Member postings for Neil Wyatt

A surface grinder for balsa wood!

Luvit!

Neil

A bit of digging suggests you are right, it's probably effectively an 'ESC' on steroids you need. There are circuits on line, but I'd want to get more experience of low-voltage ESCs first.

Neil

A new free plan has been uploaded today - Stan Bray's swing clear rear toolpost.

Neil

Do you need the servo speed control?

If its a straight 3-phase drive a 240V VFD/inverter might run it. I think they go up to 600Hz.

Neil

I was simply disappointed that such criticism was aired in public, in the ignorance that the 'team of professional people' is actually one person supported by some of a designer's time. I make no apology for raising the matter on this forum.

Of course it is not the end of the world but it demonstrates the lax attitude that abounds today towards getting things right. It used to be called 'common courtesy'.

Neil

Moving the threads was stretching my capabilities, I see you've managed to find some of them.

If anyone wants to see the full set they are all in George's album HERE

Neil

As there were a lot of single-posting threads and a couple of very short exchanges on George's  build, I have gathered them together into this thread.

I hope George will continue to add to this thread to update us on this fine model.

Neil

Edited By Neil Wyatt on 25/05/2014 11:31:51

Flow drilling has been discussed in MEW in the past, but as it wasn't in the article title I can't find it in the index.

Neil

Sorry,

I use microcontrollers ('computers on a chip' as the brains of my projects.

AVR is Atmel's microcontroller technology. It's a competitor to Microchip's PIC and is generally seen as more oriented to professional use with less support for the hobby side. Atmel provide brilliant tools and datasheets/appnotes. There's also a full implementation of the GNU C compiler chain (GNUCC/WinAVR).

**LINK**

The PIC architecture does have an awful lot more hobby support, but, at least in its earlier forms, is arguably less user friendly.

I suggest anyone wantiong to find out more googles Arduino or PicAxe

The AVR Arduino boards and PicAxe boards are a relatively easy way for those who want to get into these fascinating and flexible chips.

Neil

Please could we get a sense of proportion. No one died.

Mistakes will happen. Despite Eric's assertion, there are no additional 'proof readers' and only two people are in a position to check such things - designer and editor. Diane will have read that article some six or more times before the photo got transposed. with just two weeks to prepare each issue that makes mistakes hard to spot.

I can't understand why anyone would complain about acknowledging and correcting the mistake on line. Surely that's the sensible thing to do? It doesn't invalidate any correction that later appears in the magazine.

I have heard no cries of disgust that I didn't spot two errors in the last MEW, or that I posted a corrected table on the forum last week.

Why single out Diane for criticism?

Neil

You'd be better having the steel plate clamped horizontally, packed up from the table. Even a 25mm plate has some flex, and that's a lot of leverage that will exploit any flexibility in the vice..

Mainly though, you are climb milling and the action of the cutter is tending to lift it out of the work, it will also tend to pull the work along in a series of jerks

Try reversing the direction of cut. and see what happens.

Neil

Afraid my homebrew boards don't quite measure up to that, Andrew. Especially after I lifted tracks turning chips round...

Still a work in progress this one! Basically its a 128K ram 8-bit computer running a virtually complete version of BBC BASIC IV (although I'm technically not allowed to call it BBC BASIC, let's say it's highly compatible) with a full colour 1/4 VGA display using an extended set of the BBC VDU commands as per the BBC Master (so with higher level graphic primitives like circles, triangles etc.)

The current bugbear is the lack of a filing system - the amstrad email mini-keyboard is fun and fits with the size of the thing, but I usually write test programs on the PC and upload them via the on board USB-serial.

I haven't done any development for about 18 months, I do mean to make a fully OSFILE compatible filing system using SD cards but every time I have a go I get distracted by other bits, such as debugging the onscreen editor so I don't have to use the ghastly BBC line editor.

Neil

<edit> Oh my golly gosh! I hadn't realised just how ghastly that PCB is.

Edited By Neil Wyatt on 24/05/2014 21:49:13

Well spotted Ian, you found the deliberate mistake.

Here it is:

As you can see it's very prototype!

Neil

> just cracked open

By "the thickness of a tram ticket" - a bit hard on those constructors in Edinburgh.

Neil

Ian,

So, it seems there are files designed for safer use on the lathe:

"Designed for smooth finish lathe work on either hard or soft metals, this file has the teeth cut on a long angle. Both edges safe (uncut) to permit working next to a shoulder without injury to it. Also used for finish filing of aluminum. Files are single cut. Opposed direction of the cut on the front and back side forces the file away from the chuck during lathe work, improving safety."

**LINK**

Neil

> if you have a good indexing base

I do, it's as repeatable as swapping toolholders and changing back again.

Neil

I was given a photocopied series from Practical Electronics on an introduction to logic, and my dad was happy to order me as many free datasheets from RS as I wanted with each order. For some reason he was less happy about me ordering big chips..

I still have a ZN104E that's about 35 years old, now relocated into a crude frequency counter/generator with one of those sine/square/triangle chips.

Two books I still use for non-logic stuff are Michael Tooley's Maplin Electronic Circuits Handbook and a battered copy of The Art of Electronics first edition, that I discovered 20 years too late.

Neil

Hi Gary,

As Lofty say, the top one, otherwise there will be a time when both inlet ports are open, rather than both closed.

Neil

Hi Les,

My system has four buttons for each channel.

1 switches between inches and mm

2 goes through display options (which direction is positive, diameter mode, brightness, fractional display etc.) Cycling this also saves the current choice of ins or mm as default.

3 pulls data high

4 pulls clock high.

The Yadro site is where I originally got information on the protocol I could understand. Oddly, it doesn't mention that pulling clock high resets the read head to zero.

I think any servo system would have to have compensation built in to allow for the motor inertia, even with steppers

Neil

Not immediately easy to answer, as it may run either way, as long as both admission ports aren't uncovered at the same time, but you will need a different setting of the eccentric.

Probably the top one, but without knowing dimensions of ports and valve cavity I can't be sure. It will effect events even if the cavity is square, as in the top arrangement you will get much earlier cutoff and more expansive working.

It may be that it runs better on air with the second arrangement, and on steam with the first

If the cavity is rectangular, the answer is easy as I think Stuart usually make the valve cavity the same width as the ports.

Can you show a picture showing both the port face and the valve cavity? Or give some measurements?

Neil