Lathe leveling - do you do it with the lathe fully dressed or just the headstock and ways?

[Firstram]

If the lathe is going to stay there, why not approach this from a different direction.

I think you mentioned that you have a welder. Weld some angle iron clips on the bottom of the legs and bolt it down to the floor, use the leveling screws on small pads to roughly level the stand. X-brace the stand ends and back with 3/8" round stock (or rebar). When you do this, leave a 3/16" gap at 1 end of each rod so the weld pulls the rods tight as it cools. Once the stand is as solid as the floor, you can add a piece of 1.5 or 2" square tubing under the head stock. Level that tube front to back (to establish the plane of your lathe), weld it to the stand and use longer bolts to hold that end down solid.

On the tailstock end use long fine thread bolts and 3 nuts to make jacking screws. All of your "leveling" and twisting can now be done against a solid base while you're standing up.

 

[Larry$]

Seems like your lathe has a twist in the bed that is more than just the weight of the bed can take out. Fastening the steel stand to the floor and using the adjusting bolts to pull the twist out may be your only solution. Cast iron isn't totally stable. Old Iron has had a chance to slowly stabilize the stresses that were built in to it when it was poured. Ideally those stresses would have been allowed to get out before it was machined. If they haven't the machined surfaces will change over time. There are ways to speed the process. But they take time & $. Therefore the likelihood that they have been fully carried out on cheap iron is less likely. I'm pretty sure that Sears and Monkeyward equipment along with some far east import stuff falls in that category.

My personal experience with the warped iron thing was many years ago. I had bought a new Powermatic 6" jointer. The fence had a very obvious curve. The dealer said that was common and I just had to live with it. I called PM and asked for a technician. Got an experienced man that told me how to fix the curved cast iron fence. Turned out to be dirt simple and worked. Put the fence on two pieces of 2x4 on the floor. Stand in the middle and bounce up & down increasing how hard until you feel it give. The "give" was very obvious. I was sure I had broken it. It was nice and straight!

The in & out feed tables has some of the same issues but I couldn't get them to straighten out. Tried the tapping with a hammer thing but to no avail. Finally sold the machine to a PM lover. I later found a used 8" PM jointer that was nice and straight. Later bought a 16" Crescent with warped tables. Had everything Blanchard ground, nice and straight. But over time it has developed a slight twist that I can't adjust out. Probably relieved some stresses when it was ground. I'm sure there are people that know more about cast iron on this site. Part of my education about casting came from spending 3 days @ the Cat plant. Watching them pour some serious castings and talking to their engineers. Neat place!

 

[WobblyHand]

I use a toolmaker's flat (a 9X12 Starrett) that sits on a 3/4" thick plywood base that has three threaded legs that run in threaded inserts. The tripod arrangement allows me to level the support/bearing surface under the surface plate, just like the article recommends. If you cannot adjust the surface your plate is sitting on then calibrating the level is going to be difficult.

This is the fastest and most accurate way to calibrate your level. I place the level on the surface plate and use 1-2-3 blocks to locate it so I can accurately flip it. If I recall correctly, I've only needed to do this once and my level has remained calibrated since. I also used the same set up to calibrate my Starrett 98-6.

Made a similar stand. Initially used rubber bumpers under the flat - that was a very bad idea. The flat would shift level over time. Deleted the bumpers and place the flat directly on the plywood. Took quite a while to get the flat within the range of the level. Eventually got the surface itself within 0.5 divisions and the level within 1 division. Since this is 0.02mm/M, that's pretty good. I had to stay in the same position and was perpendicular to the level long axis. If I was along the axis, my weight on the kitchen floor would make the bubble deviate by 2 divisions.

Well, on to the next part of this adventure.

 

[mikey]

You are right; walking on the floor can change the bubble. Even loud noises can do it. Crazy, eh?

You're close. Whether that is close enough is up to you but I bet if you get it level with that thing, you'll be close with the 2-collar test.

Precision levels are nice to have because they save you a LOT of time that would otherwise be spent doing test cuts on a 2-collar bar.

 

[chatter chatter cut cut]

im late to the party but i say build yourself a heavy duty wood tool storage bench with a 2 in top or thicker and load it up with everything heavy. then slide the lathe over onto it .mine is mounted on a 2 by 6 ft 6 drawer bench with 2 in top. if you use 2 4ft long straight edges clamped to the ways at right angles and leveled across the ends the lathe can be leveled very quickly. and the twist magnified at the ends will show instantly. my lathe only took .007 shim to get leveled.

 

[Firstram]

use 2 4ft long straight edges clamped to the ways at right angles and leveled across the ends the lathe can be leveled very quickly. and the twist magnified at the ends will show instantly.

Winding sticks work great! I use this method on any welding projects that are larger than my table.

 

[WobblyHand]

im late to the party but i say build yourself a heavy duty wood tool storage bench with a 2 in top or thicker and load it up with everything heavy. then slide the lathe over onto it .mine is mounted on a 2 by 6 ft 6 drawer bench with 2 in top. if you use 2 4ft long straight edges clamped to the ways at right angles and leveled across the ends the lathe can be leveled very quickly. and the twist magnified at the ends will show instantly. my lathe only took .007 shim to get leveled.

My experience with wood benches isn't that good. I have found they sag quite a bit over time. When first setting up the toolmaker's flat on my 2" maple top (30" x 60") workbench, I found that just touching the bench or placing tools on it, caused significant level deviation. This is a bench that feels solid as a rock. It was because of this that I set up the flat upstairs on a synthetic stone counter top in my kitchen.

Very much like your idea of long straight edges for error magnification. Will have to try that sometime.