Post By AA+
9A bed rebuild
I have purchased a SB 9A and the bed is worn on it. The rest of the lathe is fine. It looks like some one rebuilt it already and left the bed alone. Can any one tell me what I can do about it and about how much it will cost to have done. What do people that are rebuilding their lathes do when it comes to wear on the beds? Is it possible to get a new bed for this? Cost? Can I have the ways rebuilt, some how? I really like this lathe but it has this issue. It was something that I overlooked when I bought it, what can I say I was really happy to get a SB in my area for sale. Thanks for any and all help you great people can provide with me.
Its expensive to do it right, easily over $1000, since it involves not only machining the bed, but then scraping the bed and all the mating components. IMHO, its just not worth it for a common, low cost lathe.
How long is your lathe bed? I've got a half-way decent 3-1/2 foot bed under a bench here. You can have it for the cost of shipping.
I have an 11" South Bend for 30+ years. When I got it the bed was highly worn with an 1/8" ridge on the ways in the middle. As I approached retirement I got it reworked by a long-time professional machinery restorer (40+ years of experience) for $1300. He had an 8 foot planer bed with two adjustable Bridgeport heads over it. So in one swipe he could redo a V way. Then the saddle sat too low, so he built it up with special plastic and also built the tailstock up. The rebuilder also remachined the dovetails of the cross feed and compound feed and built up the gibs. He frosted everything and also did true scraping of a few key parts. He complained afterwards that the lathe was much more worn than he had expected. He helped set the lathe bed up true with a Starrett level.
My own feeling was that it was worth it to me to have this done. Even by mostly not scraping (very labor intensive) the lathe was improved compared to the sway-backed previous version. After his work I spent time reworking other parts for improved accuracies, and I can see the improvement in lathe performance as a result.
Best wishes --- Allen
One of my lathes is a 9" SB. It's a great little lathe and I can see why a lot of hobby people are so high on them, however I just don't think they are a good enough machine to warrant the cost of regrinding the bed. It is very costly and unless done properly by someone with the right machine and experience the whole undertaking could very easily be a disaster. Look for another bed or complete machine. Not out to offend anyone, just my take on it.
Take Kitno's advice. Reconditioning the bed is just a small part of the job. To get an idea of what's involved-
Try doing like did in the old days just a file and hand scrape. All machine tools started this way and it is low cost as a dyi.
Originally Posted by newt
This topic seems to come up fairly often.
The cost of scraping exceeds the cost of a good used lathe. I'm not sure why they didn't fire harden them to begin with.
So my understanding is that each bed is unique, fitting the profile of carriage and tailstock and you can't merely swap them out?
Has anyone ever tried chopping the lathe bed down (sawing it in half) and moving the HS to the right. I think most of the wear is near the HS. Or, conversely could welds be done near the HS and then planed? I'm new at this so these ideas are probably foolish I'm guessing, and probably reasons for not doing it.
Watch ebay and all the forums for a good used bed. Post on those forums (and this one of course) that you are looking.
Lots of lathes get parted out, and the bed is always the hardest to sell due to shipping cost.
You may even run across a used lathe with a good bed but other issues that drop the price.
A couple years ago I bought a junker 9A for $100. After a few hours of cleanup I realized I had a pristine lathe under a lot of crud, wear was almost non-existent.
If you change the bed, you may have some minor alignment issues that will require some fitting, but you would have even more if you had your bed reground.
Thanks guys. As of right now I do not know what I will do. I guess I will look for a bed and keep an eye out on CL for another lathe. I need a bigger swing one any way so we will see what happens.
Ok, You cut the lathe bed down so that the worn section is beside the Headstock. Now there's nothing to both the Foot to.
Originally Posted by SE18
You would have to weld something there for that. Welding anything on the bed will warp it. Might even make things worse.
Also, You would have to cut the lead screw down. How much damage do you want to do. After all is said and done you might as well buy a new bed with saddle from the same machine.
Note: A worn bed does not necessarily impede the accuracy of the machine. It depends on what you are doing with it. If you're working with a large diameter piece , The Worn area probably won't interfere with the accuracy. Small diameter pieces that are short will Also not be affected. only small diameter pieces that are fairly long "extend outside the Worn area" will be affected.
in other words if you're trying to make precision lead screws, Re-grinding the bed or buying a new bed that Is not worn out will be your Best choice. Otherwise, You will never get your money back from Re-grinding.
I used to South Bend lathe with a Worn bed for many years, and was able to get spot on accuracy with most of my projects. However there were a few projects that the difference was Measurable, But not outside tolerance. it's all relative to the machine, what you're doing and how you do it.
In the 60's I saw a local machine shop cut 12" off of the bed of a bench lathe. It all depends upon if the construction of the lathe is such that you CAN just saw the bed off,and still have everything work. Best bet is likely a simple bench lathe with a drive located behind the headstock,not underneath it. It;s been so many years I can't recall the make of the lathe in question. It was used to make router bits all the time,and the carriage moved about 1 1/2" back and forth all day long in the same spot. MIGHT have been a Sheldon bench lathe.Pretty sure it wasn't a SB 9",but you might be able to cut off a SB 9". What you need to do is remove the headstock,and carefully ascertain that there is nothing on the section you wish to cut off that is needed,and is not present in the section that will be under the new headstock's location. Also,remember that you will be mounting the headstock on the part of the bed that is currently worn the most,so be prepared to shim and align it as needed. Be sure you have the ability to re align the headstock,or you will never have an accurate lathe.
One last "stupid" question, since this thread seems to have run its course. During refurbishing of my lathe, when everything was stripped off, the crazy thought occurred to me, and I mean this is really crazy, lad, why don't you fire harden the bed now that everything is off of it. It was just a fleeting thought but now I'm wondering. Bonfire for a day with bed in it, throw some carbon on the bed after 24 hours, continue heating so carbon can penetrate, then firehose it.
I'm sure no one has ever tried it but just a thought.
SE18 - it seems that after the "heat treatment" additional finishing would be required - steel loves when subjected to heat so I think grinding, at a minimum,would be required.
This would be a lot easier and a nondestructive Alternative.
Originally Posted by S_W_Bausch