Reboring an underneath drive casting from the war

[TRC]

Hello,

Ive got that underneath drive from the war (according what another gentleman of this forum said). It doesn't feature any bearing: the shaft was rolling straight on the cast iron, and it show on both the shaft and the drive itself.
I'm planning on getting it rebored, but I want to know the following:

1-Doest this have any value from an historical perspective? I don't want to destroy some part of history, but it's still a mass produce lathe.

2-Should I bore it to a slightly bigger diameter and continue running the shaft on the cast iron, or should I get it bored to a size allowing me to press sleeve in it?

I'm joining a close pic from the drive, in case I'm blind and it's just a very well hidden sleeve.

https://imgur.com/a/jgSd6Tn

 

[Dobermann]

There are so many of those things running around I can't see how it would have significant historic value. If it were mine, I would bore the shaft bores straight and sized for a couple of thousandths clearance to a new shaft.

I would be cautious about boring it to accept a bronze bushing because of the resulting cast iron wall thickness. A new bronze bushing would have to be pressed in (lightly of course) to keep it in place and a mistake in that pressing process could crack the cast iron.

Whatever you do, DO NOT bore it out and install an "Oilite" sintered bronze bushing it as a bearing. Unless you run a hardened shaft, the Oilite bushing will cut your new shaft in short order, putting you right back where you are now!

Just my 4.737 cents worth, allowing for inflation!

 

[TRC]

Whatever you do, DO NOT bore it out and install an "Oilite" sintered bronze bushing it as a bearing. Unless you run a hardened shaft, the Oilite bushing will cut your new shaft in short order, putting you right back where you are now!

I was planning on doing just that. I will use 932 (or 660) plain bronze bearing.

Does anyone know the fit that was originally there?

 

[jwearing]

Ive got that underneath drive from the war (according what another gentleman of this forum said). It doesn't feature any bearing: the shaft was rolling straight on the cast iron, and it show on both the shaft and the drive itself.

Iron is a common material for a plain bearing, it's still a bearing whether there's a sleeve pressed in or not.

1-Doest this have any value from an historical perspective? I don't want to destroy some part of history, but it's still a mass produce lathe.

How can we answer that if you don't tell us what kind of lathe you have?

2-Should I bore it to a slightly bigger diameter and continue running the shaft on the cast iron, or should I get it bored to a size allowing me to press sleeve in it?

You're proposing cutting a new shaft so the clearance is correct? Fine. If you want to keep the old shaft then you have to sleeve it.

I'm joining a close pic from the drive, in case I'm blind and it's just a very well hidden sleeve.

I have no idea what this is a picture of. Can you be more specific than "shaft"? Or take a picture from further back?

 

[texasgeartrain]

Regardless of year, a nicely operating machine will have more value than one that needs repair. So I'd make the repair. I also like c932 for bearing material.

Cut shaft first so you'll know bearing ID. Cast iron bore . 001" to . 002" smaller than OD of press fit bearing. The ID of bearing will shink by a thou or two when pressed in, so i might bore ID after its pressed in, if possible.

Oil clearance between shaft and bearing, id shoot for .001" to .002". Most oil clearances on such things come in right around .001" when new. Tighter will be bad.

 

[TRC]

How can we answer that if you don't tell us what kind of lathe you have?


You're proposing cutting a new shaft so the clearance is correct? Fine. If you want to keep the old shaft then you have to sleeve it.


I have no idea what this is a picture of. Can you be more specific than "shaft"? Or take a picture from further back?

1- 117.1C 16"x36" (or 16"x6'? The card just made me doubt)

https://imgur.com/a/hfXZP0J

2-No, I'm planning on surfacing the worn section of the original shaft to get the worn-out diameter a bit smaller (from the flywheel side extremity to slightly bellow where the first set of sleeve was running on). I'll also get the casting bored, so I can fit new brass sleeves.

3-Here is picture from further back. You can see the underneath shaft and the underneath overall.

https://imgur.com/a/rNsSTt4

Pilgrim, that IS a "bearing" and some among us consider the "Iron-bearing" SB's
superior for least TIR to the later Bronze ones.

Providing it is properly set-up .... and kept that way, of course.

Which isn't rocket-science, just tedious at the start. 'OIL' and the respect for its limits is the sustenance for goodness, thereafter..

The scoring doesn't matter as much as it LOOKS to do, BTW.

Hard chrome and precision grind of the existing spindle was the "go-to", back in the day for more expensive lathes. Costly, even then. A SB spindle one turned-down, fittted a shop-fab sleeve, then finished that in-place.

Or NOT.

MASS-produced SB's were cheap enough, and factory parts according to buy new whole assemblies, such as beds and headstocks to be fitted in-house.

Keep that low-cost, mass-produced AKA "bare minimum" market position in mind before putting an undue ration of time, money, and effort into it as if it were a Staggerwing Beech.

Nearly always it makes more sense if you LIKE an SB in really, really bad nick, to just go and find one in better condition.

Or move up to a different lathe. Most of us "met" SB's in training classes, so "it's done it's job!"

