Thread: Friday lunch prattle

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Update from friday's pictures

Very good.

Sorry I missed last Friday's chat. My daughter and I embarked on a last minute overnight hike to Lake Rhona. It was with out a doubt the most unpleasant hike I've ever done, but with a destination rivalling that of the Austrian Alps which had been the most spectacular I've witnessed to date. It's a hung lake, in the depression in the top of Mt Rhona. Pure white sandy beaches and towering ragged cliffs.

And then it rained overnight, filled up the creeks, made the track out even more of a bog, with a top of 6° c. But the destination was spectacular!

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As I type this, I can see snow down to the foot hills of Mt Wellington from my window, and appreciate my warm office all the more.

Lance

I am assuming the pic is of your daughter. That is a very big backpack: Was she carrying your gear too?

Regards
Paul

Originally Posted by Bushmiller

I am assuming the pic is of your daughter. That is a very big backpack: Was she carrying your gear too?

Yes, that was her as we were about to begin out descent on Saturday morning. And no, I had my own pack. The pack probably looks a little bulkier with the dead-dog-bag cover, but any remote overnight hike in Tas really requires a full setup in case you get snowed in or stranded by rising rivers. The tulips in the garden may herald spring's arrival, but the weather suggests otherwise.

Wow, it's Friday tomorrow, the week has just passed us by .... again


Reminder for the Friday prattle and a call out to anyone with time to join in.


This weeks topic is: Oils ain't oils - what to use for quenching things - 1988 CASTROL GTX2 Oils Ain't Oils - YouTube

As always it is great to catch up regardless.

Friday: Time: 12:00 - 12:40 AEST - or better Midday on the east coast, 11:30AM SA/NT, 10AM in WA, 2AM UTC and 9PM US Central (i think)
Yep that's lunchtime for some of us so bring a coffee and donut.


Join Zoom Meeting

Launch Meeting - Zoom

Meeting ID: 789 4886 9892
Passcode: 123

Cheers
Phil

these are the guys who use the "speciality" Quench Oils - 240mm Honyaki Gyuto in Hitachi Blue2 – Tansu Knives
Mert
has some of the most amazing knife makers here in Australia 241504417_3060116257544827_6494174475953372655_n.jpg

Cheers Jules

My apologies I didn’t realise my IPad microphone had silenced me,

Cheers Matt

We did not know.

I just want to clarify a few things that may have gotten confusing today when we were talking about annealing and normalising.

annealing.pngnormalising.png

Both screenshots come from the same website: Metal Supermarkets | Steel, Aluminum, Stainless, Hot-Rolled, Cold-Rolled, Alloy, Carbon, Galvanized, Brass, Bronze, Copper. They both say the same things to describe two slightly different processes. If metal is being annealed the cooling rate is slower and more controlled, whereas normalising is done in the open air whereby the metal is cooled slowly but not as slowly and controlled as annealing.

If getting the metal as soft and workable is the aim you would anneal. If maximum workability is not important but relieving stresses in the material is, then you would normalise because it is quicker, cheaper. and requires simpler equipment.

There are many ways that this can affect a manufacturing process but I will stick to the blade making application here as I believe that was what most of us were interested in. I will go through a series of steps involved in making a blade with annealing and normalising emphasized to show how they work together.

Once you have designed your blade(knife, plane blade, chisel,whatever) you select the type of metal you want to use.

If you are using brand new metal purchased for the purpose it will come as annealed bar stock. There is no need to anneal it. You would go straight to either forging or grinding depending on how you wish to make the blade. If you are using recycled metal, such as a leaf or coil spring you may choose to anneal it first.

If you are forging, you may, depending on the metal and the design of your blade, go straight to forging as once the metal is heated up to straighten and/or shape it the metal becomes soft while it is hot and it will cool slowly because you won't be quenching it at this stage. It won't be as soft as it would be from a proper annealing but that may not be critical to the build.

So, lets start out with a piece of leaf spring that we want to make a plane blade out of. We are aiming for optimum results so we will anneal and normalise at the appropriate points.

1. Anneal the spring. Heat it to the appropriate temperature. While it is hot you may as well straighten it. Then cool it slowly over several hours to anneal it as fully as possible (maybe up to 24 hours cooling)

2. Shape the blade form the annealed stock by forging, rolling, grinding, filing, milling, drilling etc to get the blade shape you want. Leave the cutting edge about 0.8 to 1 mm thick at this stage to minimise problems with burning the thin metal of the edge and warping.

