Member postings for Andy_G

I’d respectfully suggest using it as it is for a week or two to get the feel of it (making minor adjustments such as slideway gibs, etc.) before launching into a full strip-down.

Sometimes taking things to bits introduces new problems!

The Arc Euro Trade strip-down guide is very good.

https://www.arceurotrade.co.uk/machineguides/C3-Mini-Lathe-Dismantling-and-Reassembly-Guide.pdf

Your lathe may not be identical, but it is likely to be very, very similar.

Re questions about emergency response:

**LINK**

Thank you!

It can work - the same principle is used to cut out circles commercially. You need to start the break from the outer edge of the glass sheet and get this to run into the circle. It's likely to take quite a bit of practice.

For small diameters, the circles are broken out thermally - using cold metal cylinders roughly the same size as the circle which are placed in liquid nitrogen, then onto the glass (after scoring)

You might get somewhere using a metal cylinder from the deep freeze to get the circle to break out, but I still think you'd need to break the outer square of glass to release it.

Unless it's for entertainment value I would go to core drilling one out (very cheap diamond core drills are available on Amazon, etc. which will work fine, but *must* be used wet). Or trepanning one with a metal lap and loose carborundum powder - anything will do for a one-off: I used a boot polish tin to trepan out a secondary mirror for a telescope. Needs a fairly slow drive though (I wouldn't dream of doing it by hand).

Or just buy one!

(Edit - you need just enough pressure on the cutter for it to create a vent in the glass - it will vary with the type of cutter. You will need to take into account some movement in the glass surface - i.e. the cutter cannot be rigidly mounted - it needs to float.)

Edited By Andy Gray 3 on 15/11/2020 21:43:45

Cutting with a wheel or scribe relies on creating a vent (crack) in the glass surface that propagates through the thickness when that surface is put in tension.

Old glass becomes 'weathered' (even indoors) which both makes it harder to develop that initial crack, and also provides a plethora of microscopic defects which can lead a propagating crack to wander off.

(Sorry for 2nd message - can't seem to find how to include a separate quote).

I had read / heard the same thing (no idea where), but despite an almost unlimited supply of thin glass and repeated attempts, this never resulted in anything other than shattered glass. I would love to see someone actually doing it.

Thank you

I used a "Replacement Complete Ignition Set for Single Cylinder Gas Engines" module from Hobby King:

https://hobbyking.com/en_us/replacement-complete-ignition-set-for-single-cylinder-gas-engines.html

Unfortunately seems to be on back-order now

It needed some careful shaving down in order to hide it inside the engine pedestal.

Edited By Andy Gray 3 on 14/11/2020 18:47:18

I also weakened, having missed out on the Lidl saw due to the Welsh lockdown ban on non-essential bandsaw sales, and ordered the Aldi one. It arrived the other day and I'm favourably impressed (apart from the comedy vice, but even that can be induced to work). It's quite gratifying to hear that it's "better" than the Lidl one, rather than being a dearer version of the same thing.

The threads in the three arm mounting holes on mine were also ridiculously tight - I thought I had cross threaded them, but I hadn't.

Other than that, the saw appears quite substantial and feels very solid. It's cured me of the urge to build a power hacksaw

A normal (tungsten carbide) wheel cutter should work OK down to about 0.5mm and give clean cuts. (Look after the cutting wheel - any chips out of its edge will be reflected in the glass cut quality).

You may struggle to break off the narrow edge of the slide - it might help to scribe all of the cut lines first (in a # pattern) then break the larger pieces, leaving the narrow edge until last. This avoids the tendency of the cut to run off at the start/end of the scribe line.

You may find that lubricant (white spirit, or similar) helps.

Keep everything clean...

Edit - if you can find a good edge on the diamond, that will work, too, but it does need to be a very sharp point to create a 'vent' in the glass. A worn diamond will scribe a line, but there won't be a vent under it and the glass won't break cleanly.

Edited By Andy Gray 3 on 13/11/2020 23:27:04

Posted by woody1 on 11/11/2020 20:14:02:

I bought my angular contacts...

Just checking - if woody1 is fitting A/C bearings, there shouldn't be any need to shorten the spacer, should there? The A/C bearings are supposed to be the same width as the originals, I believe.

Just re-make in metal to the existing dimensions? (My 7X lathe is a different make with a brushless motor, or I'd offer to measure the spacer!).

Very interesting - I've not been able to find (m)any objective before / after assessments of the effects of bearing replacement.

If you were to do it again, would you go with angular contact or taper roller?

It'll be under the stairs, with the other one

Just for the record, I have had a 'Hot Stuff' branded (Vango??) stainless flask for the best part of 20 years and it still keeps drinks scalding hot all day (remnants are still luke warm next morning). It is definitely all stainless & vacuum insulated. It's just a shame that the matching cup is somewhere amongst the boulders at the foot of Cenotaph Corner in the Llanberis pass :-/

Blimmin' autocorrect...

Easy - the vacuum leamed out

Edit to add:

Fascinating details about how "the good ones" are made here, including several videos:

https://www.waterbottle.tech/manufacturing-process-of-vacuum-insulated-stainless-steel-bottles/

I would suspect a fault in a weld has resulted in gradual loss of vacuum, or some small fault in the raw tube (inclusion, lap, etc.) has opened enough to result in loss of vacuum

Edited By Andy Gray 3 on 09/11/2020 17:33:20

Work out the resistance of your potential boiler combo, and then use the P=I^2 x R formula to figure out how many amps you'd really need to get 5kW dissipation.

It's likely to be 2 orders of magnitude higher than you've guessed

Making connections for this sort of thing is also non-trivial. (I've worked with similar technology - One needs to ensure that the current is delivered uniformly, as resistivity tends to increase with temperature, so any non-uniformity results in localised hot-spots which progress very quickly to a puddle of molten metal and a gap where it used to be.)

When I did some work with diamond tooling years ago, machining steel was an absolute no-no (it reacts with the diamond under very high pressures, IIRC). CBN was needed for ferrous metals.

UK drills do tungsten carbide tipped drills which might be a better bet if cobalt ones don't work.

Carbide tipped

Cobalt for hardened steel

Be slightly careful with the shimming - it cures a symptom rather than the cause. The gib shouldn't bear on the bottom of the slide (or the top). If it does, it is either not being held properly by the adjustment screws, or is rotating slightly, which forces the lower corner into the bottom of the slide.

In an ideal world, the pressure on the gib should be at right angles to the sliding face - it isn't on the mini lathe (and many other designs, too) so there is a tendency for the gib to be pushed downwards as the adjustments are snugged up. There needs to be enough engagement of the adjustment screw tips to stop this. Also, as the gibs are so narrow, the point of action for the adjusting screws needs to be close to the sliding face to reduce the tendency of the gib to rotate, not on the back of the gib as is the default.

After trying several internet solutions without making a huge difference, the thing that sorted mine was to depen the recesses in the gib to take the tips of the dog-point adjustment screws. These need to be angled to match the adjustment screws, not flat to the gib strip itself. I managed to do this by clamping the gib to the slide itself (with the hole location overhanging) and drilling them deeper. I also had to add clearance to prevent the threaded part of the adjusting screws fouling the gib. I managed this with a 4mm end mill in a drill press. (A bit hairy, but worked OK).

11 amps will be at the rated output (11 x 24 = 240W). It will use very little current with no load.