Again.

And may go-on to train the NEXT "newbie" in "HTRAL"

SB's legendary "How To Run A Lathe" booklet.

Just to make sure I got what you said, I'm replacing the underneath drive's shaft. Mine was a WW2 "we need more lathe for to get the GI their stuff, ain't no time for pressing bearing in". The shaft was sitting directly onto the cast iron, without a sleeve.

texasgeartrain once told me that these old underneath were a pain to oiled and maintains. Therefore, the got often neglected. I presume it's my case, I presume, since I got about a pound worth of dried out oil and dust out of the oil reservoir.​

I'm not crazy enough to replace the whole spindle. This one still have oil in it, run well, and I got a .003" runout on an uncleaned part of the chuck, on the inside diameter behind the jaws.

 

[TRC]

No. You did NOT "get it".

Cast Iron has mutiple "personalities". Some of them make rather EXCELLENT bearings run directly against hardened and polished steel. So long as .... given a modicum of decent lube.

'Decent" need not be even CLOSE to "perfect". either. The bearings are durable and even "forgiving of neglect'. Within reasonable limits. TANSTAAFL.

The 'brass' ("Bronze", actually. AND NOT "Brass") sleeve was not "left out" due to shortcuts.
It was perfectly legitmate to implement a bearing EITHER way, so long as needs were satisfied.

They are better bearings that you have yet realized and NEED NO Bronze sleeve if within runing spec.

Ok, my apologies then.

As for the bearings, I'm putting the bronze one in because what I currently have, the cast iron ones, where not oiled properly by the previous owner and both the bearings and the shaft are badly worn.

As for the legitimacy of the design choice, I guess they where correct, given that this thing is still functional after 80 years. I don't have the required background to judge those. I still need to replace my bearing, a way or another.

And I'm planning on going with bronze c932 since it's easy to find and relatively good for what it is and how cheap they are. I don't know what bearings are the best in the category of plain bearings, but I'm not planning to spend hours researching the best bearings that would allow me to get one more year before a replacement is needed on my 80 year old lathe.

If you do know what would be better for this particular repair, feel free to tell me. I will surely consider it and might even go for it.

 

[TRC]

I'm not clear by this late stage of careless use of terminology, if you are doing a basic countershaft, the crucial SPINDLE .. or both.

Kindly share that (again, if I've missed it?).

It makes a difference. Bigtime.

I'm not touching the spindle. If the spindle is done for, I'm selling this thing under a nice paint and cleaning and getting a new lathe.

I'm repairing the underneath drive rn.

 

[texasgeartrain]

As theremite pointed out, c932 is commonly known as bearing bronze. Lead is a minor element in this mixture of bronze, which helps where occasional lack of lube might occur.

It machines really nice too.

 

[hudstr]

What I did is have someone with working machines help me by cutting off most of the bearing, then mount 2 flange mount bearings to flat stock and bolt them to the casting. You can use what remains of the bearings to keep the alignment, not that it really matters.

https://imgur.com/d4mYj86

You should probably just ignore thermite, they seem to be angry because they thought you were talking about spindle bearings, even though you never once mentioned a spindle and the title literally says "Reboring an underneath drive casting". You probably should have included all the photos in the first post though.

As for the underdrive bearing just being the cast iron itself, that is how they did it even before ww2 started and the need to ration materials (im 90% sure, if someone knows more please correct me). Every post, picture, and video I've seen all had just cast iron except one which was bronze, which I believe was a repair just like what you are doing.

 

[TRC]

What I did is have someone with working machines help me by cutting off most of the bearing, then mount 2 flange mount bearings to flat stock and bolt them to the casting. You can use what remains of the bearings to keep the alignment, not that it really matters.

https://imgur.com/d4mYj86

You should probably just ignore thermite, they seem to be angry because they thought you were talking about spindle bearings, even though you never once mentioned a spindle and the title literally says "Reboring an underneath drive casting". You probably should have included all the photos in the first post though.

1-Sound like a good practical solution. I don't have any machinist buddy, and my local machine shop is currently bonking me on the head (they want 500$ usd for everything, which might be a great price if it was more than a 80 yo lathe and if I was not a hobby machinist), but that gave me another idea. If I don't use the old drive, I'll just use my mill to make a new one (i'll post it later, if I go for it.) Do you have any vibration issue with this setup?

2-He might have misunderstood me (I'm not a native english speaker and even in my native language, I frequently have communication issue). I'll probably ignore him if he go off topic too much, since lengthy argument between two people draw potential away from the thread.

As theremite pointed out, c932 is commonly known as bearing bronze. Lead is a minor element in this mixture of bronze, which helps where occasional lack of lube might occur.

It machines really nice too.

Thank you, I was already planning to go with this and you just reinforced my feeling about that bronze. I used the SAE designation first since that what my dealer is using.

Plus I love machining bronze, it's fun.

[sorry, I think i missed you between two large post before]

And it is NOT critical as to runout. This is rather light-duty service and you will not be running the lathe more than a few hours a day, and probably not even EVERY day.

