Member postings for Andy_G

What has happened to Michael Gilligan's original posts?

(There were several, pointing people to various sections of the document he linked to).

Edited By Andy Gray 3 on 01/01/2021 21:41:50

Can't think what you mean...

I'll get there...

No problem - FYI the edit button is in the green banner at the top of the post.

If you use the 'direct link' from Post Image (looks like 'https://i.postimg.cc/4Nf9Zg16/IMG-4093.jpg' ) you can paste that into the box that pops up when you click the 'Image' button when composing the message. If it works, you will see the picture as you're writing.

Good luck with finding an insert!

Happy Christmas.

If you don't mind me saying, that 'Z' plate setup looks awfully erm... 'springy' - both the bracket itself and the amount of overhang it creates will count against a rigid setup.

The carriage lock in the second link is meant for fitting in the rear edge of the saddle, I think.

Good luck!

"Myford" style milling slide on a mini lathe:

It works surprisingly well IMHO, within the constraints of the limited cross slide travel and the size of the machine.

Details of my adapter plate / boring table for interest (adapt dimensions to suit). It fastens to the compound slide mounts and an additional two holes tapped into the far end of the cross slide. A removable dowel means it can be removed and replaced pretty accurately.

(I would knock the dowels out of the vertical slide base and not bother drilling for them if doing it again.)

Edit: Looking back at the original question - If one wants to use the vertical slide at an angle to the cross slide, it would probably be necessary to change to mounting location to re-centre the work on account of the limited cross slide travel. Doing away with the dowels in the vertical slide base makes this much easier - one could just drill & tap mounting holes wherever they landed on the adapter plate / boring table.

Edited By Andy Gray 3 on 28/12/2020 13:05:37

It shouldn't move around as you tighten the bolt (a very small amount of movement may be unavoidable).

The most obvious thing to check is that there isn't a lump of swarf or dirt stuck between the tailstock and the bed - Slide the tailstock off and clean the bed and mating surfaces carefully.

Also check for any damage or 'bruises'.

I couldn't see this mentioned above - apologies if I missed it. There's no point performing any alignment until the position is repeatable.

Fair cop. Didn’t want to get into righting moments, but simplified it a step too far

Point should have been that stability is a consideration as well as just displacement which requires consideration of the C of G.

Must try harder!

It won’t float for long unless the centre of gravity is also below the centre of buoyancy (lateral and transverse)

I’d be surprised if the displacement didn’t come out between 7 & 8 kg (15-18 lbs).

Anyone remember the ‘Krispie’? 36” long sailing boat built from strips of cereal packet (I built one once...).

Specific strength (strength to weight ratio) - Higher is better:

Balsa is 521 (kNm/kg)

Copper is 24.7 (kNm/kg)

For reference, carbon / epoxy composite 785 (kNm/kg)

(Ref)

So if everything was built to the same strength, a copper hull would be ~21 times heavier than balsa wood, a carbon fibre / epoxy one would be 50% lighter.

Regarding the business about calculating volume - the block coefficient gives the ratio between the volume (and displacement).of a hull as a fraction of the rectangular bounding box of the underwater dimensions. There are many references on line where one can find typical block coefficient values for different hull forms which can be applied to the model dimensions to give a idea of displacement - as already pointed out, it's best to have something in reserve for trimming & stability.

Look up ‘prismatic coefficient’ and ‘block coefficient’ - they won’t give you the answer, but should help estimating displacement. From a quick look, tug hulls typically have a block coefficient of 0.6, so will displace 60% of the theoretical length x beam x draught volume.

That photo was from your link to show the slide, so I'm not sure about those.

On the one I recently acquired (Chinese / Indian / WHY copy) the dowels are 3/8" diameter. (But I don't have T slots for them to fit into!).

Does yours not have the dowel pins that fit into the T slot to stop the base rotating?

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.

Thank you

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.

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

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

Funnily enough, this just popped up elsewhere:

(I'm a fan, in case you hadn't realised! )

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)

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:

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

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).