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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: Advice on Choosing A Mini Lathe
30/03/2019 21:40:37

I've wanted a mini-lathe for years, and finally got one, after looking at lots of the far-eastern ones.

I picked up a Sherline lathe.

It is incredible. Well put together, feels like a dream.

A fellow from Rochester, NY built a Kozo "New" Shay on one of these, and his Sherline mill. In less calendar time than it took me to do mine on larger machines, AND he cut the bevel gears himself.

There's also a Cowells, and the Peatol/Taig.

The *only* complaint about the Sherline is that all the fasteners are UNC/UNF, and I'd appreciate metric, but that's a small quibble. I did get metric feed screws.

Are these not mini-lathes as well?

Thread: emco pc turn 55 conversion to mach3
25/03/2019 10:23:56

David beat me to it - threading.

LinuxCNC works well, and blows Mach3 out of the water, from what I hear.

The reason seems to be that LinuxCNC uses two spindle sensors - one to mark 0.00 degrees, and the other divides the spindle rotation by "lots". Mach3 only has the 0.00 degrees and interpolates the spindle rotation from that.

I use "Mesa" boards, which seem to be inexpensive compared to Mach hardware. The whole stuff just works.

Note: John Stevenson (miss that guy) and I used to "argue" - he liked Mach3, I like LinuxCNC, so my comments above regarding Mach3 are from discussions with Mr. Stevenson, not my personal experience.

Thread: Completed models - just out of interest
24/03/2019 14:31:09

I echo these thoughts.

I agree with Duncan, which is why maybe we have a disagreement on the Tich locomotive - for me, getting it to go around in circles, pulling me and possibly another body, is a challenge. My larger 3-1/2" gauge 2-8-2 is much less fun, and weighs in at close to 10x what Tich does. And, with Tich, it gets plugged up after 10 minutes of running, so time to take a break and socialize.

I've finished my 3-1/2" gauge Shay locomotive, currently sitting in a glass case in our living room, and I doubt it'll get much use, if any. Nice to look at, though.

Like Thor - I just gave away a ST steam pump to a friend to get him kickstarted in stationary models, after he sold his large 7-1/4" one. He'll use it, I certainly won't.

I don't think I was always this way, so I accept that there are many ways to enjoy this hobby, so however one gets satisfaction from model engineering is fine by me.

shaycomplete_s.jpg

 

Edited By John Alexander Stewart on 24/03/2019 14:32:33

Thread: KX1 CNC Mill Clearance Offer
19/03/2019 18:08:29

Martin;

"you go into a jobbing shop today"

Most certainly, any jobbing shop is repetitive slogging. (at least from what I've come to understand)

Where I worked (NOT as a machinist; but the machinists did stuff for MY work) the guys there made one-offs on CNC mills. No manual mills. They were artisans in what they did. It was called the "model shop".

They used CNC as a tool to enable better precision and less scrapping of complex parts, and allowing redesign without issue. They were making scientific and military prototypes, so nothing (especially from us!) was cast in stone. Some of the Virtual Reality stuff I did (now in our Canadian Science and Tech museum) was CNC'd to make it look less "agricultural". In this case, they made duplicates, as one set was for a traveling road show (Europe, half way across the pacific, etc).

They could not believe that I did not have CNC at home in my shop; I, too, originally thought CNC was for blasting through material making thousands of parts, until these guys educated me.

So, I use CNC now, and I'm not going back!

Thread: Dial indicator probe threads
17/03/2019 10:35:01
Posted by Michael Gilligan on 16/03/2019 19:16:28:

Several, I'm afraid, Gerry

Try here for starters: **LINK**

http://www.longislandindicator.com/p205.html

Just a note - the link mentions M1.7, which is, IIRC, only a JIS metric standard. It's *really* close to a BA size, and my theory is that it was simply metricated way back when so that British equipment in Japan could be repaired. Yes, the thread form is different, but for many applications, it's close enough.

I also think that there's also other BA sizes mapped into odd JIS metric.

Anyway, someone may find this useful, or someone may actually come up with an equivalent chart, or...

Thread: Making nameplates
13/03/2019 21:19:43

FYI:

I made some for a friend by engraving from artwork. Did write this up for Diane, but article was probably too long and the software was free, so has not appeared in print.

In essence, I drew it up, saved it as a jpeg file, and sent it into LinuxCNC, which understands image formats and will engrave from that.

All I needed to get was some engraving cutters, From my album, the first results:

simplex truck parts

Thread: KX1 CNC Mill Clearance Offer
20/02/2019 15:26:44

Jason;

With regards to having 2 machinists (one a CNC robot);

I've found that I can't concentrate on doing complex stuff when my CNC is running. Cleaning the shop, doing the washing up in the kitchen; that kind of stuff I can do.

I've always got an ear open listening to the CNC for "strange sounds" like material coming loose, cutter dulling, etc.

I don't know why; the little KX1 (running LinuxCNC) runs for hours and hours without issues. I'd presume that Mach3 would have the same reliability, but no experience with that SW so can't comment.

Maybe it's just me being paranoid. I'd (honestly) like to hear on how others do with leaving the CNC mill running, while going and doing something else complex.

