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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: Sherline
22/04/2021 14:47:39

Dave - if you (or anyone else) wants to see what can be done on Sherline equipment, have a look at:

Chris and his Kozo Shay build

over at This fellow hails from NY state in the USA, and makes more in a day than many of us make in a year.

I made an "old Shay" from Kozo Hiraoka's plans; mainly on an Eco Compact-8, so when I followed along on how he made the "new Shay" on Sherline equipment (including cutting gears from brass) needless to say, I was both humbles and impressed.

22/04/2021 13:00:36


I, too, have a Sherline CNC lathe and mill. They were purchased for a potential house downsizing (moving to a smaller place), but that's been put on hold because of COVID, so not used as much (yet) as I had originally planned.

I've got bigger CNC mills, and use the same software. I've actually got 2 sets of software; I use Linux for work from home and one of my desktops, I also use Apple computers for software development. So, saying that:

On Linux, CamBam, and QCad, CamBam can do some lathe CAM, which has worked well with the Sherline lathe.

On Windows (which probably has not been booted in 6 months) Alibre Atom3D, and, if I remember the name correctly, Meshcam.

I just never turn on the windows computer, the Linux one is booted 24/7, so I use the 2D CAD/CAM system 100% of the time. I have tried (successfully) to run Windows in a virtual machine under Linux; it worked, but is slow and not as responsive as I'd have liked. The 2D CAD setup does things well enough for the parts I'm making.

Hope some of the above helps! John

Thread: "TINKER" tool & cutter grinder
09/04/2021 14:03:31

Wandering a little bit here.

I had a Tinker once - made by a Frank McLean, who wrote in Live Steam and has a book of his articles available from Village Press. He was the first tool designer and machinist for Lee Valley, some here might recognize the company.

I actually never used it - shortly after I purchased it, I had to move around the world (to NZ) for work; lent it and some other tools to a fellow club member who was very short of retirement funds, who subsequently passed away and the contents of his workshop auctioned off to other club members. When I returned, I found the workshop equipment I had lent in other peoples' workshops, and they had paid $$ for it so were not returning it.

Long story short - I built a Worden, 100x better, and I'd think Harold Hall's jigs are equal or better than the Tinker, if you want to use a standard bench grinder as a base.

Thread: CNC - What's the Problem?
01/04/2021 13:22:49

I use CNC extensively in my workshop. (when I get in there, that is!)

I figure that it is like the change from making parts to fit, to making parts that fit. No longer any need to stamp mating parts for assembly, the parts just fit.

Look at the Sherline CNC products, although they have gone now to an expensive CNC controller. I do have a CNC-ready Sherline lathe and 5400 mill, but have only used them for manual machining at this point. (have 2 cnc mills, a KX1 and a larger one, both LinuxCNC driven, that work well)

I am a real fan of LinuxCNC; each mill has a small computer with monitor and one of those track-ball mice things (no keyboard) so they are self-contained. When I turn power on to the electrical socket for the mill, the computer boots in a few seconds, and bobs' your uncle - ready to go.

Thread: Are we being listened to on the phone
27/03/2021 13:42:37

Just for the fun of it - circa 2014-2015, when the organization I worked for was in upheaval, I was asked (an Internet protol and app guy) to work with RF frequency guys to put forth ideas for increasing throughput on cell phones.

Anyway, I created this picture - Wired magazine with Andrew Snowden on the "cover", and a utility to show where tracking connections went - I figured that about 80% of the data transported was "fluff", 20% real-user-wished-for data.

Needless to say, the report was thrown out - these RF guys wanted RF ideas, not caring about the amount of data.

I'm sure the tracking, etc is much worse now. The red names are the sites that the tool reported as being "fluff"


Thread: Gravity and Weightlessnes
19/03/2021 13:20:40

"You are decending by vertical lift into a very deep coal mine and the only light is from a safety (Davey/Stephenson) lamp. The rope fails and the cage free falls to the bottom of the shaft. What happens to the light from safety lamp before you die? Comment: This has everything to do with gravity and weightlessness"

In the absence of "gravity induced" air flow, the lamp would go out. Now, how you'd have oxygen and no air flow in a vertical lift in free-fall, *that* is an interesting question!

Another interesting question - if you have liquid fuel, are in free-fall (say, in geostationary orbit) and are "weightless", how do you fire up a rocket engine? I mean, the fuel will just be floating about, not waiting at the bottom of the tank to flow into the engines...