Thonpson shafting is ready-made with ground finish with or without full-length keyway. Purchase of a length of that can give you a ready to use precision shaft to fit a set of off-the shelf Oilite bearings with no machining needed. Turn a shaft and support blocks to suit the stock Oilite only if you must. I cannot be bothered. Thonpson is not free, but neither is my time.

Now your countershaft can run for a long time with very little or even NO extra oiling.

The runout was the runout inside my chuck. I was saying that my spindle doesn't need any attention at the moment.

Thank you for that intervention, but I won't go for oilite because I can't bore or fit them, should I mess up the initial boring operation on my unique piece. However, I might go for them if I have to make my own underneath drive (or rollers, if I feel extra wealthy that day).

I'll also keep the Thompson's shaft in mind, that's a good ressource you gave me here.

I also don't really care if it last ten year or if I need to sacrifice a shaft and a few bushing to my lathe every year/6 month. What I do care about is that I can't repair it as it is presently.

 

[m-lud]

Hello,

Ive got that underneath drive from the war (according what another gentleman of this forum said). It doesn't feature any bearing: the shaft was rolling straight on the cast iron, and it show on both the shaft and the drive itself.
I'm planning on getting it rebored, but I want to know the following:

1-Doest this have any value from an historical perspective? I don't want to destroy some part of history, but it's still a mass produce lathe.
===================================

Doing a good repair is all that counts. Historically all machinery built in 1942 was important in winning The War.

I wouldn't hesitate to buy an 80-year-old repaired machine. With its age it's expected to need something.
Below is my south bend data card. It's almost a duplicate lathe as yours. Both our lathes were built in 1942 and delivered two months apart. In that two-month period South Bend delivered 3,772 lathes. The war machine was in full swing. We all should be thankful for the people that made parts on these machines and built the machine. There is no doubt your lathe made munition's.
Mine was at the Ford Rouge River plant. I read somewhere about a Navy training program to train machinist at the Ford River Rouge factory during 1942. 
Our lathes had blood sweat and tears poured over them. Tough times and tough people prevail.


Comparing the two cards there appears to be a couple errors but the guys building them were busy getting them built.

 

[TRC]

I wouldn't hesitate to buy an 80-year-old repaired machine. With its age it's expected to need something.
Below is my south bend data card. It's almost a duplicate lathe as yours. Both our lathes were built in 1942 and delivered two months apart. In that two-month period South Bend delivered 3,772 lathes. The war machine was in full swing. We all should be thankful for the people that made parts on these machines and built the machine. There is no doubt your lathe made munition's.
Mine was at the Ford Rouge River plant. I read somewhere about a Navy training program to train machinist at the Ford River Rouge factory during 1942. 
Our lathes had blood sweat and tears poured over them. Tough times and tough people prevail.
View attachment 369327
View attachment 369329
Comparing the two cards there appears to be a couple errors but the guys building them were busy getting them built.

Yes, I love these old machine for that. Kinda make me want to track who's been using this machine. Might even find the bastard that didn't oiled my underneath drive properly!

 

[TRC]

Be careful what you wish for.

These parlous time, his third-generation descendents might want accrued reparations - with cumulative interest - off the back of having been unfairly disadvantaged as members of an oil ration coupon starved segment of wartime industrial priorities ordering.

Worse? Take an unnatural present-day interest in lubing-up your "underneath drive", and most IMproperly!

I just want to give them the facture for the 740$ boring that my local machine shop think I'm gonna allow them to do.

 

[TRC]

Well.. "funny how we look at two sides and yet not see.."

A "shop".. or any other human-effort relevant entity, has some figure as "fully burdened hourly rate" whether they know it or not.

It matters not WHAT they do WITH the scarce hours of life, no one can buy time BACK, once used... or WASTED..

So the rate is whatever it is to pay THEIR way. At costs set in the present time and space. Not at the wages and living costs of 1940-something.

WE.. expect to get OUR crust at present-day rates for whatever work WE do.

Why would the OTHER guy not expect the same?

Page Two:

Factories have molds, jigs, fixtures, specialized machines and tooling dedicated to the most efficient, least-cost mass-production... and all the improvements to it learnt over long years at doing the same stuff, thousands of times over.

In my youth, you could "just buy" a NEW PART from South Bend. Beds, even. They weren't even all that expensive.

No longer.

"Job" or repair shops have to assess each need from a cold start, figure it out, jury-rig their general-purpose workholding .... all to do a "onesie".

Then tear it down and clear for a different "onesie" altogether.

Cost can be several orders of magnitude greater to "patch" than they were to "make".

Mankind knows HOW to rebuild an incandescent lightbulb or a ball-point pen.
But we don't ordinarily BOTHER to even recap a tire.

Don't take it badly, but you're not teaching me anything new. I'm just not paying 50% of what I paid for my machine.

I'll just have them make a comically long boring bar instead. Building a jig with my mill-drill head, a couple of welded steel thrust and a few D2"x2' "dowels pins" for lining everything would be far less expensive.