Note that I did have ONE problem with the KX1. Actually, my software and hardware; I had set up the software (hand-tuned by me - yeah right! bad idea!) so that pulses to the stepper controllers were right at the limits according to the spec sheets, and one of the stepper controllers missed a pulse (about 1 in a million) when stepping one direction. Backing off the minimal numbers solved the problem. Lesson - never trust the minimum numbers on spec sheets!

20/02/2019 15:16:39

Andrew;

For quite a while I worked at a research site that had a machine shop about the size of a football pitch.

2 friends worked there. One of them left years ago, then a year or two ago I left.

Anyway, friend #1 - "what do you have a manual mill for? All ours are CNC. You want to make one-offs - come over here and I'll show you conversational programming" (my eyes went wide open!)

Friend #2, has a shop @home, 2 CNC mills, zero manual mills. "why would anyone have a manual mill??"

These guys are machinists by profession (doing precision research projects, not metal bashing), and I'm not. So when these well trained guys ask a question and show me how a pro does it... I'm all ears.

19/02/2019 12:06:25

Posted by Jim Guthrie on 18/02/2019 20:30:14:

I've got a Centec 2A in the outside workshop that's hardly turned a wheel since the KX1 arrived.

Jim, JohnH,

the olde saying "you can lead a horse to water but you can't make it drink" applies here.

I think Neil'll work it out in the end.

18/02/2019 14:36:51

Neil - if I may:

I've got 2 CNC mills; a KX1 and another larger one.

Both have MPG controls.

I use the larger one (right now) mainly as a pillar drill; the mpg I use just magnetically sits on the table, and I can control height of the head, speed, table movement, with the mpg.

This mill has a quill for drilling holes with "finger feel"

The MPG has different scaling options, so I can easily place the table accurately or quickly.

It has a built in DRO - which in LinuxCNC I can make full screen, to quickly and pretty accurately place holes.

08/02/2019 22:49:26

Ketan;

That seems like a very kind and good offer; especially the display/damaged ones given away.

I have a KX1 that I got here in Canada, came without stepper controller. John Stevenson and I argued about it, but in the end, he came to the conclusion (by querying the factory) that it was a KX1 made for internal consumption, but somehow leaked out of China.

It has been a fantastic bit of kit. Now, I did power it myself with LinuxCNC and a Gecko G540. Can not comment on Mach3, but that seems to be ok. As mine stands, it runs for hours and hours without complaint.

The KX3 looks like another good machine.

I hope all of your stock goes to good homes, and that they get well used.

Thread: emco pc turn 55 conversion to mach3
03/02/2019 17:14:58

Geoff;

1) There's a fellow who posts here sometimes (can't remember his name at the moment) who had figured out how to drive a parallel-port equipped Emco CNC lathe from LinuxCNC. He and his father got a batch of them.

2) A local club member took his Emco Compact-5 CNC lathe and LinuxCNC'd it, including tool changer. Works very well, when he gets the chance to use it. (young family syndrome)

3) If you have a Tormach 1100, you'll know that the PathPilot upgrade (*) is LinuxCNC with a Tormach UI and conversational programming layer.

(I put a star on "upgrade" as I know we all have our own preferences, and some people have difficulty with anything other than Windows on a computer). Tormach dropped Mach in favour of LinuxCNC for a reason.

4) I CNC-converted a Unimat SL lathe, which I gave to a club member, and have recently picked up a Sherline lathe, CNC controller is my old LinuxCNC one from my Unimat-SL. Sherline's CNC controller is LinuxCNC, so that's another company who chose LinuxCNC for their products.

I'm a LinuxCNC advocate, as, not only is the price right, it just works 100% of the time for me, on 3 machines. I have converted to the "GMOCAPY" UI, which I like more than the standard UI.

Again, there's lots of choice out there; every solution has good points and bad points.

Thread: Silver soldering problems.
13/01/2019 04:59:26

Q: Do you tightly clamp the 2 pieces?

Q: Do you heat from the "other" side as the silver solder is at?

Q: Do you leave a small gap for the solder to go into?

Thought 1: You might want to centre punch some marks on one of the pieces to give that hairline gap for the solder to flow through. I centre punch *everything* that I'm silver soldering now.

Thought 2: As Jeff says, more heat and more flux. I sometimes use a "poker" rod to add more flux. Inside, I use a plumbers propane torch, which is really not good for much more than silver soldering really small stuff. You do want the pieces to come up to temperature, especially the inside of the joint....

Keep going, practice does help.

Thread: Hemingway Radius Grinding Attachment Ref: HK 1312
03/01/2019 16:14:25

Hi Rod;

I've made it, but not used it much.

I think that you'll find that the accuracy is in the setup; all it really does is hold a toolbit and allow you to move it in a circle of about 180 degrees. Fine feed is by the screw on the back of the tool holder.

I should use it more; work and family stuff has got between me and my workshop recently - so the lack of use is not a black mark on the tool design.

I made my semi-circular table on my smaller CNC mill, out of brass, 1/8" thick. Also made the tool holder slider (that slides on the semi-circular table) out of brass on my CNC mill, also.

