Member postings for Peter Cook 6

Thanks Ady for the replies.

I have a set of callipers that look identical to the RS ones, but zero reset when they power off. That is the issue, but those are a bit expensive for butchery.

I have looked at the cheap DRO units, but there simply isn't the space on the Taig to fit them.

I am probably asking in entirely the wrong place, but.

Has anyone recently purchased a set of cheap callipers which only switch off the display when they auto power off so that they retain the zero setting. If so could you let me have a pointer.

There seem to be two different versions of the electronics in cheap callipers. One type turns off completely when they power down and reset to zero on power up. The other version seems to simply turn off the display and on power up (or moving the slide) redisplays the reading.

I got a set of callipers for <£10 sometime last year off Ebay which have the second type of electronics, and recently got a tyre depth guage which does the same. The original vendor has vanished from Ebay. Other tyre depth gauges I have bought, and a different set of cheap callipers reset to zero every time they switch off. There does not seem to be any easy way to identify the difference.

I don't particularly care about the quality of the callipers as I want to butcher them to make a DRO for my Taig lathe (the fate of the first set was to make the other axis).

None of the ad's I can see (at the kind of price I would prefer for butchery) make any mention of this behaviour.

It won't. VOIP is almost certainly the technology that the callers are using to generate the spoof numbers.

Part of the problem is that there are legitimate reasons for the Caller-ID to differ from the number originating the call. Firms want their switchboard number to show, not the home phone of the person working from home. Doctors & Hospitals want to use the reception number not their private lines.

So the technology will always have the capability - and the bad guys will simply use it.

My VOIP provider lets me choose what caller-id is sent when I make a VOIP call - I have to prove that I legitimately own the number before I can add it to the list - but I currently have the VOIP number, my landline number and my mobile numbers as possible choices.

Stanley STA183069

The bar I was using was sold to me as 6082 alloy, and it does appear to machine well - now that I have got a bit more aggressive with it!

The tip about the surface layer is something that I had not realised - again thank you, and all the rest of the helpful people on this forum.

It was just the concept of hand cranking at 750rpm that initially blew me away!

Edited By Peter Cook 6 on 28/04/2021 14:24:55

Thanks. I was a bit put off by the implied speeds. But I have clearly been being far too tentative - even on my little mill.

I just experimented with a piece of aluminium ( to make HH's square tool holder for the grinding rest). New two flute cutter, WD40 lube, 2.5mm doc, 4000 rpm and crank as fast as I reasonably could. Probably 60-100mm/minute feed rate.

Hot knife and butter came to mind and the surface finish is way better than I have been getting with my tentative approach.

More learning undertaken!! Isn't this hobby fun.

I have just acquired a new 10mm two flute slot mill for cutting aluminium.

Looking at the vendors (APT Tools) website they quote speeds for slot and side milling of 5000 rpm and Feed rate of 1200mm/min (slot) 1500mm/min for side milling at doc of 5mm (slot) 10mm(side).

The mill (SX1LP) will do 5000rpm, but I don't think there is any way I can crank the handwheels (2mm/rev) at 600/750 rpm. Am I misreading the data, or are these really the sort of speeds production grade machines achieve?

What are the implications of going far slowly on the feed (I would guess 100rpm 200mm/min is about as fast as I could crank). Should I reduce the rpm to match and to keep the tooth loading fairly constant, or just go for it?

Edited By Peter Cook 6 on 27/04/2021 14:25:18

Mine is the 1970's alloy one. Bought for me by my parents when I got my first house - possibly to celebrate getting rid of me! It still works well and is (like Larry's) mostly used as a temporary bench.

The most useful accessory I have is a sheet of 19mm ply with a block screwed across the bottom so that It clamps into the vice jaws. It has M8 inserts let in at the correct spacings to tie down the power tools for which I have no other bench space ( or which I prefer to use outside). It has fixings for the bench grinder, angle grinder stand, chop saw, an old B&D drill press and a horizontal stand for the B&D two speed drill that was supplied by the same source at the same time, and which I use for wire brushing or polishing.

Thank you to everyone for the help. I am now much more prepared for my next foray into the boring head. In particular OilyRag for reminding me (politely) to think about the comparison with boring on the lathe, and that the angles required being the same. In my defence I would say that I was too concerned with the operation of the boring head itself - first time I have used one - and consequently didn't pay enough attention to the tools. Just assumed that they would be ok out of the box.

Jason was correct about the swarf. The carbide tool has about 25 (rather than 45) degrees of rake, and a couple of experiments showed that at 0.25mm cut depth the point was digging in first and then folding the resulting thin wall inwards towards the centre of the work. Down the 25mm depth it more than created a flat saucer of aluminium.

Thanks Paul for confirming it's not just my one. Why the carbide tool is the way it is I have no idea - I am not sure what operation or material would need that degree of rake. For comparison I have mounted the HSS tool (about 6 degrees) and the carbide tool in the head. (I will NOT be using them that way!)

Now I just need to find a source of 6mm shank HSS boring tools suitable for the head in a couple of lengths and/or a couple of 6mm shank insert boring tools suitable for the head.

I acquired ( for another problem) the 30mm boring head from ARC which came with a couple of tools.

