Evening all!

I've just bought Screwfix's Combination Set:

http://www.screwfix.com/app/sfd/cat/pro.jsp?id=16407



and am a bit concerned about the lack of precision compared with the
engineering squares I have.

The square head "rocks" within the centre head and the sole-plate of
the protractor head shows light when held against a true
straight-edge.

Whilst it's probably as accurate as I can cut when used for marking
within three inches of the straight edge of the work it's visibly
"off" at 10 inches.

Am I being over fussy for a tool that only costs 15UKP or should it go
back?

Is there a British Standard that covers wood-working tools and their
accuracy?

(Two years ago I wouldn't even have noticed ... but as skills have
improved I'm getting much more demanding of my tools ...)

TIA


Barley Twist
(Please put out the cats to reply direct)

This is what I should have bought:

drool

http://www.littlemachineshop.com/pro...ProductID=1838

/drool


Barley Twist
(Please put out the cats to reply direct)

Barley Twist wrote:
This is what I should have bought:

drool

http://www.littlemachineshop.com/pro...ProductID=1838

/drool


Barley Twist
(Please put out the cats to reply direct)

You pays your money and ...
Seriously though , if you bought the expensive one you'd be so terrified of
damaging it it would keep you awake at night.. :-)

Barley Twist wrote in message . ..
Evening all!

I've just bought Screwfix's Combination Set:

http://www.screwfix.com/app/sfd/cat/pro.jsp?id=16407



and am a bit concerned about the lack of precision compared with the
engineering squares I have.

The square head "rocks" within the centre head and the sole-plate of
the protractor head shows light when held against a true
straight-edge.

Whilst it's probably as accurate as I can cut when used for marking
within three inches of the straight edge of the work it's visibly
"off" at 10 inches.

Am I being over fussy for a tool that only costs 15UKP or should it go
back?

Is there a British Standard that covers wood-working tools and their
accuracy?

For £15 I'd send it back and go visit your local tool shop, check
before you buy. Even if you can work with the Screwfix thing it's
shortcomings will annoy you every time you use it.

Rgds

Noel

noel dot hegan @ virgin dot net

On Fri, 07 Nov 2003 19:51:34 +0000, Barley Twist
wrote:

How accurate should wood-working squares be?

Perfectly accurate. They should be the second-most accurate thing you
have, second only to your straight edge. Anything less is
unacceptable.

Accurate squares are cheap and easy to get. They're easy to test too.
Don't compromise. "Accurate" here means "More accurate than the rest
of my marking and cutting process".


I've just bought Screwfix's Combination Set:

I have no real use for combination sets. The protractor head is
useful, but not the other two. If I need a square, I'll use a fixed
one. If I need a centre finder, I'll use a rough one (or a finger and
pencil) because that's a low-accuracy task that I shouldn't perform by
dragging my high-accuracy tools around the logpile.

and am a bit concerned about the lack of precision compared with the
engineering squares I have.

That's the other problem with combination sets.

Basic rules for buying combination sets. They shouldn't work, but
empirically they're a good guide to quality:

- Cast iron bodies, not diecast mazak.

- Etched rule, not stamped or printed.

My combination set is a Chinese no-name, bought from Chronos Tools at
a Model Engineer show. Cost about £30 and is of high accuracy and
reasonably good quality. The adjusting "bolts" aren't as ergonomically
designed as a Starrett, and it's probably not as accurate as a
Mitutoyo, but it's close enough for jazz. I think Axminster sell
something similar
http://www.axminster.co.uk/default.asp?part=SMT031


Am I being over fussy for a tool that only costs 15UKP or should it go
back?

Wobbling clamps and non-flat machined surfaces sound unacceptable
IMHO. Apart from that, I'd not expect a £15 combination set to have
any real claim on accuracy.


--
Die Gotterspammerung - Junkmail of the Gods

"BillR" wrote in message ...

You pays your money and ...
Seriously though , if you bought the expensive one you'd be so terrified of
damaging it it would keep you awake at night.. :-)

It crossed my mind to ask why someone would want one of them things,
especially at that price; until I read post II. Then I realised the
man's a fool.

Seriously though, where would you use one of them? You couldn't use it
on a drawing board could you? Setting some sort of a machine up,
perhaps? I have no idea?

