Member postings for duncan webster

SK you're going to have to explain that, Joe isn't adding mass, he's moving an existing mass. I'd expect moving the little nut down and leaving everything else alone to effectively lengthen the pendulum and so increase period

That just comes up with an error message

If it's EN58 it is austenitic (as others have said) so it shouldn't be magnetic. I have a lump of 304 from which I've sawn bits to make superheater return bends, but it's not easy

Edited By duncan webster on 01/10/2023 13:43:50

Ah well, as the saying goes, 'you shouldn't have started from there'.

Not sure of the exact geography, but the West Clare Railway runs steam locos, they might be prepared to let you have some oil if you turn up with a suitable bottle.

It's been found, as soon as I have it in my hands and can check it still works I'll be in touch, probably middle of next week

I made one years ago for our club. I've just sent a WhatsApp round to see if it can be found, if so you're welcome to borrow it.

You've got the key press order reversed

Find one edge, say Y

Press Y0

Find the other edge

Press 1/2 followed by Y (not Y0)

Ah, that makes sense

You're going to have to explain that one to me. Starting with water absorbed in clothing and finishing with water in a bucket. This description might be called a heat pump, but it is just like a condensing drier that recycles the air. We did think of getting a condensing drier, but as it spews out 100% humidity air at slightly above room temperature there must be some residual water to condense in the house as the air cools from above ambient. We do most clothes drying in an enclosed space with a dehumidifier. Came as a great surprise to SWMBO just how much water it collects. I'd been telling her for years that drying clothes on radiators causes condensation, now she believes me.

I once had a motor with the same symptoms. Turned out to be the springs on the centrifugal switch allowing the start winding to cut out before the motor was going fast enough. Slightly stronger springs cured it.

In the absence of a Guru I've done it the old fashioned way. Thank the Lord for spreadsheets! Got the same answer for c of g as SE got, so it's promising

It doesn't work quite like that. Most of the work done turning the spanner goes into friction between the male and female thread and the face of the head against the abutment. This is why torque settings on bolts aren't that reliable, change the friction coefficient and you change the clamping load. Finer threads are more affected as the rotation for a given axial movement is more.

You need a hot water storage tank with heat pump ad it can't do instant hot water like combo boiler. You might also need bigger radiators as the temperature of the heating water is lower. I'm not sure why they don't use hot air heating with new builds, then the lower temp wouldn't matter as much. Difficult to back fit unless you have a bungalow in which case the ducting could be in the loft. You could then incorporate a heat exchanger and bleed some of the circulating air to the outside, reducing humidity and do condensation in the house.

Edited By duncan webster on 27/09/2023 15:01:31

The position of the cg isn't the issue, I'm trying to get second moment of area

Just to add complication, I've found out how to display axes 1, 2, 3 on the part end view, and they are not parallel to X & Z, I think axis 3 is parallel to Y. This means that radius of gyration around 1 or 2 doesn't help

Edited By duncan webster on 26/09/2023 22:23:11

Edited By duncan webster on 26/09/2023 22:25:43

Edited By duncan webster on 26/09/2023 22:27:12

I'm assuming this is one piece hornblocks? Quite a lot of designs have separate horncheeks, Emma Victoria and Sweet Pea come to mind. You could just saw your horns in half and fit them to the overwide slots, or make some out of bar, which gives you the chance to keep the wheelbase the same. If you want drawings of Emma Vic horns send me your email via pm

I think I've realised what I'm doing wrong, the CAD is giving me the radius of gyration of a 3D thing which will vary as I make the length longer, whereas what I want is the RoG of the 2D L shape. How do I do it?

Turn it in steps, as a very rough example, full length nominal size, 90 % of full length undersize by x, 80 % length undersize by 2x and so on. It's rough but it works (ish)

Edited By duncan webster on 26/09/2023 16:02:59

As a bit of brain stretching I'm trying to work out the position of the centre of area and the second moment of area of a bit of bent copper (crown stay). I've modelled it in Solid Edge, but can't make sense of the readout. The height of the cg looks about right (9.36mm). A hand calc assuming a square corner gets

ht of cg 9.6 mm,
Ixx = 7664 mm^4,
area = 67.5 mm^2,
radius of gyration about X = 10.6mm.

I can't get it to display the second moment of area

some time later... I've realised that axes 1, 2, 3 are not X, Y, Z as shown on the pictures. I think they pass through the cg. Is the radius of gyration relative to the cg? What does orientation of principle axes mean? I drew the L shape on the XZ plane then extruded it along Y, so Id expect axis 1 to be parallel to X and so on, but on the picture axis 2 does look parallel to Z (sorry I'd pasted the pictures in before I found how to display 1, 2 3)

Edited By duncan webster on 26/09/2023 15:57:41

It's stronger full stop, EN8 normalised has UTS 35 tsi, heat treated can be as high as 55 tsi. The yield stress also increases. These figures from a United Steel Co handbook which is about 50 years old.

Case hardening won't change the strength much at all as it's s only skin deep (sorry)