Sunday, 26 April 2009

More machining with Microscopes

Mike from Mike's Models has also been using a Microscope for machining in his workshop. In his machining experiments with a USB microscope, he looks at the problem of drilling small holes and the drill wandering and also looks at the surface finish of his cam shaft project.

Mike's Models Videos.

Tuesday, 21 April 2009

Machining under a microscope!

Although at times when making the flea circus chariot I had to use a magnifying glass I never actually did any machining using it.

John R. Bentley has rigged up a LOMO MBC-10 (LF-100) stereo microscope in his workshop which can be used with to assemble miniature components or with his Taig 4500 Micro Lathe. I've got some A5 sized fresnel lenses (page magnifiers) that give me 2x magnification which might be handy when setting up tool height etc, it's something worth experimenting with as it would only need a very simple stand.

John has also made a scale working model of a Taig lathe with working hand dials and four jaw independent chuck. I'm impressed with how he made microscopic tools from materials like piano wire which were then used to engineer the model. It makes my efforts of working with M2 Taps look positively gargantuan.

Wednesday, 15 April 2009

Bush Saw

Over the Easter weekend I was doing some gardening, i.e. chopping things up. I realised that the bush I was cutting up would make a good handle for the saw I was using.

The saw blade was from some telescopic loppers but it was a bit hard to manipulate a saw on the end of a 2m pole so I'd just been using it with some thick gloves which was far from ideal.

A 14in by 1.5in section was cut from the bush and a slot was cut in the end using the saw blade. Any rough bits were removed with a surform. A couple of holes were drilled and the blade was bolted in place with some M5 bolts. I added a bit of packing so that the blade did not move. It's likely that as the branch dries out I'll need to tighten up those bolts. It's also possible that had I made the slot a little longer then I would not have needed the packing. A final touch was to add a screw eye to the end so that I could hang it up in the gardening cupboard in the workshopshed.

Tuesday, 14 April 2009

The Model Engineer Exhibition 2009

A change of dates and a change of location for this year's Model Engineer Exhibition, the exhibition returns to Sanddown with a slightly later date in December. Just in time to get some Christmas presents for your favourite model engineer?

11th - 13th December 09
Sandown Park Race Course, Esher Surrey KT10 9AJ

Buy tickets for Model Engineer Exhibition

More details when they become available.

Wednesday, 8 April 2009

Institute of Backyard Studies

The Institute of Backyard Studies has relaunched their website with a new forum for discussion of sheds and activities related to handiness and resourcefulness.

A description of the institute by Mark Thomson Advanced Research Director.

"What I want to do is to encourage curiousity, creativity and resourcefulness and the place that it tends to happen most, in the way that I want to encourage, is in sheds.

The sort of shed culture that I am keen to propagate is about a sort of frugal thoughtfulness blended with the sort of creativity that has become unfashionable.

This website is for people who reckon that it’s no bad thing to get your hands dirty or those who don’t throw good stuff out at the drop of a hat."

Institute of Backyard Studies

Friday, 3 April 2009

Terminology - Tommy bars and Jobbers

Most hobbies have some specific terminolgy and you can feel a bit of an outsider when you don't fully understand it. Here's a couple of explainations for the Tommy Bar and Jobber.

Tommy Bar

The Tommy Bar or T-Bar is a simple rod used to help provide leverage to tighten or turn screws, for example I have a tommy bar to tighten the jaws of my three jaw chuck.

When I looked up Tommy there was a reference too British soldiers were called "Tommies", a reference to "Thomas Atkins" a term made popular in the WWI.

Websters online suggest the tommy bar name origionates in mining

A short rod used as a lever or handle for turning a jackscrew or a
spanner by being inserted loosely in the hole provided for that

I thought that this could be how the two are connected together, as
they could have been using such bars when making the trenches. Which
lead me to the following definition

TOMMY BAR Spanner or wrench for unscrewing the base of Mills bombs
(to adjust the timing fuse).

There is a strong correlation between tommybars and box spanners so
it's likely that the spanner mentioned above was some kind of box

Box Spanner with Tommy Bar


The term Jobber came up when I was reading some American websites about machining. I knew it referred to some kind of drill bit. I made some enquires and came up with the following definitions

"The name jobber is used for drills that the length of the flutes is 10 times the diameter of the drill"

"Jobber-length drills are the most common type of drill. The length of the flutes is ten times the diameter of the drill, that is they will drill a hole that is 10D deep. They normally have a parallel shank. In my boxes I also have some long series drills and a few where the flutes are only a couple of diameters long (very stiff)"

"It is believed that general purpose drill bits are called jobbers as they are/were used for jobbing work."

Thanks to all who helped in this research, specifically those from the Model Engineering Clearing House and Blokey Shed

Workshop Practice Series