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Member postings for Iain Downs

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

Thread: Cigarette Papers
13/07/2020 11:59:28

I've come across this and use green papers. I don't think the local co-op had such a variety - and I had no idea which was the thinnest.

The only thing I've found is that moistening the paper (spitting) before applying it doesn't work - it sticks to my finger better than the piece.

Instead I moisten the piece (CT90 or spit) and apply it dry. This is then much more likely to stay on the piece.


Iain

Thread: What Did You Do Today 2020
13/07/2020 08:19:44

Hi, Joseph - that's interesting, but I think I will try the last solution mentioned before I switch gain!

Mark - I started off with Pascal before C became popular, then C++, then c#, with a whole bunch of others along the way (most of which I've totally forgotten).

And I forgot to mention that my (12 year old) laptop I was planning to use for test purposes on this also died at the weekend. At least I think it's died. It seems to have got slightly worse after I've tried to fix it. Once among the most powerful laptops available, it's now an ugly bookend. Technology advances, does it not?

On a positive note I did get the drive installed, hooked up to the electronics and driven by a windows tablet. The motor moved the mill table (result!), but I'd got an earlier version of the arduino code (C++) so it peaked out to early.

Iain

12/07/2020 11:56:16

This has been a frustrating few days.

I've been building a power feed for my new mill (there's another post somewhere) and, to my surprise, the hardware and electronics have been going pretty well. I'm just applying the final coat of paint (to the metalwork).

The software not so much. Which is embarrassing as I have very limited metal working skills, but over 40 years of development experience.

I finally worked out how to get the arduino part driving the motors (help from several members here), but the part that's frustrated me is the user interface. Being a digital person, I wanted to drive it from a touch screen (slide left for faster left and so on + have some present movements).

My original idea was to use one of the various small tablets I've got as the UI. This largely failed because the tablets (early Nexus 7) don't support 'OTG' for hardware reasons. At least I think so. Opinion is not always clear on the web.

I carried on looking at this approach and tried my newer (58 quid) tablet from bangood. This does support OTG and I can drive the Arduino from it with a PlayStore serial terminal.

now to write a program. In c#, please my Java is rusty and I never learnt raw android dev (iOS, yes and Windows Phone yes, not not Android).

Now it turns out that there is limited support for USB serial on android with c#, but some nice man has ported a java library and I could run his sample program on my tablet and control the arduino with simple commands.

However, he'd written the android part in android language and not in the 'cross platform' mode which I understand. I have no desire to learn yet another coding environment. In truth, I'm having enough trouble remembering the ones I've already used. And of course I don't want to use my cheap tablet for this. As well as the expense to buy a replacement, it's really too big - I want something more phone sized!

Aha! I remembered my old windows 8 phone (Lumia 735)! Perfect size and I've written programs for it...

Hunted for it for a while and, unexpectedly, found it in one of the 4 places I thought it might be (last of the 4, naturally). Charged it up and went about doing some background research.

Oh, dear, that one won't support OTG (serial USB) either... But a Lumia 950 will which I can buy for 30 quid from eBay. Cheaper than a new tablet, I suppose.

OH. In the meantime, I'd already looked at using a Raspberry PI, but my Pis are first edition and don't play well with LCD displays unless I get one from China which takes ages and who knows if it will work or pay quite a bit more here - much the same learning curve exists there, of course, though it would be cheaper.

So I went to bed despondent, worrying how to make this work (on the cheap).

Zing! I had an idea! I could swap the USB lead for Bluetooth. Which the windows phone will support and I seemed to think I could get for Arduino. Popped downstairs to find Amazon and Google are my friends. I ordered an d8 quid UK based HC-05 for the Arduino as I'm fed up waiting rather than a 2 quid version from China (I know. A bit hypocritical) and feel I might have a way forward.

Until the next obstacle.

Phew!

Iain

07/07/2020 17:12:07

Dave - After working out that it was the floating point, it still wasn't quite working and I ended up creating a new sketch and mucking around with it - with a scope attached to one of the pins.