I wanted a 22mm hole through a 25.4mm square lump of aluminium, so thought it would be a good project to try it out on. The hole came out well in the end, but I was clearly doing something wrong. Not sure if t was speeds ( tried several from 500 - 1500), feed rate - I was feeding the boring head into the work using the quill, or the setup of the tool.

But I was making some very odd swarf even though the hole was all the way through the work (I started with a 10mm drill), and I was taking 0.25mm cuts, I was getting round disks every pass.

The tool used was the carbide on supplied with the set. I couldn't get enough depth with the HSS one.

Although the hole came out fine in the end, could someone suggest how I might modify my technique for next time?

OK your call. You are trying to do something very specialised, but don't want to put any effort into specialised tooling, or spend the sort of money  that commercial solutions need.

Good luck!!

Edited By Peter Cook 6 on 21/04/2021 23:08:11

Ebay Item 174597008491 is the holder. Mount underneath a table of some sort with the blade sticking up through a slot.

How to make a Table Saw using Angle Grinder - YouTube gives the general idea - just a different blade.

Have you thought about an angle grinder with the thin (1mm) cutting blade.

Mounts for the grinder which turns them into something resembling a circular saw are available. Mount one of those upside down under a table with the cutting disk protruding up through the slot and you would have something like a table saw using a high speed metal cutting disk.

There are several homebrew versions on the internet, but I haven't come across a commercial model. 

Edit an internet search for "angle grinder saw table" will get lots of images.

Edited By Peter Cook 6 on 21/04/2021 14:24:12

SoD's comments remind me of a piece by Lee Hutchinson on ArsTechnica a few years ago, which I think puts thing well.

"You've almost certainly never seen the place where I grew up, and you never will because it's long gone, buried by progress and made unreachable by technological erosion and the fine grind of time. What I did and learned there shaped me, but that knowledge is archaic and useless. I am a wizard whose time has passed — a brilliant steam engine mechanic standing agape in the engine room of the Starship Enterprise."

You might want to look at a tablet computer with a keyboard.

Most of the Windows 10 tablets seem to have an SD card slot. Microsoft Surface Pro 7 (at the top end) for example has an SDXC reader built in. Amazon have a Fusion 5 tablet which also has an SD card slot (towards the bottom end).

One thing to watch with EDGE is that although you can choose which search engine to use, it only uses that one for queries entered into the browser bar. As far as I can find, it's impossible to change the search engine that is used by the box in the middle of the "new page". That seems to use Bing regardless of the choice of search engine.

Thanks Michael - first time I have come across it. Filed for future need! 

Thanks Frances - now I know what it is I can see the construction. Quick waft with a small paintbrush was as far as I went. It worked OK on reassembly

Edited By Peter Cook 6 on 07/04/2021 17:55:33

Just an update for anyone interested. I obtained a new "silver" tyre gauge and swapped the front part for the one I was using as the mill DRO.

The problem of the flickering display went away. Presumably the thin coating is sufficient screening to fix the problem. There is a side benefit. Although the devices look identical apart from colour, the new one does not loose its setting when it switches itself off, and comes back on when the quill moves. The old one reset to zero when it switched off, and had to be manually switched on again - so they are different implementations.

In swapping over I had to dismantle the original device and came across another interesting curiosity. The back of the LCD does not appear to have any electrical connection with the PCB.

The display has a strip of what feels like rubber along one edge. I cannot - even with a loupe - see any contacts on the rubber.

While the PCB has a corresponding set of pads onto which the rubber strip presses

I can only presume that the strip of rubber conducts from top to bottom, but not sideways so that matching pads on the LCD connect to the pads on the board. If so that is high tech (and potentially quite useful) material in something that cost me a fiver delivered - so what did it cost to make!!

Edited By Peter Cook 6 on 07/04/2021 17:21:58

Thanks everyone, Knowing the problem is 90% of the way to the solution. I will try some of the suggestions, and have ordered a "silver" version of the gauge to see if the plating helps. However now I know what to avoid it does the job.

Mill & lighting is all earthed.

The incident reminded me of one of my favourite quotations from Isaac Asimov

The most exciting phrase to hear in science, the one that heralds new discoveries, is not “Eureka!” (I found it!) but “That’s funny …”

Edited By Peter Cook 6 on 03/04/2021 20:43:19

Thanks for all the thoughts, I did some experiments based on the ideas. Robert G8RPI's idea worked. If I touch the head of the mill with one hand while pushing the buttons all works fine.

The gauge works perfectly as a simple DRO when the machine is running or stopped. The readings correspond to the markings on the fine feed knob (without the backlash) over the full 25mm range of the quill (and the tyre gauge) as long as I keep fingers away from it. There is no sign of flicker in the readings when the mill is on or off, running or stopped.

However - the problem IS electrical interference, but not from the mill. By accident I experimented while the workshop lights were off. All worked perfectly. Switch on the overhead florescent tubes - problem reappears. If I hold the gauge very close to the florescent fittings the readings go haywire.

I can only conclude that if I don't touch the mill head while pressing the buttons I am acting as an aerial for the interference from the florescent tubes. So either a better guage to use as a DRO (one with a metal body?), some new light fittings for the workshop or simply touch the mill before zeroing.

Thanks again.

PS thanks Les I will try that next. A capacitor will be cheaper than new light fittings.

Edited By Peter Cook 6 on 03/04/2021 13:38:53