Tuesday, 30 December 2008

Terry Brown's Shed - Casting, Maching, Projects and Gingery Shaper

Today I stumbled across a goldmine of information. Terry Brown's shed stuff pages contain a large number of project he's completed over the last 7 years. There's a section on foundry work making furnaces and melting aluminium, this is complemented with a later section on the gingery shaper which has details of pattern making as well as casting. A section on the lathe with modifications to his 9"x20" lathe, simple addons such as a levers and handles, mods to the compound rest, tailstock die holder, ball turning and more. A smaller section on milling machine modifications with an auxiliary table and how he made that with fly cutters. There's some miscellaneous pages with burners, firebricks and a tiny steam engine. He finishes up with a section on his project of making the shaper.

Terry Brown's Shed - Casting, Maching, Projects and Gingery Shaper

What is a metal shaper?
For those who don't know, a shaper works a little like an electric hacksaw; it moves a tool backwards and forwards in a sawing motion cutting a slot in the metal. It's the predecessor to the milling machine with some advantages. The first is that it can use the same tools as your lathe, the second is that it can cut shaped slots using tools ground to a particular shape, something that would require multiple operations with different tools in a milling machine. It can also cut internal keyways which is difficult with most other tools. However it has mostly been replaced by the milling the machine in workshops as it removes metal more slowly.

Monday, 29 December 2008

Turning different materials

Most people use their mini-lathes to turn metal or plastic and some even venture into turning wood but I expect few will be turning lino. As a Christmas present for an uncle, I made the above lino ink stamp from some turned hemlock and some artists lino from the local art shop.

A small square of the linoleum was stuck to the faceplate with double sided tape. The lino is very soft and a little crumbly but turned well. I used a small straight parting off tool to form the outer ring of the stamp. The lettering was then hand carved using standard lino cutter tools and magnifing glass. The letter height is about 7mm. Normally lino printing is done using silkscreen inks and rollers but I found that a cheap ink pad worked well.

After turning the wood it was sanded down and treated with three coats of clear varnish. The lino stamp was simply pushed into the hole rather than gluing it. The plan has origionally been to cast the stamp out of aluminium but due to time and the weather I'd not been able to complete any castings for the last couple of months. I hope you wil agree that the results in wood came out just as well.

Tuesday, 23 December 2008

Taps of a different kind

When I built the drill drawer, I mentioned that I needed to make some trays or dividers. A trip through the bathroom section at Ikea revealed some small boxes from the Molger bathroom range that looked to be just the right size. I bought one and tried it out and it was spot on. The following week I went back and bought another. As well as being exactly the right size for my drawer (internal dimensions 300mm x 400mm) the two boxes are sturdy and made from solid walnut.

Ikea have some great bits that are just crying out for new uses such as this stainless steel knob which took my eye when writing up the article. Some of the parts have dimensions in the online and printed catalogues but others will require a trip to the Ikea shop which handily provides tape measures at the entrance.

If you are into taking Ikea bits and modifying them or adapting them then you should visit the like minded people at Ikea Hacks.

Thursday, 18 December 2008

Challenging Project?

If you are looking for a challenging workshop project and are bored with complex steam engines, grinding machines and clocks then you could always follow in the footsteps of Michael Wright who decided to build an Antikythera Device in his home workshop. He can now predict solar eclipses and the position of the moon, sun and planets.

The original was made in bronze with a wooden case, Mr Wright's replica has been made from recycled metal. The fine toothed gears and spiral dials have all been faithfully reproduced and the mechanism is fully operational.

More details of the mechanism can be seen at the project website.

Wednesday, 17 December 2008

Workshops Downunder

On reading the stats for the numbers of visitors from different countries I noticed that there's a good few people visiting from Australia. A discussion with mate Alan suggested the reason was ".au land has plenty of bodgers".

Further investigation reveals that the Australians are actively studing the subject. Not only do they have a their own Institute of Backyard Studies but they also have travelling experts in engineering, travelling with a mobile workshop with its own power and full of tools such as grinders, welding torches and a "30-tonne air-over-hydraulic press". Even their social lives revolve around workshops with a workshop themed bar.

The strangest bodger I've found in Australia is Peter "TDU" from Tesla Downunder who's "work" ranges from photographing enormous spiders to electro magnetic can crushing to high voltage experiments that could get him on the Darwin Awards.

Other Australian Workshops.

More Electrical Safety

I've previously mentioned that you need to be careful when dealing with electrics in the workshop but not everyone is quite so sensible. Uncle Wilko from the ShedBlog reported of a pensioner who decided to wired up his shed electrics directly to the local substation, in the rain. The pensioner was posthumously awarded a Darwin Award.

Tuesday, 16 December 2008

London Model Engineering Exhibition 2009

Friday 16th to Sunday 18th January 2009
Great Hall
Alexandra Palace
  • Over 1000 exhibits
  • 40 National and Regional Clubs
  • Over 90 suppliers
  • Trains, Tanks, Boats, Hovercraft, Planes
  • Kits, Machinery, Tools, Components
Book by 2nd January to save money on tickets.