I was surprised at how poor the timing was. From memory (it was last night now) with nothing happening apart from an interrupt on a timer (PORTD ^=D00001000 or something) I couldn't get more than about 250kHz or so as the blink - so 500K calls to the interrupt per second. 32 clock cycles. Hmm. Not that bad, I suppose, when you do the sums.

Iain

Thread: Installing a magnetic DRO on my VM32L
05/07/2020 19:16:52

Somewhat to my surprise, success!

Here's how I added a (supposedly) manufacturers DRO kit to my VM32L.

Firstly, I didn't rate the brackets provided. I didn't even see that they could work.

So I made my own.

dro x and y mounts.jpg

The X Axis was nice and easy. There's a 10mm slot which normally holds the scale. Rip the scale out (held in by pins), clean it up and stick the strip in there.

dro x strip and mount.jpg

At some point, I'm planning to adjust the end stops (round button on left) with a rod so they can intercept an optical sensor int the DRO mount and provide a limit for power drive. However, that can wait.

To set it up I just put a feeler gauge between the sensor on the strip and tightened up

dro x setting up.jpg

A word on cutting. I Kind of freaked about this. Is there some special way of cutting? Actually no. if it will cut metal just do it. I used tin snips, I drilled, I used a hacksaw. Careful though ,there seem to be some ridiculously fine splinters in the strip. Hacksaws aren't the best way!

I reckoned that the X axis in the slot would be fairly secure, but was less happy about the Y axis on the cheap paint of the body (meths seems to dissolve the paint. Ugh!).

So I drilled 3mm holes in the end of the strips.

dro y strip drilled.jpg

In this case I stuck the stainless fascia to the strip before mounting it. For the X I mounted the strip then stuck the tin bit on top afterwards.

With the Y I drilled and tapped one end and used that as a reference for the other (bolted one end to the base and the made sure it was aligned).

dro y strip screwed.jpg

You can see the bolts at each end in this picture.. I was happier doing this that using swarf covered magnets!

With this in place I hooked up the display and set it up and turned the handles. Whoo Whoo! The numbers changed!

dro powered up test.jpg

Finally, I tidied up the wiring. I've used sticky mounts here rather than bolting the cable to the mill. Let's see if that sticks and if not, out comes the frill!

dro wired.jpg

The DRO display is mounted on top of the motor control box. You can't really see it in this picture, But I think that's the best place for it.

I've not actually USED the thing yet, but I'm really looking forward to doing some real work with it!

Iain

Thread: What Did You Do Today 2020
05/07/2020 18:28:59

I have had a cracking weekend and a particularly good Sunday. Something bad is due to happen ...

First thing this morning, I found out why my Arduino power feed code wasn't working - after quite some time puzzling. It turns out that Aaduino interrupts and float point don't play nicely. Migrated to long integers and it just worked! I now have all the bits I need for the power feed, though sadly, I found I had no heat shrink when I came to solder up the motor connections. Amazon prime to the rescue. Perhaps tomorrow.

Next an old client came round. He's had this idea for a product and had 3 goes of getting hardware which worked - I first wrote some software for him in 2012. This time was the 3rd time of asking and we managed to get a good result for the first time! Software again, I'm afraid, but that's actually my competency!. Those of a similar disposition will be thrilled to know that it was about dealing with raw input with USB HID devices. Ugh.

Finally, and this is closer to proper engineering, I finished off fitting the newly received DRO on my mill. And it actually worked!

to be fair, I've only put X and Y on and am waiting for a bit of ally for the Z, but that shouldn't give me any problems. In truth the spindle DRO is of much more use.

I will report on that in more detail in one of my other threads.

I did think about trying to mount the power feed tonight, but two things put me off. First (and most important), if things seem to be going well, stop. It's just the universe's way of setting you up for a fall!

Secondly, I decided that some celebrations were in order and I've made it a rule not to mess with rotating machinery after a glass or two (wimpy, I know and 20 years ago. I wouldn't have cared).

