# Adjusting a machinists level?



## scattermaster (Jan 7, 2018)

Hello,
I just got a PM1236 lathe and now I want get it leveled.
I bought an Accucize Master Precision Level, number  S908-C687 from Amazon.   It was not calibrated out of the box.
  It has instructions for adjusting it but it looks like they are a very bad translation from another language maybe...
  Anyway the instructions don't make any sense to me.
A tool was included with the level.  It looks like a tiny hook spanner.  I don't see anything on the level to use it on.
There are 2 slot head screws. One on top and one on the bottom.  They seem to be be pushing on something inside but it doesn't change the bubble position.
Any Ideas out there?
thx,
Jim
Edit, 
 I got brave and just started taking it apart.  Bingo, 
 Now it all makes sense.  I just wish the instructions would have been better.  Even just a picture would have been enough.
   Oh well.
  Now I can go level my level and then finish leveling my lathe.


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## john.oliver35 (Jan 7, 2018)

Please let us know how the Accusize works out for you.  The price is right on these vs american precision bubble levels, but would like to know if they are useful.


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## Bob Korves (Jan 7, 2018)

I have a 8" Chinese level that says .0005" per 10" resolution.  It checks out at those numbers, but is somewhat fussy to calibrate, and at that resolution it takes patience and care to get good results.  It works, and gets the job done.  I paid about $80 for it new.  They have ones like it and also many others on eBay.  Be sure to understand how levels work, and how they are calibrated and zeroed..  Length does not give you accuracy, names like Starrett do not give you accuracy, fancy looks do not give you accuracy.  You must know the resolution.  Electronic levels are an even sillier game.  Make sure you know very well the meanings of accuracy, resolution, and repeatability before buying any electronic level.  Walk away from any electronic level that does not tell you all three numbers and the numbers are appropriate.  It is very easy to get cheated by not understanding what is really being sold.  There is a lot of stuff out there that might be useful for leveling your refrigerator but not much else.


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## Dabbler (Jan 7, 2018)

So...  I bought an offshore 8" machinists level, which was way off calibration.  The calibration screw was blue Loctited frozen and after much effort, I never did get it calibrated.  

Just bought a Moore and Wright 12" engineers level, off kijiji for 45$  it is perfectly calibrated, ans is wear, scratch and abuse free.  lesson learned.


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## EmilioG (Jan 8, 2018)

The level that I'd like to have is a Pratt-Whitney. Hard to find in good condition and expensive.


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## Tim9 (Jan 8, 2018)

From what I remember, basically you need to find a relatively level surface first.
   Let me first point out the method of checking a level. When placed on a level surface the level bubble will be centered.
  Now, you will rotate the level 180 degrees. It should still be centered.
  If the bubble isn’t centered, I’m guessing you can take it from there and move your adjustment in order to have the bubble centered. You can also use a shim gauge to make a “level test surface “
  The main key is the rotation of the level 180 degrees and the bubble still in the same place.
Check out the “calibration “ segment from wiki. 
https://en.m.wikipedia.org/wiki/Spirit_level


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## hermetic (Jan 8, 2018)

Find a flat and reasonably level surface, a surface plate is ideal, but any smooth surface you can make a mark on with pencil or chalk will do. place the level in the centre of  the surface, allow time for the bubble to settle,and check the reading. If the bubble reads level you can start calibration. If it does not, begin to rotate the level 1/2" at a time, allowing the bubble to settle between moves until you find a position on the surface where it reads level. When you have it reading level, draw a line on the surface down the edge of the level, and mark the position of the ends. now rotate the level 180 degrees, and put it back against the marked position on the surface, if it reads level, you are good to go! If not, adjust the bubble to remove HALF the error, rotate 180 deg and check again. Continue until the reading is exactly the same when swapped end for end, and you have it! This method assumes your level is somewhat close to being correct, if it is a country mile out, you may have to repeat the whole process a few times to home in on the dead nuts setting. hope this helps!


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## scattermaster (Jan 8, 2018)

Unfortunately I don't have anything that I can trust to be level.  Soooo, 
 I"m forced to use my unlevel lathe.   First I leveled the lathe without tampering with the level adjustment.
 Then, adjust and go back and work on the lathe again, then back to the level...(repeat)
   Kinda sneaking up on it.  I think I have it pretty close now.
 One bad thing, If I move the level to different places on the ways the readings change.  A LOT.
   I haven't stoned the ways but there are no visible burrs.  I only wiped them off with a clean rag.  Before I pass too much judgment I'll try stoning them but right now it seems like the ways are not ground straight enough to make the level happy.  (China...)


