Thread: Chisel Hardness Study, the first step.

Are we talking western red cedar (Thuja plicata) or some other fish? What's the ring count?
No guessing allowed. You think it's as dense as Acer = maple? I need numbers.
If that's what you believe, I'll predict that the ring count is 50+ per inch.
It's always boney but holds OK detail in carvings.

The doors. Just wait. Hang on to them. the use will come. Maybe not this week.
Carving woods are like that. Piles indoors and out. I'll get to some of it.
Same with carving stone. I'll get to it.

Originally Posted by BobL

Well they have cut back on everything so no doubt.

Worse still has been the cut back in lab experience.
We had 13 weeks x 3hours per semester.
These days its 12 weeks at 2 hours every fortnight so 12 hours versus 39 hours.

curious about how much of that cut-back is budget driven and how much is related to OH&S.

some years ago I read that in chemistry the number of chemicals, elements and reagents deemed "too hazardous" for student use had grown to the extent that students did almost no experimental chemistry.
Is there a similar issue in physics? What was previously OK is now "too hazardous" so can't be done meaning that if students were still allotted 39 hours of lab work, they would spend 25 of them looking at each other?

Originally Posted by ian

some years ago I read that in chemistry the number of chemicals, elements and reagents deemed "too hazardous" for student use had grown to the extent that students did almost no experimental chemistry.

Yes some experiments have been cut out and I have no problems with this happening.

I remember in my first year of university seen several windows of the Chemistry building blown in.
The story was that an organic lab class was cooking up a brew which was a precursor to something that was really explosive.
It was safe provided the reaction was not run too far.
One of the male teams in the class was not paying attention to the brew instead they were far too busy chatting up one of the few teams of females in the class.
Fortunately one of the lab assistants saw the tell tale signs that the lad's reaction had run too far (I think there was a colour change involved) and yelling out "get under the benches" picked up the flask containing the brew and threw it out an open window. The lab was on a second floor and the flask exploded when it hit the empty paved courtyard outside. No one was hurt but that experiment was taken off the books pretty quickly

Most chemistry lab work is now done with very smaller containers (micro beakers/flasks/TT) and micro balances etc so much smaller amounts of chemicals are used. While this is much safer and more environmentally friendly it can be harder to see what is going on visually. There's also more simulation of reactions which is even safer.

In my research we used to use a lot of concentrated HF and Aqua Regia to dissolve up silicate samples and it was not unusually to use 10g x3 of each acid for one sample.
These days the same experiments can be performed using <1/10
The most danger chemicals we used was HCLO4 (can explode on contact with organic mater) and we used around 0.1g at a time (3 drops), these days a micro pipette can easily deliver 1/10 of these amounts. SiCl4 was the other nasty one - a drop of that in your eye will instantaneously create a shard of glass in your eye.
We also had to purify by distillation all these chemicals in the 10's of litres amounts.
The wastage for the process was ~25% so we were forever having to dispose of 20L plastic carboys of waste acid not always in the most environmentally friendly way.
I still have about 5L of waste Aqua regia somewhere.
These days these chemicals can be purchase with sufficient purity and there are strict protocols for handling and dealing with all this stuff.

Is there a similar issue in physics? What was previously OK is now "too hazardous" so can't be done meaning that if students were still allotted 39 hours of lab work, they would spend 25 of them looking at each other?

Yes there is a similar thing happening in physics.
I remember using accessible mains power in 3rd year lab classes and those experiments were pulled in the late 1970's
Some radioactivity experiments have also been pulled
Radiation detectors are more sensitive so much smaller radiation source can be used.
Lasers also caused a few problems in the early days.

Simulations, Computer Methods and Programming seems to have more than fillrd the void created by the reduction in hands on lab work. I'm far from convinced the simulations are that effective but it does enable potentially VERY dangerous experiments to be sort fo performed that would otherwise be impossible.

Back to Liq N2 war stories here are two from the US lab where I worked.

I worked on the 7th floor or a 7 floor analytical building (with a fabulous view of the Pacific ocean and La Jolla Beach) that housed dozens of lab suites, many of which used Liq N2. At the end of the major corridors (80m long x 3m wide) on each floor there were located at least 2 x 200 L tanks of Liquid N2. When you ran out in your lab you wheeled your (typically 20L) empty tank of Liq N2 to a 200L tank and refilled. The lab ran 24/7 so students and researchers were often filling tanks on weekends. One time I was there on a Fri evening when there were very few people about and I heard a loud thud - I thought nothing of it but two minutes later I saw a very anxious looking female student waving to me through a corridor window into my lab.