So still a happy chappy and REALLY looking forward to working out how the hell I can use the DRO (the manual is close to English, so I reckon I can interpret).

Iain

Thread: Installing a magnetic DRO on my VM32L
02/07/2020 17:01:56

I'm having a think about the Y axis.

The saddle is 210 mm deep and the travel is about 230 mm.

With the length of the sensor around 40mm, I'd need about 310mm of channel which would leave 100mm sticking out the back.

The main advantage I can see with this approach is that I would be sticking the magnetic strip to a clean piece of metal and not to a suspect and rough painted surface.

I feel slightly uneasy about a 4 inch bit of 15mm channel sticking out of the saddle. Not sure if it's particularly justified!

Similarly, I've ordered some bar to replicate the Y axis mount in the pictures above - so I screw the bar to the column and stick the strip to the side of the bar.

I was thinking of spraying the strips with laquer after mounting to keep contaminants away from the sticky strips, but I'm not sure if the lacquer would survive the contaminants. Any thoughts on that.

Iain

01/07/2020 22:43:55

Ian - I get what you mean about the Y axis, but I think the travel may be greater than the depth of the saddle. I'll measure up tomorrow.

I'm cool with drilling holes!

Iain

01/07/2020 20:56:04

Jason. I agree. Also I'm near the end of my Motor Feed build and was planning to use the central position pointer to locate the optical sensor for my end stops - with the stops themselves holding a blade to interrupt the sensor.

Ian. Quite disturbing, really, I'm not quite sure what you mean by U channel on the Y axis. The strip is on the base on the sensor on the saddle so I can't see how to use a U there.

I'm going to have buy some stock to make the various brackets. I've get everything but what I need...

Iain

01/07/2020 18:13:46

Here are the instructions / photos provided by Weiss. First, I should say that I appreciate that someone took the time to take the pictures.

img_0629.jpg

img_0630.jpg

img_0631.jpg

img_0634.jpg

img_0633.jpg

img_0632.jpg

I'm not entirely sure I need to replicate all the swarf ridden bits of metal round it and I hope I can manage better alignment.

I have to say that I wouldn't call what I've received a kit. The brackets don't fit the sensors and the bar in the picture above is simply not there!

Having said that, I'm now fairly clear on what I need to do to put it all together, though I will need to make my own hardware I think...

Iain

01/07/2020 09:59:42

It looks like the groove for the ruler is a good place to put the magnetic strip - short of actually trying it. Also, It seems I have two strips. A magnetic strip with a sticky back and a steel strip with a sticky back, so installing the strips looks fairly straightforward.

There is 1.8 metres of strip (each type!) which is plenty and more to cover the range.

Less pleasing is that it's still unclear how the mounts are meant to work. The one which most looks like an X mount simply won't fit.

I will try taking the ruler out and try fitting the strips, but I'm guessing I will have to make new mounts. Which is annoying.

Iain

30/06/2020 14:46:19

What is slight scary is that it looks like they've sawn the top of that sensor in order to fit it in!

Iain

30/06/2020 12:00:20

Thanks, Jason.

Iain

30/06/2020 08:10:25

HI, Jason. That makes sense with the shape of one of the mounts. I will look into that. Can I ask you where you got the photos. I couldn't see them (or the VM32l) on either Amadeal or Weiss web site.

Iain

29/06/2020 20:38:50

Well, I agreed to pay the difference between the Non-DRO and DRO version which is £400. Having said that they appear to have forgotten to charge me and I will not remind them until I have got it all working.

It appears to be a 5 micron set up which is more than enough for my work.

Iain

29/06/2020 15:41:57

I believe that the factory installation has the strip directly on the machine.

Happily, Jorge of Amadeal has responded to my last prompt but only in so far as he's sent of a request to Weiss.

Thanks for the link to ChrisB's post - and thanks for the post, Chris! That's useful to know.

One thing I'm not clear on is if the steel strip in the photo above is just for protection in transit, or if it should be attached to the magnetic strip in operation.