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## chips&more (Jan 8, 2018)

IHMO you bought a level that is WAY too sensitive for doing a lathe. It’s a good idea to have a lathe perpendicular to gravity (level) but not necessary in most shops. Getting the twist out of the bed thought is very important. With that level you have you will pull your hair out trying to find out what’s level and not level. I would get another level not so sensitive. And then when setting up your lathe pay very close attention to bed twist. Even the Starrett master level is 0.0005”/ft and that can be hair pulling!…Dave


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## scattermaster (Jan 8, 2018)

Yeah, I didn't know when I bought it. I just thought I needed a "machinists level".  After playing with it last night I can see what you're talking about.
 It's so sensitive I can see flaws in the ways.
   I'll have to see how it goes for now.  I'm kinda Waaaaay over budget already.


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## ttabbal (Jan 8, 2018)

If you have a "regular" level (carpenter's level, hardware store level, etc)... Use that first. Get close, then use the machinist level.

Note that to calibrate a level you don't need a level surface. You need a somewhat FLAT surface. Your workbench is probably good enough, though a real surface plate is ideal. You rotate till it reads level, then flip 180 degrees in the same exact spot to prove the level calibration. It took me a bit to get my head around why it works, but it does. The downside to these hyper accurate levels is the accuracy itself. Put a hair under one side, and it detects it.  And don't touch it too much, heat expansion matters too. 

You might try getting both ends across the ways reading the same on a normal level, then use the 2 collar test to dial in the lathe's twist. You want the lathe to cut without a taper, the actual "level" isn't really that important other than the "round stuff rolls off it" factor. I would want it "regular level" for that alone, but for cutting straight it's not the most important bit.

Note this is all from me reading a LOT of stuff while I wait for my lathe, I've never done it as I don't own a machine yet, so I may need to be corrected.


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## f350ca (Jan 8, 2018)

Finding a surface area level to the accuracy of your tool will be virtually impossible. Use something solid as a base, as suggested mark the position of the level. Now add shim stock to the end till you get the bubble to centre. Measure the shim stock, then replace the stack with exactly 1/2 the thickness. Then on this created surface adjust the bubble to centre. Rotate the tool 180 degrees as a check. Repeat as needed.
I've never calibrated my 0.0005 in 10 inch one, as long as it reads the same at both ends on the bed I know there  is no twist and thats all I care about.

Greg


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## mikey (Jan 8, 2018)

In order to calibrate a precision level you need two things: a level surface and a reference to orient the level precisely when you flip it 180 degrees. 

I suggest you make a leveling table. This can be a simple piece of plywood. I use a 3/4" thick piece of Melamine coated plywood with three threaded inserts in a triangular arrangement. Bolts with nylon feet are used to level the table. In use, I clamp a small aluminum framers square to the table and then roughly level the table with a bubble level. This takes me all of 45 seconds. The table is now level and the square gives me a reference so that when I flip the machinist level end for end, it is exactly the same place.

Then follow the instructions provided in the attached document. 

My Kinex level is one of those really sensitive ones - 0.0002"/10" - and I use it often to check the level of my lathe. Before I use it, I check the calibration and most of the time it requires no adjustment but at least I know that it is reading true. I guess I'm in the minority but I happen to think that these sensitive levels are quite useful because they save time. I also own a Starrett 98 and my Kinex bubble will move an entire unit without the bubble in the Starrett even budging. When the Kinex says the lathe is level, I am maybe a cut away from dead level using a 2-collar test. So, for me, it is faster to have a good level.


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## epanzella (Jan 8, 2018)

I have a chinese machinist level .0005 x 10". It's pretty close but not dead on. As I only use it to set up my lathe I couldn't care less that it's slightly off.  It has a red mark on one end and I always use it in the same orientation across a cupla 123 blocks on my ways. It doesn't matter if the lathe is absolute level to .0005, all that matters is that the level reads the same over the length of the bed and there's no twist.  When done with the level turn a test piece and if that's good you're done.


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## RJSakowski (Jan 8, 2018)

scattermaster said:


> Hello,
> I just got a PM1236 lathe and now I want get it leveled.
> I bought an Accucize Master Precision Level, number  S908-C687 from Amazon.   It was not calibrated out of the box.
> It has instructions for adjusting it but it looks like they are a very bad translation from another language maybe...
> ...


