Tuesday, 29 November 2011

Metal Model Building - metallmodellbau.de

Just incase you had any doubts that the Germans were excellent engineers, here's the Metal Model Building Website.

I stumbled upon this fanstatic site via Achim's Mini-Bonell-II a "sitting room" universal grinding machine and thanks to the wonders of Google Translate managed to read how it was made. The article has detailed 3D cad models and discusses the design decisions for the project, some of the tooling needed and choice of materials.

There are some excellent features to this design. The dials have verneer scales to allow for accurate positioning of the angles and a toothed belt is used to cotrol the horizontal position.

There are a wide range of other articles on the site such as a toolpost milling spidle, a small IC engine, making a cutter for cutting gear wheels and one of my favourites, some enhacements to a cheap drill press entitiled "Pimp the chinese drill"

Update: Here's a link to another Bonelle grinder

Friday, 25 November 2011

It all works with Magic Smoke

I was reading the story of a chap who left his grinder on the bench whilst welding. He commented that he'd "let the magic smoke out" and hence it was now not working. The issue was that the HF from the welder had passed through the grounded metal parts of the grinder and up the mains cable to earth melting the cabling in the process.

I once let the smoke out of my grinder when vents rapidly became blocked when trying to cut through some concrete, the grinder overheated within a few seconds and I was too late to spot it.

Angle Grinding Steel Bar

I do like that phrase "let the magic smoke out" so I checked the history of it. It seems to be relatively recent and is accredited to Jay Maynard who was working with some electronics.

"Once, while hacking on a dedicated Z80 system, I was testing code by blowing EPROMs and plugging them in the system, then seeing what happened. One time, I plugged one in backwards. I only discovered that *after* I realized that Intel didn't put power-on lights under the quartz windows on the tops of their EPROMs -- the die was glowing white-hot. Amazingly, the EPROM worked fine after I erased it, filled it full of zeros, then erased it again. For all I know, it's still in service. Of course, this is because the magic smoke didn't get let out."

There is a rather dated theory that the magic smoke theory could be based on called the phlogiston theory which looks at the products of combustion. The idea is that because things are lighter when they burn then something must have been removed, this is the phlogism.

Wednesday, 23 November 2011

Model Engineering Exhibition 2011 at Sandown Park

Just a reminder of the model engineering exhibition over at Sandown Park is next month and is celebrating it's 104th Birthday.

Show Times
Friday, 9th Dec 10.00am - 5.00pm (Last admission: 4.00pm)
Saturday, 10th Dec 10.00am - 5.00pm (Last admission: 4.00pm)
Sunday, 11th Dec 10.00am - 4.00pm (Last admission: 3.00pm)

How to find the venue

As well as the usual trade stands, clubs and competition there will be a selection of loan models on show:

Doubled-Up Version Of Eric Whittle's V8 Engine - Mick Knight
Inverted Triple Waterworks Engine in three-quarter inch scale - Neil Carney
Single Cylinder Beam Engine in three-quarter inch scale - Neil Carney
Memories of Yesteryear A Harbour Diorama - Ray McMahon

Also a selection of home made tools and accessories:

Taper Turning Attachment For Myford Super 7 Lathe - Ken Willson
Stepless Anvil For Screwcutting - Ken Willson

And Locomotives:

Darjeeling Himalayan Locomotive - Ray McMahon
GWR locomotive Pansy designed by LBSC - Ray McMahon
Gas Turbine Locomotive - Ray McMahon
GWR 5 inch gauge Passenger Coach - Ray McMahon

Don't forget that if you have a special purchase to make it is worth contacting the supplier in advance to ensure that they will have an item at the show.

Also it's worth checking the latest copies of Model Engineer and Model Engineer's Workshop as the latest editions have free sunday tickets.

Friday, 18 November 2011

Ironwork of St James, Mayfair and Piccadilly

Whilst wandering the streets of London, I tend to notice the large variety of metal work on the buildings and surrounds. Here are a few images taken this week of the fantastic ironwork around St James, Mayfair and Piccadilly. There seems to be a strong art deco influence, some with a Celtic flair along with some more Victorian designs.

Monday, 14 November 2011

Amazing Meccano Crane

Thanks to the MIG Welding forum, I've found out that Marc Van Goozen from the Netherlands has built this amazing operational 1/8 scale model Liebherr crane. The crane is build from mechano parts augmented with a specialist components such as bearings, electronics and electric motors. It contains approximately 15,000 incl. nuts and bolts and took approx. 2800 hours to construct. The model's weight is about 50 kg/110 pounds in total. Marc would prefer not to say how much it cost but commented that more and more packages of parts were delivered to him as the project progressed.

Marc has kindly let me reproduce his pictures and has provided a lot of detail of how the crane was made. As you can see below the chassis is very solid, this is necessary as the crane can lift the same amount as the real crane (well to scale anyway). Marc has tested it lifting a 20kg lathe.