Opening Times:
Fri and Sat 10:00-17:30
Sun 10:00-16:00


Sunday, 14 December 2008

Screw Removal

This weekend I replaced some rusty screws on the toilet seat with some new stainless steel ones.

I was trying to think why they became so rusty and believe that perhaps they were origionally zinc plated (BZP - bright zinc plate) and that the toilet had been cleaned using acid based cleaners. Anything that says "orange" or "limescale remover" on it will likely have acid in it. These will quickly disolve the zinc allowing the steel screw underneath to rust.

I'd tried to move the screws using a screwdriver but the heads just crumbled. So I thought, why not get myself some screw extractors. Screw extractors come in two forms. The fist looks a little like a 2 blade countersink bit in reverse. The other requires drilling and works a little like a reverse tap.

Different Types of Screw Extractor

I was concerned that the tapping version might be fragile and snap. The simpler countersink like one looked more likely to be successful. I purchased some of these for a small price (approx £3 inc postage) and tried them out. My results were not very successful, the bit just skidded around on the screw head (even at very low speeds) and did not grip at all. I don't know if this was a symptom of the heads being so rusty or not. I'll give them another go next time I have some stuck screws.

I resorted to a simple drilling approach. I drilled through the heads of the screws with a drill bit approx 2/3 of the size of the head. This means that you don't have to worry about being two accurate on being in the centre. It normally results in a nice little doughnut of metal detatching itself from the shank of the screw and minimal damage to the surround. This left a reasonable length (approx 3-5mm) of screw shank poking out of the wood and I used surgical callipers to unscrew these. I've previously used a junior hacksaw to cut a slot in the top of this shank and unscrew them using a flatblade screwdriver. The drilling method would be problematic if the screw was securing a very thin sheet as you would be left with little or no shank.

A friend has recently purchased the tap like extractors so it will be interesting to see if he's had better results than mine.

Although I spotted this mini project myself, it's quite common for the MSW to find such projects for you.

Friday, 12 December 2008

Thor's Metalworking

With a name like "Thor" you are not going to take up a hobby like needlework or stamp collecting. So it's not surprising that Thor has taken up metalwork, he's also kindly shared a collection of metal work plans on his site. These plans also come with detailed instructions and photos of how he made them. I'm particularly interested in his take on the knurling tool.

Thor's Knurling Tool

Tuesday, 9 December 2008

Machining Wood in the mini lathe

I've been doing some simple wood turning in the lathe over the last few weeks. I found that the local DIY superstore sold hemlock balustrade blanks, for a couple of pounds. This is a pale wood that is fine grained and although perhaps not the best choice for turning is significantly better than the lumber from the outside of the store. It's not related to the hemlock from Shakespeare but I'd not advise eating it...

I've effectively been turning between centres to rough the wood to a round shape. The rough blank was mounted between a centre and a 3 pronged spike that I ground and filed out of a piece of hex bar. The lathe was used in the same way as for metal but using a short fat tool to remove the wood more quickly. Once round the wood was remounted in the 3 jaw chuck. The end of the wood was faced off and a small counter bore done again as if for metal.

The next step was to use some small carving chisels resting between the screws of the tool post to turning the curved portions of the wood. I chose a gouge shaped chisel. Next some sandpaper wrapped tightly and taped to a small finger of wood was used to tidy up the results. A knife like chisel was used to start the parting off process and this was finished with a junior hacksaw.

One thing that's important to remember when wood turning is that the sap of the wood can increase the corrosion of your lathe. If you don't want rusty blotches on your bed and crossslide then you need to ensure it's cleaned down comprehensively.

Monday, 8 December 2008

Keeping warm in the workshop

This weekend the temperature in the workshop shed dropped below 0°C so the electric heater was set going. It's only a little workshop and I'm not working long hours so I'm not too worried about the cost.

However the cold did determine my choice of jobs, I decided to practice brazing small sheet brass, approx 10mm square by 0.5mm thick. I'd bought some braze and flux from CupAlloys at the Model Engineering show at Ascot back in September. After a short discussion with them about the need for a significantly bigger torch if I was going to repair the gates on my drive, I focused on the smaller brazing requirements and bought some small brazing rods. These were slightly more orange than usual hence will look good when used with brass.

I had also bought some helping hands which I now used to hold some small pieces of brass sheet in place whilst I brazed them together. I disconnected the magnifying glass and used its fittings to hold some surgical clamps so that I could hold three pieces at once and braze a corner. I found that my small torch did have enough power to get the metal up to temperature but the best results were achieved by pointing the flame vertically down onto work. It was hard to see if the brass was glowing orange but the clips of the helping hands were. I'm not sure if repeated use in this way will soften the springs but I can always replace the clips if necessary.

Small torch

The plan is to make a second identical corner and then use low temperature solder to attach the two pieces together. The resulting cube will be used to test out the aging technique using copper sulphate.

Brazing of three pieces of brass

One thing to lookout for when buying helping hands is the kind of wingnuts used. Mine was cheap and used wingnuts pressed from sheet metal. One of the nuts had already failed by the time I got to use the hands so I've ordered up some new stainless steel wingnuts off of ebay and will replace them all.

Workshop Practice Series