The LocTite'd screws should not be touched .   My level has two end caps which can be removed by inserting an M4 screw and pulling.  Inside, you will see the adjustment nuts.You have to turn the both the same way, first loosening on and then tightening the other.  I would suggest that you take some pains to get you surface close to level.  While you can rotate the level on any surface to find a horizontal line, the level is affected somewhat by the level at right angles.  That is why there is a cross level vial.
I use my 9 x 12" surface plate and place shuims at three points  under it to level it.  I find that a couple of feeler gages work well.  Place a washer under the plate at the center of one side and the feeler gages at the corners on the opposite side.  Adjust the shims yto level in all directions.  It isn't necessary the the plate be perfectly level.  If it is off by a couplr of divisions, the calibration will still work,  You're just looking at having thwe same reading when you flip the level 180º.


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## scattermaster (Jan 9, 2018)

Well, 
 I did my 1st test cut last night.  I chucked up a piece of 3" alum. bar stock and cut about a foot of it down about .040".
 I checked the new diameter with a dial caliper and couldn't see any taper.  I know that's a really crude way to check but I was in a hurry and didn't feel like digging for my mics.   For now it looks like I got it pretty straight.


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## Technical Ted (Mar 23, 2018)

RJSakowski said:


> The LocTite'd screws should not be touched .   My level has two end caps which can be removed by inserting an M4 screw and pulling.  Inside, you will see the adjustment nuts.You have to turn the both the same way, first loosening on and then tightening the other.  I would suggest that you take some pains to get you surface close to level.  While you can rotate the level on any surface to find a horizontal line, the level is affected somewhat by the level at right angles.  That is why there is a cross level vial.
> I use my 9 x 12" surface plate and place shuims at three points  under it to level it.  I find that a couple of feeler gages work well.  Place a washer under the plate at the center of one side and the feeler gages at the corners on the opposite side.  Adjust the shims yto level in all directions.  It isn't necessary the the plate be perfectly level.  If it is off by a couplr of divisions, the calibration will still work,  You're just looking at having thwe same reading when you flip the level 180º.



I just got one of these: https://www.amazon.com/gp/product/B00K1NOK3E/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1

Seems to be pretty nice and so far is working well. I just finished calibrating it and will be using on my lathe soon. Mine is similar in that it has the removable end caps, but it also has a removable cap directly under (on the side of the level) the LocTite'd screw, that is used for calibration. You reach in the opening and turn the collar with the spanner. Mine only has one calibration screw/collar to tweak. I, like others, wondered why they gave me that little spanner wrench when there was a screw on top that appears it could be for calibration. The instructions that came with it were USELESS! So, I pulled one of the plastic end caps off and looked inside. That told the story.

Ted


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## arvidj (Mar 23, 2018)

My solution is similar to the one Mikey suggests. I use a surface plate with three machinists jacks under it. A few quick adjustments of the machinists jacks will get it reasonably level in two directions using either a carpenters level or even the level I am trying to calibrate. The engineers level are are never THAT far off that I can't at least get the process started and I can refine things as I go.

The other thing I do is put two strip of masking tape on the surface plate at a right angle to one another and located on the plate such that the base of the level to be calibrated will (a) be in the center of the plate and (b) one side and one end of the level will 'catch' on the tape. Note that the base of the level is definitely on the surface plate but I can gently slide the side and edge of the level up against the tape when I swap it 180 degrees. That seems to make for quick and easy yet very repeatable positioning of the level on the plate.

Once I get the level reasonably close I can then use it to fine tune the leveling of the surface plate and wash, rinse, repeat until I am satisfied.


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## tq60 (Mar 23, 2018)

For leveling a lathe the calibration does not matter a bit...follow me here.

Only thing relevant is the ways are straight and not twisted. Period. 

So place a piece of tape on top of one end if there is not an obvious difference.

Place the level in different places as needed but ALWAYS use the same way.

Meaning if resting level across the ways near the chuck place the level either way but choose one that allows the bubble to just touch a line if it is different.

Note which end is towards the front then move it to tail stock end and have it same directiin and adjust until bubble touches same line or is in same place.

Regarding calibration it is same as a square, simple to do.

Place it on a stable and solid place like across the ways.

Note where the bubble is then rotate it 180 and see if it is in same place.

Adjust 1/2 way to where it was if it moves and repeat until turning makes no change.

Once this is done you can find a level spot or make one via a chunk of 2 X 4 with 3 screws then rotate and adjust for no change and exact center.

Easy to do but takes time.



