Machinist's Level help

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seal killer
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Machinist's Level help

Post by seal killer » Mon Aug 31, 2020 4:49 pm

All--

I recently moved my equipment to its new home. Now it is time to level the lathe. I have a machinist's level, pictured below. [Well, I guess it's not pictured below. I must have forgotten how to add pictures.] I used it years ago when I bought the lathe. I used it straight out of the box and achieved what I thought were good results; the lathe performed well for me.

Since the level was stored and moved and (maybe) banged around in whatever box its box was in, I want to make sure it is accurate. Unfortunately, the instructions for doing this are totally indecipherable (read: made in China).

Should I trust it or use one of the various non-machinist levels I have and see how that turns out?

--Bill
You are what you write.

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liveaboard
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Re: Machinist's Level help

Post by liveaboard » Mon Aug 31, 2020 6:39 pm

I also have some questions about this subject; I'm not sure what qualifies as a machinist level.
this ebay article is advertised as such, I'd like to know what people think. Is it likely to be useful?
https://www.ebay.co.uk/itm/Stanley-New- ... SwriZep00e

Bill; you can level an item and then turn the level the other way around. If it's still on, it's on.

ChipMaker4130
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Re: Machinist's Level help

Post by ChipMaker4130 » Mon Aug 31, 2020 7:28 pm

Go ahead and use it. Accuracy means nothing, sensitivity is what matters. Unless you consider coolant drainage, for which a carpenters level is adequate, a lathe needn't be level at all. Just flat. Therefore you can 'level' your lathe with the bubble a couple of graduations off center, so long as you get the same reading in the same direction on both ends of the bed. I might add that for a level of unknown 'accuracy', do NOT flip the level end-for-end during the setup.

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pat1027
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Re: Machinist's Level help

Post by pat1027 » Mon Aug 31, 2020 8:00 pm

Set it on something level or reasonably close. See what it reads. Turn level 180 degrees and see if it reads the same. I set mine with a machinist level then turned a test bar.

John Hasler
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Re: Machinist's Level help

Post by John Hasler » Mon Aug 31, 2020 8:51 pm

To adjust a level set it on something not quite level: just far enough off that it reads somewhere near its maximum when up and down the slope. No need to be precise about this part. Any surface will do as long as the level doesn't teeter.


1) Rotate the level until it reads zero.

2) Set a block of some sort (a magnet, on steel or iron) against one end and another against a side to mark the exact position.

3) Rotate the level 180 degrees and set it against the blocks. It should read zero.

4) If it doesn't adjust out half the reading and go back to step 1.

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BadDog
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Re: Machinist's Level help

Post by BadDog » Mon Aug 31, 2020 9:51 pm

As stated, a level being used for "leveling" is wonderfully self referencing. No special calibration required, unless you need to quantify the angle off level normal to gravitational force.

Assuming a reasonable vial quality, you just put it on something stable that is close enough to level to get the bubble into the scale. For example, adjust your lathe enough to get it in scale, then use that. Note where the bubble sets on the scale, and then rotate 180*. Assuming no trash or other variables, if the bubble isn't the same, then adjust to split the difference, rinse, and repeat until desired accuracy is achieved. As long as everything is clean, and there is no variability in the reference surface contact (for most practical flatness), then that provides your calibration.
Russ
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seal killer
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Re: Machinist's Level help

Post by seal killer » Tue Sep 01, 2020 9:41 am

All--

As I wrote to dpeterson3 in his thread "Setting up first shop", questions are quickly answered by very knowledgeable people.

Thank you All for helping me!

BadDog, yesterday I did exactly that: I put it on the lathe (along with a six inch carpenter's level as a gross check) and brought the bubble within "shouting distance." Now that the level and the lathe have had time to thermally equalize, I will note the bubble location, flip the level 180* and adjust half the difference, if any, then repeat as necessary.

--Bill
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Harold_V
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Re: Machinist's Level help

Post by Harold_V » Tue Sep 01, 2020 3:49 pm

Do keep in mind that a level of low quality may not display error that can be the cause of tapered cuts. While level isn't critical, bed twist is, and that can't be displayed by the common 6" level. It simply can't discern small amounts of error.

It is desirable to use a high quality machinist level when setting up a lathe. The Starrett 199 or 199Z is a good example, although a similar level is made by others. They have the ability to resolve a half thou (.0005") over 12".

I would suggest that a level with the ability of the Starrett 98 be used as a minimum if you hope to achieve reasonable level.

H
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Bill Shields
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Re: Machinist's Level help

Post by Bill Shields » Tue Sep 01, 2020 3:51 pm

请按照说明进行操作
Too many things going on to bother listing them.

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liveaboard
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Re: Machinist's Level help

Post by liveaboard » Tue Sep 01, 2020 4:15 pm

Starrett 199 sells for about the price I paid for my lathe.

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BadDog
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Re: Machinist's Level help

Post by BadDog » Tue Sep 01, 2020 4:32 pm

From what I've read, and what I think I understand, the 98 is generally considered plenty accurate for leveling machines. I picked up a 12" and a 6" over the years for not much money.
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liveaboard
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Re: Machinist's Level help

Post by liveaboard » Tue Sep 01, 2020 6:09 pm

I did some reading; correct me if I'm incorrect.
Mainly what we need is sensitivity. Accuracy can be adjusted.
"regular" levels are not too sensitive, that would drive everyone nuts. The difference is the radius of the vial, high sensitivity ones are nearly straight.
And should be ground internally.
There are Chinese ones for $20 new. With import duty + tax, that will be $30 for me if I manage to get it through customs.
Otherwise, it's more like $80-100 minimum for used known name ones.
That's a lot for me; and with my wonky worn out lathe, I'm far from confident it would do anything to improve my sense of right and wrong.

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