Starrett Level Help

[sped35]

Please help me answer a dumb question? I have been trying to figure out what the differences are, between the Starrett Mechanics 98-12 and the Precision 98Z-12 levels. I've been checking online and different catalogs. What am I missing here? What is everyone using to set their machines up?

 

[joe_m]

They are the same tool but the Z comes in a fitted wooden box and the other doesn't.

 

[Old Iron]

I use 2 Lufkin 12" levels made by Starrett the same as the 98-12 both are in wood case's.

Paul

 

[fastback]

I am not so sure that that is the complete answer. I went to the Starrett site they have 4, 98 - 12 levels 2 are with the Z and 2 are with out. Each one has a different price. The Z's do have wooden cases but 2 different part numbers. In reading the specifications they all look the same, unless I am missing something.

I have and use a 98 - 18 I purchased at an antique shop. I was able to get it for $75, I noticed that he vile was not completely filled the bubble was just a bit over sized and made the reading just a little harder. Since I live in Mass I decided to take a ride to their factory. Well it ended out costing me around $135. I guess I ended out saving around 100.00 over the cost of a new one. Oh, my level originally started out as a model 97, that predates the model 98, but with the changes it is now a 98. This level is accurate to .005 per 10-inches.

Another Paul

 

[OldMachinist]

You can get the 98-12 four ways. 98-12 (part #50443)is the just the level, 98-12 w/slc(#66934) is level with letter of certification, 98Z-12 (#50446) is level with wood case and 98Z-12 w/slc(#66933) is level with case and certs.

 

[fastback]

Wow, so that certificate is pretty expensive. I would think that people that buy this level would expect it to be very accurate which I'm sure they are, but to have to pay extra for a certificate. Well that sucks. I guess what I am saying is I could buy a over the pond for less and most of them are rated a.0005. Don't get me wrong I really like my level and I did get a ticket not certificate indicating it was good for .005 I just think that if it is not certified it maybe should be less. That's my opinion anyway.

Paul

 

[lotechman]

I matched up an old Starret precision level with my two foot Stabila digital. The Stabila is good to tenths of a degree and is what I would call good construction grade in today's world. From what I could tell by placing a small wire under one end then removing it there was no greater sensitivity between the two.
I am sure that certifications are important but from a practical point of view there are some really good levels on the market that are very sensitive. I used the Stabila for my lathes and milling machine and I am happy.

 

[OldMachinist]

For places that have to have all their metrology tools certified to ISO or ANSI specs it can be cheaper to buy a tool with the certs vs having to send out a brand new tool to be certified.

 

[fastback]

Just wondering, do they need to be recertified from time to time? Is that something that can be done in house or must they be sent out?

 

[jmh8743]

http://www.ebay.com/itm/26111795164...l?_from=R40&_sacat=0&_nkw=261117951643&_rdc=1

This is an eBay item LOOK at it. look at this and the 10 second bubble radius. I do not see a means to adjust. If it does, then.....

Then look at the starrett. The Starrett:

http://www.starrett.com/metrology/m...urrentPage=1&displayMode=grid&sortBy=none/asc


Basically they used the SAME BUBBLE until they get to the "precision". All their levels on this page are adjustable. This is needed because at some time it will be dropped. I looked a each item on this page.

"80-90 seconds graduations or .005" per foot (0.42mm per meter)" meaning that it is capable of resolving about 1/2 mm in 1 meter or 0.005" per foot.

As the price goes up the vial does not change BUT the GROUND lenght does. That is the big ticket. If the surface is long and flat, short is OK. If surface is rough, need long base.

That is UNTIL you get to the PRECISION grade. "Ground and graduated main vial of 10-second accuracy; one division equals 1/2 thousandth (0.0005) of an inch per foot, or 0.04mm per meter " Big difference. 3

So, in conclusion, if you want a longer lenght, if will cost. The bubble is the same. MEANING the graduations subtend the same angle of arc.

(Now adjustment is easy. Let me know if you want to know how AND you do not need a perfectly level surface.)

One minute of arc is 1" in 300 feet (about). This is 60 seconds. (really 57") OK?

So assume you need (want, require) 0.010 max error 4 feet away. This is your decision.

1 inch/300 ft = 0.003

.010/4 = 0.0025 <= this is 0.025" per foot.

(0.0025/.003)X60 = 0.8333 X 60 = 50 seconds. SO each readable graduation on the bubble needs to be less than 50" of arc for you to acheive your goal.

for what it's worth and respectfully submitted,


Mike

The guys below have told you what they used. This is the precision of your level.
I paid >$150 for my Bridge City 15 yrs ago. A thin paper strip, 0.003, causes it to move about 1/2 grad. It is only 8" long, but sensitive bubble. I have adjusted mine numerous times over the years.