You could use it to pry open a can of paint perhaps, not a bottle of
caustic soda though. Perhaps you could squeezee the cap in the angle
and .... na..ah...

On 7 Nov 2003 20:55:33 -0800, (Michael
McNeil) wrote:



It crossed my mind to ask why someone would want one of them things,
especially at that price; until I read post II. Then I realised the
man's a fool.

Seriously though, where would you use one of them?

hmmm - having googled back I see that Mr McNeil falls prone to the odd
bit of tool lust too - but he does ask a serious question after the
slight insult ...

I'm at an age where my eyesight is difficult - moving from
shortsightedness to whatever - always having to take glasses off and
then put them back on in the course of any marking out operation.

From *experience* I've discovered that the biggest effect on the
precision (and I do know the difference between accuracy and
precision!) of the job is in transferring measurements between one
tool and another - something that's compromised if I have to take more
than a couple of measurements for a given line/point.

I've a couple of small, very cheap, combination squares that checked
out very well for both accuracy and precision - they live in a foam
lined box when not in my hands. I've found them invaluable for
transferring measurements - say the depth of a half-lap joint, the
thickness of a component, and then being able to scribe lines at that
value. Also for consistent, repeated marking at a particular
measurement.

I've a job on at the moment where I'll be working 6 inches away from
the true edge, I'd hoped that the larger combination square/set would
allow me to carry on using the *proved* technique I've developed.

I think Mr Dingley's response the most helpful:

"Perfectly accurate. They should be the second-most accurate thing you
have, second only to your straight edge. Anything less is
unacceptable."

.... thanks.


I have tracked down the British Standard for such things -
It's BS 3322 - which specifies an accuracy of 0.01mm per cm blade
length. Fairly easy to check with a long slip gauge on end and a
feeler.

Armed with which knowledge 16407 and 16969 will be going back to
Screwfix Screwfix


Barley Twist
(Please put out the cats to reply direct)

"Barley Twist" wrote in message
...
Evening all!

I've just bought Screwfix's Combination Set:

http://www.screwfix.com/app/sfd/cat/pro.jsp?id=16407



and am a bit concerned about the lack of precision compared with the
engineering squares I have.
snip
Am I being over fussy for a tool that only costs 15UKP or should it go
back?
snip

3 tools in one, so £5 per tool, so YGWYPF.

Also loads of moving parts, with the potential for wear.

If you can't rely on it then what is the point of using it?

If a good one costs $150 (do you get both of those shown in the picture for
$150?) and weighs 3.5 pounds (small club hammer?) then £15 isn't likely to
do the business.

Depends what you want it for.

If you want the fancy angles then use it for that, and use a seperate good
quality square for right angles.

This looks like a JOATMON tool to me :-)

Cheers
Dave R

Very useful tool a combination square. It should be accurate enough so
that in normal use - i.e. marking on wood with an HB pencil, no error
is obvious.
Screwfix cheaper tools are often crap - if you ask for a refund or
replacement they don't ask you to return the tool as they also know
it's crap. I've got 2 pairs of wire stripping pliers free on this
basis but unfortunately they are rubbish. I'll probably give them away
as Christmas presents.

cheers

Jacob

On Fri, 07 Nov 2003 20:29:12 +0000, Barley Twist
wrote:

This is what I should have bought:

http://www.littlemachineshop.com/pro...ProductID=1838

Not much good if you are metricised by the looks of things

PoP

Send it back !!!!!!!


On Fri, 07 Nov 2003 19:51:34 +0000, Barley Twist wrote:
Evening all!

I've just bought Screwfix's Combination Set:

http://www.screwfix.com/app/sfd/cat/pro.jsp?id=16407



and am a bit concerned about the lack of precision compared with the
engineering squares I have.

The square head "rocks" within the centre head and the sole-plate of
the protractor head shows light when held against a true
straight-edge.

Whilst it's probably as accurate as I can cut when used for marking
within three inches of the straight edge of the work it's visibly
"off" at 10 inches.

Am I being over fussy for a tool that only costs 15UKP or should it go
back?

Is there a British Standard that covers wood-working tools and their
accuracy?

(Two years ago I wouldn't even have noticed ... but as skills have
improved I'm getting much more demanding of my tools ...)

TIA


Barley Twist
(Please put out the cats to reply direct)