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Member postings for John Alexander Stewart

Here is a list of all the postings John Alexander Stewart has made in our forums. Click on a thread name to jump to the thread.

Thread: 1000 to make a Spitfire aircraft fuel tank gauge. Can it be done cheaper?
13/10/2020 04:14:22

Way back when, a colleague and family was flying in a 767 that had fuel gauge issues, and glided into Gimli Manitoba. They got on at the stop in Ottawa, and were flying out to see parents, etc.

It had zero working gauges (allowed at the time) and the tanks were not properly dip-sticked.

So, maybe a known-accurate fuel gauge, with the associated cost, on a priceless aircraft makes sense, despite the initial "wait a sec- I could give them a bargain and make 2 for that price" thought!

Thread: Engineering Sights on Google Streetview
09/10/2020 22:33:58

And, if anyone wants to see what the back of a boxpok wheel casting looks like:

**LINK**

It's in front of a block of flats, on what was part of the Canadian Locomotive Companies' land; CLC built and exported locomotives all over the world; there's at least one in running condition somewhere in France/Switzerland (ex. SNCF141Rs were built in Montreal, Kingston ON, and somewhere else in the USA)

Now, why they had to mount it with the back facing up escapes me, they look better outside side out, in my opinion!

09/10/2020 22:27:10

Does this count? (lets see if the link works...)

**LINK**

Thread: Best configuration for a Hobby CNC
28/08/2020 15:57:05

Clive;

FYI: About a decade ago, at SIGGRAPH, a 3d gantry-style router was presented, called "DIYLILCNC", and plans were available by download.

It used a Dremel for the spindle, and could do aluminum. This was when 3D printing was really doing well with home-built machines; a group thought that "subtractive machining" was something that might fly with those without tons of money for the then-current CNC mills. It used LinuxCNC if I remember correctly, so was certainly within the price range of the youngsters.

The guys seemed to be there for a couple of years, but faded out.

Maybe they were before their time, or maybe the Chinese routers are where it's at.

John.

Thread: CNC Gear Hobber
23/07/2020 12:25:30

John;

First, check your messages for Andy Pugh info.

If your mill ls like my "King Canada KC20" (sold under different names) then yes, you can send the signal to a computer; it won't give you rotation direction nor does it have an index pulse, but it's great for ensuring that the mill is running at the correct speed, no matter what gear you are in.

21/07/2020 15:14:59

John;

If you are referring to Andy Pugh's hobbing videos; it is still very relevant and in use all the time. It's LinuxCNC, which is the base for the Tormach controls now.

You can contact him via the LinuxCNC.org forum, or the mailing list, he seems to be very helpful.

It seems like any optical encoder can interface so long as it has the index pulse will work with LinuxCNC for this purpose.

It's a cost-effective solution, but one that is not off the shelf.

John.

Thread: resumption of delivery of ME to Canada
17/07/2020 17:39:45

Hi all;

I keep both an on-line and paper file system of interesting articles. Well, not any more, unfortunately.

Q: Anyone figured out how to print out articles? I do like to scribble on printed copies, as I convert to metric, or make machine-specific notes, then (usually) scan them in for my workshop records.

On my computer systems, ether printing prints nothing, or prints out the left hand side of the first column, and nothing else.

Maybe it's a user problem?

My Mac computers print blank pages;

Also, on one of my computer systems (Linux) jumbles letters - see the attached screen grab!

garbledcharacters.jpg

Yeah, I know, I should

a) not be a ludite (despite working on the html5 standards for a bit)

b) use Windows10 (which I have, but as that computer is for "Canadian Controlled Goods" work, I am loathe to do much other than work-work on it;

c) have a photographic memory so I don't need to keep notes! wink

So, advice most welcome.

Thread: milling Acrylic
13/07/2020 17:48:20

Many thanks - the support and guidance was appreciated.

The Acrylic faceplate machined with absolutely no issues, and results delivered to owner. (doing this for a friend of a friend, he's a radio nut, and had ONE piece of Acrylic of the correct size - no screw-ups allowed.

I decided to mill on my manual mill - Centec 2B, the part barely fit with maybe 5mm extra Y travel, but fit it did. On the Centec, I could have my nose down close, and adjust the feed as appropriate; next time I'll know better how to do this on CNC.

JohnS.