3. Normalise the blade to refine the grain structure and minimise stresses in the metal. The general consensus among the top knife makers is to do three normalising cycles. Heat the blade to cherry red then remove from the forge and wave it in the open air until it no longer glows. Repeat three times. After the third normalising cycle let it cool for an hour or two. We often bury the blade in vermiculite for that time to slow down the cooling a bit. It is also better than putting the blade down on a flat surface which can result in warping as the blade cools faster on one side than the other.

4. Heat treat. Heat in the forge till non-magnetic then quench in the oil. Put the blade back in the vermiculite to cool to room temperature prior to tempering.

5. Polish and sharpen

So basically, from a blade making perspective, you anneal at the start of the process to get the metal ready to work and you normalise at the end of the shaping of the metal to remove internal stresses and refine grain structure prior to heat treating.

There may well be other manufacturing processes where the order of work is quite different and the lines between the two processes can become blurred but the way I have described it would be understood by the blade makers.

I hope that clears up any murky areas.

Thank Doug

That's a good summary.

The only thing I would add is that some things are modified according to the equipment you have, the budget you have and to some extent the project you have in mind. In some ways a knife is the most difficult of all the likely projects we might attempt as the steel is relatively thin and it is easy to get distortion, burning and brittleness. In other ways the knife is easy because it is relatively small.

Chisels, plane blades (in the thicker versions), drawknives and froes, in particular, are more forgiving as the thicker steel will not reach temperature so rapidly as a thinner steel. However, they are bigger and may require larger quenching vessels, more heat and more quenching medium to achieve good results. The hardest project I had was heating a large froe as even with a heating head on the oxy set it was difficult to maintain temperature the whole way along the blade. Quenching was interesting too .

I have no specialised tools apart from access to oxy equipment for heat treating and tempering. Annealing is performed in a wood fire. Incidentally, there is an issue that is referred to during the slow cooling as "carbon migration." It is the loss of the carbon aspect to the fire itself. However, this is relatively small and if we are concerned about this we would not be recycling used leaf springs!

Recycled leaf springs are often very pitted having lived a hard life beneath a vehicle. It saves much effort if you can select leaves that are virtually defect free, but this is not always easy.

Happy forging.

Regards
Paul

Thanks Paul.

I agree with pretty much all you are saying there, but I think it is pretty much impossible to grade the difficulty of the project by catch-all descriptions such as knife, chisel, plane blade, froe etc. But I see where you are coming from in trying, but I find it an oversimplification when you consider how broad each category really is.

The smallest knife I have made is similar to the Vesper marking knife and the largest is a drop point hunting knife with more steel in it than any plane blade I have made so far. The easiest knives I have made were a small pair of Kiridashi marking knives. They were really as simple to make as plane blades, a single bevel, just some minor shaping of the blade and handle on a grinder and attaching a timber handle on one side. The difficulty in heat treating knives over plane blades is more from the thickness of the steel varying over the profile of the blade rather than the one consistent thickness you get over most plane blades.

But don't forget not all plane blades are a rectangle of metal of a consistent thickness with a bevel ground on one side. Traditionally, many are tapered, some for reasons of how they are held in the plane and others because of the traditional ways steel used to be worked that have now fallen out of favor. Then there is the extra difficulty in making a replacement blade for a Stanley type bench plane with the groove running down the middle of it. So even the consistent thickness I referred to above making plane blades easier than knives does not hold true in all cases.

Tang chisels would require a different set of skills to make from what you would need to make a socket chisel. The ease of making a froe would depend to a large extent upon equipment available and skills to use it. Even in my forge there would not be enough space to heat a large froe over its full length without moving it back and forth within the forge.

Realistically, allowing for different levels of knowledge and experience, equipment and material availability and whatever other variables you might think of, if you put up a list of 10 different specific blade designs of knives, plane blades, chisels, froes etc and asked 1000 bladesmiths to arrange them in order of difficulty you would get close to 1000 different lists.

Wow, it's Friday tomorrow, the week has just passed us by .... again


Reminder for the Friday prattle and a call out to anyone with time to join in.


This weeks topic is: Gift ideas and general catchup

As always it is great to catch up regardless.

Friday: Time: 12:00 - 12:40 AEST - or better Midday on the east coast, 11:30AM SA/NT, 10AM in WA, 2AM UTC and 9PM US Central (i think)
Yep that's lunchtime for some of us so bring a coffee and donut.


Join Zoom Meeting

Launch Meeting - Zoom

Meeting ID: 789 4886 9892
Passcode: 123

Cheers
Phil

Here is where my Julie buys stuff from for me

Men's Gifts & Collectables, NRL merchandise Guy Stuff

Cheers
Phil