Milling machine stops

[Tony Pratt 1Participant @tonypratt1]

For those who haven't any experience of CNC, you do not, I repeat do not have to program every single machining step or process. Every CNC machine I have worked on had a manual mode ie you can use it manually with some type of hand wheel plus the benefit of digital readout. When a complex or repetitive job occurs you can then do your programs and off you go.

Tony

[Gone AwayParticipant @goneaway]

Posted by Ady1 on 28/02/2012 11:27:34:

I always found slide stops too wooly for accurate work.

The leadscrew can impart too much torque and I had to be really careful as it came up against the stop.

If I "pushed" the slide up against the stop, even a bit too much, I lost accurate repeatability.

That's excatly my experience, Ady. Maybe it depends on the particular machine.

I think Andrew's comments re cnc have been taken more seriously than he intended (there was a big "grinny" attached after all). Given some of the somewhat acrimonious discussions re cnc elsewhere in these forums, I read Andrew's post as something of a tease, putting the cat amongst the pigeons.

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

Some super precision machines in the days before DRO had soft contact indicating stops . Basically moveable very short travel dial gauges prepositioned to indicate zero at the notional 'stop' position . Very facile and almost perfect repeatability .

These devices also gave useful warning of 'distance to go' for last couple of millimeteres before arriving at final 'stop' location .

A modern electronic version of the same thing would be easy to design .

Michael Williams

[Harold Hall 1Participant @haroldhall1]

I agree Sid, perhaps I did over react, my apologies Andrew

I do however, admire Wolfie for the effort he is putting into coming to terms with his small milling machine and with limited funds to further equip it, perhaps because I once found myself in the same position. Whilst I had had a lathe for 35 years I did not start using a milling machine until 25 years ago. It had been purchased 5 years earlier but had to be put in store.

I soon found, to my dismay, that a drill chuck was totally inadequate for holding end mills and a suitable chuck was to cost £100. Having paid £600 for the mill there was no way I could justify that cost with my limited means. The mill therefore would have to be resigned to being the workshops drilling machine( I only had an home made one) or I would have to make an end mill chuck, which I did. This is still in use today.

Incidentally, this was my first real effort in the workshop and was the first item I sent to the magazine for publication, from which developed my being offered the task of editor. As they say "the rest is history".

I do though feel that CNC use will be in the minority for some years to come based on the cost of equipping the workshop with it. Not only that, upkeep of computer equipment is also pricey. During my twenty years of computer owning I have had to purchase 4 PC's to keep up with the times, but all have had to return for servicing due to failures or crashes. Almost certainly the earlier ones would be unserviceable now such is the rate of change in the electronic industry. On the other hand, the cost of servicing my lathes over the 65 years since I first had one has been, one nut for the tool post and a set of screws/nuts for the gib strip adjustment on the top slide.

Also, I think we kid ourselves if we think that the majority of young people in the future will be sufficiently computer literate. Only this morning I learnt on the TV that some very small, and cheap, device has been developed to held people to come to terms with simple computer code. Perhaps someone on this forum can fill us in regarding the device.

I personally, would love to have additional machines in my workshop equipped with CNC but only as a hobby in itself, which is why many others have it in my estimation. Of course, with it there, I would also use it for my other hobby, Metalworking.

Harold

[Harold Hall 1Participant @haroldhall1]

On another subject, thanks Norman for your comments about my clock wheel crossing out method, perhaps I am breaking with tradition. Having spent my working life as a control systems engineer, mostly in high power variable speed drives systems for the printing a paper industry, tradition never came into it trying to keep up with the continual changes in the industry. No doubt that had rubbed off onto me when I retired and came into metalworking.

The clock I am making is John Parslow's clock that appeared in the Model Engineer in 2008. It is my first clock and will be the last. This is not because I have not found the task interesting, quite the reverse, but there are so many items on the "would like to do" list, many non metal working and time is running out.

Harold

[Ady1Participant @ady1]

Only this morning I learnt on the TV that some very small, and cheap, device has been developed to held people to come to terms with simple computer code. Perhaps someone on this forum can fill us in regarding the device.

——

Clive sinclair did the same thing 30 years ago with the zx80/zx81 and then there was the BBC B project

You can still do BBC Basic for Windows to write Windows executables.

If it gets kids interested then fine but programming has never been easier to get into than it has over the last 10 years.

 

Raspberry Pi

Most kids nowadays can't even be bothered to kick a ball

They're either playing with the moby phone or playing a variant of DOOM

Edited By Ady1 on 29/02/2012 10:35:44

[Sub MandrelParticipant @submandrel]

Raspberry Pi is a great idea.

My AVR-based computer runs BBC Basic, or something very close:

But for younger kids the best start in programming is 'Scratch' google "scratch MIT"

Neil

[Anonymous]

Sid: Thanks for explaining that my comment was slightly tongue-in-cheek.

Harold: No need to apologise, no harm done.

While I do have a CNC mill, and I find it very useful, it is just another tool in the box. After all a previous post in this thread shows some parts that were made entirely on manual machines. I certainly do not expect everybody to have CNC equipment; people may not want one, need one, have the money, be able to use the computer, or for a myriad of other reasons. Each to his own.

As for the shape of the hobby in the future who knows, but I suspect that it's changing. I know quite a few people in my area who have workshops in some form. Some are building model engines, many are not. Only one person belongs to the local model club and none of them post on this forum.

Regards,

Andrew

PS: I've blown a raspberry at the Raspberry; every time I looked at the Farnell website today I got a message saying did I want to register an interest in the Raspberry Pi before I could look up what I needed.

However it's cheap enough, so I might buy one later just to see how it's made. Looks like they're using package-on-package for the processor and SDRAM, pretty nifty. It would be interesting to know what design rules they had to use for the PCB.

[Gone AwayParticipant @goneaway]

Posted by Andrew Johnston on 01/03/2012 23:26:38:

Sid: Thanks for explaining that my comment was slightly tongue-in-cheek.

Tongue-in-cheek! That was the phrase. You don't know how long I sat trying to think of it but it wouldn't come. Talk about yer senior moment.

[Harold Hall 1Participant @haroldhall1]

Thanks Andrew for your comments!

Harold

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