I would imagine that SB's recommended clearance would depend on the age/design of the machine. I have an older 15" SB made in the 30's and that has beefy, two piece, split bronze bearings with oilers on top; no oil reservoir. My newer 13" SB, probably made in the 60's has the circular, thinner, one piece bearings with the oil reservoir and spring loaded oilers. I would follow the recommendations for whatever design you have.

How thin can a shim be? I don't really understand the question... make them as thick or thin as they need to be to add up to the correct clearance for your bearings.

So, shim to get the correct clearance and run it and see how it performs. Remember, you'll have to make sure you remove all twist from your lathe bed by leveling and tweaking the leveling until you get a good two collar test. If there are no issues, like gears bottoming out, etc., run it and enjoy it! Also, use a proper spindle oil. I use Mobil #10 spindle oil in my machines.

Ted

 

[Gard]

I would imagine that SB's recommended clearance would depend on the age/design of the machine. I have an older 15" SB made in the 30's and that has beefy, two piece, split bronze bearings with oilers on top; no oil reservoir. My newer 13" SB, probably made in the 60's has the circular, thinner, one piece bearings with the oil reservoir and spring loaded oilers. I would follow the recommendations for whatever design you have.

How thin can a shim be? I don't really understand the question... make them as thick or thin as they need to be to add up to the correct clearance for your bearings.

So, shim to get the correct clearance and run it and see how it performs. Remember, you'll have to make sure you remove all twist from your lathe bed by leveling and tweaking the leveling until you get a good two collar test. If there are no issues, like gears bottoming out, etc., run it and enjoy it! Also, use a proper spindle oil. I use Mobil #10 spindle oil in my machines.

Ted

Thanks for the reply, I completely agree, My lathe also has the thin one piece bushings with oil wick and spreader, exactly as shown in the 4-5-65 Maintenance form 2002 I posted the link to. I guess I will go with that one for the target spec of 0.0007" to 0.001".
The pictures in the older keep your lathe in trim booklet look exactly like my lathe, oilers on front but it never says which years it applies to.


The question I was asking was a hypothetical one of when do you need to consider replacing the bearings? Is that when there are no shims left to remove? I guess the answer is as long as the gears work, alignment is OK and oil gap is OK, temperature is OK, there is no need to consider replacing bearings

 

[Technical Ted]

The question I was asking was a hypothetical one of when do you need to consider replacing the bearings? Is that when there are no shims left to remove? I guess the answer is as long as the gears work, alignment is OK and oil gap is OK, temperature is OK, there is no need to consider replacing bearings

If it's not broke, don't fix it! I would only consider replacing the bearings if all else fails and there is an issue. As long as you can tweak it to get it within spec, or more importantly, get it to run to your satisfaction for the work you will be doing, I would run it and be happy.

I don't know of any "rule" when to replace components... It 's a judgement call based on your specific requirements, funds, work load, etc. etc. For me as a hobbyist, my answer will be different from a person with a commercial shop.

Ted

 

[SBLatheman]

I do have that book as well as some of the south bend literature. I have already removed the spindle before reading your reply, the spindle wicks look in good shape, I think I can clean and reuse. Spindle and bearings look good so I do not think I will disassemble it. The shims were 1 or 2 homemade ones so I will need to make up some new thinner ones, I do have a quantity of shim stock. The brass tube that the wick rides in on one side was pushed down flush with the cast iron bore and stuck so it will not hold the bushing in place but I think once it is assembled the expander will do the job.

The spindle is quite heavy so I think that is the reason I could not get a measure of bearing clearance without putting close to the 75 lb upward force that the book says.

Brass tube: you should put it back where it belongs or, at a minimum, re-drill the holes for the drains and the oilers and vent.
Ted

 

[Gard]

Brass tube: you should put it back where it belongs or, at a minimum, re-drill the holes for the drains and the oilers and vent.
Ted

I tried to pry it upward and could not get it to budge, it still lines up well enough with the vent hole so I can insert the wire that holds the felt down as the spindle is set in place. I think that is the only hole in it but will take a careful look at the other side. If I had another working lathe, I would be tempted to drill it out and make a new one.

 

[texasgeartrain]

Not 100% sure on yours, but standing in front of the lathe, the drain holes are to the right and left of the bearing, dead at 6 oclock. There's no oil seals to keep oil from slinging from spindle. There's basically a gutter to the right and left side of bearing with a small wire in each. The wire allows oil to drain back, instead of being air bound in the drain back hole. I'd shove a drill bit down the hole by hand to clear it out, and put wire back.

The spec for your style spindle bearing clearance is indeed .0007" to .001". Me personally, I'd aim for .001" to .0012". Too many people heat up their bearings going for .0007". Left to right end thrust I like .0005".

A little off topic to your spindle adjustment, but in the beginning you mentioned a rumble on start up. Remember the weight on spindle and how you needed to pry ? Well you might do the same for the cone pulley assembly inside the motor base, directly above the electric motor. There's two style of bearings for that pulley assembly. A little bit of a newer style takes ball or roller bearing assemblies. The older style had oil cups and the shaft rode on the bore of housing. That older style can clank around if its wore pretty good.

If its the problem, and its old style, a bore and sleeve could be a nice repair. If its roller bearings and a problem, the bearings are easily found.

 

[Gard]

Not 100% sure on yours, but standing in front of the lathe, the drain holes are to the right and left of the bearing, dead at 6 oclock. There's no oil seals to keep oil from slinging from spindle. There's basically a gutter to the right and left side of bearing with a small wire in each. The wire allows oil to drain back, instead of being air bound in the drain back hole. I'd shove a drill bit down the hole by hand to clear it out, and put wire back.

The spec for your style spindle bearing clearance is indeed .0007" to .001". Me personally, I'd aim for .001" to .0012". Too many people heat up their bearings going for .0007". Left to right end thrust I like .0005".

A little off topic to your spindle adjustment, but in the beginning you mentioned a rumble on start up. Remember the weight on spindle and how you needed to pry ? Well you might do the same for the cone pulley assembly inside the motor base, directly above the electric motor. There's two style of bearings for that pulley assembly. A little bit of a newer style takes ball or roller bearing assemblies. The older style had oil cups and the shaft rode on the bore of housing. That older style can clank around if its wore pretty good.

If its the problem, and its old style, a bore and sleeve could be a nice repair. If its roller bearings and a problem, the bearings are easily found.

My lathe is exactly the same, I cleaned all the holes with pipe cleaners, kerosene and compressed air, I think its a good idea to push a drill in there and make sure the brass tube is not blocking anything. I think I will go for the same target clearance you have stated. I am pretty sure my noise problem is that the centrifugal starter switch in the motor occasionally sticks in the start position, details in a separate post in the transformer section on PM. I have not had a chance to pull the motor yet. As near as I can tell the motor and jack shaft both have lubricated for life bearing and everything is quiet and tight.