Thread: Updating KX1 to USB or Ethernet Controller
25/01/2021 15:12:14

My KX1 has been running with LinuxCNC, a Mesa 5i25 and a Gecko G540 (parallel version) for about a decade so far.

Both of these products now come with Ethernet connectivity, if you want to go down that route. The Mesa 7i76 card has (if I remember correctly) 5 step control outputs, so you can have x,y,z,a and spindle if indeed that is what you require.

Do you really require a pulse stream for the spindle? Mine has a board inside that drives the spindle from a 0-10v isolated input - here is a link to the control board: little machine shop board. I know it's the same board because LittleMachineShop used to distribute MY old blog info with this board without attribution. sad

(The KX1 I have came without control electronics, (had steppers, limit switches, spindle speed control board) the late John Stevenson and I discussed this via email, and it seems mine was an "internal to China" model, so I just added it all. Spindle control was via the typical 0-10v input as stated above)


Thread: How to Search for Text Inside Multiple PDF Files at Once
21/01/2021 15:24:33

I keep finding Windows amazing. I'll admit to not using it much, because I seem more comfortable with Linux and MacOS on my desktop machines.

On both Mac and Linux, if you have searchable PDFs (i.e. ones with text, not just a giant image) all one needs to do is to open the file finder, and in the search box, type the text you are looking for. Voila.

It's so simple, so useful, just to search all files for the text.

Or, did I miss something? Likely, knowing me.

Thread: dual boot Dell laptop
14/01/2021 20:13:03

Assuming both are on the same physical disc. Boot in Linux.

Open a terminal window. type:

sudo update-grub

should do it. It should find the Windows partition, and put it in the GRUB boot sequence. This is the "boot loader" that runs when the system boots. Linux will find Windows, Windows will not find Linux. Of course.


If you have differing "boot bios" UEFI settings, tell me. I had to do this a little while ago - my Windows disc was installed in "DOS" mode, my Linux in UEFI, and I had to (simply) re-do the Windows one to be seen as UEFI. I'll see if I can find my notes. I had 2 discs; maybe if you have only 1 this might not be a problem. (I'm NOT an expert here!)

Thread: Linux CNC
01/01/2021 16:58:26

I run my 3 LinuxCNC based machines on old intel D525MW boards; 4gig RAM. These are dual-core 1800 mhz (or so) boards.

I have a MESA 5i25 card in each of them. In theory, they are identical for quick swapping.

Bazyle - stepper timing is fairly critical; using the "old, dumb" parallel port requires pretty exact timing; if you use a card that off-loads the critical timing stuff, almost any computer will do. (card can be plug-in, or via ethernet)

The MESA 5i25 cards (if you go that route) are pretty much plug-n-play, but be sure to order the one you wish; they are "flashed" with a configuration to match the attached device. I've re-flashed one; quite easy. 2 of my cards are for "parallel port" to Gecko G540 stepper driver boxes, one to a "Mesa 7i76 I/O card".

I did start a CNC conversion of my 2nd Emco Compact-8 lathe, put on a 3-phase motor, but work got in the way, and I inherited a little Sherline. 2nd Emco sold on, but kept the 3-phase.

You can find articles in Model Engineer by me, designed to show simple 2D CAD to CNC to actual parts; I don't have the issue numbers at hand. (yes Jason, 2D CAD; hopefully as a first step to get people going with CNC)

Of possible interest: I don't have a pillar drill anymore, but have 4 vertical mills. One of my CNC mills, if I want to manually drill, I just use that. It boots quickly, spindle control is a breeze, and I have a DRO if I want it for accurate manual placing of holes.

In my workshop, these LinuxCNC things just work. I don't worry about them; they have proven themselves incredibly reliable.

Keep going gentlemen! Hopefully 2021 will bring CNC to more of our workshops; whether LinuxCNC or some other program doesn't really matter. It's the learning and experimentation and production that matters.


Thread: CAM software for CNC Lathes - With C axis and constrained live tool
30/12/2020 21:23:48

Joe - the Real Time package for Linux has changed; as LinuxCNC (especially if driving one of the inexpensive breakout boards) needs realtime so that signals come and go without varying latency. It seems like it's fairly settled now.

That first ISO, on the top of the page is one that I would use.

