Member postings for mick

Before tapping compounds became widely available, tallow was the only medium, apart from 3 in one oil, we had to assist cutting threads.

Try using a three square swiss file and cut one face of the hexagon at a time.

A bar fed CNC lathe would use G96 constant surface speed where the RPM increases as the diameter being parted decreases so the tip has constant machining conditions for the entire operation. If you use power feed on a manual lathe the tip is laboring the closer it gets to the centre of the bar, as the surface speed is in fact decreasing, so its always best to hand feed as the operator can compensate for the surface speed by decreasing the feed rate of the parting tip, or blade, as it approaches the centre of the bar and of course using a rear mounted parting tool will always give better results.

Hi. Jason.

Its a nine cylinder rotary this time. Glad to learn that 250 is decent stuff, I was feeling a bit apprehensive as the first bar they sent me was hot rolled mild steel and its taken me several days to get them to accept that I know the difference!

I was wondering if any one has ever used cast iron 250 as its the only cast iron that most of the big boys supply. I'm use to Meehanite, but due to cost, as I need a 50mm diameter x a meter length, I thought I'd give it a try, but looking at the on line specification, it says it is a fine grain cast iron which can be polished and used for gears and cams, which I'm hoping will be perfectly okay for the cylinder liners I want to produce. Any experiences, good or bad would be appreciated. Thanks

I worked as a machinist at one engineering Gulag, where after being handed a particularly nasty job to make I quipped to the engineer next to me that I must have done some really bad in my last incarnation, to which his sage like reply was"all engineers did something really bad in their last incarnations!"

A friend of mine once described to me a particularly boring lecture on a hot summers day while on day release course at the local college, where he fell asleep. When, on being woken by the lecturer and asked, "well, what is a spur gear then lad?" his quick witted replied was, "the one you've got left over sir!

So touched was I by the reproduction of the idyllic rural 1928 workshop and sparkling prose that accompanied it that I too was moved to poetry.

' The rain pours into my workshop, which makes me cuss

as my treasured tools are all covered in rust!'

Perhaps poetry corner will become a regular feature, as I'm sure we all have a favourite little ditty

A quick and inexpensive way of fitting a digital readout, the length is altered by moving the clamp holding the depth probe

This sort of machine was only ever ment to be a training machine in order to demonstrate tool paths etc. and not intended for removing a lot of meterial. I use to have a Denford Orac for turning batchs of small components, which did what it was supposed to do, but was slow and painful to program.

As soon as they invented the pocket calculator, I was the first to bin my log tables!!!

When God was a boy we use to harden tool steel with a blow tourch in a hearth, but to better gauge the exact point to quench the steel we turned the light out. Amazing the difference between cherry and bright red that makes.

Wrong end of stick grasped on this occasion, but scaling from drawings (sometimes unavoidable) is a practice not to be encouraged. There should always be enough information on an engineering drawing to allow the machinist to produce the component drawn. The only time its acceptable to scale a drawing is to ascertain dimensions that are for features in fresh air, such as the profiles of castings. In my experience any un-dimensioned detail on any imperial drawing, should scale to a preferred fractional size and therefore easy to convert to metric. As you might have deduced I don't have a CAD system.

I use a calculator to transpose imperial to metric and visa versa to four decimal places imperial and three places metric, nothing in the home workshop needs to more accurate than that. I don't understand where the 0.2mm accuracy by using a calculator comes from, perhaps a new one is required.

After I had been handed a particularly nasty and difficult job to do by the workshop foreman, I said to an older machinist "I must have done something wrong in a pervious incarnation" the sage like reply was "all engineers did something very wrong in their previous incarnation!"

Life really is too short to worry about thermal expansion in a shed!

Oh dear, what a lot of fuss about nothing. My first wise old foreman showed me how to zero a micrometer, first trap a piece of clean white paper between the anvil and spindle and slowly pull it out, any dirt or oil will remain on the paper, then close the spindle on the anvil using the ratchet, if the reading is zero, then the readings taken there after will be true. Simple!

The sine of any angle is the vertical measurement over an inch, so if your compound has travel of say two inches, multiply the sine by two, zero the bezel and clock the fall over two inches of travel, using a DTI running along a freshly turned diameter, adjust the compound slide until the fall of a given distance equals the value of the sine.

Valves are stainless steel, so magnets aren't an option, also the valve head is 0.075'' thick, so a screw driver slot isn't any good either, I was hoping for an easy solution, so back to the drawing board, it'll be a bit tedious, but some form of bonding might have to be the way forward.

I feel sure someone will know, but where can I get hold of a small diameter suction pad to grind in eighteen inlet and exhaust valves? The valve head diameter is 11mm./ 7/16''.