Another question is if it matters which way round the strip is mounted - left to right or right to left, or if you can set this in the display box.

Iain

29/06/2020 08:36:24

Hi, experts! I need your help.

I've just taken delivery of a factory DRO kit for my Amadeal VM32L (think WM18 roughly). This has taken 6 months to get to me (I had a choice of a MT3 machine with DRO or an R8 with a factory kit coming later) due to Covid.

All the bits appear to be there, but there is not one line of instruction (other than for the display box).

So far my requests for instructions to Amadeal have not produced any results. I've pestered them again today, but I thought I would try the assembled knowledge here.

Here are the bits.

dro kit.jpg

and a close up of the magnetic tape.

dro strip.jpg

So I guess I peel of the backing tape and stick it to the mill. Is the steel cover just for transport or should it stay on?

The (badly made) brackets don't indicate which axis they are for. I can guess, I think, but I'm not comfortable doing so.

What;s the gap between the reader and the tape? Should I shield the tape when it's stuck on? Most installations seem to do so , but from what I can remember of seeing one in the warehouse in December, they're left exposed.

I'm hopeful I'll hear something from Amadeal, but if there's any advice you can give I would appreciate it.

Iain

Thread: Power feed for a VM32L mill
29/06/2020 08:27:01

This is a bit of a catch up on stuff that's been going on for the last couple of weeks.

Following making of a Spindle lock for the mill, I cut the 4mm keyway for the 12mm shaft of the leadscrew in one pulley.

motor drive 21 cutting the keyways.jpg

And a 3mm one in in the steel dog clutch half.

motor drive 22 pulley and clutch on shafts.jpg

I thought I was doing well, but then I put it all together and found that the bracket is miss-sized (or the size I used for the pulley in the design was wrong) which meant it wouldn't fit. A bit annoyed by that.

After a few minutes expressive language, I realised that I could remove the bottom plate and replace it with two bars, one at each end where the bolt holes are. I believe I'managed reasonable precision (within a thou) of the length, so it may even be better.

It looks like that works (sadly no photo, but I'll take one when all the bits are together). The dog clutch parts engage with the various turning bits mounted by hand.

With that, I Loctited (638) the bearing into it's housing and left it to dry. Next is to loctite the shaft into the bearing and make sure everything moves freely. This is the bit which scares me the most as the tolerances are pretty tight.

Whilst waiting for the loctite to set, I started on the replacement handwheel which will get bolted to the X axis pulley.

I have a piece of 4 inch aluminium bar sourced from some show somewhere as a, 'That will be useful someday'. Well it will be, but I hadn't considered how I would cut it if it was wider than needed.

In the end I drilled and tapped the hole which the handle will go in, bolted it to an angle plate and clamped that in the jaws of the bandsaw vice. This lets just enough poke out.

motor drive 23 cutting the new wheel.jpg

Whilst this makes the job possible (and lets start by saying that cutting it by hand isn't work considering), it's going VERY slowly. I've got about a quarter of the way through in about 15 minutes.

I expect this would go better with a blade with coarser teeth (as it says on the machine), but I only have the one. Hmm. It might actually be worth investing in a coarser blade. The time it would take to swap the blade would hopefully beat the time saved in the cut.

I'm also thinking about automating the thing. Very brutal engineering. Basically just hang a weight on the end of the saw! I've already got a clip to keep the trigger down for when using the saw table.

Hopefully, next time I post, the mechanics will be done....

Iain

Thread: The Workshop Progress Thread 2020
29/06/2020 08:10:15

Nothing as nice as some of these models, but this weekend I completed a spindle lock for my mill

spindlelock.jpg

As usual for me, the original idea (to have the legs a snug fit to the DRO link) failed, due to slight inaccuracies in the centering of the block on the cylinder. Bodging didn't work, so I ended up reversing the block and putting some set screws in.

It's now helped to make some keyways for me.

Iain

Thread: Constantly Having To Log In To The Website
22/06/2020 07:39:07

I'm seeing this too and also find it frustrating. It's been going on for a week or two...

Iain

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