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Scraping and setup of South Bend 16"

Ironworker15

Plastic
Joined
Dec 15, 2023
New to the site and have a few questions for those more experienced in this side of the trade than I. After years of putting it off I've finally decided to start rebuilding Dad's old South Bend 16". It's a model 8117C tool room soft bed fully tooled. Serial number dates to the late 50's. He bought it used in the 80s and ran it for years out in the barn doing mainly equipment maintenance on the family farm. Machine has been very well taken care of but has the obvious wear for its age. Im currently in the process of scraping in the compound rest as there was quite a few deep gouges in the ways on the base. I've got all the mating surfaces showing excellent contact and am now working on the gib. Now finally to my question. Should I scrape the top of the compound where the tool post sits? I've set it up on a pair of 123 blocks on the surface plate and sweeping the top with a .0001 indicator shows a .001 deviation from front to back. Throughout the scraping process I was constantly checking each way for any deviation and I have each piece within.0002" of each other. I understand this is a 60 year old machine that probably wasn't even set up this close from the factory but it's something i enjoy doing and i figure this is the machine to learn on. Any advice would be greatly appreciated. Sorry for the long post.
 
If your goal is to get a functional machine up and running in a reasonable amount of time, as long as the top of the compound is flat enough to offer good contact with the tool holder, it is good enough, being perfectly parallel with the ways does not matter (think about the level of precision any tool holder has and what matters for machining).
If, on the other hand, you need some practice to scrape for parallelism, it would be functionally useless doing so (like many things you see done by a few YouTubers), but go ahead with it.
Personally, if I were to need practice scraping for alignment (i.e. parallelism, perpendicularity, etc.), I would concentrate on something that could become useful later (e.g. a parallel, a prismatic or I-beam design straightedge, etc.).

Paolo
 
Thank you for your reply. That is my end goal with this machine. I have been scraping for a few years now on various straight edges and surface plates but haven't tackled a machine yet. The compound seemed the easiest to start on. I will move on to scraping in the cross slide ways now then. Thanks again
 
I did surface grind the top of my compound, but not so far as to scrape etc. What I would recommend in relation to rigidity is using a CA size tool post. Its larger and contact area thus larger on compound. Also this size tool post is the perfect height for the holders to hit spindle centerline, without using spacers and such.

The extra weight and contact area helps the overall rigidity.
 
I did surface grind the top of my compound, but not so far as to scrape etc. What I would recommend in relation to rigidity is using a CA size tool post. Its larger and contact area thus larger on compound. Also this size tool post is the perfect height for the holders to hit spindle centerline, without using spacers and such.

The extra weight and contact area helps the overall rigidity.
Thank you for the recommendation. I had thought about switching to a CA sized as the CXA is right at the limit for a 16" swing. 3/4" tools work fine but anything smaller needs to be shimmed to the top of the holder. Especially with boring bars. I have a 1/2" plate I surfaced for a shim under the tool post for boring. Ill be in the market for a whole CA setup soon. I will end up doing as you did and just surface grind the top of the compound. Again, thanks for the suggestions.
 
Not much to add. My 16" is from 1969 and Ted scraped mine so not really sure what he did to the compound.

Does yours have the bed distortion screws in the bed? Not sure what year they were added. Mine has it, and I don't ever want to own another lathe without them. Got it to cut a 2" aluminum bar - 12" cut length diameter is within 50 millionth's, which is measurement error. It rocks.

I added a DRO and I can routinely hit diameters to 0.0002 - .0003" from several thousandth's out.

Just wish it had more rpm.
 
Not much to add. My 16" is from 1969 and Ted scraped mine so not really sure what he did to the compound.

Does yours have the bed distortion screws in the bed? Not sure what year they were added. Mine has it, and I don't ever want to own another lathe without them. Got it to cut a 2" aluminum bar - 12" cut length diameter is within 50 millionth's, which is measurement error. It rocks.

I added a DRO and I can routinely hit diameters to 0.0002 - .0003" from several thousandth's out.

Just wish it had more rpm.
I do have the steel strips along the length of the bed if that is what you are referring too. The lathe was still quite accurate for it's age/wear I just know it could be better, plus I can never have enough projects! I learned on this lathe from my father and I will be teaching my daughter on it so it means alot to me to have it in the best condition possible. For what they were, these style South Bend lathes are great in my opinion for small job shop type work but as you stated just need a little more rpm. I do have a VFD on it and will run it up to the 1200 rpm that South Bend offered as an option.
 
