Member postings for Stub Mandrel

> I have an interest in electronics and microcontrollers as well as my workshop, but CNC doesn't really appeal to me - at the moment. I derive more pleasure (and it has to be admitted, sometimes frustration!) from using my manual machines and exercising what little skill I have.

Interesting comment Carl - I feel exactly the same way! that said, as my models get more complex necessity is making me search around for a 3D CAD drawing package I get on with, and I'm sure CNC will get it's teeth into me in time.

That said I think software has a place in the magazines, especially MEW, but no long programme listings, which should be downloadable.

Neil

Shame, a firegrate set. If it was the grate I was going to say black it with zebrite

Neil

As a reader of both magazines, I'd be quite happy to read a series on a model build in ME, but with related articles from time to time in MEW on, say, pattern making, gear cutting or CNC machining of parts in more detail than would be normal for ME.

Another example could be a CAD tutorial based around creating the drawings for a model - and then the build could be covered in ME.

Another example might be splitting the toolmaking for a clock and the actual build.

Most contributors probably would not want to split their articles in this way, but if done from time to time who knows, such an approach could get the odd reader to 'cross over' from time to time?

Neil

I clicked on this thread and got an ominous message that the website was experiencing problems... fortunately they appear to have been transient.

Neil

Hi Paul,

i use Firefox and have not ever seen this. It does sound like one of the ghastly 'helper objects' that you have to be careful to avoid downloading, even when installing useful software like Adobe Acrobat.

Neil

Jason,

I'm sure there's someone who would have bid for it on ebay - collection only

Neil

> The Chinese manufacturers are always changing their models so there is no guarantee that, even if you were to buy new, spares would be available in 5 years time.

My main use of spares has been to modify to add functions e.g. an extra handwheel that I fitted to the leadscrew. True consumables (like the toothed belt and bearings) are stock items that will still be here in 50 years time!

My Clarke Mini Lathe was bought in 1998 (so 16 years old this year) from Machine Mart. I can still do, get parts. Not long ago I bought a drive pulley for my new countershaft from Arc Euro who carry a wide range of parts, and I'm sure Machine Mart, Clarke themselves, Chester or Warco (among others) would have been able to supply.

Neil

Tension in a poly-v belt should be enough to cause 1% stretch between two marks made with the belt slack.

Neil

Coal fires are great - poke a bar into the base of the fire when it's burning low and you're off to bed. pick the horrid-looking but nice and soft and stress-free metal out of the ashes in the morning.

Fine for bars etc. to be machined all over, or chunky castings. Don't do this to stress relieve a chilled flywheel though - I did and got something resembling a pretzel back

Neatly placed holes too!

Neil

Edited By Stub Mandrel on 10/01/2014 17:48:06

> I annoy my wife by dismantling old household electrical items for parts and give them a second life.

"If you want to take it apart PLEASE can you put it in your workshop not leave it there for the next four weeks..."

> 4000Ah [presumably at 3.7 Volt] is enough to power a vehicle

It was a big phone.

Neil

Keep posting Allan!

There should be enough meat in that bar to compensate for the bow - bear in mid that you take very little off teh ends, but quite a lot in the middle which is where the bow is.. Rough turn the centre section of the bar leaving an allowance for any further movement, let it stand for a day or so, then finish turn it. Remember the critical dimension is the distance between the holes.

If you have a gas cooker, it should be able to get the bar more or less red hot. you don't need it to be glowing bright red to normalise it (i.e. stress relieve it).

Neil

I have been 'donated' a two hotplate + oven tabletop cooker to scavenge for bits. Aside from a couple of retro knobs, I'm not sure this beast has a lot to offer me

It would make a great TV programme to have model engineers compete to get the biggest pile of useful bits out of various devices against the clock. H&S might baulk at some of the techniques - such as melting solder with a turbo flame lighter and flicking components off with a screwdriver.

My wife has kindly donated me the remains of an emergency phone charger - 4000Ah of Lion battery with working charger (it charges but won't feed the phones)

One nice find was a pair of tiny (5/8" diameter) planetary reduction gearboxes from the broken wing mirror of my Astra. They and the motors partially compensated for the cost of a 'new' one from an internet scrappy.

Neil

I must be honest, Lee,

i faced that lump on all 6 surfaces to make a T-slotted table (which I milled the slideways and t-slots for on the mini-lathe too) but I only ran teh lathe at about 60 rpm because of vibration (not attached to bench).

Taking too deep cuts at such slowspeed guess what happened ... yes I had to buy a new motor. But I think this was my inexperience, not a problem with the lathe. Just because you CAN make a deep cut t 7"diameter at 60rpm doesn't mean you SHOULD!

No problem these days though - I've fitted a 0.4kw three-phase motor and I suspect the lathe would take a full 1kw.

My concern with a bigger motor though is that a jam up could crack the headstock or twist the bed.

Neil

As a very happy mini-lathe owner I can only suggest that there are mini-lathes and mini-lathes, and many of the suppliers have greatly improved their quality control. Please don't judge them all by the same standard, though if you had a "bad 'un" I realise you won't risk being caught twice.

> I wondered what these mini lathe spindles can Handle.

Neil

I'm confused - I though Andrew's results were rather impressive? Overall dimensional accuracy of about a thou sounds good to me.

It would help if it was clear what the roughness measurements were in, I assumed micrometers?

Andrew, could you clarify and give a subjective assessment of whether you think this is a good or bad result?

Neil

I found a calculator on the web that worked out a 10" steel pipe with.250" wall and an O/D of 1.250" has a yield load of about a ton if supported at each end.

I reckon a mini-lathe spindle has a bit more meat and much less length between the bearings and is probably better steel than 'pipe'.

I have no idea if that helps, but I'd guess you are talking a load of several tones to permanently deform a mini-lathe spindle - I think the cast headstock would break first.

The bearings are comparable to van-sized wheel bearings too.

I can't see how you could overload the spindle in normal use, even with a huge chuck and workpiece. A bigger risk would be damaging headstock and/or bed in the event of a big jam-up.

Neil

I'm very pleased with my 4" Zither chuck from Arc. A better bit of kit than I ever expected to have on my lathe.

Neil

Wow!

I want one of those

Neil

Firefly was covered by ME, if I recall correctly.

Neil

**LINK**

Sort of explains the process and says they have been doing it for over a century!

Neil