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Member postings for Andy Gray 3

Here is a list of all the postings Andy Gray 3 has made in our forums. Click on a thread name to jump to the thread.

Thread: Model tug boat plans
29/11/2020 11:41:15
Posted by BOB BLACKSHAW on 29/11/2020 11:18:19:

how do you convert the drawing profile to the full size,

In the olden days (when I used to make model boats) I would transfer the lines onto graph paper by tracing or carbon paper then scale that by hand to whatever size I needed (drawing out a custom grid if it wasn't a straightforward multiple).

The full lines got transferred to templates using more carbon paper.

These days, you could probably do it all with a photocopier.

Thread: Suggestions for lathe-only projects?
28/11/2020 21:17:55

Thank you

Posted by William Ayerst on 28/11/2020 20:59:10:

I assume best to use the 3-jaw for milling and the jacobs chuck for drilling, in the headstock?

With a little bit more expenditure you could get a finger collet to hold milling cutters in the headstock spindle (you would need to make a drawbar - e.g. a long bolt + collar), I guess a 6mm and/or a 10mm collet (<£10 each) could cover quite a range of milling cutters.

FWIW, In the limited amount of milling I have done on my lathe (not Myford) I find the cutters run more smoothly in a collet than in a chuck and it's easier to see what you're doing.

28/11/2020 18:17:25

I'd honestly buy a cheap pillar drill before the milling slide.

This was made just using a lathe and a cheap pillar drill. I could have done without the pillar drill, but wouldn't want to. (Apologies for blowing my own trumpet, but one can make an awful lot of things on a lathe, and many, many people have - one is only limited by one's imagination.)

 


 

(OK, I bought the gears and the sparkplug!)

 

Edited By Andy Gray 3 on 28/11/2020 18:21:27

Edited By Andy Gray 3 on 28/11/2020 18:22:32

Edited By Andy Gray 3 on 28/11/2020 18:24:41

Thread: Bearing identification
27/11/2020 14:18:07
Posted by Kiwi Bloke on 27/11/2020 10:27:39:

I still want to know what the difference is - if any!

The 99502H seems to have imperial ID & OD, but metric width:

This lists both (pdf file)

99502H

ID 0.6250" / 15.875mm

OD 1.375" / 34.925mm

Width 0.4331" / 11mm

1623

ID 0.6250"

OD 1.375"

Width 0.4375" (7/16" ) = (11.113 mm)

Edited By Andy Gray 3 on 27/11/2020 14:18:53

Thread: Another engineering masterclass
25/11/2020 20:49:57

Funnily enough, this just popped up elsewhere:

(I'm a fan, in case you hadn't realised! )
25/11/2020 17:22:25
Posted by John MC on 25/11/2020 07:24:51:

The way I look at these is would they stand up to "real world" use,

They do seem to. I particularly admire the fact that he creates useable vehicles rather than 'engineering sculptures' what would fall to pieces if started.

Here's his little 4 cylinder 350 being revved to 7k RPM and hustled around some bends (towards the end of the video)

 
(Absolutely beautiful cameo at 6:32)

Here he's riding his V10 Dodge Viper engined bike (In part 2). He reckons to have put over 9000 miles on it since it was built.

Part 1:

 

Part 2:

I find it frankly astonishing that anything so monstrous could be engineered to be usable.

The fact that he's prepared to rest his nuts on it and open the throttle to hit 200mph also speaks of man who is confident in his engineering ability.

He also claims to have over 9k miles on the Pratt & Whitney 5 litre V twin

Part 1:

Part 2:

 
 
My favourite video is where he welds together a pair of camshafts and trues them up;
 
 
 
 
He Knows What He's Doing!

Edited By Andy Gray 3 on 25/11/2020 17:23:41

Thread: Unimat 3 motor diode
23/11/2020 22:36:11

Looks like a DS 1.8 16A general purpose rectifier - 1.7A If / 1600V PIV

https://www.web-bcs.com/diode/dc/da/DS1,8-16A.php?lan=en&cl=1

(Possibly used to half-wave rectify the incoming mains to give reduced speed, based on your description, but I have no knowledge of the Unimat circuit).

Thread: Desperate times and desperate measures...
20/11/2020 09:01:03

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!

19/11/2020 13:53:20
Posted by Jay Nugent 1 on 19/11/2020 13:46:13:

My job this afternoon is downloading every drawing, manual, part number and measurement, I can possibly find on the thing...

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.

Thread: Electric vehicles
19/11/2020 12:49:50

Re questions about emergency response:

**LINK**

Thread: Horizontal hit and miss engine
15/11/2020 21:48:05

Thank you!

Thread: Cutting Small Discs out of Glass
15/11/2020 21:41:30
Posted by Georgineer on 15/11/2020 16:10:54:

It occurs to me that it should be possible to mount a piece of glass to the lathe face plate with double-sided tape, or some other adhesive. Then an ordinary glass cutter could be mounted in the top slide and brought up until it touches the glass. A single turn of the chuck by hand should scribe the line, then the circle could be broken out in the ordinary way.

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

Thread: Cutting Microscope Slide Glass
15/11/2020 12:19:41
Posted by Dave Halford on 15/11/2020 11:59:14:

For some reason old glass does not like cutting cleanly

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).

15/11/2020 12:11:32
Posted by Robert Atkinson 2 on 13/11/2020 20:45:23:

If you want to cut the very thin cover slips try a sharp pair of scissors under water. Have a tray or similar underneaith to catch any fragments.

Posted by Howi on 14/11/2020 09:55:31:

i read somewhere that you could cut glass slides for microscopes etc, by using sharp scissors under water - lots of shattered slides and cut fingers, not one cut cleanly as i desired

Posted by Brian Wood on 15/11/2020 09:49:54:

Using a good pair of strong scissors, cut the slides underwater, thin sections like microscope slides responded well to the method.

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.

Thread: Horizontal hit and miss engine
14/11/2020 18:42:12
Posted by Simon Birt on 14/11/2020 15:31:16:

Very nice and runs well. What have you used for the ignition? I am building a Farmboy and am starting to think about making sparks.

Simon

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

Thread: Lidl Portable Bandsaw
13/11/2020 23:47:57
Posted by Martin of Wick on 13/11/2020 20:47:41:

Afraid I weakened and after the dismal experience of Lidl's offering, decided to try the Aldi version (can always send it back, I reasoned and it might save me having to get a Femi!).

Arrived today, pleasantly surprised, substantially better made/finished than the Lidl version,

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

Thread: Cutting Microscope Slide Glass
13/11/2020 23:24:38

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

Thread: 7x12 Bearing Spacer
12/11/2020 18:36:05

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

I bought my angular contacts...

Posted by Neil Wyatt on 12/11/2020 11:36:06:

...I had to shorten the spacer by 4mm...

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!).

12/11/2020 18:23:12
Posted by Neil Wyatt on 12/11/2020 13:41:09:

Slightly updated versions of my articles written about 15 years ago!

Neil

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?

Thread: How can a steel thermos drinks flask fail?
10/11/2020 11:00:03
Posted by not done it yet on 09/11/2020 22:51:56:

Easy - the vacuum leaked out devil

Where did it leak to?🙂

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

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