Back to school – blacksmithing

I’ve just spent a very enjoyable and instructive day with my friend Dave (who also happens to lay hedges) learning about the principles of heat treatment of tool steel.  For those of you who have a sensitive disposition to non-wood posts – click away now!


Dave.

I need hook tools for turning bowls.  These can be bought, but sooner or later you need to make your own, and to do that you need initiation into the black art (or is that craft, or magic?)

Here are a few pictures of what we got up to in my workshop.

First we built a hearth or forge:

This is version 1. It’s built from firebricks which reflect the heat of the butane burner back onto the work without absorbing much, even better if the bricks are bright & clean (i.e. not partly blackened by having been part of my hand warmer over Winter!) as light colours reflect the heat better.

Then Dave showed me how to test the hardness of materials by a) filing and b) hitting with a hammer, which test a) hardness & b) brittleness. The silver steel Dave brought could very easily be filed and b) when hit with a hammer bent.

The we hardened it. This involves heating up to cherry red and then quenching (cooling quickly) in oil or water. Re-testing proved the steel was now a) almost impossible to file & b) broke when hammered so it was now brittle. This gives the hardness you might expect from a file for instance, very hard but very brittle. Not the right stuff for a wood turning tool, what is needed is hard and strong, i.e. flexible so that shocks will not easily break it. So the next process is tempering. In this case heating gently and observing the colour changes caused by oxidisation. First the work has to be polished so the colours can be more easily seen:

We sanded off the oil/oxide mess and then stropped it on my leather strop. Heated it to a purple/blue, quenched and tested. Now a) the file skidded across the surface of the treated section, but b) did not shatter or bend when hit with a hammer. Hey presto! Soft steel turned into the stuff that tools are made on.

Having explored the theory we put it into practice. We made a punch. Dave had brought along some thicker silver steel and ground a point on the end. The exercise was to harden this so it would mark steel (or in our case cast iron) and retain its sharp point. Same as above we heated it to cherry red:


Not quite there yet.

And quenched in oil (used engine oil in fact):


Sssssssssssss!

Then after checking it really was hard (file just skids) we tempered it.

Next up a bit of forging. I have three bill hooks I’m re-hafting for a client. Two are done, Yorkshire pattern sensible riveted jobs (see last post below). The last one is a Kentish pattern I believe, and has a short, tanged handle. This means the end of the blade is made into a soft long tail that goes right through the wooden handle and is then fastened in by peening over the end of the tang, over a washer, simple but effective. But first we rebuilt the hearth:

Now the torch is held fast in an improvised wooden vice so there’s no need to hold it.

Then we heated up the tang for forging. It needed to be a bit longer so it needed to be drawn out.

Heating:

Forging:

We also tempered a chisel as a cold chisel to make a 45 gallon oil drum into a small demonstration charcoal kiln:

And tempered it:

Then we had a go at the Bohemian bearded axe I bought on eBay a while ago. It has a soft edge that turns over (i.e, doesn’t hold its sharp edge) even when working green wood. The question was did the steel contain enough carbon to be hardened, or was it a lemon that I’d purchased that looked good, but would never work as an axe?

Here we go:


Heating.

It took quite a while to get about half the edge cherry red. We’d reached the limit of temperature we could get with the torch. But on quenching (in water this time):

It turned out that we had a hard edge. All I need to do now is get a charcoal forge working for heating up big pieces like axe heads, and for forging. Watch this space.

Oh yes, and I finally levelled the chestnut bench before I set off for the woods, photo to come before I deliver it on Thursday.

Eastburn Playing Fields opening

On Saturday Jane and I attended the opening of the extensively refurbished Eastburn Playing Fields.  This is now a great place for kids and adults with a wetland area, sturdy play equipment, running track and trackbike rock pile.  I was there with my number three lathe which was my first one and now usually lives in pieces in the garage at home.  It was it’s first outing this year, and was as ever very popular, quite a few adults and children had a go, including a lady from Todmorden who wanted me to make here a chapatti rolling pin, and she put some work into it so she could say she helped make it.

Jane was running an Aunt Sally shy which was perhaps even more popular than the lathe.  We don’t play this Oxfordshire pub game up here so it had great novelty value.  Basically you throw sticks to knock a stylised Aunt Sally from the top of a post, good simple fun.

I was very keen on meeting my neighbour who was the blacksmith Jim Cooper from Bacup who’d made beautiful seating and gates for the playing fields.

The firm is called The Pennine Forge Limited and they do some beautiful work

Get the little man with the questionmark hair – he’s a nut cracker!

The smithing luckily carried on after I’d stopped for the day

I asked for a poker/rake for our Big Bad Bessie woodburner as I need to pull logs to the front where the air comes in so the fire stays in.  Jim found that the local soil worked as a very good welding flux as he made the poker for me.  Wish I’d had my proper camera rather than my old phone.

The poker turned out rather well,  it’s great to have a poker made by a blacksmith owning the surname of another craft (cooper or barrel maker) who used to be a potter.  Jim says that potting and blacksmithing are pretty similar, starting with a formless material, the fire is just applied at opposite ends on the process.

Jim’s thinking of running some night classes, which would be a great way for me to learn how to make bowl turning hooks, which Jim was very interested in as all crafts have their peculiar tools, mostly made by smiths.  He’s made a broom squire’s clamp in the past for compressing the broom-head twigs while they’re tied.