Member postings for modeng2000

I think I just wanted convincing the cut and bend method would give a nice corner, better than just a normal bend.

John

Thanks Bernard, it would also stop the spreading on the inside of the bend.

Probably the best answer.

John

What are my chances for bending 12mm square EN3B bright mild steel bar? I am aiming for a sharp 45 degree bend. Never done this before but have watched it being done but using oxy - acetylene.

I have propane sievert burners and the usual bench vice but that is it. I have considered removing a V section on the inside of the bend and then silver soldering the joint but would prefer not to have to do this.

John

Is it carnivorous?

Thanks for helping me spend my money Rod

John

Airframe

Repair

Support

Engineering

And:- Army Reserve South East

Going back to my Dome Barograph to further investigate the ‘stiction’ as I called it. I have found the cause to be the two sleeve bearings supporting the pen shaft. When air pressure changes direction the pen indicates the true reading for a small change but then lags behind. The sleeve bearings have some looseness so that at a change of rotation the pivoting is rather like a knife edge bearing for a degree or two. Then the pen shaft begins to climb up the side of the outer part of the sleeve so causing a lag in response to the pressure change.

I have replaced these sleeve bearings with miniature instrument ball bearings ensuring that the mechanical change can be reversed if necessary. The improvement in performance has been remarkable, going from a mere indication of the atmospheric pressure changes to something that truly follows the actual readings at my local airfield.

To say the least, the barograph has been transformed and this has happened following my digesting of the previous postings and a bit of lateral thinking. So many thanks to all who offered their suggestions.

John

How about a Naffi candle?

Because it is French owned and they don't like us.

John

Yes, I had one

* Hi Joseph. The exam i took in 1989 was the RAE. At that time morse code was still an active part of the future exams. But as someone below has remarked, that was scrapped & no longer a part of the tests. *

When I progressed from G6ABA/T to G8APC and then to G4LRX the morse test was still a requirement.

Trying to learn morse with pidgeons cooing in the background was a bit off-putting.

John

Having had a centrifugal switch fail I replaced it with a timed relay that powered the start winding long enough for the motor to run up to speed.

No further problems.

John

Me too!!!

I thought it was worth following up this discussion with the present situation.

The simple bearings were cleaned and lightly oiled instead of trying to modify them looking for an improvement in reducing any stiction.

I have been plotting the readings against an on-line site over several weeks and I find that now the two graph curves are very similar. there is an off set due to a n ASL setup error but overall the barograph is working as expected.

So thanks for the advice and suggestions, all now seems to be well.

John

So Howie, what do we move on to? A sytem that isn't user friendly it seems.

John

BT have sent me an adaptor that plugs into the mains and has a socket that accepts a standard telephone plug.

This adapter 'talks' to the BT Home Hub so the corded phone can be used when the system changes.The Home Hub also has a socket labeled 'Phone' that I'll use for our cordless phones.

John

Edited By modeng2000 on 11/06/2022 16:42:07

A tap every once in a while might well be the answer.

John

Thanks for the Russel Scientific information.

John

There is another possible reason for the pen sticking, as this is a small barograph the chart length is shorter than for a normal barograph therefor the distance the pen moves across the chart is also shorter so giving less chance to unstick as compared to a full size barograph..

John

Michael, it is a dome barograph by Russel Scientific. Quite compact and I believe this has compromised the design by being enclosed in a 4"dia by 6" tall glass dome.

The Philip Collins book looks really interesting, thanks for the link.

John