What happened was she needed Liq N2 but both the 200L tanks on our floor were empty so she went hunting for other 200L tanks on other floors. Instead of taking her 20L tank to the 200L tank she decided to move the 200L tank up to her floor. This was not permitted but we all did it as we did not want to continually have to go back to the other floor to refill. On moving the big tank she had got it moving too quickly so that when she tried to get it round the corner of a corridor it hit a metal building expansion joint on the floor at an angle and tipped over. Liq N2 tanks have a pressurised vent valve designed to slowly leak N2 gas to stop them blowing up. The rate at which they vent N2 is small and of no significance provided the tanks are stored/used the right way and left in a large space. Problem was the students 200L tank had tipped over and was leaking Liq N2. The tanks are made of double walled SS and are bloody heavy and she could not lift it back up.

The other problem was she could not even stand near the leaking tank because she was wearing thongs/flip flops as was I! Flip flops were allowed in offices and staff facilities and even Harmon Craig (the famous senior volcanologist who worked in the building opposite) wore boards and thongs every day of the year (it was Southern California after all) even inside his labs - he reckoned working around volcanoes was teh real danger he had to face. Inside the clean labs I worked in we wore overshoes (for people that wore shoes to work) and we had white Crocs for the thong wearers - these were mush easier to change into and out of as we switched from lab to lab.

I grabbed a couple of pairs of crocs and we raced down two floors leaving all the corridors open as we went. Fortunately most of the Liq N2 that was leaking from the tank was also evaporating so there was only a mm deep x ~1m diameter pool of Liquid N2 around the tank and we managed to get it upright. From then onward the tanks were locked to the walls so they could only be moved by authorised persons.

The other story involved a student who was working overnight following a day where the AC refrigeration Unit for that end of the building had broken down and was unable to be repaired and was going to have to be replaced, so he decided to try and cool down a lab by dumping some 10L Liq N2 onto the floor of the lab. Given the size of the lab and the fact that there were lost of instruments with internal fans and the AC fans themselves running to stir the air this was not dangerous in terms of suffocation. The stirring is important because Liq N2 is cold and the evaporated gas will tend to settle close to the floor and displace O2. The student was working sitting down which is not that good either. Anyway the air was being mixed so not that bad. The cooling was completely ineffective because, despite being very cold, Liq N2 has very little thermal uptake, but what did happen was the Liq N2 pooled in a corner and along one wall of the lab. It cracked the very expensive acid resistant linoleum type floor covering and over the next few months it disintegrated and had to be replace because it generated dust particles and it was supposed to be a dust free lab. As you can imagine the lab manager was not happy about it - we had a pretty good idea who it was but did not find out till much later.

This was the view out of my office window
beach.jpg

I like your picture Bob.

You can see why the forces of darkness criticize the easy lives of the white tower types. Shambling around in flip flops breaking things and contemplating the scenery.

Originally Posted by rob streeper

I like your picture Bob.

You can see why the forces of darkness criticize the easy lives of the white tower types. Shambling around in flip flops breaking things and contemplating the scenery.

try this.
A = graduate student club house
B = lab where I worked - It doesn't look like it but it was a 7 floor building
C - cafeteria
NB (top) = Nude beach
M = my office
E = gully where Mexican illegals used to hang out on their way north to LA
OA = Old aquarium
NA = New Aquarium


SCRIPPS.jpg

And you wonder why the budgets are cut...

Rob,

I believe Woodcraft uses Quangsheng for their "Wood River" house brand tools... These guys are pushing hard to get up market and play with The Big Boys.... Based on their Wood River planes and new socket chisels - I would say they are not playing around.

If it was made in the UK - they would plaster that all over the ad copy...

On your PM-V11 chisels. Please contact Lee Valley... While you are not the original buyer - it is known that early on - apparently a couple prototype sets got out that were soft.. The word is that they were from when LV was still figuring out the heat treatment process... I won't guarantee they will replace them (I have no affiliation), but every other instance of this I have heard of was quickly fixed...

Also - they are made in Canada, not the USA.

The Woodcraft cranked chisels are marked "Made in U.K.". They look exactly like the Henry Taylor branded crank chisels I've seen advertised. I don't know for sure but I think it likely they are by the same maker. This set is at least several years old.

