Searching for a good quality, metric-only, 300mm steel ruler

When in doubt about words, consult a dictionary. Both of mine, paper and ink type, say a ruler is a straight edge with measuring graduations on it. Or it can be HRH etc. Both are acceptable to messrs Webster and Macquarie.

There are time when it stops you having to read upside down. e.g. When you are measuring to the left away from a right surface inside a confined space or box.

> if you want it to read from right to left turn the rule through 180.000 degrees.
And then you have to read upside down.

Rabone Chesterman No. 49 ==> sold out.

> Is it a Rule or is it a Ruler?
I wondered about this too. According to my research, if you are a trademan especially if you are a carpenter or a mason or if you are a self-righteous pedant with a burning desire to feel superior to the rest of the world, then 'rule' is the only name you will accept for the calibrated, straight-edge device they use for marking lines.

For all the rest of the known universe, we are perfectly happy to call it a 'ruler'.

But Wonkee Donkee could be right - who knows? Or as I now suspect, WAS right once but being a living thing, the language has now evolved.

> Have you thought of drawing one yourself and having it made?
Nope.

> Starrett C331
As per my original question, I would prefer to not 0.5mm and to not waste a side on Inches.

Don
 

PS It seems that some people don't understand what "good quality" means. So to get clear what I meant was a reasonable balance of things like:
- clear markings that are durable and won't rub off over time 
- tempered stainless steel that is flexible, springy and won't rust easily
- has an easy-to-read surface - ideally one that scatters light rather than reflects light like a mirror
- made to an accuracy of say better than 0.25mm
- straight/cutting edges that seem to be dead-straight 
- edges that aren't so sharp that they risk cutting your hand open
...that sort of thing.

Edited By Donald MacDonald 1 on 23/03/2022 00:32:11

**LINK**

Hmmm... I'm having a second look at this. On the upside, as well as avoiding knife jumping problem, the design seems to avoid parallax like nothing else.

But I am I correct in thinking the markings create little kicks when you try to draw a straight line?
Also the far side seems harder to use.

Either the photo is terrible or the rules themselves are extremely hard to read.
There also seems to be a lot of 0.5mm markings...

I just linked to a Rabone Chesterman 49, as you mentioned they are sold out I located a second hand one.

This thread sums up much of what is wrong with the consumer society today. The OP has a problem. So the first instinctive solution is look for some consumer item to buy to solve the problem. Followed by myriad suggestions for the perfect consumer item that will "do it all" and provide that lovely Golidlocks moment of "Just right!" and resulting shot of very addictive dopamine to the brain.

Instead of looking at what skills could be developed with a little effort to overcome the problem using existing consumer items in the OP's workshop.

Reading a ruler upside down is not that hard. It is a skill, albeit a fairly minor one, and any skill can be learned and then taken to a higher level through practice. It would not take much time at all to learn the skill and practice it until it became second nature.

I can read whole novels upside down if I want to. Because I once had a job where I often interviewed people across a desk or table and I wanted to read the notes or documents they had in front of them but they did not want to show to me necessarily. So I started reading them upside down and found it a bit faltering but not impossible. So I practiced on documents at my own desk placed upside down. Within days I could read upside down almost as well as right way up. Then at home I started reading novels held upside down and to this day I can read upside down almost as quickly and easily as right way up. The human brain is an amazing thing. But is also a slave to habit. Once you break the habit of only reading right way up and get into the habit of upside down, it is easy. Why would it not be? Reading top to bottom is only a cultural convention and not a natural human action at all.

So I'd suggest the OP take his 300mm ruler to bed with him every night and practice reading it upside down over and over. I guarantee within a week of this bedtime reaing it will be as easy as right way up.

Edited By Hopper on 23/03/2022 07:31:51

I have one, just not sure where I got it, and it's metric/imperial.

Yes, I have one too. I seldom use it, though, because the non-slip backing prevents you from sliding the rule/ruler smoothly into position; instead you often have to perform a series of tedious lifting and repositioning operations to get it where you want it. The same would apply if it was a steel straight edge.

I have a suspicion non-slip backings on rules and straight edges are there mostly for novice users who haven't yet learned to push primarily downwards with the pen or knife, rather than downwards and (more than very lightly) sideways at the same time.

Edited By Bill Phinn on 23/03/2022 12:13:43

OK... we have a WINNER.

And the winner is.... [drum-roll please]

"Kinex Flexible Metric Steel Rule 300mm"



Reasons:
- Super-simple ==> Looks pretty easy to read, even upside down
- No 0.5mm markings! ==> easy to read off the mms
- Thin (0.5mm thick) ==> very little parallax ==> easy to be accurate
- Being made from stainless steel, it makes a good cutting edge, with no risk of accidental damage from scalpel blades
- Low cost

Weaknesses:
- Overall build quality looks cheap
- Surface is bare metal with a rather directional reflection of light ==> harder to read
- One reviews claimed that it is quite easy to bend permanently out of shape
- the reverse surface is blank (I think) ==> (so no possibility of right-to-left help on the reverse side)
- It doesn't even have a non-slip rubber or cork rear
- Worse, at c.20g it may be rather hard to keep in place
- Cutting will need to be done very carefully because the blade is so thin & narrow

But... It's cheap and I needed to make a decision!

IF it does get bent out of shape, and/or I find that it is too dangerous to use with a scalpel... then I shall buy my runner-up which is...

[drum-roll, please]

"SHINWA Steel Rule Pick-Up 300mm" 

Reasons:
- No 0.5mm markings
- Very nice finish
- Easy to read markings
- Red lettering will stand out in my tool collection ==> easy to find!
- Red lettering jumps out at you so that:
a) you don't get confused about which 'decade' you are in (unlike the Kinex)
b) makes it easy to read when upside down
- Being thicker and wider than the Kinex this will make cutting slightly safer.
- "Easy pickup" gimmick might even be useful
...} Looks like a very nice piece of kit!