10/07/2020 13:13:59

Hi all; was given a task to mill a pocket and outline in a bit of 3mm Acrylic.

The searching I did here mentions turning, on-line it's with high speed spindles.

What have YOU done with a slowish (say, max 5,000rpm) spindle on either a manual or CNC mill? Say, 3mm or 4mm 2 flute cutter.

I expect to hold this piece down with double sided tape, hopefully I can get it off of the carrier again. :-|

Advice more than welcome. Thanks - JohnS.

Thread: Why are injector pipe connections made with flat mating surfaces?
11/06/2020 14:39:02

Maybe because of space, flat takes up less room.

All the fittings I make are flat faced; seem to work just fine. As a fellow live steamer once said "with flat facings, you can always stick a teflon washer in to help seal if required"

Thread: Beginner's engine build. Simplex 5"g.
29/05/2020 16:15:42

Iain;

My first build was an LBSC Tich; there were issues during the build.

No matter - if you want to do it, do it. I did - people kept saying "start with a stationary engine! Build something larger!! Purchase one and fix it up!!!" but I went down the path I wanted to go.

But you have been warned - know that you have to plan ahead and think about fits and interferences. Talk to others and go through the mentioned on-line build logs. Maybe it's part of the fun?

I'm back on my Ivatt 2-6-0 Martin Evans' design; took a break and built a Kozo Hiraoka Shay (first version) and, on coming back to the Ivatt, it hit me just how good a designer and draughtsman Kozo Hiraoka is.

I think that I'd rather build another Kozo engine than a Martin Evans' one; saying that, there's 2 Simplexes at our club, (one regular, one super) and both run and run and run with minor maintenance. (and, I think one had to have its' rear axle replaced after many, many miles on a ground track)

Thread: Delay in dispatch and delivery
22/04/2020 14:15:04

I ordered some specific steel from a UK supplier (you'd know the one, but I won't mention the name) and they packaged it up and mailed it.

Unfortunately, mail shipments between UK and Canada are slow (probably ALL shipments are slow, between anywhere that needs planes to fly) so after a few weeks it's still not here.

No problem, I've got other projects (plus full time work) keeping me busy, and if in the unlikely event it gets lost, the materials can be sourced locally, once the stores re-open after the COVID-19 shutdown.

Years ago, (mid-70s) I used to order packages from Reeves, as a kid I did not pay for air-mail. My 2nd set of Tich Cylinder Castings took over 6 months; lots of other castings and so forth took about the same length of time; a month or two for this package from the UK metals supplier will be *nothing* in comparison!

Interesting times we are currently living through.

Thread: Does CNC use a DRO
20/04/2020 15:47:50
Posted by John Haine on 20/04/2020 13:58:39:

Right! Thanks for that, I just assumed it was open loop. Interesting!

John; this is one of these interesting conundrums:

a) LinuxCNC is light-years ahead of Mach3;

b) Mach3 does well enough for most current home workshops;

c) if Mach3 is good enough, there's no incentive to update, but you're stuck with essentially dead software.

What to do?

I most certainly understand people sticking with Mach3, but I decided to try LinuxCNC and do enjoy the utter reliability of it. I've currently got 3 machines running LinuxCNC, may be 4 soon if I get off my duff. I mean, these machines are tools, like comparing a Warco or Boxford to an Emco Maximat or something; all would do a fine job in my workshop, given my skill-set.

The late John Stevenson and I exchanged lots of email, and in-person discussions over pints about LinuxCNC and it's hard-to-configure compared to Mach3 setups, and he was of course correct; for me Linux is easy, as I've been developing software on it for over 2 decades; for me Windows is rarely used and seems awkward. That's just the way life is.

By the way, I picked up a KX1 over here (Canada) years ago, without stepper controllers, and John Stevenson and I had a real discussion on it, as he said "impossible". He called the factory in China to ask what's up with mine. It ends up, it was one of a batch for internal use in China, that somehow leaked out - he did not know this, as the KX1 was his baby.

Thread: A bit of history of Mach and LinuxCNC
19/04/2020 18:56:35

I know lots of people here are Mach users, so you may like to find out a bit of background:

LinuxCNC used to be called EMC, until some company decided to patent "EMC", and somehow won. (I don't think it was much of a fight)

EMC has its' roots in the US NIST (standards); not sure of the date.

https://www.nist.gov/publications/enhanced-machine-controller-emc-open-architecture-controller-machine-tools

is a paper from 1994.

