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Member postings for duncan webster

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

Thread: Myford Super 7 at SRS for only £395
06/05/2022 15:14:55

Just realised nvr won't work with an on/off switch, but contactor will

Thread: Tools needed to build a 3 1/2in gauge Tich
06/05/2022 13:52:36

I'd build a Juliett, slightly bigger, not much more expensive, but much easier to drive when it's finished

Thread: Myford Super 7 at SRS for only £395
06/05/2022 12:27:44
Posted by Bob Mc on 02/05/2022 20:08:37:

You may notice my on-off switch housing which I thought would complement the rounded change wheel casing, the one thing I am looking for is a 'snubber' circuit since there is a definite electrical flash when the switch is turned off.....anyone point me in the right direction..? it has to switch off the induction motor.


cleaning up.



No-one else has got back on this so here's my 2 pennyworth. I'd use that switch to control a proper NVR contactor hidden elsewhere.

Thread: Emergency Radio Format
04/05/2022 16:01:47
Posted by pgk pgk on 04/05/2022 12:39:49:
Posted by blowlamp on 04/05/2022 11:22:55:
Posted by John Haine on 04/0........

A cording to Wikipedia the barracuda anti-torpedo missile can do 800kph 430knots. Stingray needs a turbo.

Ah but according to Google it won't be in service until 3056, might still beat CrossRail

03/05/2022 22:38:35
Posted by Peter Greene 🇨🇦 on 03/05/2022 18:51:32:
Posted by blowlamp on 03/05/2022 18:43:10:

Just something else to keep us on edge.

... Not for long. I figure all this means that the super-beings that are running this universe feel that the experiment has failed in this corner of it and is about to be terminated.


Edited By Peter Greene 🇨🇦 on 03/05/2022 18:52:47

So have the mice sent for the Vogons?

03/05/2022 14:38:28
Posted by John Haine on 03/05/2022 14:26:11:

Except now it will be digital! The US has had this emergency alerting via mobile for quite a while.

Is this so that 'off grid' survivalists won't get the message?

Thread: LBSC Cylinder Thread Size
02/05/2022 01:27:28

5/32 * 32 is a standard bsw size, and I think was what Meccano screws were in the olden days. Your chance of finding new screws is slim, I'd use m4

Thread: Edward Thomas. 5" gauge. Hackworth Valve Gear.
01/05/2022 17:29:20

Well if about half the maximum valve travel is 'hardly any' we must live in different universes. If for instance you had 0.125" lap and 0.01" lead, at a cutoff of say 80% the valve travel would be 0.58". The valve travel at mid gear would be 0.27". Once you've got the valve gear made, lap+lead is fixed, nothing to do with port width.

Despite RedSetter turning me down, here's the sketchhack.jpg

01/05/2022 16:10:21
Posted by Redsetter on 01/05/2022 10:04:24:
Posted by Chinkoa on 01/05/2022 09:34:47:

I've just drawn out out to scale to give a 0.010" Lead I need to shorten the v/v. by 0.098 overall to 0.980 from 1.078

Do you agree?

....... In mid gear you should get the same opening point but hardly any valve travel.

If that checks out and it is running well on air I suspect it is probably OK.

Edited By Redsetter on 01/05/2022 10:05:07

Edited By Redsetter on 01/05/2022 10:10:32

That's not correct, in mid gear you should get 2*(lap+lead).when I get home I'll post a sketch

Thread: 3D-CAD Package Shootout - Cotton Reel Example
01/05/2022 00:37:47

#2 son came round tonight. He is a bit of a CADS expert. Seems my cylinder model is all wrong, not constrained. Once I find out what that means (I have a fair idea!) I'll have another go.

Thread: UK DRIVING LICENCE [ 2022 issue ]
29/04/2022 14:30:09

SWMBO' has just reached 70. I applied for her licence renewal on the interweb as soon as possible. She has three medical conditions which could have prevented her driving, but they are all either under control or fixed. We then receive a form wanting more information about "your condition", no clue as to which one, and a threat if we don't reply her licence will be stopped. We just filled in details of the most recent and returned it "signed for". I've had government departments claiming they hadn't received something, it miraculously turned up when I said the post office say it has. Don't expect integrity or competence from these agencies. However it's not their fault, the politicians set up complex systems then employ too few untrained, underpaid people to implement them. Anyone tried filling in the long self employed tax return, we need Andrew with his PhD.

Thread: Edward Thomas. 5" gauge. Hackworth Valve Gear.
28/04/2022 22:56:08

Set as in decide upon. Once the length of the valve is decided on the lap and lead are fixed as well

28/04/2022 13:47:04

The mid gear valve travel is determined by the return crank radius and the dimensions of the vibrating lever. If you just set the lap without reference to this you could get too much or too little lead. I don't want to open another can of worms, but 0.01" is plenty of lead in 5"g loco.

If this doesn't make sense, I'll post a sketch. Don't expect brilliant valve events, Hackworth is not a good valve gear.

Edited By duncan webster on 28/04/2022 13:48:01

Thread: Alternative Ways of Retaining Shafts
28/04/2022 13:20:09

Here's one I made earlier, cost next to nothing and has cut dozens of grooves for e clips. How do you make it? Very carefully. You need a holder for the bit of HSSD, if you have a Worden or similar grinder it will be easier, but I used a bench grindertiddlytool.jpg

26/04/2022 18:06:39

Surely the piston needs to be secured to the rod? In which case turn the end of the rod down a bit for a shoulder, then a nut to secure the piston. Mine has the rod extended into the nozzle at small diameter to clear out the solder you've just sucked in

Thread: DRO Z-Axis /4th axis "combiner"
25/04/2022 23:22:20

Loads on ebay, but price has increased markedly over past year or so

Thread: Work Holding for Facing
24/04/2022 19:24:08

Can you cut it overlength, hole in each end, bolt to faceplate. When you flip it over you'll need a packer underneath as obviously you cant face where the bolts are

Thread: 3D-CAD Package Shootout - Cotton Reel Example
24/04/2022 00:23:08

Progress at last, thank the Lord for tutorials on UTube. I realised my first attempt hadn't started off correctly, so started again. I've just realised that I've drawn it 3/8" too long, but as it is a learning exercise it doesn't matter. trying to change it using smart dimension seems to move the wrong end. A job for tomorrow, as is working out how to not have those pesky dimensions all over the place

cylinder 24-04.jpg

23/04/2022 12:14:54

Thanks Gordon, found the base planes display. The locked rotation has gone away overnight, I didn't do anything other than save the model and close SE. The F3 issue is still confusing me. If I'm looking at the top view (say) and I scroll the mouse wheel it just zooms, but if I hold down the wheel and move the mouse it rotates the model. If I press shift at the same time it moves the view, doesn't rotate. Here's where I'm up to. I could have made it in metal by now! Once I've finished this I'll just mirror it.

This all started out as a way of finding the mass and CG of complicated shapes, but it grabs you.


23/04/2022 00:34:02

I've done something wrong, and I can't undo it. When I press down the scroll wheel and move the mouse, a red line appears and the model will only rotate around that line. I'm in Solid Edge, someone must know what I've done wrong.

And while I'm on, how do I make it draw on the ZX plane rather than the front face? It isn't actually showing the planes, I don't want to create another plane when there is already one there (presumably)

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