Weaknesses:
- Only one side is useful (so no possibility of right-to-left help on the reverse side)
- No non-slip grip (but being a bit heavier [c.60g] than the Kinex [c.20g] it may not need it)
- Cutting with a scalpel will still need to be done pretty carefully
- Being 1mm thick ==> slight parallax risk (?)

Well, that's my reasoning.

I'll try and pop back in due course to let you know how I get on. 

J

Edited By Donald MacDonald 1 on 24/03/2022 00:33:05

Well you certainly analiysed that issue within a millimeter of its life, literally. Well done. You will be able to measure things and cut things all with the one guiding tool. It may be an advantage that it does not have markings on the reverse side. This way you can be sure to cut a dead straight line without massive notches in it from the graduations jagging on the scalpel blade. Just be sure to angle the scalpel blade ever so slightly away from the top edge of the rule/r so it gildes along the lower edge unimpeded.

If holding the scalpel blade at 89.75 degrees to the surface being cut instead of 90.000 degrees is a problem, you might have to look at using one rule/r to measure and another ungraduated precision ground straight edge to cut with. Unless you get a guided cutter where the cutting edge runs back and forth along a linear rail in a holder on ball bearings.

Of course then you can run into problems because ball bearings always have a small amount of clearance in them that could affect accuracy by a small amount if you are doing precision work.

Sticking with the rule/r in hand, I would not be too worried about the error of parallex at 1mm thick. Develop the skill of looking straight down on the graduations to minimise the error of parallex to a few microns or so.

The wider one might be a more stable guide for dealing with the considerable sideways forces of cutting, but I think the red numbers at the 10, 20 and 3o marks would be really offputting and could result in an injury while distracted. So I concur with your first choice as the correct one.

The other factor you may need to take into account is that the edge of the scalpel blade is in effect a bevel, so even though the flat side of the blade may follow the straight edge faithfully, the actual cutting edge is at the other end of that bevel and so will be that small amount over from the straight edge. This could add another sort of error of parallex that perhaps could be accommodated by placing the straight edge that small amount to one side of where actual edge of the cut part is desired to be.

Please do let us know how you get on with it all. It is an intriguing conundrum.

Edited By Hopper on 24/03/2022 04:35:11

John stated he wanted double sided markings on the rule, and non slip back, I can't picture how that would work? I don't remember seeing anything like that but it might exist.

The Shinwa rule is also available without the pickup end if you don't like that feature. I've bought quite a few handtools from Dictum over the years and all good quality, they do the flat Shinwa in 15mm wide flexi. or 25 mm wide which would be better to hold for cutting. Shop around if you want a UK supplier.

I'd suggest you consider two rules, one for marking out and another for cutting just stick something to the back of one that you like the markings of.

Kinex also so a right to left reading rule but you would have to buy that separately as I can't see one with both and probably more hassle to swap rules than read upside down.

Edited By JasonB on 24/03/2022 07:11:19

Edited By JasonB on 24/03/2022 07:48:07

No he said Either double sides or non slip back. I've posted images of my cutting rule with NS back and there are many more options but when I used to work in the graphics/art trade this one outsold the others 10:1 as a cutting rule.

Excellent point, and one that probably has not been taken into account. I seem to recall left and right-handed ground marking knives for woodworkers - fire up the Google machine, we may be looking for those next

Rob

I suspect it's for use on delicate surfaces to avoid unacceptable scratches.

I'd not considered that, Nicholas, but could you give some everyday examples of delicate surfaces you'd want to measure and cut that would be unacceptably scratched with a bare ruler?

Aluminium sheet used for decorative covers would be a good example. A stainless steel rule easily does that. I made a bulkhead cover for a friend's kitcar at the weekend that took as long to remove handling scratches as it did to do the final fitup.

Maybe the specially textured ABS that the OP posted about earlier would mark easily, he even had a problem with fingerprints on it.

Since you ask....

Yes it's a slightly interesting question. Obviously to get the bevel error one measures the blade width then one divides by 2. Depending on what I'm doing, in general, for me anything less than 0.25mm error I tend to ignore.

Of my blades, for heavier cuts... yes I do start to think about it:
- Snap-off blade (carbide): <0.5mm ==> 0.25mm error
- Stanley Blade: < 0.6mm ==> 0.3mm error

However for these I simply ignore the error completely:
- Logan Matt Knife: 0.3mm ==> 0.15mm error
- Rotary Cutter: 0.3mm ==> 0.15mm error
- Scalpel blade (S-M): 0.4mm ==> 0.20mm error

Well... you did ask

TBH, I tend to avoid the Stanley blade except for rare brute-force situations.

IME, the other thing that CAN happen - e.g. when cutting greyboard or 'millboard' - is that particularly if you don't have the thinner blades correctly aligned... either the blade itself can bend, or it can stretch the material being cut. And on longer cuts this can create massive errors (> 1.0mm).

For straight line cuts on thing/softer materials the rotary cutter is a game-changer. For shorter cuts that need to stop at a precise point, you can't beat a nice, new scalpel blade.

Talking of which, personally I don't find Swann-Morton last very well, and I find I can damage import work quite easily with a blunt S-M blade. But at least they are cheap, so I now tend to replace blades at the start of EVERY important new cutting session.

If anyone knows of better quality /(carbide?) blade scalpel blades, please let me know.

J

Edited By Donald MacDonald 1 on 24/03/2022 12:20:11