lathe bed

I'm assuming it's a cast iron split down the middle and flat on top type of lathe bed. Yes, it could be made to level out again if you put enough of a crank on it. It could also crack the lathe bed eventually too. Depending on the lathe bed rigidity, amount of deflection, etc., you're going to have to have one heck of a board to bolt it to in order to get it back into alignment.

Give it a try,

- Andrew

In article , "AHilton" wrote: its more like two cast iron runners with a piece holding them together at each end(the runners are maybe 1/4inch max) hmm cracking the bed is bad... decision time, thanks.

If you do try and straighten it do it very, very slowly. I'm sorry I can't tell you exactly what that means but I would say over a period of days or even longer if the warpage is bad. Billh

Cracking the bed is certainly possible. It all depends on how much it needs to be adjusted.

If the difference isn't too bad, you might not notice it when turning anyway. Again, it depends on the projects you're doing. I have a lathe (a monotube bed type of one) that, basically, has the same problem (different cause though) with alignment that gets worse the farther out you have the tailstock. I use it for long, medium thick spindles (balusters around 4" diameter) and it doesn't make a difference. I can also use it for some bowls and hollowforms and it won't make a difference either.

No easy answers,

- Andrew

I really don't know much about cast iron, but was wondering if heating the bed somewhat with a butane torch would help in preventing a fracture prior to tightening the anchor bolts down?

Max

Some cast is annealed to be fairly malleable, some is quickly made and large-grained. The older the lathe, the more likely you have fine-grained iron, and can load it sl-o-o-o-wly without cracking. Shim the low broadly to distribute, pull the high with a clamp, leaving in place until the clamp itself seems loose before taking another half-turn

That said, it's probably going to warp what you strap it to before it corrects itself. You may be reduced to shimming in position when you move it.

That was my next question: can Reyd simply shim the tailstock into alignment? Might be the simplest fix.

Max

"Maxprop" wrote: (clip) can Reyd simply shim the tailstock into alignment? (clip) ^^^^^^^^^^^^ Shimming it into alignment will work only if the stand or bench is stiffer than the lathe. Also, if you shim it into alignment, you still have the risk of cracking it.

Sure. He'd have to reshim every time he moves the tailstock as it's not going to be the same offset at every point along the bed.

- Andrew

HI Reyd, With webs only at the ends it sounds like a very old maachine or an inexpensive lathe with the bed not well seasoned before it was ground or milled. Probably subsequent users didn't level it so over time it warped.

Suggestions in ascending order of foolishness not including scrapping:

1. Sell it and run
2. Cut off or shorten the bed and use as a bowl lathe or polishing head or jack shaft.
3. Use it as it is and let the tail center make its little circles or gouge its little tapers. Same as we turnerss with swivelling headstocks do. ;)
4. Decide on a permanent bench with a hardwood top. Fix quality fine thread steel bolts as large as will fit thru the feet with washers or steel plates top and bottom. Put the lathe over the bolts with adjusting nuts & washers over and under the foot pads. Using a quality machinist's level check at several spots crosswise and endwise along the entire _clean bed. Using very small fractional turns see if you can _gradually_ bring the bed into level with the adjusting nuts. permanently fix with double nuts.
5. Remove the stocks and banjo and with grinding paste and lots of sweat & elbow grease try to scrape the high spots level. Check by rubbng with hi-lighter ink on three different surface plates.
6. Have the bed ground or milled flat.
7. None of the above. This probably should head the list.

Arch

Fortiter,

Reyb,

This is the old lathe I sent you, yes?

So everyone has an idea of what you're dealing with...

Pics at:

In article , snipped-for-privacy@webtv.net (Arch) wrote: thanks for the ideas.

Probably subsequent users didn't level it so over

does the bed need to be perfectly level? would it not be good enough just to have it on a very flat surface?

cannot due to the style, the runners would be totally unsupported

worse then that, its about maybe 4-5 mm out.

thats what I figured, wasn't sure about cracking though.

? > 7. None of the above. This probably should head the list. nope:)

I was thinking of shimming in the various positions required - removable shims. Useable, but a PITA overall, and probably more danger to patience and sanity than iron.

Reyd, have you confirmed twist by use of winding sticks, or is it speculation that twist is the problem? As I look at the underside, I see what appears a Mickey Mouse tailstock block. My old beast, and most I've seen, uses a clamp block which helps align the tailstock by aligning itself in the channel. You can experiment with taped shims to eliminate play in the tailstock caused by wear _if_ the channel itself is not warped. Start with compensation for wear on the tabs that align it in the channel. Frankly, given the design, I'd be inclined to suspect wear and tear and the lack of a clamp block as the culprit.

Not always a good idea with cast iron. Could work well with steel, but cast iron is quite a rigid material which makes it good in compression, but does not take knocks and bangs well.

Alan

thought it might be at first, but its more out of alignment in diagonal direction, to and there is very little play in the tailstock, I can't rotate it at all, so it seems to be aligned side to side. but it has got its new bushings, and the tailstock is being welded up to repair the stripped screw part.

I looked at that, but the channel part has big reinforcement(i think) bumps on it, so it would not work very well, as it would need to be thin enough to move, but then wouldn't be big enough to align it.(is there an easy way to remove the bumps, while keeping the sides parrellel?

How about going to the scrap yard and getting a piece of I-beam. Drill and bolt it to the beam. Every once in a while when you think of it tighten the mounting bolts a LITTLE. More than likely it was twisted by mounting to an uneven wood bench so I would doubt the beam would bend before the bed. Give ya some extra weight to boot.

Bob, Naugatuck Ct.

That's entirely possible. As well, it spent "Idunnohowlong" in an unheated Winnipeg garage under a workbench.

djb

If you have access to a large enough surface grinder, and it's not TOO badly warped, you could grind the top.

You could also use a flat surface under the feet, putting a good dab of JB weld on each foot, setting it down on a set of washers, and leaving it overnight. I'd put a piece of wax paper under each washer first to be safe. Drill out any excess JB Weld after it has set up good.

The first will get you a flat top, the second a flat base. Neither perfect, but still a noticeable improvement until you can affford to upgrade.

Jim

Reyd wrote: