A Day at Chain Bridge Forge

Chain Bridge Forge in Spalding, UK, is a living museum with its origins dating back to the 1700s.  Located alongside the Welland river, it is run by volunteers with the aim of preserving traditional blacksmithing skills.  A few months ago I was given a gift voucher to attend a “taster day” at the forge and try my hand at blacksmithing, done the traditional way.

Saturday 19 April was the day I joined local blacksmith Ryan and 4 other visitors to learn how it’s done and have a go.  The building is fairly small and compact, and is showing its age.  Just about every available square inch displays traditional tools, implements and metal working devices.  A few anvils are positioned around the central coal-fired fire pit.  A second, portable fire pit is in the adjacent room and on a day like Saturday when they have more than 4 visitors, they can also set up a further fire pit just outside the building.  I was assigned to use the outside fire during the morning but moved inside for the afternoon session.  It was good to be outside in the cooler, fresh air, but the sunshine did make it more difficult to gauge the colour of the heated steel and therefore determine its temperature, but I think I managed ok.

We made 3 items during the day.  The first was a simple S-shaped hook.  The idea was just to give us a feel for how to work the metal and understand how it behaves at different temperatures.  Ryan would demonstrate the steps and then we all tried to replicate what he had shown us back at our respective anvils.  For a first attempt, I thought my hook turned out ok.

The second was a fire poker, which included a number of different features and techniques.  We began with the curly loop at the handle end, then moved on to the poker and side hook at the other end.  This involved bending the steel and forge welding it together for the first few centimetres along from the bend.  The final step was to heat the middle of the shaft, flatten it, and then twist it to give the decorative effect.

In the afternoon we made item 3 which is a decorative keyring ornament.  Step 1 was to flatten and curve the end into a leaf shape.  Step 2 was to put the stripes into it using a chisel.  Step 3 was to work the other end into a taper and then curl it around to form a loop and put the decorative curl in the end.  The metal is just mild steel, the same as the hook and the poker from the morning, but this one also has a brass finish on the surface.  While the metal was still warm, Ryan used a drill with a brass wire brush in the chuck to buff it all over the surface.  Because the metal was still warm, the brass rubbed off the bristles of the brush and bonded with the metal to give it the brass appearance.

It was a fun day out and I learned some new things, so very pleased to have had the opportunity.  I just about managed to avoid getting a blister on my thumb from the hammer, but I did not manage to avoid the smell of the coal fire and burning metal.  I’m sure I was not smelling of roses and violets by the time I returned home!

Enjoy the photos.

Blacksmith Ryan getting set up at the fire.

Me at the anvil.

My "s-shaped" hook and tools on the anvil.

Forge welding the end of the poker into a solid tip.  Note the sparks!

The fire poker.

The keyring ornament.

Knives 16 and 17

This next knife creation project will eventually be a set of 3 knives, all the same design, but one large and two smaller.  I cut the steel for all 3 blades at the same time, but then put the large one on the back burner while I worked on the pair of small ones in parallel.  They are almost identical except for the handle scales which are different woods.

I decided from the outset that these two smaller knives would be gifts for two of my special, but unrelated friends in America.  That meant I was working to a deadline because my next trip to the USA was scheduled for October.

The basic shape differs from all the others I have made before in that the cutting edge is perfectly straight.  The back of the spine curves gently like a dolphin’s back.  The spine is decorated with symmetrical bevels, but not sharpened, and there are a series of transverse grooves to the back end of the spine, just in front of the handle.  These grooves are partly decorative, but they also provide a comfortable thumb rest.  Because the knives are smaller, the length of the handle is such that it is only long enough for the first 3 fingers of the hand to wrap around it and the little finger will be positioned behind the back end of the handle.  That is of course, in an average size man’s hand.  The overall proportions have been chosen to give a good, balanced visual effect to the design.

My friend Craig from Mulberry, Indiana, sent me some blocks of old Teak, salvaged from the deck of the USS New Jersey during its recent restoration.  I had hoped to use some of this Teak for the scales on one of the knives, but unfortunately time and years at sea have weakened the structural integrity of the wood, making it unsuitable for knife scales.  Instead I have used Zebra wood for the one knife (the darker wood with the pronounced, striped grain), and I have used Maple for the other (the lighter colour wood).  The scales are secured with epoxy and brass pins.  The blades are made of O1 Tool Steel, hardened, polished to a mirror finish, and sharpened.  After final construction the scales were polished with a few coats of beeswax to protect the wood and give it a healthy lustre.