The PM-V11 chisels are only slightly softer than spec and given the weak influence of hardness in my data I doubt the difference I measured matters much if at all. I may probe to see if they're willing to talk to me about my findings.

Originally Posted by rob streeper

The Woodcraft cranked chisels are marked "Made in U.K.". They look exactly like the Henry Taylor branded crank chisels I've seen advertised. I don't know for sure but I think it likely they are by the same maker. This set is at least several years old..

That explains it then.. The current fodder I have seen is marked "Made in China"...

Another thing here... And it's really no use to you now because they are a few years old and all... But I discovered that it's important to test new chisels out soon as you can and take them back for exchange if one is soft... It happens even with great companies. I had to exchange a brand new Pfeil at the beginning of the month. The first was soft. The replacement was excellent.

+1 for testing edges immediately.
Dropped $50 on a Stanley spoke shave. It was as if they had forgotten to harden the blade!
Tried again and again to tune up the edge and get it going. Nope.

Told the company. Their reply was that since I had tried to sharpen it, there was a no-return policy.

I replied to say that I 'd be spreading their good news across the wood carving forums that
Canadian Woodworks has a no-return policy, even for inferior goods.
I won't return that POS for $100 now. I own the evidence.

So even if the tool edge is poor, learn what their return/exchange policy is.
Samona spokeshaves were $16.00 each, bought 2, they actually 'sing' in the wood.

Gentlemen,

Your comments about testing edges on purchase are of course validated by your experiences. I've had a few myself which is part of why I'm doing this study and why I have tried on this forum to emphasize the importance of testing (The importance of testing.) if you're engaged in toolmaking. If you don't test you'll never know and without instruments testing for hardness is very difficult.

Originally Posted by BobL

Yes some experiments have been cut out and I have no problems with this happening.

I remember in my first year of university seen several windows of the Chemistry building blown in.
The story was that an organic lab class was cooking up a brew which was a precursor to something that was really explosive.
It was safe provided the reaction was not run too far.
One of the male teams in the class was not paying attention to the brew instead they were far too busy chatting up one of the few teams of females in the class.
Fortunately one of the lab assistants saw the tell tale signs that the lad's reaction had run too far (I think there was a colour change involved) and yelling out "get under the benches" picked up the flask containing the brew and threw it out an open window. The lab was on a second floor and the flask exploded when it hit the empty paved courtyard outside. No one was hurt but that experiment was taken off the books pretty quickly

if we're talking war stories ...
dad had a very excellent one.
One time he brought home a white powder that either his lab had cooked up, or more likely was supplied in error in place of another substance.
What I do recall is the powder would explode if heated. There was no need for a spark or ignition source, just heat the powder -- the heat from a match was sufficient. Dad entertained his kids one weekend demonstrating the effect.

but dad's best story concerned a colleague.
Dad's building was a U shape, with the coronal forensics lab in one wing, and the food safety / standards lab in the other. Over the latter part of his career, dad was alternatively the head of one of these two labs.
In the late 70s, the bod then running the forensics lab got careless one Friday and left a reaction uncovered and running when the lab was closed for the weekend. I don't recall what the reaction was, but its completion, the horizontal surfaces in the lab were left with a dusting of an extremely sensitive explosive powder. One so sensitive that the change in air pressure when the lab door was open on Monday morning was sufficient to set off a blast that removed all the windows one side of the building.

needless to say that the offending "bod" moved to another government department. Curiously about 8 years later I was working in the same department.
The bod recognised my surname and gave me a little bit of grief.


love the view from your office window

beach.jpg

I never had a laboratory explosion incident but I did manage to get the teflon off a stir bar in a quiet but spectacular fashion.

Love these stories and the good thing is that we can laugh about them. In other words we have lived to tell the tale.

As a pre-teenager I had a friend who was a "mad" scientist. Even at that tender age he had his own lab at home. I remember him conducting an experiment and amongst the apparatus was a thin glass tube about a quarter inch diameter: No real surprises there. However something happened during his experiment and this glass tube exploded. I recall his bemused look. We never found any glass. It was as if it had evaporated. To this day I don't know what he was doing. Later in the day when I got home I realised I no longer had any eyebrows, but that was the extent of the damage. Today I have black healthy eyebrows. I wish I could say the same about the hair on my head, although I think eyebrows on my head would look, well, unusual .

Regards
Paul