I do have the steel strips along the length of the bed if that is what you are referring too. The lathe was still quite accurate for it's age/wear I just know it could be better, plus I can never have enough projects! I learned on this lathe from my father and I will be teaching my daughter on it so it means alot to me to have it in the best condition possible. For what they were, these style South Bend lathes are great in my opinion for small job shop type work but as you stated just need a little more rpm. I do have a VFD on it and will run it up to the 1200 rpm that South Bend offered as an option.
I was referring to these leveling screws. They are awesome! I don't think you have them as I did not see them in my 1965 catalog.

I am also going to kick it up to 1200 rpm. Ted told me the spindle should be fine but the gearing for the feed may not be happy with 1200 rpm.

IMG_3753.JPG
 
I was referring to these leveling screws. They are awesome! I don't think you have them as I did not see them in my 1965 catalog.

I am also going to kick it up to 1200 rpm. Ted told me the spindle should be fine but the gearing for the feed may not be happy with 1200 rpm.

View attachment 438264
Yes , I did have those screws. The date may be off as i went off the wells site and not from South Bend. Maybe a 66? But I definitely have that setup. Very nice indeed for leveling and turning a two collar for setup.
 
As for the spindle speeds, I set the headstock bearing clearance towards the light side of spec and keep an eye on temps. I cleaned up all the gear teeth with a file and stone as well. I do the paper trick with the gears to set the clearance and run a pretty thick gear oil. Haven't had any issues thus far. From the picture of the base of your lathe, it looks like it's a good one! Super clean.
 
As for the spindle speeds, I set the headstock bearing clearance towards the light side of spec and keep an eye on temps. I cleaned up all the gear teeth with a file and stone as well. I do the paper trick with the gears to set the clearance and run a pretty thick gear oil. Haven't had any issues thus far. From the picture of the base of your lathe, it looks like it's a good one! Super clean.
This is what it looked like a few years ago after the rebuild. Ted supplied a lot of new parts and labor. But it was made to be used so not near as clean now. But also sitting in my nice big new shop.

lathe.JPG
 
I'm not sure who Ted is ,
What? I'm sorry, but you are not allowed to own a South Bend lathe and not know Ted! LOL! SBLatheman on this site.

Ted was a SB service guy and bought out the SB NOS inventory when SB went under. Still has some NOS SB parts left. Super nice and super helpful fellow!

Some of the NOS parts I got from him included new bearings, new lead screw, tailstock, etc.
 
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Ah well seeing as how I'm new to the forum. Maybe i get a pass? I'll have to get I touch with him, I need a set of thrust bearings for the taper attachment lead screw as well as a few other odds and ends that I'd like to replace.
 
Ah well seeing as how I'm new to the forum. Maybe i get a pass? I'll have to get I touch with him, I need a set of thrust bearings for the taper attachment lead screw as well as a few other odds and ends that I'd like to replace.
Nope. No pass. He's on every SB site......... LOL!

Welcome to the site!

Oh yeah - them thrust bearings. Pretty sure I'm hoarding a spare set I got from him. I never found an exact generic replacement.
 
Nope. No pass. He's on every SB site......... LOL!

Welcome to the site!

Oh yeah - them thrust bearings. Pretty sure I'm hoarding a spare set I got from him. I never found an exact generic replacement.
They don't make one that I've found either. Im using Oilite washers for now and they work fine, but a replacement set wouldn't hurt. I'll contact him. Thank you for the information.
 
They don't make one that I've found either. Im using Oilite washers for now and they work fine, but a replacement set wouldn't hurt. I'll contact him. Thank you for the information.
Do you have a parts book? If not, PM me and I will email them to you.

Check out this thread. You have the AS841H2 and AS841T2 bearings.

 
Here are some pictures of my progress thus far. I have the compound top scraped in pretty decent I believe. Hard to get pictures of the points but you can see on the tape how it looks. Could use some more points in there but even spread anyway. May put another couple passes on it. The base needs a little more work too. There's a ridge in front of the dovetail in trying to get down. I've been checking on a surface plate with a .0001" indicator every pass to make sure I'm not digging holes or any taper. Open to comments, suggestions, or anything else. Here to learn.
 

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This is what it looked like a few years ago after the rebuild. Ted supplied a lot of new parts and labor. But it was made to be used so not near as clean now. But also sitting in my nice big new shop.

View attachment 438285
I don’t mean to derail the conversation, but can you share pictures of your DRO set up, including your scales.
 
I will move on to scraping in the cross slide ways now then.
I'd recommend scraping the bed ways and saddle before the cross slide. The cross slide needs to be set precisely square to the bed and I'm not sure how you're supposed to do that if the bed isn't straight. Are you scraping the bed or getting it ground? Pick up a copy of the Connelly book if you don't have one already.
 








 
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