Knife dimensions
Overall length: 200mm (7.9”)
Blade: 115mm (4.5”) long, 25mm (1.0”) tall at its maximum, 4mm (0.2”) thick
Handle: 85mm (3.4”) long, 25mm (1.0”) tall in the middle, 17mm (0.7”) thick

For these two knives I also made matching leather sheaths.  The sheath design is quite simple, with just a pair of slots cut in for the belt, and the leather has been moulded to hug the shape of the blade and forward section of the handle.  This shaping has stiffened the leather so that the knives almost “click” into place when inserted and they will not slip out unintentionally.  The leather is stitched using Saddle Stitch and the cut edges were smoothed with fine sandpaper before being treated with “Edge Kote” to give the darker, professional looking finish.

Enjoy the photos.

Blades shaped and bevelled before heat treatment.

Blades after heat treatment.

Blades cleaned up, and scales cut and drilled.

Scales glued and pinned.

Scales roughly shaped.

Scales fully shaped and sanded.

Sheath leather cut.

Sheaths folded and glued.

Holes punched ready for stitching.

In the “Stitching Pony”.

Sheaths stitched and ready for moulding.

Moistened leather moulded to fit the knives and left to dry.

Cut edges finished with “Edge Kote”.

All finished.  Sheaths dry.  Blades polished.  Scales waxed.

Knives in their respective sheaths.

Mike with his new knife.

Craig with his new knife.

Sand Tumbler

I’m sorry the blog has been quiet for a while – blame it on other priorities getting in the way, such as vacations and preparing to put the house on the market.  However that does not mean the Kayfa workshop has been totally idle!  In this post I will tell you about another little machine I have designed and built, which I call a “Sand Tumbler”.

The principle is that, sometimes I may want to put a satin finish on a blade rather than a shiny polish, and for that I need a way of giving the blade a gentle allover sanding that will not leave any scratch marks from traditional hand sanding.  This Sand Tumbler should do exactly that.  It is basically a plastic tube, closed at both ends, but into which I can put a quantity of sand and small stones together with the blade to be buffed.  The tube then rotates slowly for several hours, possibly overnight, and the gentle tumbling of the blade in the sand will produce the satin finish.

The main components of the device are:

1. The tube, which is cut from a length of waste water pipe about 100mm in diameter and 400mm long.  The one end is permanently closed with an end cap, but the other end can be opened because the end cap has a screw thread.
2. The roller wheels for the tube to run on.  These were repurposed from a small skateboard.
3. The drive motor and gearbox to reduce the speed but increase the torque.
4. A power supply to convert the mains power to 24V DC.
5. A speed controller for fine adjustment of the drum’s rotational speed.  Experimentation will confirm, but I anticipate a speed of around 50-60 rpm will be good.
6. A toothed drive belt and pulleys to connect the gearbox to the main tube.
7. An on/off switch.
8. The frame that everything is mounted on or in.

My first attempt repurposed the motor from an old overlocker, but I could not slow the speed enough without overloading the motor and it burned out very quickly.  I then purchased a 24V DC motor with fitted gearbox that was theoretically powerful enough for this application, and it does work as expected, but I think the power rating is still insufficient because the motor runs very hot after about 10-15 minutes.  I will soon replace this with a more powerful motor that will be “man enough” for the job.  Until such time I am nervous about putting it to work too strenuously, so a full demonstration of its capability must wait for another day.

Until then, enjoy the photos.

The full Sand Tumbler device.  The power supply, speed controller and drive motor are housed within the wooden box.  The toothed drive belt is on the left side of this view.  The digital display gives the percentage rotation of full speed and the knob to its left is for adjusting the speed.

View from the right showing the power supply unit that converts mains AC to 24V DC.  The green button is a secondary isolation switch for safety purposes, if required.

View from the left showing the drive end with motor, gearbox and toothed drive belt.

Video showing the unit in operation.  (Turn down the volume before running the video!)

Trinket Box

Trying something different after the display box in my last post, I made a general purpose trinket box.