One of the reasons it can lift so much weight is, like the full sized crane it has operational out-rigger legs. These were one of the custom made items, made from aluminium and steel tube. To protect the table, the pads have foam backing.

The boom extension is constructed from girders and strips and is chain driven to avoid the problems of stretching associated with cables. This also makes assembly and servicing easier.

The slewing bearing is a standard industry part and it sits on the chassis with an adapter ring. The slewing gear pinion is driven by a gearbox motor. Some of the gears are standard sizes but some had to be specially laser cut as Meccano themselves never made such parts.

Not all of the crane is purely functional, Marc wanted some decorative parts too. The drivers cab is fitted out with a chair, opening window and side mirrors. Even details like steps and exhausts have been added.

The control of the system is via a joystick and switches, no computer is needed but as the motors are controlled with relays it should be possible to interface it. There are 13 motors, 8 on the undercarriage, and 5 on the superstructure. The lifting ram has a 24v motor and gearbox. So that the DC motors do not slip when the crane is at a standstill, the motor terminals are shorted out. This effectively acts as an electronic brake.

See the crane in action:

You can read more about the crane and find details of it's load factors etc over at the MIG Welding forum. You can also see more pictures of the crane at Marc's Meccano Gallery. Thanks again to Marc for sharing this project with us.

All pictures copyright Marc Van Goozen.

Friday, 11 November 2011

Wire Strippers

This month the UKToolCentre asked me to write them an article for their blog. Given they were a tool company I got thinking about what tools I had and if I had a favourite. After a bit of a think I concluded that I did not have a favorite as every tool does a different job but I did have some tools that I'd had for a very long time.

The tools I've had the longest are those for working with electronics, so I've got a 25 year old pair of pliers and an equally old set of wire cutters. I did have a soldering iron at a young age too but that eventually had to be replaced.

Selection of pliers, strippers and cutters

You can read the rest of my thoughts on wirestrippers over at the UkToolCentre blog.

Friday, 4 November 2011

Rival Model Engineering Magazines and Events

I'm a subscriber to "Model Engineers Workshop" a UK magazine that details projects for building tools and accessories for model engineering. In the latest edition there's a free ticket for the Model Engineer Exhibition over at Sandown Park Racecourse on 9, 10 and 11 December 2011.

Model Engineers Workshop #182

I also occationally read Model Engineer and Engineering in Miniature. In the November Engineering in Miniature there are a couple of interesting comments. The first is that their rival show at Alexandra Palace in January will have a model competition which is one of the differences in the shows I pointed out last year. The other comment was from the magazine editor in that there will be more workshop projects articles in the magazine in future, for example the next edition is to include TIG Welding and a Spark Eroding machine. Obviously they are trying to lure readers over from MEW. I won't be cancelling my subscription just yet but some competition is between the magazines and exhibitions hopefully will keep both at a high quality.

Wednesday, 2 November 2011

More shed roof project

As mentioned in the earlier post, I used to have some corrugated PVC on my shed roof and although it let in lots of light it also also let any heat out and then baked in the summer. There were also a selection of leaks. So I needed to replace the shed roof.

Old plastic roof

I was important that I still had the light but I also wanted to have better thermal insulation and keep the budget from skyrocketting. My other constraint was that I did not want to loose any roof height with the new roof. Again to control costs, I needed to be able assemble the roof myself so that restricted me with regards to large or specialist materials.

The solution was a three layered design like an icecream sandwich. The inner later was to be tongue and groove cladding, the middle a wooden framework containing insulation and the top which was a sheet of OSB. The whole thing was then topped with roof felt. On the south side I incorporated a sheet of polycarbonate to act as a window.

The first layer of cladding was simple to add, being simply nailed in place. Luckly my helper spotted that the roof was not square and we compensated for this by adjusting the spacing of one end of the planks so that the top plank lined up nicely with the roof ridge.

Installing the planking from inside
The middle was built as a frame on the grass. Although the shed looks rectangular from the front, it has a corner missing where the cupboards have been added on one side. This made the first frame tricky to build.
Frame build
The roof was also not flat so long screws were used to bend the frame into place. Extra bracing was added to stop the wood from cracking. We used drywall screws as they are coated to avoid corrosion, thin and self pilotting. However on some of the older timbers we did drill pilot holes as the wood had hardened. Frame installation
This was then filled with insulation and a sheet of OSB was screwed to the top.
The water proofing was provided in the form of 2 layers of felt. The first was an underfelt which does not have stone chippings on it. The top later was a traditional cap sheet which had some nice green stone on it to protect the bitumen layer underneath. I had origionally thought about using a bitumen mastic to glue the felt in place but we decided to nail the felt down using clout nails. Roof felt layers
The two of us assembled this half of the roof in a day. This was made easier by the fact we could access the roof from ladders inside the shed. In the final part I'll tell you about how the window was fitted.
Thanks again to Alan from 2020 media for his help and his acrobatic skills hanging upside down nailing in the felt.

Workshop Practice Series