Sent from my SAMSUNG-SGH-I337Z using Tapatalk


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## Bob Korves (Mar 23, 2018)

tq60 said:


> Only thing relevant is the ways are straight and not twisted. Period.


Ultimately, the only thing needed is for the lathe to cut straight and square and without taper.  Whatever it takes to get it there works.  Straight and parallel ways are probably the best place to start.


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## arvidj (Mar 24, 2018)

tq60 said:


> For leveling a lathe the calibration does not matter a bit...follow me here.
> 
> Only thing relevant is the ways are straight and not twisted. Period.


Agreed. I didn't say what I used it for once it was calibrated. Just responding to the title about how I calibrated mine.

The method you suggest is similar to the one Mikey and I suggested. I just happen to have the surface plate and machinist jacks handy.


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## woodchucker (Mar 24, 2018)

scattermaster said:


> Unfortunately I don't have anything that I can trust to be level.  Soooo,
> I"m forced to use my unlevel lathe.   First I leveled the lathe without tampering with the level adjustment.
> Then, adjust and go back and work on the lathe again, then back to the level...(repeat)
> Kinda sneaking up on it.  I think I have it pretty close now.
> ...


it doesn't have to be level, you just have to read the same when you flip it 180.
So if it's just on the first tick, then when you flip it 180 it needs to be on that tick...


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## 100LL (Mar 24, 2018)

What would a metrology shop charge to calibrate a 199 Starrett master level?  Ballpark.  Just curious


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## Bob Korves (Mar 24, 2018)

Calibrating a bubble level is a not very difficult shop job, not a metrology shop job.  About the only thing you can do to a bubble level that is not physically damaged is adjust the vial, and the vial is self proving.


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## ddickey (Mar 24, 2018)

Slowly rotate your level on a surface plate. At some point in the rotation your level will find level.


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## 100LL (Mar 25, 2018)

SO what’s the point in buying a high quality machinist level?  Is there any point?


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## JimDawson (Mar 25, 2018)

100LL said:


> SO what’s the point in buying a high quality machinist level?  Is there any point?



It allows you to get two ends of a surface in the same plane, like a lathe bed.  Most machine tools don't need to be level, but they can't have any twist in them.  Level or ''square to the earth'' is a good point of reference.  The more accurately you can read that point of reference the more square you are going to be.


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## woodchucker (Mar 25, 2018)

100LL said:


> SO what’s the point in buying a high quality machinist level?  Is there any point?


it's very easy to calibrate.  Don't overthink this. A machinists level is very sensitive. But also very calibrateable. you want it to read the same in either flip of 180.  Then it is calibrated.


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## Bob Korves (Mar 25, 2018)

The 199 is quite sensitive, so be ready to take your time calibrating it.  It takes some time for the bubble to center, and the level should be tested in exactly the same position with 180 degree end for end turns to achieve the same reading with the level facing both ways.  The surface should be level enough that the bubble lines up somewhere near center, with the end of the bubble within the calibrated lines, and spotlessly clean, no debris at all that can cause erratic readings, also a rigid enough setup to not move around.  Some kind of fences, like steel bars, can be laid out for returning the level to the same location for each test.  Give yourself lots of time to be able to get it right.  Sometimes it goes quite quickly, other times it takes longer.  The first time can possibly be quite slow, until you get the hang of it.  The bubble needs to give the exact same reading with the level in both positions.  It never needs to be in the center for doing the calibration.


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## woodchucker (Mar 25, 2018)

Bob Korves said:


> . It *never *needs to be in the center for doing the calibration.


slight correction: It *DOESN'T *needs to be in the center for doing the calibration.  
Both statements are correct. if it winds up being in the center, well, hey you are lucky. But it doesn't need to be. It just needs to read the same.
Bob's idea of a fence is a good way of ensuring the same position. BUT always wipe with your fingers both the surface plate and the level b4 setting down to remove any dust. A machinists level is so sensitive a spec of dirt or dust can affect the reading.


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## RJSakowski (Mar 25, 2018)

100LL said:


> SO what’s the point in buying a high quality machinist level?  Is there any point?


There are two things which distinguish a machinists level from the garden variety level.  The first is the sensitivity and the second is that the base is very very flat.  

A typical carpenter's or mason's level has a sensitivity of .1"/10" whereas a Starrett series 98 has a sensitivity of .005"/12 " or 240 times better.  The Starrett 199 series has a sensitivity  of .0005"/12" or 2400 times better.


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