Member postings for colin hawes

Aluminium bronze, horrible stuff to drill. Colin

Normally a 2.1 drill would be used for M2.5 thread as there is likely to be slight deformation of most materials as well as the cutting action and that extra 0.05 mm allows for that. Colin

Qualified engineers are a highly intelligent but too reserved species which is why they are not rated as highly as doctors or lawyers by society. Everybody uses engineered equipment The misuse of the title "Engineer" is another reason for lack of appreciation by the average person. We need to greatly promote knowledge of the skills and mathematical abilities of people entitled to call themselves "engineer". Colin

Over many years my ex- scrapheap horizontal flat belt Clarke mill has often been very useful for cutting thick (3/8 to 2) inch steel plate that is too big to fit into my bandsaw. It has been used many times to turn 24 inch and bigger wheels. It's not a massive machine, with 18" traverse, but it is amazingly rigid. I also use the larger end mills and face mills with the job on its side. Very useful machine. Colin

I have often turned wood on my metal lathe ,it needs a very sharp high rake tool preferably a high speed and works best on hard woods. Colin

Tolerances are for making spare parts interchangeable or special fits such as force fits where a critical difference between parts is necessary so actual precise dimensions are unlikely to be essential on models. Colin

HSS tools are the most economical way to go for a beginner and will machine all the metals you are likely to use in model making but carbide tips are very useful to machine cast iron at a higher speed. Colin

A small built up layer of debris can cause your problem if it is the type with plain metal wheels (no rubber tyres). It can sometimes be cured by cleaning the wheels with emery cloth. Colin

When I was working as a toolmaker fractional dimensions were only used for an unimportant dimension such as the base of a drill jig and had a tolerance of +/- 1/64 th of an inch. Apart from standard threads, everything else was dimensioned decimally anyway, normally in "thous", e.g. 1.002, often in "tenths", e,g, 1.0002, so it was very similar to metric dimensioning apart from the basic unit of one inch as opposed to one millimetre.

Having many imperial tools and old but excellent imperial machines I naturally welcome imperial drawing dimensions but I have had to work professionaly with both systems so I really am not bothered by mixing them when making things. A lot of what I do now is restoring parts of vintage motorbikes which are generally measured in inches anyway. I do have a metric micrometer, digital calliper and a DRO so conversion is easy anyway. Incidentally , what's imperial weight got to do with machining things? Colin

Neil, thank you for your references, they are what I was really looking for and it has shown me that it would take too much of my model making time to attempt a rewind with uncertain results so I shall now consider whether to get a rewind done or convert to electronic ignition in the interests of reliability. Colin

Thank you for your advice ,Clogs and Martin, I guessed it might be a bit of a problem so I am more likely to avoid this one; reluctantly as I have always been one to have a go at anything. Colin

Has anybody tried to rewind a lucas motorcycle magneto and what is the wire spec, gauge, number of turns and length of wire used for primary and secondary windings? I am thinking about attempting this and any information would be of interest. Colin

There is a difference between machining at production rates with a jet of coolant and machining on hobby machines with a low or non existent coolant flow. It is my opinion that many amateurs go for published production rates at the expense of tool and machine life expectancy and machining mild steel with HSS on a hobby machine should not be producing blue chips. Colin

Edited By colin hawes on 29/07/2018 15:41:56

Your 12 mm cutter should be nearer 500 - 600 RPM for general machining of non free-cutting mild steel. Colin

A Stellite drill made from a round Stellite rod with a three sided pyramid shaped point will drill though a hardened file or a HSS cutter. It has to be run at high speed with quite a lot of pressure on a machine and it gets red hot. Stellite cannot be softened by the heat and it can be easily sharpened on an offhand grinder. This is a method which I have used many times in the past when a hole is needed through a hardened component. Colin

I spent a week, off and on, looking for the red handled chain spanner which I've had for more than 20 years to remove the car's oil filter. The one day I walked into my shed and saw it straightaway; it has a blue handle! Colin

My wooden workshop is at least 12 years old and has a concrete floor with gravel under it and a damp proof plastic membrane between. There is a small, shallow, ditch around it that drains away any water to a lower level. I have an old carpet on the floor and it is always dry. The concrete is about 3" thick and supports my heavy machines adequately. Colin

Can you buy replacement probes for these older Verdict lever indicators? I've got one with the ball broken off. Colin

It seems to me that things are further complicated by the number of teeth engaged at any moment and if a rolling contact on one of them takes the strain off a sliding one.Colin