A while ago I did see a message from Art Fenerty requesting permission to use some of the EMC code for Windows, but I can't seem to locate that anymore.

But, the following message from 2002 might help shed some light:

http://emc.sourceforge.net/NIST-archive/msg05363.html

"Pieces of EMC were used as a base for Art Fenerty's Master CNC and

Mach-1, which does run on some Windows systems, but it is NOT EMC."

I find it really interesting that this "stuff" has been around for at least 25 years; I would not have guessed it.

Anyway, FYI, or TMI, or whatever, for what is a rainy day here. JohnS.

 

 

Edited By John Alexander Stewart on 19/04/2020 18:57:08

Thread: Manual control of CNC
19/04/2020 18:44:54

Adrian;

Any CNC controller (I use LinuxCNC) can have "MPG"s attached. My CNC mills (plural) all have them.

When I worked in a Canadian Govt. research site, the machine shop made one-offs for all kinds of prototypes; one day in there getting some work done for a project, and talking to the machinist, he asked me

"how many manual mills do you see in here?"

I looked around, the place was about the size of a basketball court, and said "none"

His next question was "then why do you use such an archaic thing as a manual mill?"

He showed me how they used a CNC mill for making one-off parts, and I was converted.

I don't even have a pillar drill; all drilling is done on a CNC machine either under program, or hole by hole with a quill and handle.

Something to ponder while waiting for COVID-19 to pass. JohnS.

Thread: Morning tea
15/04/2020 14:08:36

Over here (Ottawa, Canada) we are maybe finally getting warmer weather, although we do have a nice dusting of snow this morning.

As such, lots of people are getting out. To keep the 2m distance, locally some roads are closed off, and people are walking, walking dogs, cycling, etc.

City parks, you can walk though, but don't linger. Closed off dog parks are locked shut if possible, or just off limits. Playground equipment is off limits.

We can't drive over to the province of Quebec (which I can see from my driveway), as there are police checkpoints. Mind you, somehow our Prime Minister managed to evade the checkpoints, and went to his cottage in Quebec for the weekend.

People are very good about the social distancing, although my wife did have an occurrence in a pharmacy, where some young woman breezed past her, my wife getting elbowed, so not 100% of people are "with it".

Interesting times....

Thread: Smokebox front ring for Tich ???
30/03/2020 21:13:42

My large boiler tich - the front ring is just a push-in. I did it in my bench vice, blocks of wood, and slowly pressed it in, lots of measuring to ensure that it was going in straight.

It hasn't moved since the 1980s, doubt if it will now!

Thread: Old Computers - why do people bother
06/02/2020 20:21:23

For those of us raised on 8-bit computers, Bill Godbout, a name from the past for the S-100 bus and CompuPro, died in a forest fire in California late 2018.

https://en.wikipedia.org/wiki/Bill_Godbout

(nicer story - back in high-school (pre University) I was making 1802-based computers (only diagnostic tool was a volt meter; one could single-step the 1802 and verify my wire-wrap wiring) I got a newsletter called Ipso-Facto, and it ends up that one of the executive of that newsletter is a model engineer, and ended up purchasing My Centec mill from him - it's only later I realized that we had coresponded by letter decades previously. Bert deKat is his name)

Thread: Milling machine & Shaper query
28/01/2020 12:39:43

Steven;

Like IanT's wants vs. needs; I've had two shapers in my workshop. Now I have none.

The last to go was a Drummond hand shaper. Another shaper came past my nose, and I turned it down.

My reason is that, in my limited workshop time, milling machines make so much more sense, especially when one considers the space taken.

I sat down and wondered: "What do I want to do - use random bits of machinery for it's own sake, or use machinery to make things?"

I also built a Worden T&C grinder from Hemingway, which works well for sharpening everything from milling cutters to drill bits to lathe tools.

Like everything, it's all what you are happiest doing!

Thread: Ally Pally Exhibition
16/01/2020 22:28:47

Pete - Thanks for the very positive attitude.

I have attended maybe 1/2 dozen exhibitions in the UK over the years; living in Canada, it's a long way to go for a day out; "you guys" have it very good! I hope you meet many other good souls

I hope that the Ally Pally exhibition (and of course, the others around Britain) in 2020 are a great success.

John.

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