618 Headstock Alignment

The spindle wasn't even close to being parallel with the ways. A close inspection shows cracks on both sides of the bed. The crack are in line with the chuck side of the headstock housing. Playing with shims under the lathe legs I got the vertical offset down from 0.023" over about 8 inches to about 0.09". That took about 3/16 worth of shims under the foot pretty much below the cracks. The horizontal offset was better, but is still off about .006" over 8 inches.

I'm beginning to believe the only way to get the lathe where I want it to be is to replace the base and the cost of that makes it more likely that there will be a modern mini lathe in my future.

Thanks for everyones ideas.
 
Thats really unfortunate, looks like someone might have dropped it or something. Regardless, it's a real drag and I feel for you.

-frank
 
marchyman,

This has nothing to do with your alignment problem but although your lathe is a 6x18, it is not a 618. The 618 is the Atlas model number of the lathe with Timken spindle bearings. Yours is a 101.07301.

WRT your problem, it's just my opinion that you are spinning your wheels attempting to shim the errors out. You need to replace that bed. I'll add that yours is the first one that I ever heard of that was cracked.
 
As a thought.
You pretty much never see beds come up on ebay as they are just too much to ship.

But all the parts that you see on ebay came off a lathe and there was a bed attached to them at some point.

If any of the parts sellers are local to you, you could try emailing the vendors.
They typically sell of the beds for scrap, but if you could do a local pickup you might get a good one cheap.
 
If this was my lathe here is what I would try first, all depending on whether I would be doing light turning or more heavy stuff.

First make a good base for it. For my 618 I made a support out of multiple layers of MDF glued together to form a flat thick base.

Next drill 3/8" holes in the feet close to the base so that a piece of all thread could be passed through the head stock foot, under the bed and through the tailstock foot.

Next bolt the headstock end to the base. Now with nuts on the allthread, start drawing the feet together to see if you can close up the gap. Check alignment. If you can get it back in alignment bolt the tailstock feet down, lock the nuts on the all thread.

If it doesn't work you aren't out much, and the lathe should have a good base anyway.

David
 
If you braze or weld the crack in the bed, you will most likely create warping issues which could destroy any alignment built into it. On the other hand, a crack like that could grow to the point where bed breaks in two.

I think that I would bridge the break with a short length of angle iron mating to the side bottom of the bed, drilling and tapping holes into the casting. An L shaped piece, with a cross section something like this:Mend Plate.JPG

You may have to cut relief for the half nuts, depending on the location of the break and you should clean up the casting for a better fit. I would use flat head screws on the front surface for clearance for the apron but the back and bottom can be hex head or socket head screws. I would also bed the angle with epoxy to fill any irregularities and help to stabilize the mend.

It is possible that you could correct some of your alignment problems by loading a stout bar between centers to straighten out the bend caused by the cracks. I would do so with caution, however as rather than closing the gap, you may further the crack. Perhaps a better idea would be to use two bar clamps to pull the lathe feet together.

You won't be able to restore the lathe to pristine condition but you will be amazed at how much you can do with a less than perfect machine.
 
I think if you consider my post and RJ's you may be able to still get a useful lathe. I was thinking of "sister" strips or "fish plates" over the crack along with JB weld once all is brought back to true.

You can'/t make it any worse and I think you could make a huge improvement.

Let us know what you decide.

David
 
I'm afraid that I have to disagree with any attempts to weld a cracked lathe bed. The lathe already has too many issues with alignment. Any welding will most likely just add more. Given the number of Atlas parts that turn up on eBay, there are a lot of beds floating around. You just need to find one with good ways.
 
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