Member postings for John Haine

Please can anyone help! A while back there was a thread on the causes of poor turned finish, in which someone posted some very useful information on speeds and feeds for tct and hss tooling, but now I can't find it! Could anyone point me to it please?

Um, it's a beautiful engine but I have a feeling it's a double expansion based on the Leak design. The 3rd "cylinder" I decided was a piston valve on the basis that underneath it was an eccentric rather than crank. The original Leak design has slide valves on both cylinders IIRC (there is one part built under my bench).

Shapeways steel goes up to 800 odd degrees.

You might be able to print them. See:

http://www.shapeways.com/materials/steel

you would need to generate a CAD model.

It looks as if the web browser on an attached PC (on USB port) is used as the user interface to control the machine, upload design files etc. The processor controlling the machine simply serves a web page to the browser.

"They showed you then selecting a part by clicking on a file [ where from ? ] and it went away and printed."

I imagine in the video they simply used the browser to find the file on the PC, which a browser can happily do. Internet connection not needed. Basically it avoids the user having to load any specific software on his PC, all the functional software runs on the printer's own processor.

"What about where on the bed it needs to be ? Support matrix ? or % of support ?"

Apart from the mechanical construction and the user interface it looks like the operation is basically the same as the RepRap and the same principles will apply.

It's a Myford - Dickson type. It is mounted 90 degrees out, the hole should be bottom right so the tool holder fitted would be in the boring bar position at the back. I think the hole must be for a location dowel should you want to use one but it isn't necessary. Manufacture these days is a bit generic, I bought mine new in an unmarked box from G&M Tools. I think you can get holders from Kirjeng and maybe RDG Tools? They are very good.

Not so! Height gauge extremely useful to measure height of top of workpiece above cnc mill table!

Ian, I suspect that the pots you used are log types intended to be used as volume controls. A VFD should use a linear type.

I remember a drawbar design in mew a few years ago recommending high tensile steel! If you tightened that up to anywhere near the steel yield strength you'd never get the taper out again! I've never had a problem with studding stripping used for draw bars or tee bolts, though I tend to get the stainless stuff now as it's better finished.o

Mail just sent.

Harry, was that John me? No pm received yet...

Why is using studding for a drawbar "improvising"?

Harry, pm me your email address and I can send you some photos I took this evening of the bolt off mine which will give you the dimensions. Trying to use this site to transfer them is making me lose the will to live.

Assuming your lathe has an mt2 spindle taper, the usual approach is to put the mt2 blank in that with a drawbar to hold it in. Another way is to buy an mt2 female to parallel adapter (rdg have these I think?), hold the blank in that again with a drawbar, and hold the adapter in the 4 jaw to get it dead on centre. This is assuming that the blank has a threaded hole in the small end for a drawbar? If not, and it has a tang, then it isn't really suitable for a boring head which will need to be positively held in the spindle of whatever machine you are using it in.

There's an error in the CNC in the Workshop article in the latest MEW which could cause some head scratching. In the 3rd column of the first page there is a little bit of g code that is supposed to take the drill 1 mm above the work, then centre drill in 2 pecks of 3 then 6 mm. Unfortunately the z values given are 3 and 6 mm rather than -3 and -6 mm, so the drill won't break the metal surface at all! The same error is repeated in the text a few lines below, so it's not just in the g code transcription.

On the next page there's another bit of code to drill holes to 20 mm deep in 3 pecks. I think the intention is to use a safe z 1 mm above the work, but in the 3rd line z is set to the work surface z=0. This time though the drill depths are given correctly as negative z values.

This is an exercise so I guess that is why the peck drill instruction isn't used?

i must say this series seems to be making glacial progress, as well as apparently spending more time describing general purpose milling accessories than specifically CNC.

KB controls are scr based, not MOSFET. On mine when it recently stalled, the fuse blew. Are you sure it isn't just a fuse?