Combination square wear...

[bugbear]

I picked up a Rabone/Chesterman 1912 combo square over the weekend, for a friend who moving into her own flat, and needs a basic toolkit.

As usual, I checked the ruler for being straight and parallel. Holy Sh*t! At the stock end it was massively hollowed away on both edges.

Measuring shows a "waist" around 2" long a 3/100" (call it a 1/32" if you like fractions) deep.

I'm now in the process of removing this fault, and can confirm that the ruler is properly hardened, so the wear is not the result of a cheap, soft ruler.

EDIT; it's not hardened!

I cannot work out how this much wear occurred - the tool doesn't appear to have been abused, the head has most of its paint, and the rule is otherwise not excessively dinged or marked.

BugBear

 

[matthewwh]

If you suddenly find that your flattening gets easier it could be that the rule is case hardened - 'crunchy on the outside, soft on the inside'.

 

[David C]

That bad habit of sliding the square when checking component squareness?

David

 

[bugbear]

That bad habit of sliding the square when checking component squareness?

David

Hmm. If you did that whilst checking a BRICK for squareness, it might just explain what I'm seeing :lol: :lol: :lol:

These tools are used by site carpenters (and builders) who are not known for their gentleness!

BugBear

 

[Woodchips2]

Maybe caused by opening too many beer bottles :roll:

Regards Keith

 

[Peter Sefton]

I have a Robone Combination square that I bought when an apprentice it wasn't a cheap tool from memory. It has only ever had light workshop use but over the years has become very inaccurate. I kept it for use as a pencil gauge but that has now been replaced with an Incra T rule which is much better for the job.

 

[bugbear]

I have a Robone Combination square that I bought when an apprentice it wasn't a cheap tool from memory. It has only ever had light workshop use but over the years has become very inaccurate. I kept it for use as a pencil gauge but that has now been replaced with an Incra T rule which is much better for the job.

They're not cheap s/h on eBay - around 20-52 (!!!) quid.

BugBear

 

[Spindle]

Hi

A combination square should not be regarded as a precision instrument, however I am mystified and intrigued as to how BB's square has arrived at it's present condition - is the wear repeated to any degree at the other end of the rule?

Regards Mick

 

[tobytools]

Hi

A combination square should not be regarded as a precision instrument, however I am mystified and intrigued as to how BB's square has arrived at it's present condition - is the wear repeated to any degree at the other end of the rule?

Regards Mick

It depends what combination square you have.

http://www.classichandtools.com/acatalo ... Tools.html

I believe them to be regarded as such. It's what they are.

TT

 

[bugbear]

Hi

A combination square should not be regarded as a precision instrument, however I am mystified and intrigued as to how BB's square has arrived at it's present condition - is the wear repeated to any degree at the other end of the rule?

Regards Mick

Combination square vary in quality, precision and price, over a very wide range, from cheap objects (Am Tech, Rolson etc) useful for DIY projects around the house, to items good enough for some metalworking and pattern making tasks. Price range is from a coupla' quite to around a 100. My normal workshop square is a lovely Moore and Wright. Too old to be as accurate as it once was, but beautifully made, accurate enough for the purposes I put it to, and a joy to handle.

And to answer your question - no, the wear on the 1912 is localised to one end. :-k

BugBear

 

[CHJ]

I came across a 'square' that had been repeatedly used by someone clamped across the end of stock in a vice to "square up the ends" with a file.

It was obviously no longer square or straight edged for that matter, wonder if someone has been using this item in a similar fashion.

 

[Phil Pascoe]

:lol: that reminds me of a friend years ago using emery cloth to clean his rusty feeler gauges.

 

[bugbear]

:lol: that reminds me of a friend years ago using emery cloth to clean his rusty feeler gauges.

Indeed. I'm always nervous (and conscious of the problem) when I'm cleaning s/h metrology. This is where even a rough mental concept of tolerances comes in useful.

BugBear

 

[Sheffield Tony]

The common and cheap combination squares really are poor; I have acquired a couple of the sort with an auminium (or worse) stock. Even in the unlikely event that they are accurate to start with, the bottom of the slot in the stock simply wears away as the rule is adjusted !

Quite how the steel rule part of a good square wears away is a mystery though.

 

[Trafalgar]

My guess is that it somehow became out-of-square and was then used for something else, a use that will be forever lost to history most likely. It seems doubtful that the sort of wear you describe happened during its use as a square.

 

[Spindle]

It depends what combination square you have.

Hi

I have Starrett and Moore and Wright sets - neither of which I would regard as precision tools.

Engineer's squares and protractors are the precision equivalents of combination sets. In fact a good quality carpenter's square is more than likely to be as, if not more precise.

If you visit the Moore and Wright or Starrett sites you will not find the accuracy of combination squares quoted, (unlike that of engineering squares).

However Joseph Marple's squares are manufactured to a standard, (BS3322).

Regards Mick

 

[Phil Pascoe]

I did read (a long while ago) that it was only the inside of a carpenters square that had to conform, not the outside. I have no way of verifying this - does anyone know?

 

[bugbear]

Finished getting this square tuned up this morning; turns out (despite early signs) the rule was NOT hardened, it was quite soft. In the end I was able to just file it, which I did with reference to my trusty (but cheap) granite surface and some thick engineer's blue (on the first face) and then used a micrometer to reference the second face against the first.

I'm not sure why this combo (Rabone/Chesterman 1912) is going for such high money s/h on eBay. It's carpenter quality, not engineering quality.

BugBear

 

[matthewwh]

If you visit the Moore and Wright or Starrett sites you will not find the accuracy of combination squares quoted, (unlike that of engineering squares).

There was only ever one standard for combination squares which was

"0.004in maximum deviation between the stock and the blade, the blades to be straight to a thou per foot."

The standard is now defunct , hence it is not quoted, but the really expensive versions by Moore & Wright, Browne & Sharp etc probably still hit it. The only sub £130ish combi squares that still conform religiously are Starrett. When compared in a straight 'apples with apples' at the same quality they are a fraction of the price of any of the others, which is why we switched from the affordable version from M&W to a wider selection from Starrett.



Some people suck their teeth at the prices, but when you consider that you can pick up a Starrett student square for under £40 and in accuracy terms it will punch its weight against competitors at at £200+, I reckon they are very good value.

 

[bugbear]

"0.004in maximum deviation between the stock and the blade, the blades to be straight to a thou per foot."

So my 30 thou of wear took it out of spec? :lol: :lol: :lol:

BugBear