Just download the iso, burn it to a USB, and boot. You should be able (if it is as it was) to run LinuxCNC directly, without installing it, just to test drive it.

32 or 64 bit - don't worry about it. Try that ISO on the top of the page.

(Am I pushing? Well, Tormach went from Mach to LinuxCNC-based software, and paid $$ for work on the trajectory planner in LinuxCNC, so why not use what a successful company uses?? They also use MESA hardware, so you are following fairly closely a known, successful path)

30/12/2020 17:50:24


on all of my machines, I use the MESA 5i25 cards. I use the parallel ("printer" cable option.

On one machine (a small CNC lathe) I use a Gecko G540; on my older Seig KX1, the same.

On my larger mill, and ex-project CNC lathe, a MESA 7i76.

(I hate giving advice, so use your judgment )

I think for you, a MESA 5i25 and 7i76 combo. It gives you lots of stepper outputs, lots of signal outputs, inputs, spindle encoder, "0-10v isolated" spindle control, etc, etc. Way more i/o than you'll need, but better too much than too little. You've got the brains to figure out a) what you need i/o wise, and b) what else you can do once you have it running.

There is a "plug-n-go kit" for the combination:

Anyway, my 0.02c - it's what I use and I find it well supported and incredibly reliable.

And, if it matters, my 3 machines are running an old Intel board, dual-core, obsolete from about 6 years ago; more than enough power to run the machines, with i/o, MPG controllers, touch probes, 4th axes, and so on.


30/12/2020 15:16:12


lists an ISO download.

I do know that there was an issue going from one real-time kernel to a newer one; this gave the LinuxCNC team a bit of an issue. Looks like it's solved.

Note that with "smart" cards like the MESA ones, perfect real-time is not required; with the old parallel port, servicing that port did require quick and timely response. (I use the MESA cards in all of my machines)

I can fully understand the frustration when LinuxCNC was going through that real-time transition, but with an ISO, maybe it'll install nicely. Knowing what I do from seeing your work here, I'd expect that once it is running, and you comprehend the flexibility, you'll be very happy.

Whatever you do, keep doing, and (especially) keep posting!


29/12/2020 20:12:14


As you may not (yet) know, Tormach PathPilot is basically LinuxCNC with a simple install and conversational programming -enabled GUI by default.

The potential issue is setting the correct ports/cards for your system; Tormach sells it configured for their machines. They have a new lathe on the market.

It used to be (have not looked at in a while) that it used MESA cards; I'd assume it is still the same.

Last I read, you can get it on a USB stick. Maybe worth a look, and a web search for others using it.

By the way, yes, LinuxCNC seems to have gone through a bit of a rough patch with documentation and install, but once you figure it out, the thing *just works*. Incredible piece of software. (I have 3 machines with SSD drives and dedicated computers; flick the power switch by the machine, the PC boots, and you are good to go)

One of my mills, with a two-step pulley system on the spindle; I have it automatically figure out what "gear" it is in, and adjust accordingly, thus if you ask for (say) 1,000 rpm, you get it, as close as the sensor, etc, can get it.

Thread: Retro Computing (on Steroids)
17/12/2020 00:04:16
Posted by Frances IoM on 16/12/2020 22:45:55:
It was very early it may have been in first yrs of the 80's - certainly by 82 at latest - what the science museum got was a working machine built from the surviving working models, but I know mine was in full working order when I swapped it with the company for a 286 system so I assumed most of the gift was my machine - I was a consultant and paid towards my machine (meant I was free to use it for other purposes (I wrote cross-assembers in C for use in teaching lab + later on a set of tools for a universal cross assembler for industrial use) - I know I was first staff member to have a home computer that was not a toy tho by current standards it was slow, I still have the CRT terminal) - I think the company (only a small startup) had the machines a few months before me - the operating system was IDRIS - a unix 'lookalike' by a guy who left Bell labs - Bill Plauger rings a bell but it was 40 yrs ago + my memory is not what it was

Edited By Frances IoM on 16/12/2020 22:48:37

Ok, that makes more sense - I left high-school (Canada) in 1978 and University in 1982, and a lot changed in that time. That's how I remember time-frames - In high school it was the 1802 and 8080, by the end of University, it was totally changed. Things went quickly back then. (I guess they do today, too).