Thread: Simple and accurate home "switch"
31/12/2018 14:38:30

Coming in late to this;

I think John Haine did a great job in making a simple, accurate home switch.

I understand the potential issues, but, I assume John does as well. What's wrong with making things rather than buying them?

Kudos to John Haine.

Here's one I did for a Unimat SL; since given on to another club member for his enjoyment:

(I expect to do the same for a little Sherline CNC lathe I've picked up)

 

 

Edited By John Alexander Stewart on 31/12/2018 14:40:02

Thread: CNC machines in the Uk
28/12/2018 22:16:26

Barrie;

I read your comment about the Wabeco and handles for manual movement.

1) Look for "MPG"s - these things allow you to move the axes with a knob on the MPG, much like you'd do with a manual mill, and you have a built-in DRO as well. And, one can set the speed of the movement, so you have fine movement and the ability to get the table to move quite a lot without lots of cranking of the handle.

2) Your software should also allow you to manually move the machine table. With a mouse.

3) I have 2 CNC mills, one has a spindle quill on it. I don't have a pillar drill, and, while I do have another largish mill with a quill, I tend to just use this CNC one in manual mode. I flip on the power - the computer boots up, and it's ready to use. The MPG gives me axis movement, spindle speed setting, and a DRO.

4) LinuxCNC (and, likely PathPilot, which is LinuxCNC with a different GUI) has built-in the ability to engrave from image files, like JPGs.

5) My CNC mills do not have any keyboards in the common "computer" sense. I do have track balls and do have numeric keypads connected, but these last ones are rarely used, as the computer screen allows you to select numbers. If I had touch screens, I'd not even bother with the trackballs.

All in all, my CNC mills get used more than any other thing in my workshop, I'd expect.

This is all fun stuff.

Edited By John Alexander Stewart on 28/12/2018 22:19:57

Thread: Vertical milling attachment vs combo lathe/mill??
14/12/2018 16:43:41

Mike - I've kept out of this, because it's easy to put forth ones' wishes as fact. (and, what's been presented are also my wishes and suggestions, so that is not a complaint on the posters at all)

May I add some alternative thoughts on a combo machine?

1) the published author Kozo Hiraoka has an Emco 7" lathe with the vertical milling attachment, and he's produced excellent work; in his 8x8 (foot) workshop.

2) the published author Bill Harris had a 9" South Bend lathe and a vertical slide, and made 1.5" and 2.5" scale Shay locomotives, both are well regarded designs. He used a table saw with abrasive pad on a disc for his sanding work.

3) For a while, I only had room (barely) for an Emco Compact-8 with the wimpy vertical head. I did lots of good work on that combo; that and a bench vise and a 25mm wide belt Linisher machine was all that I had power-tool wise.

4) MANY models were made in workshops equipped with a lathe and, if they were lucky, a vertical slide.

Yes, a machine for each job is ideal, but without the space, one does what one can do. You may need to use your noggin to get around the limitations, but you'll probably need to use your noggin with whatever machinery you obtain, so no loss there.

Anyway, thoughts on this (freezing rain here) Friday.

Thread: CNC router
29/11/2018 20:44:57

Keith;

There's many answers to your CNC question and each are right. (John Haine and Rod Ashton are two people who I make sure I read their posts - experienced people who always give good advice)

I've got 2 4-axis mills running something called LinuxCNC, and did have a little CNC'd Unimat lathe, running LinuxCNC, until I gave the lathe part away.

It all just runs. One mill runs a Gecko G540 stepper driver via a parallel port (this is the one used in my articles in Model Engineer) the other mill has a MESA 5i25 and 7i77 card set. I've got 2 other projects (CNC) on the go, and they'll use LinuxCNC.

You can try LinuxCNC from a USB stick, to see if you and it get along. LinuxCNC is free; if you try it and don't get along with it, you have learnt something for zero out-of-pocket costs.

I've also used it's engraving functionality to make nameplates from a jpg file; worked fine, especially for the price! All you need to do is to feed it an image file, and it'll ask some questions.

Thread: 'shop tip from 1921
25/11/2018 12:59:39

A fellow around the corner here in Canada got a new house a few years ago after cleaning up something with gasoline (petrol) in his basement.

Lots of us have natural gas powered domestic water heaters - big vertical cylinders with a pilot flame on the bottom.

Needless to say, pouring gasoline down the drain, having the fumes waft up and around the water heater was a recipe for disaster.

All survived; house rebuilt; not a trick I'd have chosen to get redecorating done!

Thread: Space Ship leaves Earth's Atmosphere
25/11/2018 01:40:23

Neil;

I have a bunch of Model Engineers from when it went through it's "Sci-fi" phase, back in the late 50s or early 60s.

I do remember years ago reading an article where the author was describing what the earth looked like from space, with hand-drawn sketches.

It dawned on me later that *no human* in the history of mankind had seen these views, now we take them for granted.

Gosh, even a fellow Canadian (whom I have met in my old line of work) did a music video from space...

(which, when you watch it, is probably the best bit of PR for the space program of anything yet produced)

Interesting times indeed...

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