The majority of the box is made from Sepile wood, which has a deep red colour. The stripes on the lid are alternating Sepile and Beech. These strips are glued onto a backing of simple Birch plywood, just to provide some rigidity. The base is from the same plywood. After sanding and assembly I polished the box with several coats of beeswax, giving a smooth, glossy shine. The inside base is covered with felt and there are small magnets inserted in the front corners of the base and lid to help keep the lid closed securely.

Overall dimensions are:

Length 225 mm (8.86")

Width 135 mm (5.31")

Height 75 mm (2.95")

Enjoy the photos.

Knife 15 and Display Box

I'm back to tell the story of my latest creation - Knife 15, which is a gift for Richard, my friend of many years.

The basic shape of the knife is similar to one I have done before, which I know was one of Richard's favourites, but with some adjustments.

The blade is my old reliable O1 Tool Steel, full tang design.  The bolsters are aluminium with aluminium pins.  The scales are English Oak with brass pins.  The decorative wavy design continues all the way around the tang between the scales, created by using black epoxy.

Dimensions are:

Blade

Length = 140 mm ( 5.51" )

Height = 45 mm ( 1.77" )

Thickness = 4 mm ( 0.16" )

Handle

Length = 125 mm ( 4.92" )

Height = 37 mm ( 1.46" ) at its maximum

Thickness = 20 mm ( 0.79" )

The blade flat surfaces have been polished to a mirror finish.  The bevels have been polished, but the grinding marks have been left for visual effect.  The Oak has been treated with Lemon oil polish to enhance the rich natural beauty of the wood.  The bolsters have also been polished to a shiny finish.

This time, instead of a leather sheath, I decided to make a wooden box to store and protect the knife, as well as being a display feature in itself.  The box is made of Beech wood, sanded smooth with a slight chamfer around the top surface of the lid.  It has been polished to an extremely smooth glossy finish using beeswax.  The overall effect makes it feel a bit like glass to the touch.  Inside there is an insert of grey foam with a recess cut out for the the thickness of the handle.  The inside surface of the lid is lined with green felt.  Tucked inside the edges of the lid and base in matching positions are a few small but very strong magnets which help to keep the lid closed, minimising the chances of it flipping open unintentionally.

Box external dimensions

Length = 292 mm ( 11.50" )

Width = 84 mm ( 3.31" )

Height = 48 mm ( 1.89" )

This afternoon it was handed over to its new owner who seems very pleased with the result.

Enjoy the photos and videos!

Blade template glued onto the steel, ready for cutting

Cutting out the rough shape with an angle grinder

Rough blade shape

Grinding the blade to its correct shape

More cleaning up of the blade

Blade cleaned up and smoothed off

First stage of marking and shaping for the wavy decoration around the tang

Arcs filed in all the way around

Rough shape of the aluminuim bolsters - I cut and shaped them together as if one piece to ensure they were identical in size and shape.

Bolsters in place to check for initial size and fit

Parallel score marks down the edge of the blade to show the centre, ready for grinding the bevels

Blade on the bevel grinding jig with the first few passes of the bevel ground in

Bevel grinding jig in position for shaping in front of the grinding belt

Items ready for heat treatment

The forge ready for heat treatment

Video - Heat treatment.  Note how I check for the correct temperature by checking the magnetic transition before quenching in the oil.

Video - Checking the hardness.

The file skates over the surface of the steel without biting in.

Heat treatment complete and initial cleanup done

Wavy design cleaned up ready for fitting the scales

Blade cleaned up and polished

Bolsters shaped and ready for fitting

Bolsters fitted in place, clamped while the epoxy cures

Scales glued and pinned in place, clamped tightly while the black epoxy cures

Scales smoothed off to their approximate shape

Assembly complete, scales shaped and smoothed.  Bolsters and blade polished.

Top of the handle showing the wavy design along the spine

Bottom of the handle showing how the wavy design extends all the way around the tang

Scales drying after being polished with Lemon Oil polish

Putting the final sharp edge on the blade

Beech wood before I started the box construction.

At this stage it was so rough I did not even know that it was Beech!

Same piece of Beech, planed all round using my new planer/thicknesser

(see my previous blog post)

Same piece of Beech, cut into pieces for the box and lid

Box construction - inserts for the hinges

Box construction - Base sections glued together

Box construction - Base and lid assembled and sanded smooth

Box fully assembled and polished.  Note the chamfer around the edges of the top.

Box internals - foam insert and green felt

Box with the knife in place

Close up of the box corner showing one of the small magnets