Can anyone identify these markings?

[DSEL74]

I was told the markings are the "Grade" for precession of the grinding. I thought my surface plate was a "AAA" so these marking have nothing in common with that.

The item was made in the USSR and came out of the Boeing Factory.

302782

[DSEL74]

I found this reference in regards to calibrating during manufacture of a vernier calliper.


5. Inspection of straightness deviation of the jaws measuring surfaces
Means of verification – a straightedge type LD of the accuracy class 1
according to GOST 8026-75, reference gauge blocks of the accuracy grade 1
according to GOST 9038-90 and an optical flat type PI 60 mm of the accuracy
grade 2 according to GOST 2923-75.


So I am guessing this is a reference to part of the making, but still no clearer in understanding it.

[.RC.]

USSR and now Russia are metric...

The grading system AA, A and B are imperial...

Metric is 00, 0, 1

B and 1 are workshop grade...

Gost 8026-75 seems to be a Russian Standard...

[DSEL74]

Any ideas on the :
(Symbol) 6 K n(looking thing) 1 L(upside down) OCT????


I guess the small symbol could be a makers mark.

Ending in OCT, i thought maybe it was a date, but October is Октя́брьская so it would be OKT not OCT

[DSEL74]

Upside down L is g in english
The square n could be I

But that still doesn't help me at all.
http://www.stsavaskola.net/The_Russian_Alphabet.gif

[DSEL74]

google translate gives me this

6 кл 1 г ОCТ = 6 cl 1 g OCT
Russian = English

[RayG]

Hi Dale,

How big is the surface plate? Any more pictures?

Here is the ISO standard for surface plates... but it's the standard for Granite.. http://www.backsaw.net/ISO8512-2.pdf

I don't have the one for cast iron.

Ray

[Evanism]

Just emailed Ilya, he's Russian

[DSEL74]

Ray I have 4 surface plates the largest is at a guess 1200 x 600mm the other three are small ones.

Just to clarify as looking back at my original post it may be unclear the markings I am trying to decipher are off a Cast iron straight edge. I was just referring to the surface plate as my only experience with this type of grading the other items I have are all unmarked, large and small Vee blocks, parallels etc.

[DSEL74]

Just emailed Ilya, he's Russian
Thanks Evanism, hopefully he can shed some light on it.

[Ilya]

ГОСТ is the abbreviation for the 'National Standard". According to the web site of russian standards, this particular standard is now replaced with the new one, and I couldn't find a copy of the old one. It is hard to read that technical language, but this standard apparently defines some measuring precision for rulers, micrometers, etc. I will try digging more later today.

[Ilya]

I found that the straight edges 1.6m that satisfy this standard cost (depending on style) from $600 to $1500 in Russia. That must be a pretty straight straight edge.

I am not a big expert in precision, but it looks like the precision is marked by "кл 1", аnd I am not sure what it means. I just found that these sort of straight edges can be used to test flatness down to at least 0.02mm.

[DSEL74]

Ilya, Looks like your on the right track and thanks for the info you've managed to find.


test flatness down to at least 0.02mm does that mean 0.02mm over 1.6m???


"Symbol" "6" "кл 1"(Grade of precision) ГОСТ is the abbreviation for the 'National Standard" 8026-75 (gives us the Gost 8026-75 Russian Standard) USSR obviously the place of origin.

I wonder how the "6" relates to the "кл 1" could it be 6 in 1?? as in 0.006mm over 1m??

[Ilya]

It proves to be hard to find - a lot of lists with tools saying that they satisfy the standard, but cannot find what the standard means exactly. What is this thing that this is printed on?

[DSEL74]

Ilya, it is a large cast iron straight edge the I beam or parallel type not the hump back design.




Here is a conversation I had with a Russian Australian girl on facebook, she has no knowledge of tools and measuring…..she is a dancer. Her answers are in bold



I think it's 6kg and 1gram (кл= kilogram and г=gram) but might be different depends on the context ,..

It is the accuracy of a precision engineering measuring tool. It measures straightness or flatness.

1г is definitely to do with the mass.... But 6 кл could also mean class 6 (like a rating) And considering the item I'd say that's exactly what it means


So what does the г mean? Is that definitely grams or could it be another weight? It is a huge piece of iron.

I don't think it's there because it's how much it weighs, I think that might be the marking for the precision of measurement ....

Is mass a factor when measuring flatness?

Not really……It could be if there was a level of deflection or expansion an contraction due to temperature but I doubt that would be relevant in this case. If it was made in England it woulsd say something along the lines of accurate to 0.002mm over 1m or over the length of the item. OCT referring to national standard (abbreviation) and 8026-75 being the actual standard being used.


And that is where I lost her.. lol

[Ilya]

There is definitely no weight information there, letter "Г" is the part of ГОСТ abbreviation. So "ГОСТ 8026-75" refers to the document.

"кл" is the abbreviation for "класс" - class, category. Definitely not kilograms, they have different abbreviation.

So far reading all those documents, my current guess is that 6 is the type of the straight edge (i.e. shape). "кл 1" is precision, which from general statements I found, mean relative 1% accuracy. At the same time this doesn't sound like really precise.