Many years ago, I was on an overnight train (would have been autumn/winter 1982, maybe spring 1983) I went on an overnight train here in Canada (almost 9 hours long journey), almost nobody on it. My task was to further a S-100 bus-based 1802/8085 computer, wire-wrapped. The old crusty conductor (they were all crusty old conductors back then) came by and said in the typical gruff voice "What you building, a Bomb??" I said "Yeah", his answer "Good luck" and kept on walking, checking to see if anyone was likely going to give him trouble.

These days, that cocky little kid would be taken down by a SWAT team or something equivalent.


16/12/2020 22:23:53
Posted by Frances IoM on 15/12/2020 21:50:02:
IanT - I'm old - Honeywell 316 + 516s - one of my home computers is in the Science museum collection (long story but one of the first UK built machines - 68008 based running a variant of Unix in the late70s)

Well, my shared Virtual Reality stuff is in the Canadian Science and Tech museum; I can confirm that by the time I created this stuff, we were well and truly into Hexadecimal.

(I remember the 68008 being released - are you sure about the decade? I would have pegged it later; in the 70s, it was almost all 8 bit processors, if I remember that far back correctly) (no matter, those were the fun days; I loved the 1802 because as a kid, I could single step it and debug the hardware with only a really inexpensive analogue volt meter)

15/12/2020 11:37:50

Dear SOD;

Sure, Python's great, I use it a bit at work. However, I have to use C99; Shader work and OpenCL Kernels require this. (have to run on older code platforms sometimes, sticking to OpenCL, OpenGL for the moment)

Your request is tailored to using a language like Python; if I reworded it to something like "find ALL the palindromes in the set [0->2,147,483,647] and return a flag indicating which one is set" then I'd win hands-down, especially with a good graphics card.

BR - JohnS.

Thread: Have You considered getting a 3D printer
12/12/2020 13:41:25

I have one, from 2014 which is not very good. It's been sitting collecting dust for a couple of years now.

At work, I had the use of a Stratasys, but that lab's closed down. Every once in a while I think of picking another one up for home, but... (have CNC metalworking machines and a lack of time for *those*...)

Here's a picture of my Printrbot Simple - laser cut wood, Dremel sanding disks and fishing line for axis drives... Was High Tech at the time!



Thread: Message from ARC to our customers in the E.U.
11/12/2020 14:56:47

Breakups are interesting. The instigators (or, hopefully, unsuccessful instigators) always expect things to go their own way.

Over here in Canada, we have Quebec popping up the idea of separation, and Alberta and the west.

I read this recently, in an obituary of one of our indigenous leaders:

"Although he was friendly with the Quebec separatist leader René Lévesque, Mr. Gros-Louis remained a federalist. During a 1992 appearance at a Quebec National Assembly committee studying Quebec sovereignty, Mr. Gros-Louis was asked by a Parti Québécois legislator whether First Nations in a separate Quebec would insist on forming their own mini-states, turning Quebec into a “Swiss cheese full of holes.” To which Mr. Gros-Louis responded. “We’ll leave you the holes and we’ll keep the cheese.”"

Things like, taking the James Bay hydroelectric dam, cities like (I assume) Montreal and Quebec, etc. leaving the Quebecois with the dregs.

You open Pandoras' box, and you never know what you'll let out.



10/12/2020 17:02:50
But if it is a significant business, rent a wharehouse in Boulogne (or wherever) I am sure that other small businesses will get wise & shared arrangements can be set up.,

Sam - this happens a lot with businesses that are in Canada, but deal with the USA.

Even for individuals - google "shipping to Ogdensburg" - Canadians around here will ship to an address just across the border, then drive over, and declare the goods on return. (not now though due to COVID the border's closed).

I have not bothered doing this yet, but I know multiple people who use this service - a bit of a ride in the car, about $10.00 for the bridge tolls, and pick up your parcel, and skip the $$ customs import fees that would be put on the package.

Sure, you have to pay duty on the border, but there is some exemptions for day-trips, from what I understand.

(if I miss picking up a parcel, last time I drove to the local UPS depot, it was 2 hours round trip with city driving - almost faster to drive to the USA...)


I used to purchase stuff from the USA and ship to Canada, but as 99% of it is from China, I order directly now, and sometimes the parts + postage from china is LESS than the shipping from the USA, and that's not even taking into account the markup by the companies in the USA.


Funny world - John.

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