[DSEL74]

Means of verification – a straightedge type LD accuracy class 1 according
to GOST 8026-75; feeler with thickness of 0.02 mm and accuracy class 2
according to GOST 882-75.


In the document I am reading if the straight edge is a class 1, and the item being tested is a class 2, if it has a 0.02mm gap it fails to pass as a class 2.

So it would suggest that class 1 would need to be above 0.01mm.

How accurate do you need to be when building a Boeing 744??? I think I need to also look at what similar items are accurate to.

[RayG]

In the document I am reading if the straight edge is a class 1, and the item being tested is a class 2, if it has a 0.02mm gap it fails to pass as a class 2.

So it would suggest that class 1 would need to be above 0.01mm.

How accurate do you need to be when building a Boeing 744??? I think I need to also look at what similar items are accurate to.

Hi Dale,

0.0001" per 12" (0.01 mm per meter) is ball park for precision cast iron straight edges.. Still need to see what it looks like tho, is it camel back? parallel sided? how long is it?

Ray

[DSEL74]

302829 Its 1000mm long

302830

302831 Little light surface rust on the ends which I will have to address soon.

I said it was cast but it may be milled? The centre has flycutter marks, but looks grey under the flaking black coating.

[Stustoys]

I'm wondering if it's a staight edge(or at at least what "we" call a straight edge)?
It looks way to light. More like the biggest parrallel I've seen....Maybe for set ups on a plate?

Stuart

[RayG]

Hi Dale,

It looks a bit on the thin side as far as the rigidity required in a precision straight edge. Although the Suburban style might not be much deeper? CAST IRON STRAIGHT EDGES by Suburban Tool, Inc. (http://www.subtool.com/st/se-ci_cast_iron_straight_edges.html)

The working surfaces should be ground, rather than milled.

Ray

[DSEL74]

it is a lot lighter than the hump backs I have seen and some of the parallels even.

The edges are ground, its the channel down the middle has mill marks under the paint or coating.



Dimensionally it is similar to this one in Rays link but lighter still, 1000mm x 15mm x 60mm


MODEL
LENGTH
WIDTH
HEIGHT
WT(#)
PRICE
(US$)










SE-36-CI
36"
1-1/2"
3"
27
$ 741




There are precision straight edges that are thinner than this which look like large blank rulers. What would you guys suggest it is then???

This still would be useful in setting up machines and marking out operations on the surface plate I hope. Or did I waste my money??

[DSEL74]

Made in USA not USSR 0.0003" over full length.Taft-Peirce STEEL STRAIGHT EDGES by Suburban Tool, Inc. (http://www.subtool.com/tp/9169_taft-peirce_steel_straight_edges.html)

looks just like it.

http://www.subtool.com/tp/imgs/9169-24%20Steel%20Straight%20Edge.jpg


MODEL #
LENGTH
WIDTH
HEIGHT
STRAIGHT &
PARALLEL
WT (#)
PRICE
(US$)











9169-36
36"
3/8"
2-1/2"
0.0003"
9
$ 935





Made of heat treated alloy steel.
Edges precision ground, parallel and straight.
All sizes are proportioned for proper balance between rigidity and weight.
Sizes 24" and longer have marked support points which should be used to minimize deflection due to gravity.
When not in use, these straight edges should be hung vertically by the hole provided in one end.








STRAIGHT EDGES
NO. 9169 SERIES

http://www.auto-met.com/subtool/taft/img/taft_9169.jpg


Taft-Peirce Steel Straight Edges provide an extremely accurate reference surface for scribing straight lines and for checking surface straightness and flatness. All sizes are proportioned for proper balance between rigidity and weight. Sizes 36" and longer have marked support points which should be used to minimize deflection due to gravity. Properly supported and cared for, these straight edges will retain their accuracy almost indefinitely. When not in use, they should be hung vertically by the hole provided in one end. Steel Straight Edges may be readily self-checked by inverting them on proper support points and indicating both sides at the center.

SPECIFICATIONS
No. 9169 Steel Straight Edges are made of high quality alloy steel, scientifically heat treated for maximum stability and wear resistance. Edges are precision ground parallel and straight within limits listed in the table below. Orders should specify both Style Number and Length.
Checking the accuracy of a properly supported Steel Straight Edge. One edge is indicated in the center as shown;then the straight edge is turned over and the opposite edge indicated in the same manner.




302846

[.RC.]

They are for checking straightness on things.... Like engine blocks and other things that need to be flat.... You put feeler gauges underneath or look for light....

Would be handy to have...

Straight edges for scraping purposes are only much heavier because they are 50mm+ wide and need extra support to stop that extra weight from warping....

[DSEL74]

Just had a 80+ year old engineer turn up to visit, so I thought I'd get his opinion on it. In his opinion it is a straight edge and he had used plenty of that same size and design. He used to have one the same which he used as a master to make smaller straight edges. So that is reassuring.


Still would like to know what the markings are though.

[Machtool]

I had with a Russian Australian girl on facebook, she has no knowledge of tools and measuring…..she is a dancer. Her answers are in bold

I don't suppose we could see a picture of the dancer? R.C's in the market for a good woman.

Just kidding. Phil. :D